C FOR COMPUTERZ

19) HISTORY OF COMPUTER 'S PERIPHERAL DEVICES

2009-05-30T14:49:00.000-07:00

by engr. AFAN BK

This category focuses on the history and timeline of various items used in computers, Each item is explained in general, providing information suitable for everyone from beginners to advanced users.
Take a cruise through history to discover some of the key developments that have brought us to our present state of computing, including the development of numbers, the introduction of mechanical aids to calculation, the evolution of electronics, and the impact of electronics on computing.
No one person may be credited with the invention of computers, but several names stand proud in the crowd. The following offers some of the more notable developments and individuals, with great regret for any omissions.

1- CR- ROMS

CD-R is an abbreviation of compact disc recordable. Operating on the same premise as a CD, a CD-R is thin disc made of polycarbonate with 120mm diameter used to store music or data. However, unlike conventional CD media, a CD-R has dye core instead of a metal core. A laser is used to etch "pits" into the dye so that the disc can later be read by the laser in a CD-ROM drive or CD player. Once used, a CD-R cannot be erased and reused, but it can be recorded in multiple sessions by using UDF format. A cdrw, though, can be reused.
There was some incompatability with CD-R and older CD-ROM drives. This was primarily due to the lower reflectivity of the CD-R disc. In general, CD drives marked as 8x or greater will usually read CD-R discs.

2- DVD ROMS

DVD started as the Digital Video Disc but now means Digital Versatile Disc or just DVD. It is a multi-application family of optical disc formats for read-only, recordable and re-writable applications. The main features of the DVD formats are:
Backwards compatibility with current CD media. All DVD hardware will play audio CDs and CD-ROMs (although not all hardware will play CD-Rs or CD-RWs).
Physical dimensions identical to compact disc but using two 0.6 mm thick substrates, bonded together.
Single-layer/dual-layer and single/double sided options.
Up to 4.7 GB read-only capacity per layer, 8.5 GB per side maximum.
Designed from the outset for video, audio and multimedia, not just audio.
All formats use a common file system (UDF).
Digital and analogue copy protection for DVD-Video and DVD-Audio built into standard.
Recordable and re-writable versions are part of the family.
DVD started in 1994 as two competing formats, Super Disc (SD) and Multimedia CD (MMCD). DVD now is the result of an agreement by both camps on a single standard to meet the requirements of all the various industries involved.

3- FLOPPY DISKETTES

In 1971, an IBM team led by Alan Shugart invented the 8-inch floppy diskette. This floppy was an 8" plastic disk coated with magnetic iron oxide; data was written to and read from the disk's surface. The nickname "floppy" came from it's flexibility. The floppies were considered revolutionary devices at the time for its portability which provided a new and easy physical means of transporting data from one computer to another.
A floppy disk is a circle of magnetic material similar to any kind of recording tape; one or two sides of the disk are used for recording. The disk drive grabs the floppy by its center and spins it like a record inside its housing. The read/write head, much like the head on a tape deck, contacts the surface through an opening in the plastic shell, or envelope.

4- HARD DISK DRIVES

The hard disk drive has short and fascinating history. In 24 years it evolved from a monstrosity with fifty, two foot diameter disks holding five MBytes (5,000 bytes) of data to today's drives measuring 3 /12 inches wide and an inch high (and smaller) holding more than 70 GBytes (70,000,000,000 bytes/characters). Here, then, is the short history of this marvelous device.
Before the disk drive there were drums... In 1950 Engineering Research Associates of Minneapolis built the first commercial magnetic drum storage unit for the U.S. Navy, the ERA 110. It could store one million bits of data and retrieve a word in 5 thousandths of a second.
In 1956 IBM invented the first computer disk storage system, the 305 RAMAC (Random Access Method of Accounting and Control). This system could store five MBytes. It had fifty, 24-inch diameter disks!
By 1961 IBM had invented the first disk drive with air bearing heads and in 1963 they introduced the removable disk pack drive. In 1970 the eight inch floppy disk drive was introduced by IBM. My first floppy drives were made by Shugart who was one of the "dirty dozen" who left IBM to start their own companies. In 1981 two Shugart 8 inch floppy drives with enclosure and power supply cost me about $350.00. They were for my second computer. My first computer had no drives at all.
In 1973 IBM shipped the model 3340 Winchester sealed hard disk drive, the predecessor of all current hard disk drives. The 3340 had two spindles each with a capacity of 30 MBytes, and the term "30/30 Winchester" was thus coined.
Seagate ST4053 40 MByte 5 1/4 inch, full-height "clunker" with ST506 interface and voice coil circa 1987. My cost was $435.00. In 1980, Seagate Technology introduced the first hard disk drive for microcomputers, the ST506. It was a full height (twice as high as most current 5 1/4" drives) 5 1/4" drive, with a stepper motor, and held 5 Mbytes. My first hard disk drive was an ST506. I cannot remember exactly how much it cost, but it plus its enclosure, etc. was well over a thousand dollars. It took me three years to fill the drive. Also, in 1980 Phillips introduced the first optical laser drive. In the early 80's, the first 5 1/4" hard disks with voice coil actuators (more on this later) started shipping in volume, but stepper motor drives continued in production into the early 1990's. In 1981, Sony shipped the first 3 1/2" floppy drives.
In 1983 Rodime made the first 3.5 inch rigid disk drive. The first CD-ROM drives were shipped in 1984, and "Grolier's Electronic Encyclopedia," followed in 1985. The 3 1/2" IDE drive started it's existence as a drive on a plug-in expansion board, or "hard card." The hard card included the drive on the controller which, in turn, evolved into Integrated Device Electronics (IDE) hard disk drive, where the controller became incorporated into the printed circuit on the bottom of the hard disk drive. Quantum made the first hard card in 1985.
In 1986 the first 3 /12" hard disks with voice coil actuators were introduced by Conner in volume, but half (1.6") and full height 5 1/4" drives persisted for several years. In 1988 Conner introduced the first one inch high 3 1/2" hard disk drives. In the same year PrairieTek shipped the first 2 1/2" hard disks.
In 1997 Seagate introduced the first 7,200 RPM, Ultra ATA hard disk drive for desktop computers and in February of this year they introduced the first 15,000 RPM hard disk drive, the Cheetah X15. Milestones for IDE DMA, ATA/33, and ATA/66 drives follow: 1994 DMA, Mode 2 at 16.6 MB/s -- 1997 Ultra ATA/33 at 33.3 MB/s -- 1999 Ultra ATA/66 at 66.6 MB/s

5- IDE ( INTELLIGENT DRIVER ELECTRONICS)

Compaq started the development of the IDE interface. This standard was designed specially for the IBM PC and can achieve high data transfer rates through a 1:1 interleave factor and caching by the actual disk controller - the bottleneck is often the old AT bus and the drive may read data far quicker than the bus can accept it, so the cache is used as a buffer. Theoretically 1MBps is possible but 700KBps is perhaps more typical of such drives. This standard has been adopted by many other models of computer, such the Acorn Archimedes A4000 and above. A later improvement was EIDE, laid down in 1989, which also removed the maximum drive size of 528MB and increased data transfer rates.

6- MODEMs

Modem, device that converts between analog and digital signals. Digital signals, which are used by computers, are made up of separate units, usually represented by a series of 1's and 0's. Analog signals vary continuously; an example of an analog signal is a sound wave. Modems are often used to enable computers to communicate with each other across telephone lines. A modem converts the digital signals of the sending computer to analog signals that can be transmitted through telephone lines. When the signal reaches its destination, another modem reconstructs the original digital signal, which is processed by the receiving computer. If both modems can transmit data to each other simultaneously, the modems are operating in full duplex mode; if only one modem can transmit at a time, the modems are operating in half duplex mode.
To convert a digital signal to an analog one, the modem generates a carrier wave and modulates it according to the digital signal. The kind of modulation used depends on the application and the speed of operation for which the modem is designed. For example, many high-speed modems use a combination of amplitude modulation, where the amplitude of the carrier wave is changed to encode the digital information, and phase modulation, where the phase of the carrier wave is changed to encode the digital information. The process of receiving the analog signal and converting it back to a digital signal is called demodulation. The word "modem" is a contraction of its two basic functions: modulation and demodulation.
Dennis C. Hayes invented the PC modem in 1977, establishing the critical technology that allowed today's online and Internet industries to emerge and grow. He sold the first Hayes modem products to computer hobbyists in April of 1977 and founded D.C. Hayes Associates, Inc., the company known today as Hayes Corp., in January of 1978. Hayes quality and innovation resulted in performance enhancements and cost reductions that led the industry in the conversion from leased line modems to intelligent dial modems - the PC Modem.
Hayes-Compatible, in computer science, an adjective used to describe a modem that responds to the same set of commands as a modem manufactured by Hayes Microcomputer Products, originators of the de facto standard for microcomputer modems.

7- MONITORS

Often referred to as a monitor when packaged in a separate case, the display is the most-used output device on a computer. The display provides instant feedback by showing your text and graphic images as you work or play. Most desktop displays use a cathode ray tube (CRT), while portable computing devices such as laptops incorporate liquid crystal display (LCD), light-emitting diode (LED), gas plasma or other image projection technology. Because of their slimmer design and smaller energy consumption, monitors using LCD technologies are beginning to replace the venerable CRT on many desktops.
Displays have come a long way since the blinking green monitors in text-based computer systems of the 1970s. Just look at the advances made by IBM over the course of a decade: In 1981, IBM introduced the Color Graphics Adapter (CGA), which was capable of rendering four colors, and had a maximum resolution of 320 pixels horizontally by 200 pixels vertically. IBM introduced the Enhanced Graphics Adapter (EGA) display in 1984. EGA allowed up to 16 different colors and increased the resolution to 640x350 pixels, improving the appearance of the display and making it easier to read text. In 1987, IBM introduced the Video Graphics Array (VGA) display system. Most computers today support the VGA standard and many VGA monitors are still in use. IBM introduced the Extended Graphics Array (XGA) display in 1990, offering 800x600 pixel resolution in true color(16.8 million colors) and 1,024x768 resolution in 65,536 colors. Most displays sold today support the Ultra Extended Graphics Array (UXGA) standard. UXGA can support palette of up to 16.8 million colors and resolutions of up to 1600x1200 pixels, depending on the video memory of the graphics card in your computer. The maximum resolution normally depends on the number of colors displayed. For example, your card might require that you choose between 16.8 million colors at 800x600, or 65,536 colors at 1600x1200.
The combination of the display modes supported by your graphics adapter and the color capability of your monitor determine how many colors can be displayed. For example, a display that can operate in SuperVGA (SVGA) mode can display up to 16,777,216 (usually rounded to 16.8 million) colors because it can process a 24-bit-long description of a pixel. The number of bits used to describe a pixel is known as its bit depth. With a 24-bit bit depth, 8 bits are dedicated to each of the three additive primary colors -- red, green and blue. This bit depth is also called true color because it can produce the 10,000,000 colors discernible to the human eye, while a 16-bit display is only capable of produ cing 65,536 colors. Displays jumped from 16-bit color to 24-bit color because working in 8-bit increments makes things a whole lot easier for developers and programmers.
Briefly, the measure of how much space there is between a display's pixels. When considering dot pitch, remember that smaller is better. Packing the pixels closer together is fundamental to achieving higher resolutions. A display normally can support resolutions that match the physical dot (pixel) size as well as several lesser resolutions. For example, a display with a physical grid of 1280 rows by 1024 columns can obviously support a maximum resolution of 1280x1024 pixels. It usually also supports lower resolutions such as 1024x768, 800x600, and 640x480.
In monitors based on CRT technology, the refresh rate is the number of times that the image on the display is drawn each second. If your CRT monitor has a refresh rate of 72 Hertz (Hz), then it cycles through all the pixels from top to bottom 72 times a second. Refresh rates are very important because they control flicker, and you want the refresh rate as high as possible. Too few cycles per second and you will notice a flickering, which can lead to headaches and eye strain.

8- MOUSE POINTERS

Years before personal computers and desktop information processing became commonplace or even practicable, Douglas Engelbart had invented a number of interactive, user-friendly information access systems that we take for granted today: the computer mouse was one of his inventions. At the Fall Joint Computer Conference in San Francisco in 1968, Engelbart astonished his colleagues by demonstrating the aforementioned systems---using an utterly primitive 192 kilobyte mainframe computer located 25 miles away! Engelbart has earned nearly two dozen patents, the most memorable being perhaps for his "X-Y Position Indicator for a Display System": the prototype of the computer "mouse" whose convenience has revolutionized personal computing.
Mouse (computer), a common pointing device, popularized by its inclusion as standard equipment with the Apple Macintosh. With the rise in popularity of graphical user interfaces in MS-DOS; UNIX, and OS/2, use of mice is growing throughout the personal computer and workstation worlds. The basic features of a mouse are a casing with a flat bottom, designed to be gripped by one hand; one or more buttons on the top; a multidirectional detection device (usually a ball) on the bottom; and a cable connecting the mouse to the computer. By moving the mouse on a surface (such as a desk), the user typically controls an on-screen cursor. A mouse is a relative pointing device because there are no defined limits to the mouse's movement and because its placement on a surface does not map directly to a specific screen location. To select items or choose commands on the screen, the user presses one of the mouse's buttons, producing a "mouse click."
Mouse Patent # 3,541,541 issued 11/17/70 for X-Y Position Indicator For A Display System Douglas Engelbart's patent for the mouse is only a representation of his pioneering work in the design of modern interactive computer environments.

9- PLOTTERS

A plotter is a vector graphics printing device that connects to a computer.
Plotters print their output by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. They can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens.
Another difference between plotters and printers is that a printer is aimed primarily at printing text. This makes it fairly easy to control, simply sending the text to the printer is usually enough to generate a page of output. This is not the case of the line art on a plotter, where a number of printer control languages were created to send the more detailed information like "draw a line from here to here". The most popular of these is likely HPGL.
Early plotters were created by attaching ball-point pens to drafting pantographs and driving the machines with motors controlled by the computer. This had the disadvantage of being somewhat slow to move, as well as requiring floor space equal to the size of the paper. Later versions worked by placing the paper over a roller which moved the paper back and forth for X motion, while the pen moved back and forth on a single arm for Y motion. Another change was the addition of an elecrtically controlled clamp to hold the pens, which allowed them to be changed and thus create multi-colored output.
For a time in the 1980's smaller "home-use" plotters became popular for experimentation in computer graphics. But their low speed meant they were not useful for general printing purposes, and you would need another conventional printer for those jobs. With the widespread availability of high-resolution inkjets and laser printers, plotters have all but disappeared.
Plotters are used primarily in drafting and CAD applications, where they have the advantage of working on very large paper sizes while maintaining high resolution. Another use has been found by replacing the pen with a cutter, and in this form plotters can be found in many garment and sign shops.

10- SOUND CARDS

Computers were never designed to handle sound. About the only audio you'd hear from an early computer were beeps, designed to tell you if there was a problem. Computer games manipulated these beeps, to produce truly awful music as an accompaniment to games like Space Invaders. However, surely there was more to sounds than beeps? Thankfully a company from the Far East recognised this, and made the original Sound Blaster sound card for the now ancient ISA bus. It could record real audio and play it back, something of a quantum leap. It also had a MIDI interface, still common on sound cards today, which could control synthesisers, samplers and other electronic music equipment. It could "create" sounds by using FM synthesis, which were not that realistic but were nevertheless better than simple beeps. The quality of the audio was 8 bit 11 kHz, so sounded roughly like an AM radio.
The sound card is quite a complicated piece of electronics. The most important parts are the ADC and DAC. The ADC (Analogue-to-Digital convertor) takes in analogue signals, for example from a microphone and converts them to digital signals for the computer to store. The DAC (Digital-to-Analogue convertor) does the opposite. However, in the future there will be no need for either, since both speakers and microphones will be able to directly record and playback digital signals directly. The heart of a CD player is also the DAC. CD players tend to sound better than the average, because they generally cost more and are simpler devices. Hence the DAC component of a CD player tends to be more expensive (and thus better quality). Having said that, the quality of DACs on sound cards is improving all the time.
The advantage of digital audio (ie. storing audio as 1s and 0s) is that no matter how many times it is copied it remains identical, and does not degrade like analogue sources, such as vinyl. The next major development for sound cards was the leap up to 16 bit 44.1 kHz stereo audio, ie. CD quality. However, this posed problems for the archaeic ISA bus, which had problems playing back and recording more than one track at the same time. This effectively meant it was difficult to use your computer to make phone calls on the internet (since you couldn't talk and hear at the same time!) or use it as a multitrack audio editor (for musicians). The PCI bus solved this problem. Nowadays virtually all soundcards are PCI. Currently we are seeing 24 bit 96 kHz sound cards emerging, which promise even better sound quality than CDs! Some sound cards also decode Dolby Digital sound, so you can connect computer speakers to them for surround sound, when playing back DVDs. High-end sound cards also come with digital inputs and outputs, letting you bypass the sound cards convertors and use external ones.
Recently there has been the advent of the USB and Firewire buses. These enable you to connect fast external devices to your computer. Sound cards attached to the USB bus cannot playback as many tracks simultaneously as a PCI sound card. However, for people other than musicans this is hardly relevant. Also being external they can be used on more than one machine and on laptops, which notoriously have poor sound cards. There are also several external Firewire sound cards. These are quite expensive and designed to playback and record many tracks. Consequently they are a waste of money if all you do is watch DVDs or play MP3s on your computer.
Sound on the PC has come a long way since all those beeps twenty years ago!

11- TOUCH SCREENS

A touch screen is a special type of visual display unit with a screen which is sensitive to pressure or touching. The screen can detect the position of the point of touch. The design of touch screens is best for inputting simple choices and the choices are programmable. The device is very user-friendly since it 'talks' with the user when the user is picking up choices on the screen.
Touch technology turns a CRT, flat panel display or flat surface into a dynamic data entry device that replaces both the keyboard and mouse. In addition to eliminating these separate data entry devices, touch offers an "intuitive" interface. In public kiosks, for example, users receive no more instruction than 'touch your selection.'
Specific areas of the screen are defined as "buttons" that the operator selects simply by touching them. One significant advantage to touch screen applications is that each screen can be customized to reflect only the valid options for each phase of an operation, greatly reducing the frustration of hunting for the right key or function.
Pen-based systems, such as the Palm Pilot® and signature capture systems, also use touch technology but are not included in this article. The essential difference is that the pressure levels are set higher for pen-based systems than for touch.
Touch screens come in a wide range of options, from full color VGA and SVGA monitors designed for highly graphic Windows® or Macintosh® applications to small monochrome displays designed for keypad replacement and enhancement.
Specific figures on the growth of touch screen technology are hard to come by, but a 1995 study last year by Venture Development Corporation predicted overall growth of 17%, with at least 10% in the industrial sector.
According to Jim Sido, IBM's National Marketing Manager for Food Service Products, this year should see even greater growth than last year.
John Muhlberger, Director of Product Management at PAR Microsystems estimated that, for POS applications, touch screen terminals outsell keyboard terminals about 4:1, even though the touch terminals cost somewhat more.
Other vendors agree that touch screen technology is becoming more popular because of its ease-of-use, proven reliability, expanded functionality, and decreasing cost.

18) HISTORY OF PRINTING

2009-05-30T14:43:00.000-07:00

by engr. AFAN BK

The history of printing began as an attempt to make easier and reduce the cost of reproducing multiple copies of documents, fabrics, wall papers and so on. Printing streamlined the process of communication, and contributed to the development of commerce, law, religion and culture.

1- WOODBLOCK PRINTING

Woodblock printing is a technique for printing text, images or patterns used widely throughout East Asia and originating in China in antiquity as a method of printing on textiles and later paper. As a method of printing on cloth, the earliest surviving examples from China date to before 220, and from Egypt to the 4th century. Ukiyo-e is the best known type of Japanese woodblock art print. Most European uses of the technique on paper are covered by the art term woodcut, except for the block-books produced mainly in the fifteenth century.

The use of round "cylinder seals" for rolling an impress onto clay tablets goes back to early Mesopotamian civilization before 3,000 BCE, where they are the most common works of art to survive, and feature complex and beautiful images. In both China and Egypt, the use of small stamps for seals preceded the use of larger blocks. In Egypt, Europe and India, the printing of cloth certainly preceded the printing of paper or papyrus; this was probably also the case in China. The process is essentially the same - in Europe special presentation impressions of prints were often printed on silk until at least the seventeenth century.

1.1- In China

The earliest woodblock printed fragments to survive are from China and are of silk printed with flowers in three colours from the Han dynasty (before 220 CE). The earliest Egyptian printed cloth dates from the 4th century.

It is clear that the Chinese were the first by several centuries to use the process to print solid text, and equally that, much later, in Europe the printing of images on cloth developed into the printing of images on paper (woodcuts). It is also now established that the use in Europe of the same process to print substantial amounts of text together with images in block-books only came after the development of movable type in the 1450s.

1.2- In the Islamic world

Block printing, called tarsh in Arabic was developed in Arabic Egypt during the 9th-10th centuries, mostly for prayers and amulets. It is unclear whether the print blocks were made from metal or wood or other materials. This technique, however, appears to have had very little influence outside of the Muslim world. Though Europe adopted woodblock printing from the Muslim world, initially for fabric, the technique of metal block printing was also unknown in Europe. Block printing later went out of use in Islamic Central Asia after movable type printing was introduced from China.

1.3- In Europe

Block printing first came to Christian Europe as a method for printing on cloth, where it was common by 1300. Images printed on cloth for religious purposes could be quite large and elaborate, and when paper became relatively easily available, around 1400, the medium transferred very quickly to small woodcut religious images and playing cards printed on paper. These prints were produced in very large numbers from about 1425 onwards.

Around the mid-century, block-books, woodcut books with both text and images, usually carved in the same block, emerged as a cheaper alternative to manuscripts and books printed with movable type. These were all short heavily illustrated works, the bestsellers of the day, repeated in many different block-book versions: the Ars moriendi and the Biblia pauperum were the most common. There is still some controversy among scholars as to whether their introduction preceded or, the majority view, followed the introduction of movable type, with the range of estimated dates being between about 1440–1460.

The volume of Joseph Needham's Science and Civilization in China dealing with Paper and printing has a chapter that suggests that "European block printers must not only have seen Chinese samples, but perhaps had been taught by missionaries or others who had learned these un-European methods from Chinese printers during their residence in China.", but he also admitted that the "only evidence of European printing transmitted from China is a lack of counterevidence". However, paper itself was needed for the printing process and this came to Europe via trade with the Arabs from China. Historians acknowledge that paper indeed came from China without which printing would have been impossible, however, there is less direct evidence of the influence of printing technology from Asia and its influence on European printing technology.

2- STENCIL

Stencils may have been used to color cloth for a very long time; the technique probably reached its peak of sophistication in Katazome and other techniques used on silks for clothes during the Edo period in Japan. In Europe, from about 1450 they were very commonly used to colour old master prints printed in black and white, usually woodcuts. This was especially the case with playing-cards, which continued to be coloured by stencil long after most other subjects for prints were left in black and white. Stenciling back in the 2600 BC's was different. They used color from plants and flowers such as indigo (which extracts blue). Stencils were used for mass publications, as the type didn't have to be hand-written.

3- MOVABLE TYPE

Movable type is the system of printing and typography using movable pieces of metal type, made by casting from matrices struck by letterpunches.

Around 1040, the first known movable type system was created in China by Bi Sheng out of porcelain. Metal movable type was first invented in Korea during the Goryeo Dynasty (around 1230). Neither movable type system was widely used, one reason being the enormous Chinese character set.

It is traditionally summarized that Johannes Gutenberg, of the German city of Mainz, developed European movable type printing technology around 1439 and in just over a decade, the European age of printing began. However, the details show a more complex evolutionary process spread over multiple locations. Also, Johann Fust and Peter Schöffer experimented with Gutenberg in Mainz.

Compared to woodblock printing, movable type page-setting was quicker and more durable. The metal type pieces were more durable and the lettering was more uniform, leading to typography and fonts. The high quality and relatively low price of the Gutenberg Bible (1455) established the superiority of movable type, and printing presses rapidly spread across Europe, leading up to the Renaissance, and later all around the world. Today, practically all movable type printing ultimately derives from Gutenberg's movable type printing, which is often regarded as the most important invention of the second millennium.

Gutenberg is also credited with the introduction of an oil-based ink which was more durable than previously used water-based inks. Having worked as a professional goldsmith, Gutenberg made skillful use of the knowledge of metals he had learned as a craftsman. Gutenberg was also the first to make his type from an alloy of lead, tin, and antimony, known as type metal, printer's lead, or printer's metal, which was critical for producing durable type that produced high-quality printed books, and proved to be more suitable for printing than the clay, wooden or bronze types used in East Asia. To create these lead types, Gutenberg used what some considered his most ingenious invention, a special matrix wherewith the moulding of new movable types with an unprecedented precision at short notice became feasible. Within a year of printing the Gutenberg Bible, Gutenberg also published the first coloured prints.

The invention of the printing press revolutionized communication and book production leading to the spread of knowledge. Rapidly, printing spread from Germany by emigrating German printers, but also by foreign apprentices returning home. A printing press was built in Venice in 1469, and by 1500 the city had 417 printers. In 1470 Johann Heynlin set up a printing press in Paris. In 1473 Kasper Straube published the Almanach cracoviense ad annum 1474 in Kraków. Dirk Martens set up a printing press in Aalst (Flanders) in 1473. He printed a book about the two lovers of Enea Piccolomini who became pope Pius II.In 1476 a printing press was set up in England by William Caxton. Belarusian Francysk Skaryna printed the first book in Slavic language on August 6, 1517. The Italian Juan Pablos set up an imported press in Mexico City in 1539. The first printing press in Southeast Asia was set up in the Philippines by the Spanish in 1593. Stephen Day was the first to build a printing press in North America at Massachusetts Bay in 1638, and helped establish the Cambridge Press.

The Gutenberg press was much more efficient than manual copying and still was largely unchanged in the eras of John Baskerville and Giambattista Bodoni, over 300 years later. By 1800, Lord Stanhope had constructed a press completely from cast iron, reducing the force required by 90% while doubling the size of the printed area. While Stanhope's "mechanical theory" had improved the efficiency of the press, it still was only capable of 250 sheets per hour. German printer Friedrich Koenig would be the first to design a non-manpowered machine—using steam. Having moved to London in 1804, Koenig soon met Thomas Bensley and secured financial support for his project in 1807. Patented in 1810, Koenig had designed a steam press "much like a hand press connected to a steam engine." The first production trial of this model occurred in April 1811.

3.1- Flat-bed printing press

A printing press is a mechanical device for applying pressure to an inked surface resting upon a medium (such as paper or cloth), thereby transferring an image. The systems involved were first assembled in Germany by the goldsmith Johann Gutenberg in the mid-15th century. Printing methods based on Gutenberg's printing press spread rapidly throughout first Europe and then the rest of the world, replacing most block printing and making it the sole progenitor of modern movable type printing. As a method of creating reproductions for mass consumption, The printing press has been superseded by the advent of offset printing.

Johannes Gutenberg's work in the printing press began in approximately 1436 when he partnered with Andreas Dritzehen—a man he had previously instructed in gem-cutting—and Andreas Heilmann, owner of a paper mill. It was not until a 1439 lawsuit against Gutenberg that official record exists; witnesses testimony discussed type, an inventory of metals (including lead) and his type mold.

Others in Europe were developing movable type at this time, including goldsmith Procopius Waldfoghel of France and Laurens Janszoon Coster of the Netherlands. They are not known to have contributed specific advances to the printing press. While the Encyclopædia Britannica Eleventh Edition had attributed the invention of the printing press to Coster, the company now states that is incorrect.

4- PRINTING HOUSES

Early printing houses (near the time of Gutenberg) were run by "master printers." These printers owned shops, selected and edited manuscripts, determined the sizes of print runs, sold the works they produced, raised capital and organized distribution. Some master printing houses, like that of Aldus Manutius, became the cultural centre for literati such as Erasmus.

Print shop apprentices: Apprentices, usually between the ages of 15 and 20, worked for master printers. Apprentices were not required to be literate, and literacy rates at the time were very low, in comparison to today. Apprentices prepared ink, dampened sheets of paper, and assisted at the press. An apprentice who wished to learn to become a compositor had to learn Latin and spend time under the supervision of a journeyman.
Journeyman printers: After completing their apprenticeships, journeyman (so called from the French "journée" for day) printers were free to move employers. This facilitated the spread of printing to areas that were less print-centred.

Compositors: Those who set the type for printing.

Pressmen: the person who worked the press. This was physically labour intensive.

The earliest-known image of a European, Gutenberg-style print shop is the Dance of Death by Matthias Huss, at Lyon, 1499. This image depicts a compositor standing at a compositor's case being grabbed by a skeleton. The case is raised to facilitate his work. The image also shows a pressman being grabbed by a skeleton. At the right of the printing house a bookshop is shown.

4.1- Financial aspects

Court records from the city of Mainz document that Johannes Fust was, for some time, Gutenberg's financial backer.

By the sixteenth century jobs associated with printing were becoming increasingly specialized. Structures supporting publishers were more and more complex, leading to this division of labour. In Europe between 1500 and 1700 the role of the Master Printer was dying out and giving way to the bookseller—publisher. Printing during this period had a stronger commercial imperative than previously. Risks associated with the industry however were substantial, although dependent on the nature of the publication.

Bookseller publishers negotiated at trade fairs and at print shops. Jobbing work appeared in which printers did menial tasks in the beginning of their careers to support themselves.

1500–1700: Publishers developed several new methods of funding projects.

1.Cooperative associations/publication syndicates—a number of individuals shared the risks associated with printing and shared in the profit. This was pioneered by the French.

2.Subscription publishing—pioneered by the English in the early 17th century. A prospectus for a publication was drawn up by a publisher to raise funding. The prospectus was given to potential buyers who signed up for a copy. If there were not enough subscriptions the publication did not go ahead. Lists of subscribers were included in the books as endorsements. If enough people subscribed a reprint might occur. Some authors used subscription publication to bypass the publisher entirely.

3.Installment publishing—books were issued in parts until a complete book had been issued. This was not necessarily done with a fixed time period. It was an effective method of spreading cost over a period of time. It also allowed earlier returns on investment to help cover production costs of subsequent installments.
The Mechanick Exercises, by Joseph Moxon, in London, 1683, was said to be the first publication done in installments.

Publishing trade organizations allowed publishers to organize business concerns collectively. Systems of self-regulation occurred in these arrangements. For example, if one publisher did something to irritate other publishers he would be controlled by peer pressure. Such systems are known as cartels, and are in most countries now considered to be in restraint of trade. These arrangements helped deal with labour unrest among journeymen, who faced difficult working conditions. Brotherhoods predated unions, without the formal regulations now associated with unions.

5- ROTARY PRINTING PRESS

A rotary printing press is a printing press in which the impressions are curved around a cylinder so that the printing can be done on long continuous rolls of paper, cardboard, plastic, or a large number of other substrates. Rotary drum printing was invented by Richard March Hoe in 1847, and then significantly improved by William Bullock in 1863.

6- INTAGLIO

Intaglio (pronounced in-TAL-yo) is a family of printmaking techniques in which the image is incised into a surface, known as the matrix or plate. Normally, copper or zinc plates are used as a surface, and the incisions are created by etching, engraving, drypoint, aquatint or mezzotint. Collographs may also be printed as intaglio plates. To print an intaglio plate the surface is covered in thick ink and then rubbed with tarlatan cloth to remove most of the excess. The final smooth wipe is usually done by hand, sometimes with the aid of newspaper or old public phone book pages, leaving ink only in the incisions. A damp piece of paper is placed on top and the plate and paper are run through a printing press that, through pressure, transfers the ink from the recesses of the plate to the paper.

7- LITHOGRAPHY ( 1796)

Invented by Bavarian author Aloys Senefelder in 1796, lithography is a method for printing on a smooth surface. Lithography is a printing process that uses chemical processes to create an image. For instance, the positive part of an image would be a hydrophobic chemical, while the negative image would be water. Thus, when the plate is introduced to a compatible ink and water mixture, the ink will adhere to the positive image and the water will clean the negative image. This allows for a relatively flat print plate which allows for much longer runs than the older physical methods of imaging (e.g., embossing or engraving).

8- CHROMOLITHOGRAPHY

Chromolithography was the first method for making true multi-color prints. Earlier attempts at polychromed printing relied on hand-coloring. The type of color printing stemmed from the process of lithography, and it includes all types of lithography that are printed in color. It replaced coloring prints by hand, and eventually served as a replica of a real painting. Lithographers sought to find a way to print on flat surfaces with the use of chemicals instead of relief or intaglio printing. Depending on the amount of colors present, a chromolithograph could take months to produce. To make what was once referred to as a “’chromo’”, a lithographer, with a finished painting in front of him, gradually built and corrected the print to look as much as possible like the painting in front of him, sometimes using dozens of layers. The process can be very time consuming and cumbersome contingent upon the skill of the lithographer.

The technique for using color in printing was invented in 1796 in Germany. Considering the fact that it stemmed from lithography, there have been debates over whether chromolithography was created by Alois Senefelder, the same person who came up with printing by way of lithography. Senefelder introduced colored lithography in his 1818 Vollstaendiges Lehrbuch der Steindruckerey (A Complete Course of Lithography), and in the work, Senefelder told of his plans to print using color and he also explained the colors he wished to be able to print someday. Although Senefelder recorded ideas on chromolithography, it turns out that other countries besides Germany, such as France and England, were also heavily involved in trying to find a new way to print in color. Godefroy Engelmann of Mulhouse proved to be one of the few searching for ways to produce colored printed images when he was awarded his patent on chromolithography in July 1837. Even after Engelmann received his award, disputes over whether chromolithography was already being used continued to rise. Some sources point to the idea that chromolithography was already being used in areas of printing such as the production of playing cards.

9- OFFSET PRESS ( 1870s)

Offset printing is a widely used printing technique where the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a film of water, keeping the non-printing areas ink-free.

10- SCREEN PRINTING (1907)

Screenprinting has its origins in simple stencilling, most notably of the Japanese form (katazome), used who cut banana leaves and inserted ink through the design holes on textiles, mostly for clothing. This was taken up in France. The modern screenprinting process originated from patents taken out by Samuel Simon in 1907 in England. This idea was then adopted in San Francisco, California, by John Pilsworth in 1914 who used screenprinting to form multicolor prints in a subtractive mode, differing from screenprinting as it is done today.

11- FLEXOGRAPHY

Flexography (also called surface printing), often abbreviated to flexo, is a method of printing most commonly used for packaging (Labels, Tape, Bags, Boxes, Banners, Etc).

A flexo print is achieved by creating a mirrored master of the required image as a 3D relief in a rubber or polymer material. A measured amount of ink is deposited upon the surface of the printing plate (or printing cylinder) using an anilox roll. The print surface then rotates, contacting the print material which transfers the ink.

Originally flexo printing was basic in quality. Labels requiring high quality have generally been printed Offset until recently. In the last few years great advances have been made to the quality of flexo printing presses.

The greatest advances though have been in the area of PhotoPolymer Printing Plates, including improvements to the plate material and the method of plate creation. —usually photographic exposure followed by chemical etch, though also by direct laser engraving.

12- PHOTOCOPIER ( 1960s)

Xerographic office photocopying was introduced by Xerox in the 1960s, and over the following 20 years it gradually replaced copies made by Verifax, Photostat, carbon paper, mimeograph machines, and other duplicating machines. The prevalence of its use is one of the factors that prevented the development of the paperless office heralded early in the digital revolution.

13- THERMAL PRINTER

A thermal printer (or direct thermal printer) produces a printed image by selectively heating coated thermochromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head. The coating turns black in the areas where it is heated, producing an image.

14- LASER PRINTER ( 1969)

The laser printer, based on a modified xerographic copier, was invented at Xerox in 1969 by researcher Gary Starkweather, who had a fully functional networked printer system working by 1971. Laser printing eventually became a multibillion-dollar business for Xerox.

The first commercial implementation of a laser printer was the IBM model 3800 in 1976, used for high-volume printing of documents such as invoices and mailing labels. It is often cited as "taking up a whole room," implying that it was a primitive version of the later familiar device used with a personal computer. While large, it was designed for an entirely different purpose. Many 3800s are still in use.

The first laser printer designed for use with an individual computer was released with the Xerox Star 8010 in 1981. Although it was innovative, the Star was an expensive ($17,000) system that was only purchased by a small number of laboratories and institutions. After personal computers became more widespread, the first laser printer intended for a mass market was the HP LaserJet 8ppm, released in 1984, using a Canon engine controlled by HP software. The HP LaserJet printer was quickly followed by other laser printers from Brother Industries, IBM, and others.

Most noteworthy was the role the laser printer played in popularizing desktop publishing with the introduction of the Apple LaserWriter for the Apple Macintosh, along with Aldus PageMaker software, in 1985. With these products, users could create documents that would previously have required professional typesetting.

15- DOT MATRIX PRINTER ( 1970)

A dot matrix printer or impact matrix printer refers to a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter. Unlike a typewriter or daisy wheel printer, letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies.

Each dot is produced by a tiny metal rod, also called a "wire" or "pin", which is driven forward by the power of a tiny electromagnet or solenoid, either directly or through small levers (pawls). Facing the ribbon and the paper is a small guide plate (often made of an artificial jewel such as sapphire or ruby) pierced with holes to serve as guides for the pins. The moving portion of the printer is called the print head, and when running the printer as a generic text device generally prints one line of text at a time. Most dot matrix printers have a single vertical line of dot-making equipment on their print heads; others have a few interleaved rows in order to improve dot density.

16- INKJET PRINTERS

Inkjet printers are a type of computer printer that operates by propelling tiny droplets of liquid ink onto paper.

17- DYE-SUBLIMATION PRINTER

A dye-sublimation printer (or dye-sub printer) is a computer printer which employs a printing process that uses heat to transfer dye to a medium such as a plastic card, printer paper or poster paper. The process is usually to lay one color at a time using a ribbon that has color panels. Most dye-sublimation printers use CMYO colors which differs from the more recognised CMYK colors in that the black dye is eliminated in favour of a clear overcoating. This overcoating (which has numerous names depending on the manufacturer) is effectively a thin laminate which protects the print from discoloration from UV light and the air while also rendering the print water-resistant. Many consumer and professional dye-sublimation printers are designed and used for producing photographic prints.

18- DIGITAL PRESS ( 1993)

Digital printing is the reproduction of digital images on a physical surface, such as common or photographic paper or paperboard-cover stock, film, cloth, plastic, vinyl, magnets, labels etc.

It can be differentiated from litho, flexography, gravure or letterpress printing in many ways, some of which are;

Every impression made onto the paper can be different, as opposed to making several hundred or thousand impressions of the same image from one set of printing plates, as in traditional methods.

The Ink or Toner does not absorb into the substrate, as does conventional ink, but forms a layer on the surface and may be fused to the substrate by using an inline fuser fluid with heat process(toner) or UV curing process(ink).

It generally requires less waste in terms of chemicals used and paper wasted in set up or makeready(bringing the image "up to color" and checking position).

It is excellent for rapid prototyping, or small print runs which means that it is more accessible to a wider range of designers and more cost effective in short runs.

19- 3D PRINTING

Three-dimensional printing is a method of converting a virtual 3D model into a physical object. 3D printing is a category of rapid prototyping technology. 3D printers typically work by 'printing' successive layers on top of the previous to build up a three dimensional object. 3D printers are generally faster, more affordable and easier to use than other additive fabrication technologies.

20- TECHNOLOGICAL DEVELOPMENTS

20.1 Woodcut

Woodcut is a relief printing artistic technique in printmaking in which an image is carved into the surface of a block of wood, with the printing parts remaining level with the surface while the non-printing parts are removed, typically with gouges. The areas to show 'white' are cut away with a knife or chisel, leaving the characters or image to show in 'black' at the original surface level. The block is cut along the grain of the wood (unlike wood engraving where the block is cut in the end-grain). In Europe beechwood was most commonly used; in Japan, a special type of cherry wood was popular.

Woodcut first appeared in ancient China. From 6th century onward, woodcut icons became popular and especially flourished in Buddhist texts. Since the 10th century, woodcut pictures appeared in inbetweenings of Chinese literature, and some banknotes, such as Jiaozi (currency). Woodcut New Year picture are also very popular with the Chinese.

In China and Tibet printed images mostly remained tied as illustrations to accompanying text until the modern period. The earliest woodblock printed book, the Diamond Sutra contains a large image as frontispiece, and many Buddhist texts contain some images. Later some notable Chinese artists designed woodcuts for books, the individual print develop in China in the form of New Year picture as an art-form in the way it did in Europe and Japan.

In Europe, Woodcut is the oldest technique used for old master prints, developing about 1400, by using on paper existing techniques for printing on cloth. The explosion of sales of cheap woodcuts in the middle of the century led to a fall in standards, and many popular prints were very crude. The development of hatching followed on rather later than in engraving. Michael Wolgemut was significant in making German woodcut more sophisticated from about 1475, and Erhard Reuwich was the first to use cross-hatching (far harder to do than in engraving or etching). Both of these produced mainly book-illustrations, as did various Italian artists who were also raising standards there at the same period. At the end of the century Albrecht Dürer brought the Western woodcut to a level that has never been surpassed, and greatly increased the status of the single-leaf (ie an image sold separately) woodcut.

20.2- Engraving

Engraving is the practice of incising a design onto a hard, flat surface, by cutting grooves into it. The result may be a decorated object in itself, as when silver, gold or steel are engraved, or may provide an intaglio printing plate, of copper or another metal, for printing images on paper, which are called engravings. Engraving was a historically important method of producing images on paper, both in artistic printmaking, and also for commercial reproductions and illustrations for books and magazines. It has long been replaced by photography in its commercial applications and, partly because of the difficulty of learning the technique, is much less common in printmaking, where it has been largely replaced by etching and other techniques. Other terms often used for engravings are copper-plate engraving and Line engraving. These should all mean exactly the same, but especially in the past were often used very loosely to cover several printmaking techniques, so that many so-called engravings were in fact produced by totally different techniques, such as etching.

In antiquity, the only engraving that could be carried out is evident in the shallow grooves found in some jewellery after the beginning of the 1st Millennium B.C. The majority of so-called engraved designs on ancient gold rings or other items were produced by chasing or sometimes a combination of lost-wax casting and chasing.

In the European Middle Ages goldsmiths used engraving to decorate and inscribe metalwork. It is thought that they began to print impressions of their designs to record them. From this grew the engraving of copper printing plates to produce artistic images on paper, known as old master prints in Germany in the 1430s. Italy soon followed. Many early engravers came from a goldsmithing background. The first and greatest period of the engraving was from about 1470 to 1530, with such masters as Martin Schongauer , Albrecht Dürer , and Lucas van Leiden.

20.3- Etching

Etching is the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio in the metal (the original process—in modern manufacturing other chemicals may be used on other types of material). As an intaglio method of printmaking it is, along with engraving, the most important technique for old master prints, and remains widely used today.

20.4- Halftoning

Halftone is the reprographic technique that simulates continuous tone imagery through the use of equally spaced dots of varying size. 'Halftone' can also be used to refer specifically to the image that is produced by this process.

The idea of halftone printing originates from William Fox Talbot. In the early 1850s he suggested using "photographic screens or veils" in connection with a photographic intaglio process.

Several different kinds of screens were proposed during the following decades, but the first half-tone photo-engraving process was invented by Canadians George-Édouard Desbarats and William Leggo Jr. On October 30, 1869, Desbarats published the Canadian Illustrated News which became the world’s first periodical to successfully employ this photo-mechanical technique; featuring a full page half-tone image of His Royal Highness Prince Arthur, from a photograph by Notman. Ambitious to exploit a much larger circulation, Debarats and Leggo went to New York and launched the New York Daily Graphic in March 1873, which became the world’s first illustrated daily.

The first truly successful commercial method was patented by Frederic Ives of Philadelphia in 1881. But although he found a way of breaking up the image into dots of varying sizes he did not make use of a ===screen===. In 1882 the German George Meisenbach patented a halftone process in England. His invention was based on the previous ideas of Berchtold and Swan. He used single lined screens which were turned during exposure to produce cross-lined effects. He was the first to achieve any commercial success with relief halftones.

20.5- Xerography

Xerography (or electrophotography) is a photocopying technique developed by Chester Carlson in 1938 and patented on October 6, 1942.

In 1937 Bulgarian physicist Georgi Nadjakov found that when placed into electric field and exposed to light, some dielectrics acquire permanent electric polarization in the exposed areas. That polarization persists in the dark and is destroyed in light. Chester Carlson, the inventor of photocopying, was originally a patent attorney and part-time researcher and inventor. His job at the patent office in New York required him to make a large number of copies of important papers. Carlson, who was arthritic, found this a painful and tedious process. This prompted him to conduct experiments with photoconductivity. Carlson experimented with "electrophotography" in his kitchen and in 1938, applied for a patent for the process. He made the first "photocopy" using a zinc plate covered with sulfur. The words "10-22-38 Astoria" were written on a microscope slide, which was placed on top of more sulfur and under a bright light. After the slide was removed, a mirror image of the words remained. Carlson tried to sell his invention to some companies, but because the process was still underdeveloped he failed. At the time multiple copies were made using carbon paper or duplicating machines and people did not feel the need for an electronic machine. Between 1939 and 1944, Carlson was turned down by over 20 companies, including IBM and GE, neither of which believed there was a significant market for copiers.

17) HEWLETT- PACKARD ( HP) PRINTERS

2009-05-30T14:38:00.000-07:00

by engr. AFAN BK

The Hewlett-Packard Company, commonly referred to as HP, is a technology corporation headquartered in Palo Alto, California, United States. HP is the largest technology company in the world and operates in nearly every country. HP specializes in developing and manufacturing computing, storage, and networking hardware, software and services. Major product lines include personal computing devices, enterprise servers, related storage devices, as well as a diverse range of printers and other imaging products. Other product lines, including electronic test equipment and systems, medical electronic equipment, solid state components and instrumentation for chemical analysis were spun off as Agilent Technologies in 1999.

HP markets its products to households, small to medium size businesses and enterprises both directly, via online distribution, consumer-electronics and office-supply retailers, software partners and major technology vendors.

HP posted US $91.7 billion in annual revenue in 2006 compared to US$91.4 billion for IBM, making it the world's largest technology vendor in terms of sales. In 2007 the revenue was $104 billion, making HP the first IT company in history to report revenues exceeding $100 billion.

HP is the largest worldwide seller of personal computers, surpassing rival Dell, according to market research firms Gartner and IDC reported in January 2008; the gap between HP and Dell widened substantially at the end of 2007, with HP taking a near 3.9% market share lead. HP is also the 5th largest software company in the world. It is one of the only American PC-focused computer companies publicly traded under the New York Stock Exchange.

1- COMPANY HISTORY

1.1- Founding

William (Bill) Hewlett and David (Dave) Packard both graduated in electrical engineering from Stanford University in 1935. The company originated in a garage in nearby Palo Alto during a fellowship they had with a past professor, Frederick Terman at Stanford during the Great Depression. Terman was considered a mentor to them in forming Hewlett-Packard.

The partnership was formalized in 1939 with an investment of US$538. Hewlett and Packard tossed a coin to decide whether the company they founded would be called Hewlett-Packard or Packard-Hewlett. Packard won the coin toss but named their electronics manufacturing enterprise the "Hewlett-Packard Company". HP incorporated on August 18, 1947, and went public on November 6, 1957.

Of the many projects they worked on, their very first financially successful product was a precision audio oscillator, the Model HP200A. Their innovation was the use of a small light bulb as a temperature dependent resistor in a critical portion of the circuit. This allowed them to sell the Model 200A for $54.40 when competitors were selling less stable oscillators for over $200. The Model 200 series of generators continued until at least 1972 as the 200AB, still tube-based but improved in design through the years. At 33 years, it was perhaps the longest-selling basic electronic design of all time.

One of the company's earliest customers was The Walt Disney Company, which bought eight Model 200B oscillators (at $71.50 each) for use in certifying the Fantasound surround sound systems installed in theaters for the movie Fantasia.

1.2- Early years

The company was originally rather unfocused, working on a wide range of electronic products for industry and even agriculture. Eventually they elected to focus on high-quality electronic test and measurement equipment.

From the 1940s until well into the 1990s the company concentrated on making electronic test equipment – signal generators, voltmeters, oscilloscopes, frequency counters, thermometers, time standards, wave analyzers, and many other instruments. A distinguishing feature was pushing the limits of measurement range and accuracy; many HP instruments were more sensitive, accurate, and precise than other comparable equipment.

Following the pattern set by the company's first product, the 200A, test instruments were labelled with three to five digits followed by the letter "A". Improved versions went to suffixes "B" through "E". As the product range grew wider HP started using product designators starting with a letter for accessories, supplies, software, and components.

1.3- The 1960s

HP is recognized as the symbolic founder of Silicon Valley, although it did not actively investigate semiconductor devices until a few years after the "Traitorous Eight" had abandoned William Shockley to create Fairchild Semiconductor in 1957. Hewlett-Packard's HP Associates division, established around 1960, developed semiconductor devices primarily for internal use. Instruments and calculators were some of the products using these devices.

HP partnered in the 1960s with Sony and the Yokogawa Electric companies in Japan to develop several high-quality products. The products were not a huge success, as there were high costs in building HP-looking products in Japan. HP and Yokogawa formed a joint venture (Yokogawa-Hewlett-Packard) in 1963 to market HP products in Japan. HP bought Yokogawa Electric's share of Hewlett-Packard Japan in 1999.

HP spun off a small company, Dynec, to specialize in digital equipment. The name was picked so that the HP logo "hp" could be turned upside down to be the logo "dy" of the new company. Eventually Dynec changed to Dymec, then was folded back into HP. HP experimented with using Digital Equipment Corporation minicomputers with its instruments. But after deciding that it would be easier to buy another small design team than deal with DEC, HP entered the computer market in 1966 with the HP 2100 / HP 1000 series of minicomputers. These had a simple accumulator-based design, with registers arranged somewhat similarly to the Intel x86 architecture still used today. The series was produced for 20 years, in spite of several attempts to replace it, and was a forerunner of the HP 9800 and HP 250 series of desktop and business computers.

1.4- The 1970s

The HP 3000 was an advanced stack-based design for a business computing server, later redesigned with RISC technology, that has only recently been retired from the market. The HP 2640 series of smart and intelligent terminals introduced forms-based interfaces to ASCII terminals, and also introduced screen labeled function keys, now commonly used on gas pumps and bank ATMs. Although scoffed at in the formative days of computing, HP would eventually surpass even IBM as the world's largest technology vendor in sales.

HP is identified by Wired magazine as the producer of the world's first marketed, mass-produced personal computer, the Hewlett-Packard 9100A, introduced in 1968. HP called it a desktop calculator because, as Bill Hewlett said, "If we had called it a computer, it would have been rejected by our customers' computer gurus because it didn't look like an IBM. We therefore decided to call it a calculator, and all such nonsense disappeared." An engineering triumph at the time, the logic circuit was produced without any integrated circuits; the assembly of the CPU having been entirely executed in discrete components. With CRT display, magnetic-card storage, and printer, the price was around $5000. The machine's keyboard was a cross between that of a scientific calculator and an adding machine. There was no alphabetical keyboard.

Steve Wozniak, co-founder of Apple, originally designed the Apple I computer while working at HP and offered it to them under their right of first refusal to his work, but they did not take it up as the company wanted to stay in scientific, business, and industrial markets.

The company earned global respect for a variety of products. They introduced the world's first handheld scientific electronic calculator in 1972 (the HP-35), the first handheld programmable in 1974 (the HP-65), the first alphanumeric, programmable, expandable in 1979 (the HP-41C), and the first symbolic and graphing calculator, the HP-28C. Like their scientific and business calculators, their oscilloscopes, logic analyzers, and other measurement instruments have a reputation for sturdiness and usability (the latter products are now part of spin-off Agilent's product line). The company's design philosophy in this period was summarized as "design for the guy at the next bench".

The 98x5 series of technical desktop computers started in 1975 with the 9815, and the cheaper 80 series, again of technical computers, started in 1979 with the 85. These machines used a version of the BASIC programming language which was available immediately after they were switched on, and used a proprietary magnetic tape for storage. HP computers were similar in capabilities to the much later IBM Personal Computer, although the limitations of available technology forced prices to be high.

1.5- The 1980s

In 1984, HP introduced both inkjet and laser printers for the desktop. Along with its scanner product line, these have later been developed into successful multifunction products, the most significant being single-unit printer/scanner/copier/fax machines. The print mechanisms in HP's tremendously popular LaserJet line of laser printers depend almost entirely on Canon's components (print engines), which in turn use technology developed by Xerox. HP develops the hardware, firmware, and software that convert data into dots for the mechanism to print.

In 1987, the Palo Alto garage where Hewlett and Packard started their business was designated as a California State historical landmark.

1.6- The 1990s

In the 1990s, HP expanded their computer product line, which initially had been targeted at university, research, and business customers, to reach consumers.

HP also grew through acquisitions, buying Apollo Computer in 1989 and Convex Computer in 1995.

Later in the decade HP opened hpshopping.com as an independent subsidiary to sell online, direct to consumers; in 2005 the store was renamed "HP Home & Home Office Store."

In 1999, all of the businesses not related to computers, storage, and imaging were spun off from HP to form Agilent. Agilent's spin-off was the largest initial public offering in the history of Silicon Valley. The spin-off created an $8 billion company with about 30,000 employees, manufacturing scientific instruments, semiconductors, optical networking devices, and electronic test equipment for telecom and wireless R&D and production.

In July 1999, HP appointed Carly Fiorina as CEO, the first female CEO of a company in the Dow Jones Industrial Average. Fiorina served as CEO during the tech downtown of the turn of the 2nd millenium. During her tenure, the market halved HP’s value commensurate with other tech companies at the time and the company incurred heavy job losses. The HP Board of Directors asked Fiorina to step down in 2005, and she resigned on February 9, 2005.

1.7- 2000 and beyond

Compaq merger. HP merged with Compaq in 2002. Compaq itself had bought Tandem Computers in 1997 (which had been started by ex-HP employees), and Digital Equipment Corporation in 1998. Following this strategy HP became a major player in desktops, laptops, and servers for many different markets. After the merger with Compaq, the new ticker symbol became "HPQ", a combination of the two previous symbols, "HWP" and "CPQ", to show the significance of the alliance. In 2006 hp outsourced its enterprise support to countries with lower cost workers: the Spanish support (for Spain) moved to Slovakia, the German support moved to Bulgaria, English support moved to Costa Rica, and so on.

EDS purchase. On May 13, 2008, HP and Electronic Data Systems announced [13] that they had signed a definitive agreement under which HP would purchase EDS. On June 30, HP announced that the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 had expired. "The transaction still requires EDS stockholder approval and regulatory clearance from the European Commission and other non-U.S. jurisdictions and is subject to the satisfaction or waiver of the other closing conditions specified in the merger agreement." The agreement was finalized on August 26, 2008 and it was publicly announced that EDS would be re-branded "EDS an HP company."

HP also expanded its presence in Israel first with the acqusistion in 2002 of Indigo Digital Press and in November 2005 with the acquisition of Scitex Vision from Scitex Corporation Ltd..

In October 2008, Hewlett-Packard (Canada) Co. was named one of "Canada's Top 100 Employers" by Mediacorp Canada Inc., and was featured in Maclean's newsmagazine. Later that month, Hewlett-Packard (Canada) Co. was also named one of Greater Toronto's Top Employers, which was announced by the Toronto Star newspaper.

2- TECHNOLOGY & PRODUCTS

HP has successful lines of printers, scanners, digital cameras, calculators, PDAs, servers, workstation computers, and computers for home and small business use computers; many of the computers came from the 2002 merger with Compaq. HP today promotes itself as supplying not just hardware and software, but also a full range of services to design, implement and support IT infrastructure.

The three business segments: Enterprise Storage and Servers (ESS), HP Services (HPS), and HP Software are structured beneath the broader Technology Solutions Group (TSG).

2.1- Imaging and Printing Group (IPG)

According to HP's 2005 U.S. SEC 10-K filing, HP's Imaging and Printing Group is "the leading imaging and printing systems provider in the world for printer hardware, printing supplies and scanning devices, providing solutions across customer segments from individual consumers to small and medium businesses to large enterprises." This division is currently headed by Vyomesh Joshi.

Products and technology associated with the Imaging and Printing Group include:

Inkjet and LaserJet printers, consumables and related products

Officejet all-in-one multifunction printer/scanner/faxes

Large Format Printers

Indigo Digital Press

HP Web Jetadmin printer management software

HP Output Management suite of software, including HP Output Server

LightScribe optical recording technology that laser-etches labels on disks

HP Photosmart digital cameras and photo printers

HP SPaM Hosted within IPG, SPaM is an internal consulting group that supports all HP businesses on mission-critical strategic and operation decisions.

On December 23, 2008, HP releases iPrint Photo for iPhone a free downloadable

software application that allows to print 4" x 6" photo.

2.2- Personal Systems Group (PSG)

HP's Personal Systems Group claims to be "one of the leading vendors of personal computers ("PCs") in the world based on unit volume shipped and annual revenue."[16]

Personal Systems Group products/technology include:

Business PCs and accessories

Consumer PCs and accessories including the HP Pavilion, Compaq Presario and VoodooPC series

Workstations for Unix, Windows and Linux systems

Handheld Computing including iPAQ Pocket PC handheld computing devices (from Compaq)

Digital "Connected" Entertainment including HP MediaSmart TVs, HP MediaSmart
Servers, HP MediaVaults, and DVD+RW drives. HP resold the Apple iPod until November 2005.

Home Storage Servers

2.3- Technology Solutions Group (TSG)

TSG incorporates Technical services, EDS, HP Software, Enterprise Storage and Servers Group (ESS) and ProCurve Networking.

2.4- Office of Strategy and Technology

HP's Office of Strategy and Technology, under Executive Vice President Shane Robison:

Steers the company's $3.6 billion research and development investment — including HP Labs.

Fosters the development of the company's global technical community.

Leads the company's strategy and corporate development efforts — including mergers, acquisitions, divestitures, intellectual property licensing, venture capital partnerships, and the ProCurve Networking Business Unit.

Performs worldwide corporate marketing activities — including external and internal communications, brand marketing, customer intelligence, and corporate affairs.

3- ENVIRONMENTAL RECORD

In 1998, the United States Environmental Protection Agency‎ sought a $2.5 million penalty against Hewlett Packard for violations against the Substance Control Act. The PA EPA alleged that the company had not filed a Pre-Manufacturing Notice (PMN) before it began manufacturing and exporting chemicals. Without filing these PMNs, the EPA cannot conduct risk analysis of new chemicals.

In 2002, Scorecard.org ranked Hewlett Packard facilities in the top 10-20 percentile for total environmental releases and top 30-40 percentile for air releases of recognized developmental toxicants. It also showed that HPs factory in Puerto Rico released 246 lb (112 kg) of air released TRI pollutants, and had a total of 483,136 lb (219,147 kg) of production related wastes.

In July 2007, the company announced that it had met its target, set in 2004, to recycle 1 billion pounds of electronics and toner and ink cartridges. It has set a new goal of recycling a further 2 billion pounds of hardware by the end of 2010. In 2006, the company recovered 187 million pounds of electronics, 73 percent more than its closest competitor.

4- HP CERTIFIED PROFESSIONALS

Hewlett-Packard's Certified Professional (HP-CP) program was developed to confirm the technical skills, sales competencies and knowledge that is required to propose and deploy, service and support technology and solutions sold by HP. HP-CP is intended for customers, resellers, and HP employees.

5- SPONSORSHIPS

HP has many sponsorships. One well known sponsorship is of Walt Disney World's Epcot Park's Mission: SPACE. Others can be found on Hewlett-Packard's website . From 1995 to 1999 they were the shirt sponsor of English Premier League club Tottenham Hotspur. They also sponsored the BMW Williams Formula 1 team. Hewlett-Packard also has the naming rights arrangement for the HP Pavilion at San Jose, home of the San Jose Sharks NHL hockey team.

6- PRODUCT LEGACY

Agilent Technologies, not HP, retains the direct product legacy of the original company founded in 1939. Agilent's current portfolio of electronic instruments are descended from HP's very earliest products. HP entered the computer business only after its instrumentation competencies were well-established.

After the acquisition of Compaq in 2002, HP has maintained the "Compaq Presario" brand on low-end home desktops and laptops, the "HP Compaq" brand on business desktops and laptops, and the "HP ProLiant" brand on Intel-architecture servers. (The "HP Pavilion" brand is used on home entertainment laptops and all home desktops.)

HP uses DEC's "StorageWorks" brand on storage systems; Tandem's "NonStop" servers are now branded as "HP Integrity NonStop".

16) LASER PRINTERS

2009-05-30T14:32:00.000-07:00

by engr. AFAN BK

A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers (MFPs), laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.

1- OVERVIEW

A laser beam projects an image of the page to be printed onto an electrically charged rotating drum coated with selenium. Photoconductivity removes charge from the areas exposed to light. Dry ink (toner) particles are then electrostatically picked up by the drum's charged areas. The drum then prints the image onto paper by direct contact and heat, which fuses the ink to the paper.

Laser printers have many significant advantages over other types of printers. Unlike impact printers, laser printer speed can vary widely, and depends on many factors, including the graphic intensity of the job being processed. The fastest models can print over 200 monochrome pages per minute (12,000 pages per hour). The fastest color laser printers can print over 100 pages per minute (6000 pages per hour). Very high-speed laser printers are used for mass mailings of personalized documents, such as credit card or utility bills, and are competing with lithography in some commercial applications.

The cost of this technology depends on a combination of factors, including the cost of paper, toner, and infrequent drum replacement, as well as the replacement of other consumables such as the fuser assembly and transfer assembly. Often printers with soft plastic drums can have a very high cost of ownership that does not become apparent until the drum requires replacement.

A duplexing printer (one that prints on both sides of the paper) can halve paper costs and reduce filing volumes. Formerly only available on high-end printers, duplexers are now common on mid-range office printers, though not all printers can accommodate a duplexing unit. Duplexing can also give a slower page-printing speed, because of the longer paper path.

In comparison with the laser printer, most inkjet printers and dot-matrix printers simply take an incoming stream of data and directly imprint it in a slow lurching process that may include pauses as the printer waits for more data. A laser printer is unable to work this way because such a large amount of data needs to output to the printing device in a rapid, continuous process. The printer cannot stop the mechanism precisely enough to wait until more data arrives, without creating a visible gap or misalignment of the dots on the printed page.

Instead the image data is built up and stored in a large bank of memory capable of representing every dot on the page. The requirement to store all dots in memory before printing has traditionally limited laser printers to small fixed paper sizes such as letter or A4. Most laser printers are unable to print continuous banners spanning a sheet of paper two meters long, because there is not enough memory available in the printer to store such a large image before printing begins.

2- HISTORY

The laser printer was invented at Xerox in 1969 by researcher Gary Starkweather, who had an improved printer working by 1971 and incorporated into a fully functional networked printer system by about a year later. The prototype was built by modifying an existing xerographic copier. Starkweather disabled the imaging system and created a spinning drum with 8 mirrored sides, with a laser focused on the drum. Light from the laser would bounce off the spinning drum, sweeping across the page as it traveled through the copier. The hardware was completed in just a week or two, but the computer interface and software took almost 3 months to complete.

The first commercial implementation of a laser printer was the IBM model 3800 in 1976, used for high-volume printing of documents such as invoices and mailing labels. It is often cited as "taking up a whole room," implying that it was a primitive version of the later familiar device used with a personal computer. While large, it was designed for an entirely different purpose. Many 3800s are still in use.[citation needed]

The first laser printer designed for use with an individual computer was released with the Xerox Star 8010 in 1981. Although it was innovative, the Star was an expensive ($17,000) system that was purchased by only a relatively small number of businesses and institutions. After personal computers became more widespread, the first laser printer intended for a mass market was the HP LaserJet 8ppm, released in 1984, using a Canon engine controlled by HP software. The HP LaserJet printer was quickly followed by laser printers from Brother Industries, IBM, and others.

As with most electronic devices, the cost of laser printers has fallen markedly over the years. In 1984, the HP LaserJet sold for $3500[3], had trouble with even small, low resolution graphics, and weighed 71 pounds (32 kg). Low end monochrome laser printers often sell for less than $75 as of 2008. These printers tend to lack onboard processing and rely on the host computer to generate a raster image (see Winprinter), but still will outperform the LaserJet Classic in nearly all situations.

3- HOW IT WORKS

There are typically seven steps involved in the laser printing process:

3.1- Raster image processing

Each horizontal strip of dots across the page is known as a raster line or scan line. Creating the image to be printed is done by a Raster Image Processor (RIP), typically built into the laser printer. The source material may be encoded in any number of special page description languages such as Adobe PostScript (PS) , HP Printer Command Language (PCL), or Microsoft XML Page Specification (XPS) , as well as unformatted text-only data. The RIP uses the page description language to generate a bitmap of the final page in the raster memory. Once the entire page has been rendered in raster memory, the printer is ready to begin the process of sending the rasterized stream of dots to the paper in a continuous stream.

3.2- Charging

A corona wire (in older printers) or a primary charge roller projects an electrostatic charge onto the photoreceptor (otherwise named the photoconductor unit), a revolving photosensitive drum or belt, which is capable of holding an electrostatic charge on its surface while it is in the dark.

Numerous patents describe the photosensitive drum coating as a silicon sandwich with a photocharging layer, a charge leakage barrier layer, as well as a surface layer. One version uses amorphous silicon containing hydrogen as the light receiving layer, Boron nitride as a charge leakage barrier layer, as well as a surface layer of doped silicon, notably silicon with oxygen or nitrogen which at sufficient concentration resembles machining silicon nitride; the effect is that of a light chargeable diode with minimal leakage and a resistance to scuffing.

3.3- Exposing

The laser is aimed at a rotating polygonal mirror, which directs the laser beam through a system of lenses and mirrors onto the photoreceptor. The beam sweeps across the photoreceptor at an angle to make the sweep straight across the page; the cylinder continues to rotate during the sweep and the angle of sweep compensates for this motion. The stream of rasterized data held in memory turns the laser on and off to form the dots on the cylinder. (Some printers switch an array of light emitting diodes spanning the width of the page, but these devices are not "Laser Printers".) Lasers are used because they generate a narrow beam over great distances. The laser beam neutralizes (or reverses) the charge on the white parts of the image, leaving a static electric negative image on the photoreceptor surface to lift the toner particles.

3.4- Developing

The surface with the latent image is exposed to toner, fine particles of dry plastic powder mixed with carbon black or coloring agents. The charged toner particles are given a negative charge, and are electrostatically attracted to the photoreceptor where the laser wrote the latent image. Because like charges repel, the negatively charged toner will not touch the drum where light has not removed the negative charge.

The overall darkness of the printed image is controlled by the high voltage charge applied to the supply toner. Once the charged toner has jumped the gap to the surface of the drum, the negative charge on the toner itself repels the supply toner and prevents more toner from jumping to the drum. If the voltage is low, only a thin coat of toner is needed to stop more toner from transferring. If the voltage is high, then a thin coating on the drum is too weak to stop more toner from transferring to the drum. More supply toner will continue to jump to the drum until the charges on the drum are again high enough to repel the supply toner. At the darkest settings the supply toner voltage is high enough that it will also start coating the drum where the initial unwritten drum charge is still present, and will give the entire page a dark shadow.

3.5- Transferring

The photoreceptor is pressed or rolled over paper, transferring the image. Higher-end machines use a positively charged transfer roller on the back side of the paper to pull the toner from the photoreceptor to the paper.

3.6- Fusing

The paper passes through rollers in the fuser assembly where heat and pressure (up to 200 Celsius) bond the plastic powder to the paper.
One roller is usually a hollow tube (heat roller) and the other is a rubber backing roller (pressure roller). A radiant heat lamp is suspended in the center of the hollow tube, and its infrared energy uniformly heats the roller from the inside. For proper bonding of the toner, the fuser roller must be uniformly hot.

The fuser accounts for up to 90% of a printer's power usage. The heat from the fuser assembly can damage other parts of the printer, so it is often ventilated by fans to move the heat away from the interior. The primary power saving feature of most copiers and laser printers is to turn off the fuser and let it cool. Resuming normal operation requires waiting for the fuser to return to operating temperature before printing can begin.

Some printers use a very thin flexible metal fuser roller, so there is less mass to be heated and the fuser can more quickly reach operating temperature. This both speeds printing from an idle state and permits the fuser to turn off more frequently to conserve power.

If paper moves through the fuser more slowly, there is more roller contact time for the toner to melt, and the fuser can operate at a lower temperature. Smaller, inexpensive laser printers typically print slowly, due to this energy-saving design, compared to large high speed printers where paper moves more rapidly through a high-temperature fuser with a very short contact time.

3.7- Cleaning

When the print is complete, an electrically neutral soft plastic blade cleans any excess toner from the photoreceptor and deposits it into a waste reservoir, and a discharge lamp removes the remaining charge from the photoreceptor.

Toner may occasionally be left on the photoreceptor when unexpected events such as a paper jam occur. The toner is on the photoconductor ready to apply, but the operation failed before it could be applied. The toner must be wiped off and the process restarted.

Waste toner cannot be reused for printing because it can be contaminated with dust and paper fibers. A quality printed image requires pure, clean toner. Reusing contaminated toner can result in splotchy printed areas or poor fusing of the toner into the paper. There are some exceptions however, most notably some Brother and Toshiba laser printers, which use a patented method to clean and recycle the waste toner.

3.8- Multiple steps occurring at once

Once the raster image generation is complete all steps of the printing process can occur one after the other in rapid succession. This permits the use of a very small and compact unit, where the photoreceptor is charged, rotates a few degrees and is scanned, rotates a few more degrees and is developed, and so forth. The entire process can be completed before the drum completes one revolution.

Different printers implement these steps in distinct ways. Some "laser" printers actually use a linear array of light-emitting diodes to "write" the light on the drum (see LED printer). The toner is based on either wax or plastic, so that when the paper passes through the fuser assembly, the particles of toner melt. The paper may or may not be oppositely charged. The fuser can be an infrared oven, a heated pressure roller, or (on some very fast, expensive printers) a xenon flash lamp. The Warm Up process that a laser printer goes through when power is initially applied to the printer consists mainly of heating the fuser element. Many printers have a toner-conservation mode, called "Economode" by Hewlett-Packard, which uses about half as much toner but produces a lighter draft-quality output.

4- COLOR LASER PRINTERS

Color laser printers use colored toner (dry ink), typically cyan, magenta, yellow, and black (CMYK), with a printing pass for each toner color.

Color adds complexity to the printing process because very slight misalignments known as registration errors can occur between printing each color, causing unintended color fringing, blurring, or light/dark streaking along the edges of colored regions. To permit a high registration accuracy, some color laser printers use a large belt the size of a full sheet of paper to generate the image. All three or four layers of toner are precisely applied to the belt, and the combined layers are then applied to the paper in a single step.

Color laser printers typically require four times as much memory as a monochrome printer to print the same size document, because each of the three CMY or four CMYK color separations needs to be rasterized and stored in memory before printing can begin.

5- DPI RESOLUTIONS

1200 DPI printers are commonly available during 2008.

2400 DPI electrophotographic printing plate makers, essentially laser printers that print on plastic sheets, are also available.

6- LASER PRINTER MAINTENANCE

Most consumer and small business laser printers use a cartridge that combines the photoreceptor (sometimes called "photoconductor unit") with the supply toner and waste toner bottles and various wiper blades. When the supply toner is consumed, replacing the cartridge automatically replaces the photoreceptor, waste toner bottle, and blades.

Some small consumer printers use a separate toner bottle that can be replaced several times separately from the photoreceptor, allowing for a much lower cost of operation. High-volume business laser printers separate all components into individual modules.

After printing about fifty thousand pages, typical maintenance is to vacuum the mechanism, and clean or replace the paper handling rollers. The rollers have a thick rubber coating, which eventually suffers wear and becomes covered with slippery paper dust. They can usually be cleaned with a damp lint-free rag and there are chemical solutions that can help restore the traction of the rubber.

After one hundred thousand pages, it is common for the fuser assembly to either wear out or need replacing. The fuser heating rollers are often coated with an oil that prevents toner from sticking to the rollers. A small amount of the oil coating is absorbed by each piece of paper passing through the fuser, eventually requiring the oil supply to be replenished or the pressure roller assembly to be completely replaced. It is common for the fuser assembly to be left unmaintained until the toner starts sticking to the rollers, which creates a repeating ragged line on every printed page due to the rollers not being smooth anymore.

Color laser printers are typically more expensive and higher maintenance than monochrome laser printers since they contain more imaging components. Color laser printers intended for high volume use may require supplies that monochrome printers do not use, while the least expensive consumer color laser printers are expected to wear out and fail four times faster during color printing, compared to monochrome printing.

Due to current market incentives, the least expensive consumer color laser printers often cost less than the total value of the replacement parts inside the printer. The photoreceptor assembly for example may last 100,000 pages but may cost as much to replace as buying a new printer with new toner cartridges included.

7- SAFETY HAZARDS, HEALTH RISKS, & PRECAUTION

7.1- Shock hazards

Although modern printers include many safety interlocks and protection circuits, it is possible for a high voltage or a residual voltage to be present on the various rollers, wires, and metal contacts inside a laser printer. Care should be taken to avoid unnecessary contact with these parts to reduce the potential for painful electrical shock.

7.2- Toner clean-up

Toner particles are designed to have electrostatic properties and can develop static-electric charges when they rub against other particles, objects, or the interiors of transport systems and vacuum hoses. Because of this and its small particle size, toner should not be vacuumed with a conventional home vacuum cleaner. Static discharge from charged toner particles can ignite dust in the vacuum cleaner bag or create a small explosion if sufficient toner is airborne. This may damage the vacuum cleaner or start a fire. In addition, toner particles are so fine that they are poorly filtered by conventional household vacuum cleaner filter bags and blow through the motor or back into the room.

Toner particles melt (or fuse) when warmed. Small toner spills can be wiped up with a cold, damp cloth.

If toner spills into the laser printer, a special type of vacuum cleaner with an electrically conductive hose and a high efficiency (HEPA) filter may be needed for effective cleaning. These are called ESD-safe (Electrostatic Discharge-safe) or toner vacuums. Similar HEPA-filter equipped vacuums should be used for clean-up of larger toner spills.

Toner is easily cleaned from most water-washable clothing. As toner is a wax or plastic powder with a low melting temperature, it must be kept cold during the cleaning process. Washing a toner stained garment in cold water is often successful. Even warm water is likely to result in permanent staining. The washing machine should be filled with cold water before adding the garment. Washing through two cycles improves the chances of success. The first may use hand wash dish detergent, with the second cycle using regular laundry detergent. Residual toner floating in the rinse water of the first cycle will remain in the garment and may cause a permanent graying. A clothes dryer or iron should not be used until it is certain that all the toner has been removed.

7.3- Ozone hazards

As a natural part of the printing process, the high voltages inside the printer can produce a corona discharge that generates a small amount of ionized oxygen and nitrogen, forming ozone and nitrogen oxides. In larger commercial printers and copiers, a carbon filter in the air exhaust stream breaks down these oxides to prevent pollution of the office environment.

However, some ozone escapes the filtering process in commercial printers, and ozone filters are not used in many smaller consumer printers. When a laser printer or copier is operated for a long period of time in a small, poorly ventilated space, these gases can build up to levels at which the odor of ozone or irritation may be noticed. A potential for creating a health hazard is theoretically possible in extreme cases.

7.4- Respiratory health risks

According to a recent study conducted in Queensland, Australia, some printers emit sub-micrometre particles which some suspect may be associated with respiratory diseases. Of 63 printers evaluated in the Queensland University of Technology study, 17 of the strongest emitters were made by Hewlett-Packard and one by Toshiba. The machine population studied, however, was only those machines already in place in the building and was thus biased toward specific manufacturers. The authors noted that particle emissions varied substantially even among the same model of machine. According to Professor Morawska of Queensland University, one printer emitted as many particles as a burning cigarette.

"The health effects from inhaling ultrafine particles depend on particle composition, but the results can range from respiratory irritation to more severe illness such as cardiovascular problems or cancer." (Queensland University of Technology).
A 2006 study in Japan found that laser printers increase concentrations of styrene, xylenes, and ozone, and that ink-jet printers emitted pentanol.

Muhle et al. (1991) reported that the responses to chronically inhaled copying toner, a plastic dust pigmented with carbon black, titanium dioxide and silica were also similar qualitatively to titanium dioxide and diesel exhaust.

15) PRINTERS COMPUTING

2009-05-30T14:29:00.000-07:00

by engr. AFAN BK

In computing, a printer is a peripheral which produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most newer printers, a USB cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless or Ethernet), and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time.

In addition, a few modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image capture devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit, and can function as photocopiers. Printers that include non-printing features are sometimes called Multifunction Printers (MFP), Multi-Function Devices (MFD), or All-In-One (AIO) printers. Most MFPs include printing, scanning, and copying among their features. A Virtual printer is a piece of computer software whose user interface and API resemble that of a printer driver, but which is not connected with a physical computer printer.

Printers are designed for low-volume, short-turnaround print jobs; requiring virtually no setup time to achieve a hard copy of a given document. However, printers are generally slow devices (30 pages per minute is considered fast; and many inexpensive consumer printers are far slower than that), and the cost per page is actually relatively high. The printing press remains the machine of choice for high-volume, professional publishing. However, as printers have improved in quality and performance, many jobs which used to be done by professional print shops are now done by users on local printers; see desktop publishing. The world's first computer printer was a 19th century mechanically driven apparatus invented by Charles Babbage for his Difference Engine.

1- PRINTING TECHNOLOGY

Printers are routinely classified by the underlying print technology they employ; numerous such technologies have been developed over the years. The choice of print engine has a substantial effect on what jobs a printer is suitable for, as different technologies are capable of different levels of image/text quality, print speed, low cost, noise; in addition, some technologies are inappropriate for certain types of physical media (such as carbon paper or transparencies).

Another aspect of printer technology that is often forgotten is resistance to alteration: liquid ink such as from an inkjet head or fabric ribbon becomes absorbed by the paper fibers, so documents printed with a liquid ink sublimation printer are more difficult to alter than documents printed with toner or solid inks, which do not penetrate below the paper surface.

Checks should either be printed with liquid ink or on special "check paper with toner anchorage". For similar reasons carbon film ribbons for IBM Selectric typewriters bore labels warning against using them to type negotiable instruments such as checks. The machine-readable lower portion of a check, however, must be printed using MICR toner or ink. Banks and other clearing houses employ automation equipment that relies on the magnetic flux from these specially printed characters to function properly.

2- MODERN PRINT-TECHNOLOGY

The following printing technologies are routinely found in modern printers,

2.1- Toner-based printers

Toner-based printers work using the Xerographic principle that is used in most photocopiers: by adhering toner to a light-sensitive print drum, then using static electricity to transfer the toner to the printing medium to which it is fused with heat and pressure.

The most common type of toner-based printer is the laser printer, which uses precision lasers to cause toner adherence. Laser printers are known for high quality prints, good print speed, and a low (Black and White) cost-per-copy. They are the most common printer for many general-purpose office applications, but are much less common as consumer printers due to their high initial cost - although this cost is dropping.

Laser printers are available in both color and monochrome varieties.

Another toner based printer is the LED printer which uses an array of LEDs instead of a laser to cause toner adhesion to the print drum.

Recent research has also indicated that Laser printers emit potentially dangerous ultrafine particles, possibly causing health problems associated with respiration and cause pollution equivalent to cigarettes. The degree of particle emissions varies with age, model and design of each printer but is generally proportional to the amount of toner required. Furthermore, a well ventilated workspace would allow such ultrafine particles to disperse thus reducing the health side effects.

2.2- Liquid inkjet printers

Inkjet printers operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any sized page. They are the most common type of computer printer for the general consumer due to their low cost, high quality of output, capability of printing in vivid color, and ease of use.

2.3- Solid ink printers

Solid Ink printers, also known as phase-change printers, are a type of thermal transfer printer. They use solid sticks of CMYK colored ink (similar in consistency to candle wax), which are melted and fed into a piezo crystal operated print-head. The printhead sprays the ink on a rotating, oil coated drum. The paper then passes over the print drum, at which time the image is transferred, or transfixed, to the page.

Solid ink printers are most commonly used as color office printers, and are excellent at printing on transparencies and other non-porous media. Solid ink printers can produce excellent results. Acquisition and operating costs are similar to laser printers. Drawbacks of the technology include high power consumption and long warm-up times from a cold state.

Also, some users complain that the resulting prints are difficult to write on (the wax tends to repel inks from pens), and are difficult to feed through Automatic Document Feeders, but these traits have been significantly reduced in later models. In addition, this type of printer is only available from one manufacturer, Xerox, manufactured as part of their Xerox Phaser office printer line. Previously, solid ink printers were manufactured by Tektronix, but Tek sold the printing business to Xerox in 2001.

2.4- Dye-sublimation printers

A dye-sublimation printer (or dye-sub printer) is a printer which employs a printing process that uses heat to transfer dye to a medium such as a plastic card, paper or canvas. The process is usually to lay one color at a time using a ribbon that has color panels. Dye-sub printers are intended primarily for high-quality color applications, including color photography; and are less well-suited for text. While once the province of high-end print shops, dye-sublimation printers are now increasingly used as dedicated consumer photo printers.

2.5- Inkless printers

2.5.1 - Thermal printers work by selectively heating regions of special heat-sensitive paper. Monochrome thermal printers are used in cash registers, ATMs, gasoline dispensers and some older inexpensive fax machines. Colors can be achieved with special papers and different temperatures and heating rates for different colors. One example is the ZINK technology.

2.5.2- UV printersXerox is working on an inkless printer which will use a special reusable paper coated with a few micrometres of UV light sensitive chemicals. The printer will use a special UV light bar which will be able to write and erase the paper. As of early 2007 this technology is still in development and the text on the printed pages can only last between 16-24 hours before fading.

3- OBSOLETE & SPECIAL PURPOSE PRINTING TECHNOLOGIES

The following technologies are either obsolete, or limited to special applications though most were, at one time, in widespread use.

Impact printers rely on a forcible impact to transfer ink to the media, similar to the action of a typewriter. All but the dot matrix printer rely on the use of formed characters, letterforms that represent each of the characters that the printer was capable of printing. In addition, most of these printers were limited to monochrome printing in a single typeface at one time, although bolding and underlining of text could be done by overstriking, that is, printing two or more impressions in the same character position. Impact printers varieties include, Typewriter-derived printers, Teletypewriter-derived printers, Daisy wheel printers, Dot matrix printers and Line printers. Dot matrix printers remain in common use in businesses where multi-part forms are printed, such as car rental service counters. An overview of impact printing contains a detailed description of many of the technologies used.

Pen-based plotters were an alternate printing technology once common in engineering and architectural firms. Pen-based plotters rely on contact with the paper (but not impact, per se), and special purpose pens that are mechanically run over the paper to create text and images.

3.1- Typewriter-derived printers

Several different computer printers were simply computer-controllable versions of existing electric typewriters. The Friden Flexowriter and IBM Selectric typewriter were the most-common examples. The Flexowriter printed with a conventional typebar mechanism while the Selectric used IBM's well-known "golf ball" printing mechanism. In either case, the letter form then struck a ribbon which was pressed against the paper, printing one character at a time. The maximum speed of the Selectric printer (the faster of the two) was 15.5 characters per second.

3.2- Teletypewriter-derived printers

The common teleprinter could easily be interfaced to the computer and became very popular except for those computers manufactured by IBM. Some models used a "typebox" that was positioned (in the X- and Y-axes) by a mechanism and the selected letter from was struck by a hammer. Others used a type cylinder in a similar way as the Selectric typewriters used their type ball. In either case, the letter form then struck a ribbon to print the letterform. Most teleprinters operated at ten characters per second although a few achieved 15 CPS.

3.3- Daisy wheel printers

Daisy-wheel printers operate in much the same fashion as a typewriter. A hammer strikes a wheel with petals (the daisy wheel), each petal containing a letter form at its tip. The letter form strikes a ribbon of ink, depositing the ink on the page and thus printing a character. By rotating the daisy wheel, different characters are selected for printing.

These printers were also referred to as letter-quality printers because, during their heyday, they could produce text which was as clear and crisp as a typewriter (though they were nowhere near the quality of printing presses). The fastest letter-quality printers printed at 30 characters per second.

3.4- Dot-matrix printers

In the general sense many printers rely on a matrix of pixels, or dots, that together form the larger image. However, the term dot matrix printer is specifically used for impact printers that use a matrix of small pins to create precise dots. The advantage of dot-matrix over other impact printers is that they can produce graphical images in addition to text; however the text is generally of poorer quality than impact printers that use letterforms (type).

Dot-matrix printers can be broadly divided into two major classes:

Ballistic wire printers (discussed in the dot matrix printers article)
Stored energy printers
Dot matrix printers can either be character-based or line-based (that is, a single horizontal series of pixels across the page), referring to the configuration of the print head.

At one time, dot matrix printers were one of the more common types of printers used for general use - such as for home and small office use. Such printers would have either 9 or 24 pins on the print head. 24-pin print heads were able to print at a higher quality. Once the price of inkjet printers dropped to the point where they were competitive with dot matrix printers, dot matrix printers began to fall out of favor for general use.

Some dot matrix printers, such as the NEC P6300, can be upgraded to print in color. This is achieved through the use of a four-color ribbon mounted on a mechanism (provided in an upgrade kit that replaces the standard black ribbon mechanism after installation) that raises and lowers the ribbons as needed. Color graphics are generally printed in four passes at standard resolution, thus slowing down printing considerably. As a result, color graphics can take up to four times longer to print than standard monochrome graphics, or up to 8-16 times as long at high resolution mode.

Dot matrix printers are still commonly used in low-cost, low-quality applications like cash registers, or in demanding, very high volume applications like invoice printing. The fact that they use an impact printing method allows them to be used to print multi-part documents using carbonless copy paper (like sales invoices and credit card receipts), whereas other printing methods are unusable with paper of this type. Dot-matrix printers are now (as of 2005) rapidly being superseded even as receipt printers.

3.5- Line printers

Line printers, as the name implies, print an entire line of text at a time. Three principal designs existed. In drum printers, a drum carries the entire character set of the printer repeated in each column that is to be printed. In chain printers (also known as train printers), the character set is arranged multiple times around a chain that travels horizontally past the print line. In either case, to print a line, precisely timed hammers strike against the back of the paper at the exact moment that the correct character to be printed is passing in front of the paper. The paper presses forward against a ribbon which then presses against the character form and the impression of the character form is printed onto the paper.

Comb printers represent the third major design. These printers were a hybrid of dot matrix printing and line printing. In these printers, a comb of hammers printed a portion of a row of pixels at one time (for example, every eighth pixel). By shifting the comb back and forth slightly, the entire pixel row could be printed (continuing the example, in just eight cycles). The paper then advanced and the next pixel row was printed. Because far less motion was involved than in a conventional dot matrix printer, these printers were very fast compared to dot matrix printers and were competitive in speed with formed-character line printers while also being able to print dot-matrix graphics.

Line printers were the fastest of all impact printers and were used for bulk printing in large computer centres. They were virtually never used with personal computers and have now been replaced by high-speed laser printers.

The legacy of line printers lives on in many computer operating systems, which use the abbreviations "lp", "lpr", or "LPT" to refer to printers.

3.6- Pen-based plotters

A plotter is a vector graphics printing device which operates by moving a pen over the surface of paper. Plotters have been (and still are) used in applications such as computer-aided design, though they are being replaced with wide-format conventional printers (which nowadays have sufficient resolution to render high-quality vector graphics using a rasterized print engine). It is commonplace to refer to such wide-format printers as "plotters", even though such usage is technically incorrect.

4 - OTHER PRINTERS

A number of other sorts of printers are important for historical reasons, or for special purpose uses:

Digital minilab (photographic paper)

Electrolytic printers

Microsphere (special paper)

Spark printer

barcode printer multiple technologies, including: thermal printing, inkjet printing, and laser printing barcodes

Billboard / sign paint spray printers

Laser etching (product packaging) industrial printers.

5- PRINTING MODE

The data received by a printer may be:

1.a string of characters
2.a bitmapped image
3.a vector image
Some printers can process all three types of data, others not.

Character Printers (such as Daisy wheel printers) can handle only plain text data or rather simple point plots.

Pen Plotters typically process vector images. Inkjet based Plotters can adequately reproduce all three.

Modern printing technology, such as laser printers and inkjet printers, can adequately reproduce all three. This is especially true of printers equipped with support for PostScript and/or PCL; which includes the vast majority of printers produced today.

Today it is common to print everything (even plain text) by sending ready bitmapped images to the printer, because it allows better control over formatting. Many printer drivers do not use the text mode at all, even if the printer is capable of it.

6- MONOCHROME, COLOR & PHOTO PRINTERS

A monochrome printer can only produce an image consisting of one color, usually black. A monochrome printer may also be able to produce various tones of that color, such as a grey-scale.

A color printer can produce images of multiple colors.

A photo printer is a color printer that can produce images that mimic the color range (gamut) and resolution of photographic methods of printing. Many can be used autonomously (without a computer), with a memory card or USB connector.

7- THE PRINTERS MANUFACTURING BUSINESS

Often the razor and blades business model is applied. That is, a company may sell a printer at cost, and make profits on the ink cartridge, paper, or some other replacement part. This has caused legal disputes regarding the right of companies other than the printer manufacturer to sell compatible ink cartridges.

8- PRINTING SPEED

The speed of early printers was measured in units of characters per second. More modern printers are measured in pages per minute. These measures are used primarily as a marketing tool, and are not well standardised. Usually pages per minute refers to sparse monochrome office documents, rather than dense pictures which usually print much more slowly. PPM are most of the time referring to A4 paper in Europe and letter paper in the US, resulting in a 5-10% difference.

14) HISTORY OF VIDEO GAMES

2009-05-30T14:20:00.000-07:00

by engr. AFAN BK

Video games were introduced as a commercial entertainment medium in 1971, becoming the basis for a new entertainment industry in the late 1970s/early 1980s in the United States, Japan, and Europe. After a disastrous industry collapse in 1983 and a subsequent rebirth two years later, the video game industry has experienced sustained growth for over two decades to become a $11 billion industry, which rivals the motion picture industry as the most profitable entertainment industry in the world.

Origins

A device called the Cathode-Ray Tube Amusement Device was patented in the United States by Thomas T. Goldsmith Jr. and Estle Ray Mann. The patent was filed on January 25, 1947 and issued on December 14, 1948. It described using eight vacuum tubes to simulate a missile firing at a target and contains knobs to adjust the curve and speed of the missile. Because computer graphics could not be drawn electronically at the time, small targets were drawn on a simple overlay and placed on the screen.

In 1949-1950, Charly Adama created a "Bouncing Ball" program for MIT's Whirlwind computer. While the program was not yet interactive, it was a precursor to games soon to come.

In February 1951, Christopher Strachey tried to run a draughts programme he had written for the NPL Pilot ACE. The program exceeded the memory capacity of the machine and by October, Strachey had recoded his program for a machine at Manchester with a larger memory capacity.

OXO, a graphical version of tic-tac-toe, was created by A.S. Douglas in 1952 at the University of Cambridge, in order to demonstrate his thesis on human-computer interaction. It was developed on the EDSAC computer, which uses a cathode ray tube displaying memory contents as a visual display. The player competes against the computer.

1950s–1960s

The majority of early computer games ran on university mainframe computers in the United States and were developed by individuals as a hobby. The limited accessibility of early computer hardware meant that these games were small in number and forgotten by posterity.

In 1959-1961, a collection of interactive graphical programs were created on the TX-0 machine at MIT:

Mouse in the Maze: which allowed users to place maze walls, bits of cheese, and (in some versions) glasses of martini by way of a light pen interacting with the screen. One could then release the mouse and watch it traverse the maze to find the goodies.
HAX: By adjusting two switches on the console, various graphical displays and sounds could be made.

Tic-Tac-Toe: Using the light pen, the user could play a simple game of naughts and crosses against the computer.
In 1961, a group of students at MIT, including Steve Russell, programmed a game titled Spacewar! on the DEC PDP-1, a new computer at the time. The game pitted two human players against each other, each controlling a spacecraft capable of firing missiles, while a black hole in the center of the screen created a large hazard for the crafts. The game was eventually distributed with new DEC computers and traded throughout the then-primitive internet. Spacewar! is credited as the first influential computer game.

In 1966, Ralph Baer created a simple video game named Corndog that displayed on a standard television set, the first to do so. With the assistance of Baer, Bill Harrison created the light gun and developed several video games with Bill Rusch in 1967. Ralph Baer continued development, and in 1968 a prototype was completed that could run several different games such as table tennis and target shooting.

In 1969, AT&T computer programmer Ken Thompson wrote a game called Space Travel for the MULTICS operating system. This game simulated various bodies of the solar system and their movements and the player could attempt to land a spacecraft on them. AT&T pulled out of the MULTICS project, and Thompson ported the game to FORTRAN code running on the GECOS operating system of the General Electric GE 635 mainframe computer. Runs on this system cost about $75 per hour, and Thompson looked for a smaller, less expensive computer to use. He found an underused PDP-7, and he and Dennis Ritchie started porting the game to PDP-7 assembly language. In the process of learning to develop software for the machine, the development process of the UNIX operating system began, and Space Travel has been called the first UNIX application.

In 1958 William Higinbotham created a game using an oscilloscope and analog computer. Aptly titled Tennis for Two, it was used to entertain visitors of the Brookhaven National Laboratory in New York. Tennis for Two showed a simplified tennis court from the side, featuring a gravity-controlled ball that needed to be played over the "net," unlike its successors. The game was played with two box-shaped controllers, both equipped with a knob for trajectory, and a button for hitting the ball. Tennis for Two was exhibited for two seasons before its dismantlement in 1959.

1970s

At this time, computer and video game development split to many areas, such as arcade machines, university computers, handhelds, and home computers.

Golden age of video arcade games

In September 1971, the Galaxy Game was installed at a student union at Stanford University. Based on Spacewar!, this was the first coin-operated video game. Only one was built, using a DEC PDP-11/20 and vector display terminals. In 1972 it was expanded to be able to handle four to eight consoles.

Also in 1971, Nolan Bushnell and Ted Dabney created a coin-operated arcade version of Spacewar! and called it Computer Space. Nutting Associates bought the game and manufactured 1,500 Computer Space machines, with the release taking place in November 1971. The game was unsuccessful due to its long learning-curve, but was a landmark, being the first mass-produced video game and the first offered for commercial sale.

Bushnell and Dabney felt they did not receive enough earnings by licensing Computer Space to Nutting Associates. Atari was founded in 1972. The first arcade video game with widespread success was Atari's PONG, released the same year. The game is loosely based on table tennis: a ball is "served" from the center of the court and as the ball moves towards their side of the court each player must manoeuvre their bat to hit the ball back to their opponent. Atari sold 19,000 PONG machines, creating many imitators.

The arcade game industry entered its Golden Age in 1978 with the release of Space Invaders by Taito, a success that inspired dozens of manufacturers to enter the market. In 1979, Atari released Asteroids. Color arcade games became more popular in 1979 and 1980 with the arrival of titles such as Pac-Man. The Golden Age saw a prevalence of arcade machines in malls, traditional storefronts, restaurants and convenience stores.

Dawn of Console Gaming (First Generation)

1972 saw the launch of console based videogames with the original Magnavox Odyssey system in the USA. This had no gaming cartridges, but only a few programmed games in the console. The games featured a plastic sheet overlay, that was placed on the television picture tube and held by static electricity, which would define the gaming space such as a basketball court or tennis court.

Philips bought Magnavox and released a different game in Europe in using the Odyssey brand in 1974 and an evolved game that Magnavox had been developing for the US market. In all the Odyssey system achieved sales of 2 million units.

University mainframe computers

University mainframe game development blossomed in the early 1970s. There is little record of all but the most popular games, as they were not marketed, or regarded as a serious endeavor. The people, generally students, writing these games often were doing so illicitly, making questionable use of very expensive computing resources, and thus were not anxious to let very many people know what they were doing. There were, however, at least two notable distribution paths for the student game designers of this time.

The PLATO system was an educational computing environment designed at the University of Illinois and which ran on mainframes made by Control Data Corporation. Games were often exchanged between different PLATO systems.

DECUS was the user group for computers made by Digital Equipment Corporation (DEC), and distributed programs, including games, that would run on the various types of DEC computers.

A number of noteworthy games were also written for Hewlett Packard minicomputers such as the HP2000.

Highlights of this period, in approximate chronological order, include:

1971: Don Daglow wrote the first computer baseball game on a DEC PDP-10 mainframe at Pomona College. Players could manage individual games or simulate an entire season. Daglow went on to team with programmer Eddie Dombrower to design Earl Weaver Baseball, published by Electronic Arts in 1987.

1971: Star Trek was created, probably by Mike Mayfield on a Sigma 7 minicomputer at MIT. This is the best-known and most widely played of the 1970s Star Trek titles, and was played on a series of small "maps" of galactic sectors printed on paper or on the screen. It was the first major game to be ported across hardware platforms by students. Daglow also wrote a popular Star Trek game for the PDP-10 during 1971–1972, which presented the action as a script spoken by the TV program's characters. A number of other Star Trek themed games were also available via PLATO and DECUS throughout the decade.

1972: Gregory Yob wrote Hunt the Wumpus for the PDP-10, a hide-and-seek game, though it could be considered the first text adventure. Yob wrote it in reaction to existing hide-and-seek games such as Hurkle, Mugwump (game), and Snark.
1974: Both Maze War (on the Imlac PDS-1 at the NASA Ames Research Center in California) and Spasim (on PLATO) appeared, pioneering examples of early multi-player 3D first person shooters.

1974: Brad Fortner and others developed Airfight as an educational flight simulator. To make it more interesting, all players shared an airspace flying their choice of military jets, loaded as desired with weapons, fuel and the desire to shoot down other players. Despite mediocre graphics and slow screen refresh, it became a popular game on the PLATO system. Airfight was the inspiration for what became the Microsoft Flight Simulator.

1975: Will Crowther wrote the first text adventure game as we would recognize it today, Adventure (originally called ADVENT, and later Colossal Cave). It was programmed in Fortran for the PDP-10. The player controls the game through simple sentence-like text commands and receives descriptive text as output. The game was later re-created by students on PLATO, so it is one of the few titles that became part of both the PLATO and PDP-10 traditions.

1975: Before the mid-1970s games typically communicated to the player on paper, using teletype machines or a line printer, at speeds ranging from 10 to 30 characters per second with a rat-a-tat-tat sound as a metal ball or belt with characters was pressed against the paper through an inked ribbon by a hammer. By 1975, many universities had discarded these terminals for CRT screens, which could display thirty lines of text in a few seconds instead of the minute or more that printing on paper required. This led to the development of a series of games that drew "graphics" on the screen.

1975: Daglow, then a student at Claremont Graduate University, wrote the first Computer role playing game on PDP-10 mainframes, Dungeon. The game was an unlicensed implementation of the new role playing game Dungeons & Dragons. Although displayed in text, it was the first game to use line of sight graphics, top-down dungeon maps that showed the areas that the party had seen or could see, allowing for light or darkness, the different vision of elves and dwarves, etc.

1975: At about the same time the RPG dnd, also based on Dungeons and Dragons first appeared on PLATO system CDC computers. For players in these schools dnd, not Dungeon, was the first computer role-playing game.

1977: Kelton Flinn and John Taylor create the first version of Air, a text air combat game that foreshadowed their later work creating the first-ever graphical online multi-player game, Air Warrior. They would found the first successful online game company, Kesmai, now part of Electronic Arts. As Flinn has said: "If Air Warrior was a primate swinging in the trees, AIR was the text-based amoeba crawling on the ocean floor. But it was quasi-real time, multi-player, and attempted to render 3-D on the terminal using ASCII graphics. It was an acquired taste."

1977: The writing of the original Zork was started by Dave Lebling, Marc Blank, Tim Anderson, and Bruce Daniels. Unlike Crowther, Daglow and Yob, the Zork team recognized the potential to move these games to the new personal computers, and they founded text adventure publisher Infocom in 1979. The company was later sold to Activision. In a classic case of "connections", Lebling was a member of the same D&D group as Will Crowther, but not at the same time. Lebling has been quoted as saying "I think I actually replaced him when he dropped out. Zork was 'derived' from Advent in that we played Advent … and tried to do a 'better' one. There was no code borrowed … and we didn’t meet either Crowther or Woods until much later."

1980: Michael Toy, Glenn Wichman and Ken Arnold released Rogue on BSD Unix after two years of work, inspiring many roguelike games ever since. Like Dungeon on the PDP-10 and dnd on PLATO, Rogue displayed dungeon maps using text characters. Unlike those games, however, the dungeon was randomly generated for each play session, so the path to treasure and the enemies who protected it were different for each game. As the Zork team had done, Rogue was adapted for home computers and became a commercial product.

Home computers

While the fruit of development in early video games appeared mainly (for the consumer) in video arcades and home consoles, the rapidly evolving home computers of the 1970s and 80s allowed their owners to program simple games. Hobbyist groups for the new computers soon formed and game software followed.

Soon many of these games (at first clones of mainframe classics such as Star Trek, and then later clones of popular arcade games) were being distributed through a variety of channels, such as printing the game’s source code in books (such as David Ahl’s BASIC Computer Games), magazines (Creative Computing), and newsletters, which allowed users to type in the code for themselves. Early game designers like Crowther, Daglow and Yob would find the computer code for their games—which they had never thought to copyright—published in books and magazines, with their names removed from the listing. Early home computers from Apple, Commodore, Tandy and others had many games that people typed in.

Another distribution channel was the physical mailing and selling of floppy disks, cassette tapes and ROM cartridges. Soon a small cottage industry was formed, with amateur programmers selling disks in plastic bags put on the shelves of local shops, or sent through the mail. Richard Garriott distributed several copies of his 1980 computer role-playing game Akalabeth: World of Doom in plastic bags before the game was published.

1977

In 1977, manufacturers of older obsolete consoles and Pong clones sold their systems at a loss to clear stock, creating a glut in the market and causing Fairchild and RCA to abandon their game consoles. Only Atari and Magnavox stayed in the home console market.

" SECOND GENERATION (1976–1980)"

In the earliest consoles, the computer code for one or more games was hardcoded into microchips using discrete logic, and no additional games could ever be added. By the mid-1970s video games were found on cartridges. Programs were burned onto ROM chips that were mounted inside plastic cartridge casings that could be plugged into slots on the console. When the cartridges were plugged in, the general-purpose microprocessors in the consoles read the cartridge memory and ran whatever program was stored there. Rather than being confined to a small selection of games included in the box, consumers could now amass libraries of game cartridges. The first of these consoles to use the ROM cartridge format was the Fairchild 'Video Entertainment System (VES), released in 1976.

Three machines dominated the second generation of consoles in North America, far outselling their rivals:

In 1977, Atari released its ROM cartridge based console called the Video Computer System (VCS), later called Atari 2600. Nine games were designed and released for the holiday season. It would quickly become by far the most popular of all the early consoles.
Intellivision, introduced by Mattel in 1980. Though chronologically part of what is called the "8-bit era", the Intellivision had a unique processor with instructions that were 10 bits wide (allowing more instruction variety and potential speed), and registers 16 bits wide. The system, which featured graphics superior to the older Atari 2600, rocketed to popularity.
ColecoVision, an even more powerful machine, appeared in 1982. Its sales also took off, but the presence of three major consoles in the marketplace and a glut of poor quality games began to overcrowd retail shelves and erode consumers' interest in video games. Within a year this overcrowded market would crash.
In 1979, Activision was created by disgruntled former Atari programmers. It was the first third-party developer of video games.

1980s

In the early 1980s, the computer gaming industry experienced its first major growing pains. Publishing houses appeared, with many honest businesses (and in rare cases such as Electronic Arts, successfully surviving to this day) alongside fly-by-night operations that cheated the games' developers. While some early 80s games were simple clones of existing arcade titles, the relatively low publishing costs for personal computer games allowed for many bold, unique games, a legacy that continues to this day. The primary gaming computers of the 1980s emerged in 1982: the Commodore 64, Apple II (although the Apple II started in 1977) and Sinclair ZX Spectrum. The ZX Spectrum was mostly used and known only in the UK, whilst the USA had the Apple II, Commodore 64, and Atari 800. Over the run of 15 years, the Apple II had a total of almost 20,000 programs, making it the 8-bit computer with the most software overall.

The Golden Age of Arcade Games reached its full steam in the 1980s, with many technically innovative and genre-defining games in the first few years of the decade. Defender (1980) established the scrolling shooter and was the first to have events taking place outside the player’s view, displayed by a radar view showing a map of the whole playfield. Battlezone (1980) used wireframe vector graphics to create the first true three-dimensional game world. 3D Monster Maze (1981) was the first 3D game for a home computer, while Dungeons of Daggorath (1982) added various weapons and monsters, sophisticated sound effects, and a "heartbeat" health monitor. Pole Position (1982) used sprite-based, pseudo-3D graphics when it pioneered the "rear-view racer format" where the player’s view is behind and above the vehicle, looking forward along the road with the horizon in sight. The style would remain in wide use even after true 3D graphics became standard for racing games. Pac-Man (1980) was the first game to achieve widespread popularity in mainstream culture and the first game character to be popular in his own right. Dragon's Lair (1983) was the first laserdisc game, and introduced full-motion video to video games. Journey Escape, a videogame developed by Data Age for the Atari 2600 console, and released in 1982, stars the rock band Journey, one of the world's most popular acts at the time, and is based on their album of the same name.

With Adventure establishing the genre, the release of Zork in 1980 further popularized text adventure games in home computers and established developer Infocom’s dominance in the field. As these early computers often lacked graphical capabilities, text adventures proved successful. When affordable computers started catching up to and surpassing the graphics of consoles in the late 1980s, the pure text adventure's popularity waned in favor of graphic adventures and other genres. The text adventure would eventually be known as interactive fiction and a small dedicated following has kept the genre going, with new releases being nearly all free.

Also published in 1980 was Roberta Williams' Mystery House, for the Apple II. It was the first graphic adventure on home computers. Graphics consisted entirely of static monochrome drawings, and the interface still used the typed commands of text adventures. It proved very popular at the time, and she and husband Ken went on to found Sierra On-Line, a major producer of adventure games. Mystery House remains largely forgotten today.

In August 1982, the Commodore 64 was released to the public. It found initial success because it was marketed and priced aggressively. It had a BASIC programming environment and advanced graphic and sound capabilities for its time, similar to the ColecoVision console. It also utilized the same game controller ports popularized by the Atari 2600, allowing gamers to use their old joysticks with the system. It would become the most popular home computer of its day in the USA and many other countries and the best-selling single computer model of all time internationally.

At around the same time, the Sinclair ZX Spectrum was released in the United Kingdom and quickly became the most popular home computer in many areas of Western Europe, and later the Eastern bloc due to the ease with which clones could be produced.

SuperSet Software created Snipes, a text-mode networked computer game in 1983 to test a new IBM Personal Computer based computer network and demonstrate its capabilities. Snipes is officially credited as being the original inspiration for Novell NetWare. It is believed to be the first network game ever written for a commercial personal computer and is recognized alongside 1974’s Maze War (a networked multiplayer maze game for several research machines) and Spasim (a 3D multiplayer space simulation for time shared mainframes) as the precursor to multiplayer games such as 1987's MIDI Maze, and Doom in 1993.

The true modern adventure game would be born with the Sierra King's Quest series in 1984. It featured color graphics and a third person perspective. An on-screen player-controlled character could be moved behind and in front of objects on a 2D background drawn in perspective, creating the illusion of pseudo-3D space. Commands were still entered via text. LucasArts would do away with this last vestige feature of text adventures when its 1987 adventure Maniac Mansion built with its SCUMM system allowed a point-and-click interface. Sierra and other game companies quickly followed with their own mouse-driven games.

With Elite in 1984, David Braben and Ian Bell ushered in the age of modern style 3D graphics, creating a game with convincing vector worlds, full 6 degree freedom of movement, and thousands of visitable planetary systems. Initially only available for the BBC Micro and Acorn Electron, the success of this title caused it eventually to be ported to all popular formats, including the Commodore 64, Sinclair ZX Spectrum, Commodore Amiga, Atari ST and even the Nintendo Entertainment System, although this version only received a European release.

The IBM PC compatible computer became a technically competitive gaming platform with IBM’s PC/AT in 1984. The new 16-color EGA display standard allowed its graphics to approach the quality seen in popular home computers like the Commodore 64. The primitive 4-color CGA graphics of previous models had limited the PC’s appeal to the business segment, since its graphics failed to compete with the C64 or Apple II. The sound capabilities of the AT, however, were still limited to the PC speaker, which was substandard compared to the built-in sound chips used in many home computers. Also, the relatively high cost of the PC compatible systems severely limited their popularity in gaming.

The Apple Macintosh also arrived at this time. It lacked the color capabilities of the earlier Apple II, instead preferring a much higher pixel resolution, but the operating system support for the GUI attracted developers of some interesting games (e.g. Lode Runner) even before color returned in 1987 with the Mac II.

In computer gaming, the later 1980s are primarily the story of the United Kingdom’s rise to prominence. The market in the UK was primely positioned for this task: personal computer users were offered a smooth scale of power versus price, from the Sinclair ZX Spectrum up to the Amiga; developers and publishers were in close enough proximity to offer each other support; and the NES made much less of an impact than it did in the United States, due to the enormous popularity of personal computers there, even though it outsold all the other home consoles (such as the Sega Master System)

The arrival of the Atari ST and Commodore Amiga in 1985 was the beginning of a new era of 16-bit machines. For many users they were too expensive until later on in the decade, at which point advances in the IBM PC’s open platform had caused the IBM PC compatibles to become comparably powerful at a lower cost than their competitors. The VGA standard developed for IBM’s new PS/2 line in 1987 gave the PC the potential for 256-color graphics. This was a big jump ahead of most 8-bit home computers but still lagging behind platforms with built-in sound and graphics hardware like the Amiga, causing an odd trend around '89-91 towards developing to a seemingly inferior machine. Thus while both the ST and Amiga were host to many technically excellent games, their time of prominence proved to be shorter than that of the 8-bit machines, which saw new ports well into the 80s and even the 90s.

Dedicated sound cards started to address the issue of poor sound capabilities in IBM PC compatibles in the late 1980s. AdLib set an early de facto standard for sound cards in 1987, with its card based on the Yamaha YM3812 sound chip. This would last until the introduction of Creative Labs' Sound Blaster in 1989, which took the chip and added new features while remaining compatible with AdLib cards, and creating a new de facto standard. However, many games would still support these and rarer things like the Roland MT-32 and Disney Sound Source into the early 90s. The initial high cost of sound cards meant they would not find widespread use until the 1990s.

Shareware gaming first appeared in the mid 1980s, but its big successes came in the 1990s.

Early online gaming

Dialup bulletin board systems were popular in the 1980s, and sometimes used for online game playing. The earliest such systems, in the late 1970s and early 1980s, had a crude plain-text interface, but later systems made use of terminal-control codes (the so-called ANSI art, which included the use of IBM-PC-specific characters not actually part of an ANSI standard) to get a pseudo-graphical interface. Some BBSes offered access to various games which were playable through such an interface, ranging from text adventures to gambling games like blackjack (generally played for "points" rather than real money). On multiuser BBSs (where more than one person could be online at once), there were sometimes games allowing the different users to interact with one another; some such games of the fantasy role-playing variety were known as MUDs, for "multi-user dungeons". These games eventually evolved into what are known today as MMORPG.

Commercial online services also arose during this decade, starting with a plain-text interface similar to BBSs (but operated on large mainframe computers permitting larger numbers of users to be online at once), and moving by the end of the decade to fully-graphical environments using software specific to each personal computer platform. Popular text-based services included CompuServe, The Source, and GEnie, while platform-specific graphical services included PlayNET and Quantum Link for the Commodore 64, AppleLink for the Apple II and Macintosh, and PC Link for the IBM PC, all of which were run by the company which eventually became America Online; and a competing service, Prodigy. Interactive games were a feature of these services, though until 1987 they used text-based displays, not graphics.

Handheld LCD games

Nintendo's Game & Watch line began in 1980. The success of these LCD handhelds spurred dozens of other game and toy companies to make their own portable games, many being copies of Game & Watch titles or adaptations of popular arcade games. Improving LCD technology meant the new handhelds could be more reliable and consume less batteries than LED or VFD games, most only needing watch batteries. They could also be made much smaller than most LED handhelds, even small enough to wear on one’s wrist like a watch. Tiger Electronics borrowed this concept of videogaming with cheap, affordable handhelds and still produces games in this model to the present day.

Video game crash of 1983

At the end of 1983, the industry experienced losses more severe than the 1977 crash. This was the "crash" of the video game industry, as well as the bankruptcy of several companies that produced North American home computers and video game consoles from late 1983 to early 1984. It brought an end to what is considered to be the second generation of console video gaming. Causes of the crash include the production of poorly designed games such as E.T. the Extra-Terrestrial and Pac-Man for the Atari 2600 that suffered due to extremely tight deadlines. It was discovered that more Pac-Man cartridges were manufactured than there were systems made. In addition, so many E.T. the Extra-Terrestrial cartridges were left unsold that Atari allegedly buried thousands of cartridges in a landfill in New Mexico.

" THIRD GENERATION(1984–1994) "

In 1984, the computer gaming market took over from the console market following the crash of that year; computers offered equal gaming ability and since their simple design allowed games to take complete command of the hardware after power-on, they were nearly as simple to start playing with as consoles.

In 1985, the North American video game console market was revived with Nintendo’s release of its 8-bit console, the Famicom, known outside Asia as Nintendo Entertainment System (NES). It was bundled with Super Mario Bros. and instantly became a success. The NES dominated the North American and the Japanese market until the rise of the next generation of consoles in the early 1990s. Other markets were not as heavily dominated, allowing other consoles to find an audience like the Sega Master System in Europe, Australia and Brazil (though it was sold in North America as well).

In the new consoles, the gamepad took over joysticks, paddles, and keypads as the default game controller included with the system. The gamepad design of an 8 direction Directional-pad (or D-pad for short) with 2 or more action buttons became the standard.

The Legend of Zelda series made its debut in 1986 with The Legend of Zelda. Around the same time, the Dragon Quest series debuted with Dragon Quest (1986), and has created a phenomenon in Japanese culture ever since. Shortly thereafter, the Japanese company Square was struggling and Hironobu Sakaguchi decided to make his final game, titled Final Fantasy (1987), a role-playing game (RPG) modeled after Dragon Quest, and the Final Fantasy series was born as a result. Final Fantasy would later go on to become the most successful RPG franchise. Hideo Kojima’s Metal Gear series also made its debut with the release of Metal Gear (1987) on the MSX2 computer, giving birth to the stealth game genre. Metal Gear was ported to the NES shortly after. In 1989, Capcom released Sweet Home (1989) on the NES, which served as a precursor to the survival horror genre.

In 1988, Nintendo published their first issue of Nintendo Power magazine.

1990s

The video game industry matured into a mainstream form of entertainment in the 1990s. Major developments of the 1990s included the beginning of a larger consolidation of publishers, higher budget games, increased size of production teams and collaborations with both the music and motion picture industries. Examples of this would be Mark Hamill's involvement with Wing Commander III or Quincy Jones' introduction of QSound.

The increasing computing power and decreasing cost of processors as the Intel 80386, Intel 80486, and the Motorola 68030, caused the rise of 3D graphics, as well as "multimedia" capabilities through sound cards and CD-ROMs. Early 3D games began with flat-shaded graphics (Elite, Starglider 2 or Alpha Waves[10] ), and then simple forms of texture mapping (Wolfenstein 3D).

In the early 1990s, shareware distribution was a popular method of publishing games for smaller developers, including then-fledgling companies such as Apogee (now 3D Realms), Epic Megagames (now Epic Games), and id Software. It gave consumers the chance to try a trial portion of the game, usually restricted to the game’s complete first section or "episode", before purchasing the rest of the adventure. Racks of games on single 5 1/4" and later 3.5" floppy disks were common in many stores, often only costing a few dollars each. Since the shareware versions were essentially free, the cost only needed to cover the disk and minimal packaging. As the increasing size of games in the mid-90s made them impractical to fit on floppies, and retail publishers and developers began to earnestly mimic the practice, shareware games were replaced by shorter demos (often only one or two levels), distributed free on CDs with gaming magazines and over the Internet.

In 1992 the game Dune II was released. It was by no means the first in the genre (several other games can be called the very first real-time strategy game, see the History of RTS), but it set the standard game mechanics for later blockbuster RTS games such as Warcraft: Orcs & Humans, Command & Conquer, and StarCraft. The RTS is characterized by an overhead view, a "mini-map", and the control of both the economic and military aspects of an army. The rivalry between the two styles of RTS play—Warcraft style, which used GUIs accessed once a building was selected, and C&C style, which allowed construction of any unit from within a permanently visible menu—continued into the start of the next millennium.

Alone in the Dark (1992), while not the first survival horror game, planted the seeds of what would become known as the survival horror genre today. It established the formula that would later flourish on CD-ROM based consoles, with games such as Resident Evil and Silent Hill.

Adventure games continued to evolve, with Sierra Entertainment’s King's Quest series, and LucasFilms'/LucasArts' Monkey Island series bringing graphical interaction and the creation of the concept of "point-and-click" gaming. Myst and its sequels inspired a new style of puzzle-based adventure games. Published in 1993, Myst itself was one of the first computer games to make full use of the new high-capacity CD-ROM storage format. Despite Myst’s mainstream success, the increased popularity of action-based and real-time games led adventure games and simulation video games, both mainstays of computer games in earlier decades, to begin to fade into obscurity.

It was in the 1990s that Maxis began publishing its successful line of "Sim" games, beginning with SimCity, and continuing with a variety of titles, such as SimEarth, SimCity 2000, SimAnt, SimTower, and the best-selling PC game in history, The Sims, in early 2000.

In 1996, 3dfx Interactive released the Voodoo chipset, leading to the first affordable 3D accelerator cards for personal computers. These devoted 3D rendering daughter cards performed a portion of the computations required for more-detailed three-dimensional graphics (mainly texture filtering), allowing for more-detailed graphics than would be possible if the CPU were required to handle both game logic and all the graphical tasks. First-person shooter games (notably Quake) were among the first to take advantage of this new technology. While other games would also make use of it, the FPS would become the chief driving force behind the development of new 3D hardware, as well as the yardstick by which its performance would be measured, usually quantified as the number of frames per second rendered for a particular scene in a particular game.

Several other, less-mainstream, genres were created in this decade. Looking Glass Studios' Thief: The Dark Project and its sequel were the first to coin the term "first person sneaker", although it is questionable whether they are the first "first person stealth" games. Turn-based strategy progressed further, with the Heroes of Might and Magic (HOMM) series (from The 3DO Company) luring many mainstream gamers into this complex genre.

The first true MUDs (Multi-User Dungeons) were developed in the early 90s. Id Software’s 1996 game Quake pioneered play over the Internet in first-person shooters. Internet multiplayer capability became a de facto requirement in almost all FPS games. Other genres also began to offer online play, including RTS games like Microsoft Game Studios’ Age of Empires, Blizzard’s Warcraft and StarCraft series, and turn-based games such as Heroes of Might and Magic. MMORPGs (Massively multiplayer online role-playing game), such as Ultima Online and EverQuest freed users from the limited number of simultaneous players in other games and brought the MUD concept of persistent worlds to graphical multiplayer games. Developments in web browser plug-ins like Java and Adobe Flash allowed for simple browser-based games. These are small single player or multiplayer games that can be quickly downloaded and played from within a web browser without installation. Their most popular use is for puzzle games, side-scrollers, classic arcade games, and multiplayer card and board games.

Few new genres have been created since the advent of the FPS and RTS, with the possible exception of the third-person shooter. Games such as Grand Theft Auto III, Tom Clancy's Splinter Cell, Enter the Matrix, and Hitman all use a third-person camera perspective, but are otherwise very similar to their first-person counterparts.

Decline of arcades

With the advent of 16-bit and 32-bit consoles, home video games began to approach the level of graphics seen in arcade games. An increasing number of players would wait for popular arcade games to be ported to consoles rather than going out. Arcades experienced a resurgence in the early to mid 1990s with games such as Street Fighter II and Mortal Kombat and other games in the one-on-one fighting game genre, and NBA Jam. As patronage of arcades declined, many were forced to close down. Classic coin-operated games have largely become the province of dedicated hobbyists and as a tertiary attraction for some businesses, such as movie theaters, batting cages, miniature golf, and arcades attached to game stores such as F.Y.E..

The gap left by the old corner arcades was partly filled by large amusement centers dedicated to providing clean, safe environments and expensive game control systems not available to home users. These are usually based on sports like skiing or cycling, as well as rhythm games like Dance Dance Revolution, which have carved out a large slice of the market. Dave & Buster's and GameWorks are two large chains in the United States with this type of environment. Aimed at adults, they feature full service restaurants with full liquor bars and have a wide variety of video game and hands on electronic gaming options. Chuck E. Cheese's is a similar type of establishment focused towards children.

Handhelds come of age

In 1989, Nintendo released the Game Boy, the first handheld console since the ill-fated Microvision ten years before. The design team headed by Gunpei Yokoi had also been responsible for the Game & Watch systems. Included with the system was Tetris, a popular puzzle game. Several rival handhelds also made their debut around that time, including the Sega Game Gear and Atari Lynx (the first handheld with color LCD display). Although most other systems were more technologically advanced, they were hampered by higher battery consumption and less third-party developer support. While some of the other systems remained in production until the mid-90s, the Game Boy remained at the top spot in sales throughout its lifespan.

Mobile phone gaming

Mobile phones became videogaming platforms when Nokia installed Snake onto its line of mobile phones in 1998. Soon every major phone brand offered "time killer games" that could be played in very short moments such as waiting for a bus. Mobile phone games early on were limited by the modest size of the phone screens that were all monochrome and the very limited amount of memory and processing power on phones, as well as the drain on the battery.

" FOURTH GENERATION (1989–1997) "

The Sega Mega Drive (known in North America as the Sega Genesis) proved its worth early on after its debut in 1989. Nintendo responded with its own next generation system known as the Super NES in 1991. The TurboGrafx-16 debuted early on alongside the Genesis, but did not achieve a large following in the U.S. due to a limited library of games and excessive distribution restrictions imposed by Hudson.

The intense competition of this time was also a period of not entirely truthful marketing. The TurboGrafx-16 was billed as the first 16-bit system but its central processor was an 8-bit HuC6280, with only its HuC6260 graphics processor being a true 16-bit chip. Additionally, the much earlier Mattel Intellivision contained a 16-bit processor. Sega, too, was known to stretch the truth in its marketing approach; they used the term "Blast Processing" to describe the simple fact that their console's CPU ran at a higher clock speed than that of the SNES (7.67 MHz vs 3.58 MHz).

In Japan, the 1987 success of the PC Engine (as the TurboGrafx-16 was known there) against the Famicom and CD drive peripheral allowed it to fend off the Mega Drive (Genesis) in 1988, which never really caught on to the same degree as outside Japan. The PC Engine eventually lost out to the Super Famicom, but, due to its popular CD add-ons, retained enough of a user base to support new games well into the late 1990s.

CD-ROM drives were first seen in this generation, as add-ons for the PC Engine in 1988 and the Mega Drive in 1991. Basic 3D graphics entered the mainstream with flat-shaded polygons enabled by additional processors in game cartridges like Virtua Racing and Star Fox.

SNK's Neo-Geo was the most expensive console by a wide margin when it was released in 1990, and would remain so for years. It was also capable of 2D graphics in a quality level years ahead of other consoles. The reason for this was that it contained the same hardware that was found in SNK's arcade games. This was the first time since the home Pong machines that a true-to-the-arcade experience could be had at home.

" FIFTH GENERATION (1994–2002) "

In 1993, Atari re-entered the home console market with the introduction of the Atari Jaguar. Also in 1993, The 3DO Company released the 3DO Interactive Multiplayer, which, though highly advertised and promoted, failed to catch up to the sales of the Jaguar, due its high pricetag. Both consoles had very low sales and few quality games, eventually leading to their demise. In 1994, three new consoles were released in Japan: the Sega Saturn, the PlayStation, and the PC-FX, the Saturn and the PlayStation later seeing release in North America in 1995. The PlayStation quickly outsold all of its competitors, with the exception of the aging Super Nintendo Entertainment System, which still had the support of many major game companies.

After many delays, Nintendo released its 64-bit console, the Nintendo 64 in 1996. The flagship title, Super Mario 64, became a defining title for 3D platformer games.

PaRappa the Rapper popularized rhythm, or music video games in Japan with its 1996 debut on the PlayStation. Subsequent music and dance games like beatmania and Dance Dance Revolution became ubiquitous attractions in Japanese arcades. While Parappa, DDR, and other games found a cult following when brought to North America, music games would not gain a wide audience in the market until the next decade.

Other milestone games of the era include Rare's Nintendo 64 title GoldenEye 007 (1997), which was critically acclaimed for bringing innovation as being the first major first-person shooter that was exclusive to a console, and for pioneering certain features that became staples of the genre, such as scopes, headshots, and objective-based missions.[citation needed] The Legend of Zelda: Ocarina of Time (1998), Nintendo's 3D debut for the The Legend of Zelda adventure game series featured innovations such as Z-targeting, used in later games of similar genres.

Nintendo's choice to use cartridges instead of CD-ROMs for the Nintendo 64, unique among the consoles of this period, proved to have negative consequences. While cartridges were faster and combated piracy, CDs could hold far more data and were much cheaper to produce, causing many game companies to turn to Nintendo's CD-based competitors. In particular, SquareSoft, which had released all previous games in its Final Fantasy series for Nintendo consoles, now turned to the PlayStation; Final Fantasy VII (1997) was a huge success, establishing the popularity of role-playing games in the west and making the PlayStation the primary console for the genre.

By the end of this period, Sony had become the leader in the video game market. The Saturn was moderately successful in Japan but a failure in North America and Europe, leaving Sega outside of the main competition. The N64 achieved huge success in North America and Europe, though it never surpassed PlayStation's sales. The N64 was also successful in Japan, even though it failed to repeat the tremendous success of the Famicom and Super Famicom there due to stiff competition by PlayStation.

" SIXTH GENERATION (1998–2008) "

In the sixth generation of video game consoles, Sega exited the hardware market, Nintendo fell behind, Sony solidified its lead in the industry, and Microsoft developed a gaming console.

The Dreamcast, introduced in 1998, opened the generation but failed to become a hit, and faded from the market before the subsequent consoles appeared. Sega retreated to the third-party game market. Sony opened the new decade with the PlayStation 2, which would go on to become the top-selling sixth generation console. Nintendo followed a year later with the GameCube, their first disc-based console. Though more or less equal with Sony's system in technical specifications, the GameCube suffered from a lack of third-party games compared to Sony's system, and was hindered by a reputation for being a "kid's console" and lacking the mature games the current market appeared to want.

Before the end of 2001, Microsoft Corporation, best known for its Windows operating system and its professional productivity software, judged the console market profitable for entry with the decline of Sega and Nintendo, and introduced the Xbox. Based on Intel's Pentium III CPU, the console used much PC technology to leverage its internal development. In order to maintain its hold in the market, Microsoft reportedly sold the Xbox at a significant loss[11]and concentrated on drawing profit from game development and publishing. Shortly after its release in November 2001 Bungie Studio's Halo: Combat Evolved instantly became the driving point of the Xbox's success, and the Halo Series would later go on to become one of the most successful console shooters of all time. By the end of the generation, the Xbox had drawn even with the GameCube in sales globally, but since nearly all of its sales were in North America, it pushed Nintendo into third place in the American market.

Nintendo still dominated the handheld gaming market in this generation. The Game Boy Color, in 1998, and then the Game Boy Advance in 2001, maintained Nintendo's market position. Finnish cellphone maker Nokia entered the handheld scene with the N-Gage, but it failed to win a significant following.

Online gaming rises to prominence

As affordable broadband Internet connectivity spread, many publishers turned to online gaming as a way of innovating. Massively multiplayer online role-playing game (MMORPGs) featured significant titles for the PC market like World of Warcraft and Ultima Online. Historically, console based MMORPGs have been few in number due to the lack of bundled Internet connectivity options for the platforms. This made it hard to establish a large enough subscription community to justify the development costs. The first significant console MMORPGs were Phantasy Star Online on the Sega Dreamcast (which had a built in modem and after market Ethernet adapter), followed by Final Fantasy XI for the Sony PlayStation 2 (an aftermarket Ethernet adapter was shipped to support this game). Every major platform released since the Dreamcast has ether been bundled with the ability to support an Internet connection or has had the option available as an aftermarket add-on.

Rise of casual PC games

Beginning with PCs, a new trend in casual gaming, games with limited complexity that were designed for shortened or impromptu play sessions, began to draw attention from the industry. Many were puzzle games, such as Popcap's Bejeweled and Diner Dash, while others were games with a more relaxed pace and open-ended play. The biggest hit was The Sims by Maxis, which went on to become the best selling computer game of all time, surpassing Myst.

Console gaming largely continued the trend established by the PlayStation toward increasingly complex, sophisticated, and adult-oriented gameplay. Most of the successful sixth-generation console games were games rated T and M by the ESRB, including many now-classic gaming franchises such as Halo, Resident Evil, and Grand Theft Auto, the latter of which was notable for both its success and its notoriety. Even Nintendo, widely known for its aversion to adult content (with very few exceptions most notably Conker's Bad Fur Day for the Nintendo 64), published its first M-rated game, Silicon Knights's Eternal Darkness: Sanity's Requiem, and the GameCube was the temporary exclusive platform for Capcom's Resident Evil 4. This trend in hardcore console gaming would partially be reversed with the 7th generation release of the Wii.

" SEVENTH GENERATION ( 2004 TO PRESENT) "

A major rift opened in console gaming philosophy and design in the seventh generation, with some calling the identification of video game "generations" questionable and arbitrary, while PC gaming began to go into relative decline as major publishers steered their efforts to consoles.

The generation opened early for handheld consoles, as Nintendo introduced their Nintendo DS and Sony premiered the PlayStation Portable (PSP) within a month of each other in 2004. While the PSP boasted superior graphics and power, following a trend established since the mid 1980s, Nintendo gambled on a lower-power design but featuring a novel control interface. The DS's two screens, one of which was touch-sensitive, proved extremely popular with consumers, especially young kids and middle-aged gamers, who were drawn to the device by Nintendo's Nintendogs and Brain Age series, respectively. While the PSP attracted a significant portion of veteran gamers, the DS allowed Nintendo to continue its dominance in handheld gaming. Nintendo updated their line with the Nintendo DS Lite in 2006, and the Nintendo DSi in 2008 (Japan) and 2009 (Americas and Europe), while Sony updated the PSP in 2007. Nokia withdrew their N-Gage platform in 2004 but reintroduced it in late 2008. Now with the release of the Apple Inc. iPhone and iPod Touch, 3D gaming is more portable than ever and offers a range of new sensors, including but not limited to, the accelerometer.

In console gaming, Microsoft stepped forward first in November 2005 with the Xbox 360, and Sony followed in 2006 with the PlayStation 3, released in Europe in March 2007. Setting the technology standard for the generation, both featured high-definition graphics, large hard disk-based secondary storage, integrated networking, and a companion on-line gameplay and sales platform, with Xbox Live and the PlayStation Network, respectively. Both were formidable systems that were the first to challenge personal computers in power while offering a relatively modest price compared to them. While both were more expensive than most past consoles, the Xbox 360 enjoyed a substantial price edge, selling for either $300 or $400 depending on model, while the PS3 launched with models priced at $500 and $600. The top-of-the-line PS3 was the most expensive game console on the market since Panasonic's version of the 3DO, which was around $700.

Nintendo was not expected to compete credibly at all, with most industry analysts predicting a distant third place finish for its new Revolution console, later renamed Wii, introduced a couple days after the PS3, and one even going so far as to predict a market exit similar to Sega. Instead, Nintendo pulled off an industry turnaround in business. While the Wii's power was greater than that of last generation's consoles, it was clearly behind Microsoft and Sonys' consoles, and Nintendo themselves refused to publish or confirm technical specifications, instead touting the console's new control scheme, featuring motion-based control and infrared-based pointing. Many gamers, publishers, and analysts dismissed the Wii as an underpowered curiosity, but were surprised as the console sold out through the 2006 Christmas season, and remained so through the next 18 months, becoming the fastest selling game console in most of the world's gaming markets.

Increases in development budgets

With high definition video an undeniable hit with veteran gamers seeking immersive experiences, expectations for visuals in games along with the increasing complexity of productions resulted in a spike in the development budgets of gaming companies. While many game studios saw their Xbox 360 projects pay off, the unexpected weakness of PS3 sales resulted in heavy losses for some developers, and many publishers broke previously arranged PS3 exclusivity arrangements or cancelled PS3 game projects entirely in order to cut losses.

Nintendo capitalizes on casual gaming

Meanwhile, Nintendo took cues from PC gaming and their own success with the Nintendo Wii, and crafted games that capitalized on the intuitive nature of motion control. Emphasis on gameplay turned comparatively simple games into unlikely runaway hits, including the bundled game, Wii Sports, and Wii Fit. As the Wii sales spiked, many publishers were caught unprepared and responded by assembling hastily-created titles to fill the void. Although some hardcore games continued to be produced by Nintendo, many of their classic franchises were reworked into "bridge games", meant to provide new gamers crossover experiences from casual gaming to deeper experiences, including their flagship Wii title, Super Mario Galaxy, which in spite of its standard-resolution graphics dominated critics' "best-of" lists for 2007. Many others, however, strongly criticized Nintendo for its apparent spurning of its core gamer base in favor of a demographic many warned would be fickle and difficult to keep engaged.

Motion controls revolutionize game control

The way gamers interact with games changed dramatically, especially with Nintendo's wholesale embrace of motion control as a standard method of interaction. The Wii Remote implemented the principles well enough to be a worldwide success, but Sony also experimented with motion in its Sixaxis and subsequently DualShock3 controller for the PS3, and Microsoft continually mentions interest in developing the technology for the Xbox 360. While the Wii's infrared-based pointing system has been praised widely, and cited as a primary reason for the success of games such as Nintendo's Metroid Prime 3: Corruption and EA's Medal of Honor: Heroes 2, reliable motion controls have been more elusive. Even the most refined motion controls fail to achieve 1-to-1 reproduction of player motion on-screen. Nintendo's 2008 announcement of its MotionPlus module was intended to address critics' concerns.

Alternate controllers are also continuing to be important in gaming, as the increasingly involved controllers associated with Red Octane's Guitar Hero series and Harmonix's Rock Band demonstrate. Nintendo has produced a some add-on attachments meant to adapt the Wii Remote to specific games, such as the Wii Zapper for shooting games and the Wii Wheel for driving games. They also extended control capabilities to players' feet with the introduction of the Balance Board with Wii Fit, with third party titles from THQ, EA, and others that will integrate foot control coming in late 2008 and early 2009.

13) HISTORY OF THE " WORLD WIDE WEB"

2009-05-30T14:17:00.000-07:00

by engr. AFAN BK

The World Wide Web ("WWW" or simply the "Web") is a global information medium which users can read and write via computers connected to the Internet. The term is often mistakenly used as a synonym for the Internet itself, but the Web is a service that operates over the Internet, as e-mail does. The history of the Internet dates back significantly further than that of the World Wide Web.

The hypertext portion of the Web in particular has an intricate intellectual history; notable influences and precursors include Vannevar Bush's Memex, IBM's Generalized Markup Language, and Ted Nelson's Project Xanadu.

Today, the Web and the Internet allow connectivity from literally everywhere on earth—even ships at sea and in outer space

The concept of a home-based global information system goes at least as far back as "A Logic Named Joe", a 1946 short story by Murray Leinster, in which computer terminals, called "logics," were in every home. Although the computer system in the story is centralized, the story captures some of the feeling of the ubiquitous information explosion driven by the Web.

1980-91: Development of the World Wide Web

In 1980, the Englishman Tim Berners-Lee, an independent contractor at the European Organization for Nuclear Research (CERN), Switzerland, built ENQUIRE, as a personal database of people and software models, but also as a way to play with hypertext; each new page of information in ENQUIRE had to be linked to an existing page.

In 1984 Berners-Lee returned to CERN, and considered its problems of information presentation: physicists from around the world needed to share data, with no common machines and no common presentation software. He wrote a proposal in March 1989 for "a large hypertext database with typed links", but it generated little interest. His boss, Mike Sendall, encouraged Berners-Lee to begin implementing his system on a newly acquired NeXT workstation. He considered several names, including Information Mesh, The Information Mine (turned down as it abbreviates to TIM, the WWW's creator's name) or Mine of Information (turned down because it abbreviates to MOI which is "Me" in French), but settled on World Wide Web.

He found an enthusiastic collaborator in Robert Cailliau, who rewrote the proposal (published on November 12, 1990) and sought resources within CERN. Berners-Lee and Cailliau pitched their ideas to the European Conference on Hypertext Technology in September 1990, but found no vendors who could appreciate their vision of marrying hypertext with the Internet.

By Christmas 1990, Berners-Lee had built all the tools necessary for a working Web: the HyperText Transfer Protocol (HTTP) 0.9, the HyperText Markup Language (HTML), the first Web browser (named WorldWideWeb, which was also a Web editor), the first HTTP server software (later known as CERN httpd), the first web server (http://info.cern.ch), and the first Web pages that described the project itself. The browser could access Usenet newsgroups and FTP files as well. However, it could run only on the NeXT; Nicola Pellow therefore created a simple text browser that could run on almost any computer. To encourage use within CERN, they put the CERN telephone directory on the web — previously users had had to log onto the mainframe in order to look up phone numbers.

Paul Kunz from the Stanford Linear Accelerator Center visited CERN in May 1991, and was captivated by the Web. He brought the NeXT software back to SLAC, where librarian Louise Addis adapted it for the VM/CMS operating system on the IBM mainframe as a way to display SLAC’s catalog of online documents; this was the first web server outside of Europe and the first in North America.

On August 6, 1991, Berners-Lee posted a short summary of the World Wide Web project on the alt.hypertext newsgroup. This date also marked the debut of the Web as a publicly available service on the Internet.

The WorldWideWeb (WWW) project aims to allow all links to be made to any information anywhere. The WWW project was started to allow high energy physicists to share data, news, and documentation. We are very interested in spreading the web to other areas, and having gateway servers for other data. Collaborators welcome!" —from Tim Berners-Lee's first message

An early CERN-related contribution to the Web was the parody band Les Horribles Cernettes, whose promotional image is believed to be among the Web's first five pictures.

1992-1995: Growth of the WWW

In keeping with its birth at CERN, early adopters of the World Wide Web were primarily university-based scientific departments or physics laboratories such as Fermilab and SLAC.

Early websites intermingled links for both the HTTP web protocol and the then-popular Gopher protocol, which provided access to content through hypertext menus presented as a file system rather than through HTML files. Early Web users would navigate either by bookmarking popular directory pages, such as Berners-Lee's first site at http://info.cern.ch/, or by consulting updated lists such as the NCSA "What's New" page. Some sites were also indexed by WAIS, enabling users to submit full-text searches similar to the capability later provided by search engines.

There was still no graphical browser available for computers besides the NeXT. This gap was filled in April 1992 with the release of Erwise, an application developed at Helsinki University of Technology, and in May by ViolaWWW, created by Pei-Yuan Wei, which included advanced features such as embedded graphics, scripting, and animation. Both programs ran on the X Window System for Unix.

Students at the University of Kansas adapted an existing text-only hypertext browser, Lynx, to access the web. Lynx was available on Unix and DOS, and some web designers, unimpressed with glossy graphical websites, held that a website not accessible through Lynx wasn’t worth visiting.

Early Browsers

The turning point for the World Wide Web was the introduction of the Mosaic web browser in 1993, a graphical browser developed by a team at the National Center for Supercomputing Applications (NCSA) at the University of Illinois at Urbana-Champaign (UIUC), led by Marc Andreessen. Funding for Mosaic came from the High-Performance Computing and Communications Initiative, a funding program initiated by then-Senator Al Gore's High Performance Computing and Communication Act of 1991 also known as the Gore Bill.

The origins of Mosaic had begun in 1992. In November 1992, the NCSA at the University of Illinois (UIUC) established a website. In December 1992, Andreessen and Eric Bina, students attending UIUC and working at the NCSA, began work on Mosaic. They released an X Window browser in February 1993. It gained popularity due to its strong support of integrated multimedia, and the authors’ rapid response to user bug reports and recommendations for new features.

The first Microsoft Windows browser was Cello, written by Thomas R. Bruce for the Legal Information Institute at Cornell Law School to provide legal information, since more lawyers had access to Windows than to Unix. Cello was released in June 1993.

After graduation from UIUC, Andreessen and James H. Clark, former CEO of Silicon Graphics, met and formed Mosaic Communications Corporation to develop the Mosaic browser commercially. The company changed its name to Netscape in April 1994, and the browser was developed further as Netscape Navigator.

Web organization

In May 1994 the first International WWW Conference, organized by Robert Cailliau, was held at CERN; the conference has been held every year since. In April 1993 CERN had agreed that anyone could use the Web protocol and code royalty-free; this was in part a reaction to the perturbation caused by the University of Minnesota announcing that it would begin charging license fees for its implementation of the Gopher protocol.

In September 1994, Berners-Lee founded the World Wide Web Consortium (W3C) at the Massachusetts Institute of Technology with support from the Defense Advanced Research Projects Agency (DARPA) and the European Commission. It comprised various companies that were willing to create standards and recommendations to improve the quality of the Web. Berners-Lee made the Web available freely, with no patent and no royalties due. The World Wide Web Consortium decided that their standards must be based on royalty-free technology, so they can be easily adopted by anyone.

1996-1998: Commercialization of the WWW

By 1996 it became obvious to most publicly traded companies that a public Web presence was no longer optional. Though at first people saw mainly the possibilities of free publishing and instant worldwide information, increasing familiarity with two-way communication over the "Web" led to the possibility of direct Web-based commerce (e-commerce) and instantaneous group communications worldwide. More dotcoms, displaying products on hypertext webpages, were added into the Web.

1999-2001: "Dot-com" boom and bust

The low interest rates in 1998–99 helped increase the start-up capital amounts. Although a number of these new entrepreneurs had realistic plans and administrative ability, most of them lacked these characteristics but were able to sell their ideas to investors because of the novelty of the dot-com concept.

Historically, the dot-com boom can be seen as similar to a number of other technology-inspired booms of the past including railroads in the 1840s, radio in the 1920s, transistor electronics in the 1950s, computer time-sharing in the 1960s, and home computers and biotechnology in the early 1980s.

In 2001 the bubble burst, and many dot-com startups went out of business after burning through their venture capital and failing to become profitable.

2002-Present: The Web becomes ubiquitous

In the aftermath of the dot-com bubble, telecommunications companies had a great deal of overcapacity as many Internet business clients went bust. That, plus ongoing investment in local cell infrastructure kept connectivity charges low, and helping to make high-speed Internet connectivity more affordable. During this time, a handful of companies found success developing business models that helped make the World Wide Web a more compelling experience. These include airline booking sites, Google's search engine and its profitable approach to simplified, keyword-based advertising, as well as Ebay's do-it-yourself auction site and Amazon.com's big selection of books.

This new era also begot social networking websites, such as MySpace, Xanga, Friendster, and Facebook, which, though unpopular at first, very rapidly gained acceptance in becoming a major part of youth culture.

Web 2.0

Beginning in 2002, new ideas for sharing and exchanging content ad hoc, such as Weblogs and RSS, rapidly gained acceptance on the Web. This new model for information exchange, primarily featuring DIY user-edited and generated websites, was coined Web 2.0.

The Web 2.0 boom saw many new service-oriented startups catering to a new, democratized Web. Some believe it will be followed by the full realization of a Semantic Web.

Tim Berners-Lee originally expressed the vision of the Semantic Web as follows:

""I have a dream for the Web [in which computers] become capable of analyzing all the data on the Web – the content, links, and transactions between people and computers. A ‘Semantic Web’, which should make this possible, has yet to emerge, but when it does, the day-to-day mechanisms of trade, bureaucracy and our daily lives will be handled by machines talking to machines. The ‘intelligent agents’ people have touted for ages will finally materialize.""

Tim Berners-Lee, 1999

Predictably, as the World Wide Web became easier to query, attained a higher degree of usability, and shed its esoteric reputation, it gained a sense of organization and unsophistication which opened the floodgates and ushered in a rapid period of popularization. New sites such as Wikipedia and its sister projects proved revolutionary in executing the User edited content concept. In 2005, 3 ex-PayPal employees formed a video viewing website called YouTube. Only a year later, YouTube was proven the most quickly popularized website in history, and even started a new concept of user-submitted content in major events, as in the CNN-YouTube Presidential Debates.

Continued extension of the World Wide Web has focused on connecting devices to the Internet, coined Intelligent Device Management. As Internet connectivity becomes ubiquitous, manufacturers have started to leverage the expanded computing power of their devices to enhance their usability and capability. Through Internet connectivity, manufacturers are now able to interact with the devices they have sold and shipped to their customers, and customers are able to interact with the manufacturer (and other providers) to access new content.

12) HISTORY OF THE "INTRENET"

2009-05-30T14:11:00.000-07:00

by engr. AFAN BK

Before the widespread internetworking that led to the Internet, most communication networks were limited by their nature to only allow communications between the stations on the network, and the prevalent computer networking method was based on the central mainframe computer model. Several research programs began to explore and articulate principles of networking between separate physical networks, leading to the development of the packet switching model of digital networking. These research efforts included those of the laboratories of Donald Davies (NPL), Paul Baran (RAND Corporation), and Leonard Kleinrock's MIT and UCLA.The research led to the development of several packet-switched networking solutions in the late 1960s and 1970s, including ARPANET and the X.25 protocols. Additionally, public access and hobbyist networking systems grew in popularity, including unix-to-unix copy (UUCP) and FidoNet. They were however still disjointed separate networks, served only by limited gateways between networks. This led to the application of packet switching to develop a protocol for inter-networking, where multiple different networks could be joined together into a super-framework of networks. By defining a simple common network system, the Internet protocol suite, the concept of the network could be separated from its physical implementation. This spread of inter-network began to form into the idea of a global inter-network that would be called 'The Internet', and this began to quickly spread as existing networks were converted to become compatible with this. This spread quickly across the advanced telecommunication networks of the western world, and then began to penetrate into the rest of the world as it became the de-facto international standard and global network. However, the disparity of growth led to a digital divide that is still a concern today.

Following commercialisation and introduction of privately run Internet Service Providers in the 1980s, and its expansion into popular use in the 1990s, the Internet has had a drastic impact on culture and commerce. This includes the rise of near instant communication by e-mail, text based discussion forums, and the World Wide Web. Investor speculation in new markets provided by these innovations would also lead to the inflation and collapse of the Dot-com bubble, a major market collapse. But despite this, the Internet continues to grow.

Before the Internet

In the 1950s and early 1960s, prior to the widespread inter-networking that led to the Internet, most communication networks were limited in that they only allowed communications between the stations on the network. Some networks had gateways or bridges between them, but these bridges were often limited or built specifically for a single use. One prevalent computer networking method was based on the central mainframe method, simply allowing its terminals to be connected via long leased lines. This method was used in the 1950s by Project RAND to support researchers such as Herbert Simon, in Pittsburgh, Pennsylvania, when collaborating across the continent with researchers in Sullivan, Illinois, on automated theorem proving and artificial intelligence.The research led to the development of several packet-switched networking solutions in the late 1960s and 1970s, including ARPANET and the X.25 protocols. Additionally, public access and hobbyist networking systems grew in popularity, including unix-to-unix copy (UUCP) and FidoNet. They were however still disjointed separate networks, served only by limited gateways between networks. This led to the application of packet switching to develop a protocol for inter-networking, where multiple different networks could be joined together into a super-framework of networks. By defining a simple common network system, the Internet protocol suite, the concept of the network could be separated from its physical implementation. This spread of inter-network began to form into the idea of a global inter-network that would be called 'The Internet', and this began to quickly spread as existing networks were converted to become compatible with this. This spread quickly across the advanced telecommunication networks of the western world, and then began to penetrate into the rest of the world as it became the de-facto international standard and global network. However, the disparity of growth led to a digital divide that is still a concern today.

Three terminals and an ARPA

A fundamental pioneer in the call for a global network, J.C.R. Licklider, articulated the ideas in his January 1960 paper, Man-Computer Symbiosis.

"A network of such [computers], connected to one another by wide-band communication lines [which provided] the functions of present-day libraries together with anticipated advances in information storage and retrieval and [other] symbiotic functions."

In October 1962, Licklider was appointed head of the United States Department of Defense's Advanced Research Projects Agency, now known as DARPA, within the information processing office. There he formed an informal group within DARPA to further computer research. As part of the information processing office's role, three network terminals had been installed: one for System Development Corporation in Santa Monica, one for Project Genie at the University of California, Berkeley and one for the Compatible Time-Sharing System project at the Massachusetts Institute of Technology (MIT). Licklider's identified need for inter-networking would be made obvious by the apparent waste of resources this caused.

"For each of these three terminals, I had three different sets of user commands. So if I was talking online with someone at S.D.C. and I wanted to talk to someone I knew at Berkeley or M.I.T. about this, I had to get up from the S.D.C. terminal, go over and log into the other terminal and get in touch with them. [...] I said, it's obvious what to do (But I don't want to do it): If you have these three terminals, there ought to be one terminal that goes anywhere you want to go where you have interactive computing. That idea is the ARPAnet."

Packet switching

At the tip of the inter-networking problem lay the issue of connecting separate physical networks to form one logical network, with much wasted capacity inside the assorted separate networks. During the 1960s, Donald Davies (NPL), Paul Baran (RAND Corporation), and Leonard Kleinrock (MIT) developed and implemented packet switching. Early networks used for the command and control of nuclear forces were message switched, not packet-switched, although current strategic military networks are, indeed, packet-switching and connectionless. Baran's research had approached packet switching from studies of decentralisation to avoid combat damage compromising the entire network.

Networks that led to the Internet

"1) ARPANET"

Promoted to the head of the information processing office at DARPA, Robert Taylor intended to realize Licklider's ideas of an interconnected networking system. Bringing in Larry Roberts from MIT, he initiated a project to build such a network. The first ARPANET link was established between the University of California, Los Angeles and the Stanford Research Institute on 22:30 hours on October 29, 1969. By December 5, 1969, a 4-node network was connected by adding the University of Utah and the University of California, Santa Barbara. Building on ideas developed in ALOHAnet, the ARPANET grew rapidly. By 1981, the number of hosts had grown to 213, with a new host being added approximately every twenty days.

ARPANET became the technical core of what would become the Internet, and a primary tool in developing the technologies used. ARPANET development was centered around the Request for Comments (RFC) process, still used today for proposing and distributing Internet Protocols and Systems. RFC 1, entitled "Host Software", was written by Steve Crocker from the University of California, Los Angeles, and published on April 7, 1969. These early years were documented in the 1972 film Computer Networks: The Heralds of Resource Sharing.

International collaborations on ARPANET were sparse. For various political reasons, European developers were concerned with developing the X.25 networks. Notable exceptions were the Norwegian Seismic Array (NORSAR) in 1972, followed in 1973 by Sweden with satellite links to the Tanum Earth Station and University College London.

" 2) X.25 and public access "

Following on from ARPA's research, packet switching network standards were developed by the International Telecommunication Union (ITU) in the form of X.25 and related standards. In 1974, X.25 formed the basis for the SERCnet network between British academic and research sites, which later became JANET. The initial ITU Standard on X.25 was approved in March 1976. This standard was based on the concept of virtual circuits.

The British Post Office, Western Union International and Tymnet collaborated to create the first international packet switched network, referred to as the International Packet Switched Service (IPSS), in 1978. This network grew from Europe and the US to cover Canada, Hong Kong and Australia by 1981. By the 1990s it provided a worldwide networking infrastructure.

Unlike ARPAnet, X.25 was also commonly available for business use. Telenet offered its Telemail electronic mail service, but this was oriented to enterprise use rather than the general email of ARPANET.

The first dial-in public networks used asynchronous TTY terminal protocols to reach a concentrator operated by the public network. Some public networks, such as CompuServe used X.25 to multiplex the terminal sessions into their packet-switched backbones, while others, such as Tymnet, used proprietary protocols. In 1979, CompuServe became the first service to offer electronic mail capabilities and technical support to personal computer users. The company broke new ground again in 1980 as the first to offer real-time chat with its CB Simulator. There were also the America Online (AOL) and Prodigy dial in networks and many bulletin board system (BBS) networks such as FidoNet. FidoNet in particular was popular amongst hobbyist computer users, many of them hackers and amateur radio operators.

" 3) UUCP "

In 1979, two students at Duke University, Tom Truscott and Jim Ellis, came up with the idea of using simple Bourne shell scripts to transfer news and messages on a serial line with nearby University of North Carolina at Chapel Hill. Following public release of the software, the mesh of UUCP hosts forwarding on the Usenet news rapidly expanded. UUCPnet, as it would later be named, also created gateways and links between FidoNet and dial-up BBS hosts. UUCP networks spread quickly due to the lower costs involved, and ability to use existing leased lines, X.25 links or even ARPANET connections. By 1981 the number of UUCP hosts had grown to 550, nearly doubling to 940 in 1984. - Sublink Network, operating since 1987 and officialy founded in Italy in 1989, based its interconnectivity upon UUCP to redistribute mail and news groups messages throughout its Italian nodes (about 100 at the time) owned both by private individuals and small companies. Sublink Network represented possibly one of the first examples of the internet technology becoming progress through popular diffusion.

Merging the networks and creating the Internet

" TCP/IP "

With so many different network methods, something was needed to unify them. Robert E. Kahn of DARPA and ARPANET recruited Vinton Cerf of Stanford University to work with him on the problem. By 1973, they had soon worked out a fundamental reformulation, where the differences between network protocols were hidden by using a common internetwork protocol, and instead of the network being responsible for reliability, as in the ARPANET, the hosts became responsible. Cerf credits Hubert Zimmerman, Gerard LeLann and Louis Pouzin (designer of the CYCLADES network) with important work on this design.

The specification of the resulting protocol, RFC 675 - Specification of Internet Transmission Control Program, by Vinton Cerf, Yogen Dalal and Carl Sunshine, Network Working Group, December, 1974, contains the first attested use of the term internet, as a shorthand for internetworking; later RFCs repeat this use, so the word started out as an adjective rather than the noun it is today.

With the role of the network reduced to the bare minimum, it became possible to join almost any networks together, no matter what their characteristics were, thereby solving Kahn's initial problem. DARPA agreed to fund development of prototype software, and after several years of work, the first somewhat crude demonstration of a gateway between the Packet Radio network in the SF Bay area and the ARPANET was conducted. On November 22, 1977 a three network demonstration was conducted including the ARPANET, the Packet Radio Network and the Atlantic Packet Satellite network—all sponsored by DARPA. Stemming from the first specifications of TCP in 1974, TCP/IP emerged in mid-late 1978 in nearly final form. By 1981, the associated standards were published as RFCs 791, 792 and 793 and adopted for use. DARPA sponsored or encouraged the development of TCP/IP implementations for many operating systems and then scheduled a migration of all hosts on all of its packet networks to TCP/IP. On January 1, 1983, TCP/IP protocols became the only approved protocol on the ARPANET, replacing the earlier NCP protocol.

ARPANET to Several Federal Wide Area Networks: MILNET, NSI, and
NSFNet

After the ARPANET had been up and running for several years, ARPA looked for another agency to hand off the network to; ARPA's primary mission was funding cutting edge research and development, not running a communications utility. Eventually, in July 1975, the network had been turned over to the Defense Communications Agency, also part of the Department of Defense. In 1983, the U.S. military portion of the ARPANET was broken off as a separate network, the MILNET. MILNET subsequently became the unclassified but military-only NIPRNET, in parallel with the SECRET-level SIPRNET and JWICS for TOP SECRET and above. NIPRNET does have controlled security gateways to the public Internet.

The networks based around the ARPANET were government funded and therefore restricted to noncommercial uses such as research; unrelated commercial use was strictly forbidden. This initially restricted connections to military sites and universities. During the 1980s, the connections expanded to more educational institutions, and even to a growing number of companies such as Digital Equipment Corporation and Hewlett-Packard, which were participating in research projects or providing services to those who were.

Several other branches of the U.S. government, the National Aeronautics and Space Agency (NASA), the National Science Foundation (NSF), and the Department of Energy (DOE) became heavily involved in Internet research and started development of a successor to ARPANET. In the mid 1980s, all three of these branches developed the first Wide Area Networks based on TCP/IP. NASA developed the NASA Science Network, NSF developed CSNET and DOE evolved the Energy Sciences Network or ESNet.

More explicitly, NASA developed a TCP/IP based Wide Area Network, NASA Science Network (NSN), in the mid 1980s connecting space scientists to data and information stored anywhere in the world. In 1989, the DECnet-based Space Physics Analysis Network (SPAN) and the TCP/IP-based NASA Science Network (NSN) were brought together at NASA Ames Research Center creating the first multiprotocol wide area network called the NASA Science Internet, or NSI. NSI was established to provide a total integrated communications infrastructure to the NASA scientific community for the advancement of earth, space and life sciences. As a high-speed, multiprotocol, international network, NSI provided connectivity to over 20,000 scientists across all seven continents.

In 1984 NSF developed CSNET exclusively based on TCP/IP. CSNET connected with ARPANET using TCP/IP, and ran TCP/IP over X.25, but it also supported departments without sophisticated network connections, using automated dial-up mail exchange. This grew into the NSFNet backbone, established in 1986, and intended to connect and provide access to a number of supercomputing centers established by the NSF.

Transition towards an Internet

The term "Internet" was adopted in the first RFC published on the TCP protocol: (nternet Transmission Control Program, December 1974.)It was around the time when ARPANET was interlinked with NSFNet, that the term Internet came into more general use, with "an internet" meaning any network using TCP/IP. "The Internet" came to mean a global and large network using TCP/IP. Previously "internet" and "internetwork" had been used interchangeably, and "internet protocol" had been used to refer to other networking systems such as Xerox Network Services.

As interest in wide spread networking grew and new applications for it arrived, the Internet's technologies spread throughout the rest of the world. TCP/IP's network-agnostic approach meant that it was easy to use any existing network infrastructure, such as the IPSS X.25 network, to carry Internet traffic. In 1984, University College London replaced its transatlantic satellite links with TCP/IP over IPSS.

Many sites unable to link directly to the Internet started to create simple gateways to allow transfer of e-mail, at that time the most important application. Sites which only had intermittent connections used UUCP or FidoNet and relied on the gateways between these networks and the Internet. Some gateway services went beyond simple e-mail peering, such as allowing access to FTP sites via UUCP or e-mail.

TCP/IP becomes worldwide

The first ARPANET connection outside the US was established to NORSAR in Norway in 1973, just ahead of the connection to Great Britain. These links were all converted to TCP/IP in 1982, at the same time as the rest of the ARPANET.

CERN, the European Internet, the link to the Pacific and beyond

Between 1984 and 1988 CERN began installation and operation of TCP/IP to interconnect its major internal computer systems, workstations, PCs and an accelerator control system. CERN continued to operate a limited self-developed system CERNET internally and several incompatible (typically proprietary) network protocols externally. There was considerable resistance in Europe towards more widespread use of TCP/IP and the CERN TCP/IP intranets remained isolated from the Internet until 1989.

In 1988 Daniel Karrenberg, from CWI in Amsterdam, visited Ben Segal, CERN's TCP/IP Coordinator, looking for advice about the transition of the European side of the UUCP Usenet network (much of which ran over X.25 links) over to TCP/IP. In 1987, Ben Segal had met with Len Bosack from the then still small company Cisco about purchasing some TCP/IP routers for CERN, and was able to give Karrenberg advice and forward him on to Cisco for the appropriate hardware. This expanded the European portion of the Internet across the existing UUCP networks, and in 1989 CERN opened its first external TCP/IP connections. This coincided with the creation of Réseaux IP Européens (RIPE), initially a group of IP network administrators who met regularly to carry out co-ordination work together. Later, in 1992, RIPE was formally registered as a cooperative in Amsterdam.

At the same time as the rise of internetworking in Europe, ad hoc networking to ARPA and in-between Australian universities formed, based on various technologies such as X.25 and UUCPNet. These were limited in their connection to the global networks, due to the cost of making individual international UUCP dial-up or X.25 connections. In 1989, Australian universities joined the push towards using IP protocols to unify their networking infrastructures. AARNet was formed in 1989 by the Australian Vice-Chancellors' Committee and provided a dedicated IP based network for Australia.

The Internet began to penetrate Asia in the late 1980s. Japan, which had built the UUCP-based network JUNET in 1984, connected to NSFNet in 1989. It hosted the annual meeting of the Internet Society, INET'92, in Kobe. Singapore developed TECHNET in 1990, and Thailand gained a global Internet connection between Chulalongkorn University and UUNET in 1992.

Mobile phones and the Internet

The first mobile phone to have Internet connectivity was the Nokia 9000 Communicator, launched in Finland in 1996. The concept of a mobile phone based Internet did not take off until prices came down from that model and the network providers started to develop systems and services to enable the Internet on phones. NTT DoCoMo in Japan launched the first mobile Internet service, i-Mode in 1999 and this is considered the birth of the mobile phone based Internet. In 2001 the mobile phone based email system by Blackberry and its iconic phones were launched in America.

To make better use of the small screen and tiny keypad and one-handed operation typical of mobile phones, a simpler programming environment was created for the mobile phone Internet, called WAP for Wireless Application protocol. Most mobile phone Internet services operate on WAP.

The growth of the mobile phone based internet was initially a primarily Asian phenomenon with Japan, South Korea and Taiwan all soon finding the majority of their Internet users accessing by phone rather than by PC. Developing World countries followed next, with India, South Africa, Kenya, Philippines and Pakistan all reporting that the majority of their domestic Internet users accessed on a mobile phone rather than on a PC.

The European and North American use of the Internet was influenced by a large installed base of personal computers, and the growth of mobile phone Internet use was more gradual, but had reached national penetration levels of 20%-30% in most Western countries. In 2008 the cross-over happened, when more Internet access devices were mobile phones than personal computers. In many parts of the developing world, the ratio is as much as 10 mobile phone users to one PC user on the Internet.

Digital divide

While developed countries with technological infrastructures were joining the Internet, developing countries began to experience a digital divide separating them from the Internet. On an essentially continental basis, they are building organizations for Internet resource administration and sharing operational experience, as more and more transmission facilities go into place.

Africa
Asia and Oceania
Latin America

Africa

At the beginning of the 1990s, African countries relied upon X.25 IPSS and 2400 baud modem UUCP links for international and internetwork computer communications. In 1996 a USAID funded project, the Leland initiative, started work on developing full Internet connectivity for the continent. Guinea, Mozambique, Madagascar and Rwanda gained satellite earth stations in 1997, followed by Côte d'Ivoire and Benin in 1998.

Africa is building an Internet infrastructure. AfriNIC, headquartered in Mauritius, manages IP address allocation for the continent. As do the other Internet regions, there is an operational forum, the Internet Community of Operational Networking Specialists.

There are a wide range of programs both to provide high-performance transmission plant, and the western and southern coasts have undersea optical cable. High-speed cables join North Africa and the Horn of Africa to intercontinental cable systems. Undersea cable development is slower for East Africa; the original joint effort between New Partnership for Africa's Development (NEPAD) and the East Africa Submarine System (Eassy) has broken off and may become two efforts.

Asia and Oceania

The Asia Pacific Network Information Centre (APNIC), headquartered in Australia, manages IP address allocation for the continent. APNIC sponsors an operational forum, the Asia-Pacific Regional Internet Conference on Operational Technologies (APRICOT).

In 1991, the People's Republic of China saw its first TCP/IP college network, Tsinghua University's TUNET. The PRC went on to make its first global Internet connection in 1995, between the Beijing Electro-Spectrometer Collaboration and Stanford University's Linear Accelerator Center. However, China went on to implement its own digital divide by implementing a country-wide content filter.

Latin America

As with the other regions, the Latin American and Caribbean Internet Addresses Registry (LACNIC) manages the IP address space and other resources for its area. LACNIC, headquartered in Uruguay, operates DNS root, reverse DNS, and other key services.

Opening the network to commerce

The interest in commercial use of the Internet became a hotly debated topic. Although commercial use was forbidden, the exact definition of commercial use could be unclear and subjective. UUCPNet and the X.25 IPSS had no such restrictions, which would eventually see the official barring of UUCPNet use of ARPANET and NSFNet connections. Some UUCP links still remained connecting to these networks however, as administrators cast a blind eye to their operation.

During the late 1980s, the first Internet service provider (ISP) companies were formed. Companies like PSINet, UUNET, Netcom, and Portal Software were formed to provide service to the regional research networks and provide alternate network access, UUCP-based email and Usenet News to the public. The first dial-up on the West Coast, Best Internet, now Verio, opened in 1986. The first dialup ISP in the East was world.std.com, opened in 1989.

This caused controversy amongst university users, who were outraged at the idea of noneducational use of their networks. Eventually, it was the commercial Internet service providers who brought prices low enough that junior colleges and other schools could afford to participate in the new arenas of education and research.

By 1990, ARPANET had been overtaken and replaced by newer networking technologies and the project came to a close. In 1994, the NSFNet, now renamed ANSNET (Advanced Networks and Services) and allowing non-profit corporations access, lost its standing as the backbone of the Internet. Both government institutions and competing commercial providers created their own backbones and interconnections. Regional network access points (NAPs) became the primary interconnections between the many networks. The final commercial restrictions ended in May 1995 when the National Science Foundation ended its sponsorship of the Internet backbone."A Brief History of the Internet"

IETF and a standard for standards

The Internet has developed a significant subculture dedicated to the idea that the Internet is not owned or controlled by any one person, company, group, or organization. Nevertheless, some standardization and control is necessary for the system to function.

The liberal Request for Comments (RFC) publication procedure engendered confusion about the Internet standardization process, and led to more formalization of official accepted standards. The IETF started in January 1985 as a quarterly meeting of U.S. government funded researchers. Representatives from non-government vendors were invited starting with the fourth IETF meeting in October of that year.

Acceptance of an RFC by the RFC Editor for publication does not automatically make the RFC into a standard. It may be recognized as such by the IETF only after experimentation, use, and acceptance have proved it to be worthy of that designation. Official standards are numbered with a prefix "STD" and a number, similar to the RFC naming style. However, even after becoming a standard, most are still commonly referred to by their RFC number.

In 1992, the Internet Society, a professional membership society, was formed and the IETF was transferred to operation under it as an independent international standards body.

NIC, InterNIC, IANA and ICANN

The first central authority to coordinate the operation of the network was the Network Information Centre (NIC) at Stanford Research Institute (SRI) in Menlo Park, California. In 1972, management of these issues was given to the newly created Internet Assigned Numbers Authority (IANA). In addition to his role as the RFC Editor, Jon Postel worked as the manager of IANA until his death in 1998.

As the early ARPANET grew, hosts were referred to by names, and a HOSTS.TXT file would be distributed from SRI International to each host on the network. As the network grew, this became cumbersome. A technical solution came in the form of the Domain Name System, created by Paul Mockapetris. The Defense Data Network—Network Information Center (DDN-NIC) at SRI handled all registration services, including the top-level domains (TLDs) of .mil, .gov, .edu, .org, .net, .com and .us, root nameserver administration and Internet number assignments under a United States Department of Defense contract. In 1991, the Defense Information Systems Agency (DISA) awarded the administration and maintenance of DDN-NIC (managed by SRI up until this point) to Government Systems, Inc., who subcontracted it to the small private-sector Network Solutions, Inc.

Since at this point in history most of the growth on the Internet was coming from non-military sources, it was decided that the Department of Defense would no longer fund registration services outside of the .mil TLD. In 1993 the U.S. National Science Foundation, after a competitive bidding process in 1992, created the InterNIC to manage the allocations of addresses and management of the address databases, and awarded the contract to three organizations. Registration Services would be provided by Network Solutions; Directory and Database Services would be provided by AT&T; and Information Services would be provided by General Atomics.

In 1998 both IANA and InterNIC were reorganized under the control of ICANN, a California non-profit corporation contracted by the US Department of Commerce to manage a number of Internet-related tasks. The role of operating the DNS system was privatized and opened up to competition, while the central management of name allocations would be awarded on a contract tender basis.

Use and culture

E-mail and Usenet

E-mail is often called the killer application of the Internet. However, it actually predates the Internet and was a crucial tool in creating it. E-mail started in 1965 as a way for multiple users of a time-sharing mainframe computer to communicate. Although the history is unclear, among the first systems to have such a facility were SDC's Q32 and MIT's CTSS.

The ARPANET computer network made a large contribution to the evolution of e-mail. There is one report indicating experimental inter-system e-mail transfers on it shortly after ARPANET's creation. In 1971 Ray Tomlinson created what was to become the standard Internet e-mail address format, using the @ sign to separate user names from host names.

A number of protocols were developed to deliver e-mail among groups of time-sharing computers over alternative transmission systems, such as UUCP and IBM's VNET e-mail system. E-mail could be passed this way between a number of networks, including ARPANET, BITNET and NSFNet, as well as to hosts connected directly to other sites via UUCP. See the history of SMTP protocol.

From gopher to the WWW

As the Internet grew through the 1980s and early 1990s, many people realized the increasing need to be able to find and organize files and information. Projects such as Gopher, WAIS, and the FTP Archive list attempted to create ways to organize distributed data. Unfortunately, these projects fell short in being able to accommodate all the existing data types and in being able to grow without bottlenecks.

One of the most promising user interface paradigms during this period was hypertext. The technology had been inspired by Vannevar Bush's "Memex" and developed through Ted Nelson's research on Project Xanadu and Douglas Engelbart's research on NLS. Many small self-contained hypertext systems had been created before, such as Apple Computer's HyperCard. Gopher became the first commonly-used hypertext interface to the Internet. While Gopher menu items were examples of hypertext, they were not commonly perceived in that way.

11) HISTORY OF THE "GUI"

2009-05-30T14:00:00.000-07:00

by engr. AFAN BK

The graphical user interface (GUI), understood as the use of graphic icons and a pointing device to control a computer, has over the last four decades a steady history of incremental refinements built on some constant core principles. Several vendors have created their own windowing systems based on independent code but sharing the same basic elements that define the WIMP paradigm. There have been important technological achievements and enhancements to the general interaction were given in small steps over previous systems and there have been a few significant breakthroughs in terms of use, but the same organizational metaphors and interaction idioms are still in use.

Initial developments

Early dynamic information devices such as radar displays, where input devices where used for direct control of computer-created data, set the basis for later improvements of graphical interfaces.

The concept of a windowing system was introduced by the first real-time graphic display systems for computers: the SAGE Project and Ivan Sutherland's Sketchpad.

Augmentation of Human Intellect (NLS)

Doug Engelbart's Augmentation of Human Intellect project at SRI in the 1960s developed the On-Line System (NLS), which incorporated a mouse-driven cursor and multiple windows used to work on hypertext. Engelbart had been inspired, in part, by the memex desk based information machine suggested by Vannevar Bush in 1945. Much of the early research was based on how young humans learn.

Xerox PARC

Engelbart's work directly led to the advances at Xerox PARC. Several people went from SRI to Xerox PARC in the early 1970s. In 1973 Xerox PARC developed the Xerox Alto personal computer. It was the first computer to use the desktop metaphor and graphical user interface (GUI). It was not a commercial product, but several thousand units were built and were heavily used at PARC and at several universities for many years. The Alto greatly influenced the design of personal computers in the following decades, notably the Macintosh and the first Sun workstations.

In 1974, work began on Gypsy, the first bitmap What-You-See-Is-What-You-Get (WYSIWYG) cut & paste editor. In 1975, Xerox engineers demonstrated a Graphical User Interface "including icons and the first use of pop-up menus".

The 80s: Early commercial developments

Short for Graphical User Interface, the GUI was first developed at Xerox PARC by Alan Kay, Douglas Engelbart, and a group of other researchers. A GUI uses windows, icons, and menus to carry out commands such as opening files, deleting files, moving files, etc. and although many GUI Operating Systems are operated by using a mouse, the keyboard can also be used by using keyboard shortcuts or arrow keys.

Beginning in 1979, started by Steve Jobs and led by Jef Raskin, the Lisa and Macintosh teams at Apple Computer (which included former members of the Xerox PARC group) continued to develop such ideas. The Macintosh, released in 1984, was the first commercially successful product to use a GUI. A desktop metaphor was used, in which files looked like pieces of paper; directories looked like file folders; there were a set of desk accessories like a calculator, notepad, and alarm clock that the user could place around the screen as desired; and the user could delete files and folders by dragging them to a trash can on the screen. Drop down menus were also introduced.

There is still some controversy over the amount of influence that Xerox's PARC work, as opposed to previous academic research, had on the GUIs of Apple's Lisa and Macintosh, but it is clear that the influence was extensive, because first versions of Lisa GUIs even lacked icons. These prototype GUIs are at least mouse driven, but completely ignored the WIMP concept.Note also that Apple was invited by PARC to view their research, and a number of PARC employees subsequently moved to Apple to work on the Lisa and Macintosh GUI. However, the Apple work extended PARC's considerably, adding manipulatable icons and a fixed menu bar and direct manipulation of objects in the file system.

In 1986 the Apple IIgs was launched, a very advanced model of the Apple II successful series, based on 16-bit technology (in fact, virtually two machines into one). It came with a new operating system, the Apple GS/OS, which features a Finder-like GUI, very similar to that of the Macintosh series, able to deal with the advanced graphic abilities of its Video Graphics Chip (VGC).

Graphical Environment Manager (GEM)

Digital Research (DRI) created the Graphical Environment Manager as an add-on program for personal computers. GEM was developed to work with existing CP/M and MS-DOS operating systems on business computers such as IBM-compatibles. It was developed from DRI software, known as GSX, designed by a former PARC employee. The similarity to the Macintosh desktop led to a copyright lawsuit from Apple Computer, and a settlement which involved some changes to GEM. This was to be the first of a series of 'look and feel' lawsuits related to GUI design in the 1980s.

GEM received widespread use in the consumer market from 1985, when it was made the default user interface built in to the TOS operating system of the Atari ST line of personal computers. It was also bundled by other computer manufacturers and distributors, such as Amstrad. Later, it was distributed with the best-selled Digital Research version of DOS for IBM PC compatibles, the DR-DOS 6.0. The GEM desktop faded from the market with the withdrawal of the Atari ST line in 1992 and with the popularity of the Microsoft Windows 3.0 in the PC front by the same years.

DeskMate

Tandy's DeskMate appeared in the early 1980's on its TRS-80 machines and was ported to its Tandy 1000 range in 1984. Like most PC GUIs of the time it depended on MS-DOS. The application was popular at the time and included a number of programs like Draw, Text and Calendar as well as attracting outside investment such as Lotus 1-2-3 for DeskMate.

Amiga Intuition and the Workbench

The Amiga computer was launched by Commodore in 1985 with a GUI called Workbench based on an internal engine which drives all the input events called Intuition, and developed almost entirely by RJ Mical. The first versions used a blue/orange/white/black default palette, which was selected for high contrast on televisions and composite monitors. Workbench presented directories as drawers to fit in with the "workbench" theme. Intuition was the widget and graphics library that made the GUI work. It was driven by user events through the mouse, keyboard, and other input devices.

Due to a mistake made by the Commodore sales department, the first floppies of AmigaOS which were released with Amiga1000 named the whole OS "Workbench". Since then, users and CBM itself referred to "Workbench" as the nickname for the whole AmigaOS (including Amiga DOS, Extras, etc.). This common consent ended with release of version 2.0 of AmigaOS, which re-introduced proper names to the installation floppies of AmigaDOS, Workbench, Extras, etc.).

Early versions of AmigaOS did treat the Workbench as just another window on top of a blank screen, but this is due to the ability of AmigaOS to have invisible screens with a chromakey or a genlock - one of the most advanced features of Amiga platform - even without losing the visibility of Workbench itself. In later AmigaOS versions Workbench could be set as a borderless desktop.

Amiga users were able to boot their computer into a command line interface (aka. CLI/shell). This was a keyboard-based environment without the Workbench GUI. Later they could invoke it with the CLI/SHELL command LoadWB which performs the task to load Workbench GUI.

Like most GUIs of the day Amiga's Intuition followed Xerox, and sometimes Apple's lead, but a CLI was included which dramatically extended the functionality of the platform, but Cli/Shell of Amiga is not just a simple text based interface like in MS-DOS but it is another graphic process driven by Intuition engine and with same gadgets included in Amiga graphics.library and serving the GUI process and CLI/Shell interface integrates itself with the Workbench, sharing the same privileges with the GUI.

MS-DOS file managers and utility suites

Because most of the very early IBM PC and compatibles lacks any common true graphical capability (they only shared the 80-column basic text mode compatible with the original MDA display adapter), a series of file managers arose, including Microsoft's DOS Shell, which features typical GUI elements as menus, push buttons, lists with scrollbars and mouse pointer. The name Text user interface was later invented to name this kind of interface. Many MS-DOS text mode applications, like the default text editor for MS-DOS 5.0 (and related tools, like QBasic), also shared the same philosophy. The IBM DOS Shell included with IBM DOS 5.0 (circa 1992) supported both text display modes and actual graphics display modes, making it both a TUI and a GUI, depending on the chosen mode.

Advanced file managers for MS-DOS were able to redefine character shapes with EGA and better display adapters, giving some basic low resolution icons and graphical interface elements, including an arrow (instead of a coloured cell block) for the mouse pointer. When the display adapter lacks the ability to change the character's shapes, they default to the CP437 character set found in the adapter's ROM. Some popular utility suites for MS-DOS, as Norton Utilities (pictured) and PC Tools used these techniques as well.

DESQview was a text mode multitasking program introduced in July 1985. Running on top of MS-DOS, it allowed users to run multiple DOS programs concurrently in windows. It was the first program to bring multitasking and windowing capabilities to a DOS environment in which existing DOS programs could be used. DESQview was not a true GUI but offered certain components of one, such as resizable, overlapping windows and mouse pointing.

Applications under MS-DOS with proprietary true GUIs

To take the maximum advantage possible in lack of a true common GUI under MS-DOS, the most of the graphical applications which worked with EGA, VGA and better graphic cards had proprietary built-in GUIs, before the MS-Windows age. One of the best known was Deluxe Paint, a popular painting software with a typical WIMP interface.

The original Adobe Acrobat Reader executable file for MS-DOS was able to run on both the standard Windows 3.x GUI and the standard DOS command prompt. When it was launched from the command prompt, it provides its own true GUI (on VGA), which provides the full of its functionality to read PDF files.

Microsoft Windows (16-bit versions)

Windows 1.0 was a GUI for the MS-DOS operating system that had been the OS of choice for IBM PC and compatible computers since 1981. Windows 2.0 followed, but it wasn't until the 1990 launch of Windows 3.0, based on Common User Access that its popularity truly exploded. The GUI has seen minor redesigns since, mainly the networking enabled Windows 3.11 and its Win32s 32-bit patch. The 16-bit line of MS Windows were discontinued with the introduction of Windows 95 and Windows NT 32-bit based architecture in the 1990's.

The main window of a given application can occupy the full screen in maximized status. The users must then to switch between maximized applications using the Alt+Tab keyboard shortcut; no alternative with the mouse except for de-maximize. When none of the running application windows is maximized, switching can be done by clicking on a partially visible window, as is the common way in other GUIs.

In 1988, Apple sued Microsoft for copyright infringement of the LISA and Apple Macintosh GUI. The court case lasted 4 years before almost all of Apple's claims were denied on a contractual technicality. Subsequent appeals by Apple were also denied. Microsoft and Apple apparently entered a final, private settlement of the matter in 1997.

GEOS

GEOS was launched in 1986. Originally written for the 8-bit home computer Commodore 64 and shortly after, the Apple II series it was later ported to IBM PC systems. It came with several application programs like a calendar and word processor, and a cut-down version served as the basis for America Online's DOS client. Compared to the competing Windows 3.0 GUI it could run reasonably well on simpler hardware. But it was targeted at 8-bit machines and the 16-bit computer age was dawning.

The X Window System

The standard windowing system in the Unix world is the X Window System (commonly X11 or X), first released in the mid-1980s. The W Window System (1983) was the precursor to X; X was developed at MIT as Project Athena. Its original purpose was to allow users of the newly emerging graphic terminals to access remote graphics workstations without regard to the workstation's operating system or the hardware. Due largely to the availability of the source code used to write X, it has become the standard layer for management of graphical and input/output devices and for the building of both local and remote graphical interfaces on virtually all Unix, Linux and other Unix-like operating systems.

X allows a graphical terminal user to make use of remote resources on the network as if they were all located locally to the user by running a single module of software called the X server. The software running on the remote machine is called the client application. X's network transparency protocols allow the display and input portions of any application to be separated from the remainder of the application and 'served up' to any of a large number of remote users. X is available today as free software.

The 1990s: Mainstream usage of the desktop

The widespread adoption of the PC platform at homes and small business popularized computers among people with no formal training. This created a fast growing market, opening an opportunity for commercial exploitation and of easy-to-use interfaces and making economically viable the incremental refinement of the existing GUIs for home systems.

Also, the spreading of Highcolor and Truecolor capabilities of display adapters providing thousands and millions of colors, along with faster CPUs and accelerated graphic cards, cheaper RAM, storage devices up to an order of magnitude larger (from megabytes to gigabytes) and larger bandwidth for telecom networking at lower cost helped to create an environment in which the common user was able to run complicated GUIs which began to favor aesthetics.

Windows 95 and "a computer in every home" (the 32-bit versions)

After Windows 3.11, Microsoft began to develop a new consumer-oriented version of the operating system. Windows 95 was intended to integrate Microsoft's formerly separate MS-DOS and Windows products and includes an enhanced version of DOS, often referred to as MS-DOS 7.0. It also featured a significant redesign of the GUI, dubbed "Cairo", which was eventually used in Windows NT 4.0. Both Win95 and WinNT were 32-bit based technologies, which could exploit the abilities of the Intel 80386 CPU, as the preemptive multitasking and up to 4GiB of linear address memory space. In the marketplace, Windows 95 was an unqualified success, promoting a general upgrade to 32-bit technology, and within a year or two of its release had become the most successful operating system ever produced.

Windows 95 saw the beginning of the Browser wars when the World Wide Web began receiving a great deal of attention in the popular culture and mass media. Microsoft at first did not see potential in the Web and Windows 95 was shipped with Microsoft's own online service called The Microsoft Network, which was dial-up only and was used primarily for its own content, not internet access. As versions of Netscape Navigator and Internet Explorer were released at a rapid pace over the following few years, Microsoft used its desktop dominance to push its browser and shape the ecology of the web mainly as a monoculture.

Windows 95 (and its 32-bits professional counterpart Windows NT) evolved through the years into Windows 98, Windows ME, Windows 2000 and Windows XP, sharing the same basic GUI themes (in the XP, the user can even switch to the classical Windows 95/NT look). With Windows 98, the Active Desktop theme was introduced, allowing a HTML approach for the desktop, but this feature was coldly received by customers, who frequently disabled it. At the end, Windows Vista definitively discontinued it, but has a new SideBar on the desktop.

Mac OS

The Macintosh's GUI has been infrequently revised since 1984, with major updates including System 7, and underwent its largest revision with the introduction of the "Aqua" interface in 2001's Mac OS X. It was a new operating system built primarily on technology from NeXTStep with UI elements of the original Mac OS grafted on. Mac OS X uses a technology called Quartz for graphics rendering and drawing on-screen. Some interface features of Mac OS X are inherited from NeXTStep (such as the Dock, the automatic wait cursor, or double-buffered windows giving a solid appearance and flicker-free window redraws), while others are inherited from the old Mac OS operating system (the single system-wide menu-bar). Mac OS X v10.3 introduced features to improve usability including Exposé which is designed to make finding open windows easier.

With Mac OS X v10.4, new features were added, including Dashboard (a virtual alternate desktop for mini specific-purpose applications) and a search tool called Spotlight, which provides users with an option for searching through files instead of browsing through folders.

In 2007 with the release of 10.5 Leopard the look of the OS was revised again. Brushed metal was removed in favor of the Unified theme made up of grey gradients. It is very similar to the style iTunes has had since version 6.0. It also incorporates Coverflow into the Finder In addition the dock has been changed to become a reflective shelf with the application icons sitting on it. The menu bar has the option of partial transparency, and all windows have an increased drop shadow.

GUIs built on the X Window System

In the early days of X Window development, Sun Microsystems and AT&T attempted to push for a GUI standard called OPEN LOOK in competition with Motif. OPEN LOOK was a well-designed standard developed from scratch in conjunction with Xerox, while Motif was a collective effort that fell into place, with a look and feel patterned after Windows 3.11. Many who worked on OPEN LOOK at the time appreciated its design coherence.[citation needed] Motif prevailed in the UNIX GUI battles and became the basis for the Common Desktop Environment (CDE). CDE was based on VUE (Visual User Environment), a proprietary desktop from Hewlett-Packard that in turn was based on the Motif look and feel.

10) HISTORY OF PROGRAMMING LANGUAGES

2009-05-30T13:58:00.000-07:00

by engr. AFAN BK

This article discusses the major developments in the history of programming languages. For a detailed timeline of events, see the timeline of programming languages.

Before 1940

The first programming languages predate the modern computer. At first, the languages were codes.

During a nine-month period in 1842-1843, Ada Lovelace translated Italian mathematician Luigi Menabrea's memoir on Charles Babbage's newest proposed machine, the Analytical Engine. With the article, she appended a set of notes which specified in complete detail a method for calculating Bernoulli numbers with the Engine, recognized by some historians as the world's first computer program. But some biographers debate the extent of her original contributions versus those of her husband.

The Jacquard loom used holes in punched cards to represent sewing loom arm movements in order to generate decorative patterns automatically.

Herman Hollerith realized that he could encode information on punch cards when he observed that railroad train conductors would encode the appearance of the ticket holders on the train tickets using the position of punched holes on the tickets. Hollerith then proceeded to encode the 1890 census data on punch cards.

The first computer codes were specialized for the applications. In the first decades of the twentieth century, numerical calculations were based on decimal numbers. Eventually it was realized that logic could be represented with numbers, as well as with words. For example, Alonzo Church was able to express the lambda calculus in a formulaic way. The Turing machine was an abstraction of the operation of a tape-marking machine, for example, in use at the telephone companies. However, unlike the lambda calculus, Turing's code does not serve well as a basis for higher-level languages — its principal use is in rigorous analyses of algorithmic complexity.

Like many "firsts" in history, the first modern programming language is hard to identify. From the start, the restrictions of the hardware defined the language. Punch cards allowed 80 columns, but some of the columns had to be used for a sorting number on each card. Fortran included some keywords which were the same as English words, such as "IF", "GOTO" (go to) and "CONTINUE". The use of a magnetic drum for memory meant that computer programs also had to be interleaved with the rotations of the drum. Thus the programs were more hardware dependent than today.

To some people the answer depends on how much power and human-readability is required before the status of "programming language" is granted. Jacquard looms and Charles Babbage's Difference Engine both had simple, extremely limited languages for describing the actions that these machines should perform. One can even regard the punch holes on a player piano scroll as a limited domain-specific programming language, albeit not designed for human consumption.

The 1940s

In the 1940s the first recognizably modern, electrically powered computers were created. The limited speed and memory capacity forced programmers to write hand tuned assembly language programs. It was soon discovered that programming in assembly language required a great deal of intellectual effort and was error-prone.

In 1948, Konrad Zuse published a paper about his programming language Plankalkül. However, it was not implemented in his time and his original contributions were isolated from other developments.

Some important languages that were developed in this period include:

1943 - Plankalkül (Konrad Zuse)
1943 - ENIAC coding system
1949 - C-10

The 1950s and 1960s

In the 1950s the first three modern programming languages whose descendants are still in widespread use today were designed:

FORTRAN (1955), the "FORmula TRANslator, invented by John W. Backus et al.;
LISP, the "LISt Processor", invented by John McCarthy et al.;
COBOL, the COmmon Business Oriented Language, created by the Short Range Committee, heavily influenced by Grace Hopper.
Another milestone in the late 1950s was the publication, by a committee of American and European computer scientists, of "a new language for algorithms"; the Algol 60 Report (the "ALGOrithmic Language"). This report consolidated many ideas circulating at the time and featured two key language innovations:

arbitrarily nested block structure: meaningful chunks of code could be grouped into statement blocks without having to be turned into separate, explicitly named procedures;
lexical scoping: a block could have its own variables that code outside the chunk cannot access, let alone manipulate.
Another innovation, related to this, was in how the language was described:

a mathematically exact notation, Backus-Naur Form (BNF), was used to describe the language's syntax. Nearly all subsequent programming languages have used a variant of BNF to describe the context-free portion of their syntax.
Algol 60 was particularly influential in the design of later languages, some of which soon became more popular. The Burroughs large systems were designed to be programmed in an extended subset of Algol.

Algol's key ideas were continued, producing Algol 68:

syntax and semantics became even more orthogonal, with anonymous routines, a recursive typing system with higher-order functions, etc.;
not only the context-free part, but the full language syntax and semantics were defined formally, in terms of Van Wijngaarden grammar, a formalism designed specifically for this purpose.
Algol 68's many little-used language features (e.g. concurrent and parallel blocks) and its complex system of syntactic shortcuts and automatic type coercions made it unpopular with implementers and gained it a reputation of being difficult. Niklaus Wirth actually walked out of the design committee to create the simpler Pascal language.

Overview:

1951 - Regional Assembly Language
1952 - Autocode
1954 - FORTRAN
1955 - FLOW-MATIC (forerunner to COBOL)
1957 - COMTRAN (forerunner to COBOL)
1958 - LISP
1958 - ALGOL 58
1959 - FACT (forerunner to COBOL)
1959 - COBOL
1962 - APL
1962 - Simula
1964 - BASIC
1964 - PL/I

1967-1978: establishing fundamental paradigms

The period from the late 1960s to the late 1970s brought a major flowering of programming languages. Most of the major language paradigms now in use were invented in this period:

Simula, invented in the late 1960s by Nygaard and Dahl as a superset of Algol 60, was the first language designed to support object-oriented programming.
C, an early systems programming language, was developed by Dennis Ritchie and Ken Thompson at Bell Labs between 1969 and 1973.
Smalltalk (mid 1970s) provided a complete ground-up design of an object-oriented language.
Prolog, designed in 1972 by Colmerauer, Roussel, and Kowalski, was the first logic programming language.
ML built a polymorphic type system (invented by Robin Milner in 1973) on top of Lisp, pioneering statically typed functional programming languages.
Each of these languages spawned an entire family of descendants, and most modern languages count at least one of them in their ancestry.

The 1960s and 1970s also saw considerable debate over the merits of "structured programming", which essentially meant programming without the use of GOTO. This debate was closely related to language design: some languages did not include GOTO, which forced structured programming on the programmer. Although the debate raged hotly at the time, nearly all programmers now agree that, even in languages that provide GOTO, it is bad style to use it except in rare circumstances. As a result, later generations of language designers have found the structured programming debate tedious and even bewildering.

Some important languages that were developed in this period include:

1970 - Pascal
1970 - Forth
1972 - C
1972 - Smalltalk
1972 - Prolog
1973 - ML
1978 - SQL (initially only a query language, later extended with programming constructs)

The 1980s: consolidation, modules, performance

The 1980s were years of relative consolidation. C++ combined object-oriented and systems programming. The United States government standardized Ada, a systems programming language intended for use by defense contractors. In Japan and elsewhere, vast sums were spent investigating so-called "fifth generation" languages that incorporated logic programming constructs. The functional languages community moved to standardize ML and Lisp. Rather than inventing new paradigms, all of these movements elaborated upon the ideas invented in the previous decade.

However, one important new trend in language design was an increased focus on programming for large-scale systems through the use of modules, or large-scale organizational units of code. Modula, Ada, and ML all developed notable module systems in the 1980s. Module systems were often wedded to generic programming constructs---generics being, in essence, parameterized modules (see also parametric polymorphism).

Although major new paradigms for programming languages did not appear, many researchers expanded on the ideas of prior languages and adapted them to new contexts. For example, the languages of the Argus and Emerald systems adapted object-oriented programming to distributed systems.

The 1980s also brought advances in programming language implementation. The RISC movement in computer architecture postulated that hardware should be designed for compilers rather than for human assembly programmers. Aided by processor speed improvements that enabled increasingly aggressive compilation techniques, the RISC movement sparked greater interest in compilation technology for high-level languages.

Language technology continued along these lines well into the 1990s.

Some important languages that were developed in this period include:

1983 - Ada
1983 - C++
1985 - Eiffel
1987 - Perl
1989 - FL (Backus)

The 1990s: the Internet age

The 1990s saw no fundamental novelty, but much recombination as well as maturation of old ideas. A big driving philosophy was programmer productivity. Many "rapid application development" languages emerged, which usually came with an IDE, garbage collection, and were descendants of older languages. All such languages were object-oriented. These included Object Pascal, Visual Basic, and C#. Java was a more conservative language that also featured garbage collection and received much attention. More radical and innovative than the RAD languages were the new scripting languages. These did not directly descend from other languages and featured new syntaxes and more liberal incorporation of features. Many consider these scripting languages to be more productive than even the RAD languages, but often because of choices that make small programs simpler but large programs more difficult to write and maintain. Nevertheless, scripting languages came to be the most prominent ones used in connection with the Web.

Some important languages that were developed in this period include:

1990 - Haskell
1991 - Python
1991 - Java
1993 - Ruby
1993 - Lua
1994 - ANSI Common Lisp
1995 - JavaScript
1995 - PHP
2000 - C#
2008 - JavaFX Script

Current trends

Programming language evolution continues, in both industry and research. Some of the current trends include:

Mechanisms for adding security and reliability verification to the language: extended static checking, information flow control, static thread safety.

Alternative mechanisms for modularity: mixins, delegates, aspects.

Component-oriented software development.

Metaprogramming, reflection or access to the abstract syntax tree
Increased emphasis on distribution and mobility.

Integration with databases, including XML and relational databases.

Support for Unicode so that source code (program text) is not restricted to those characters contained in the ASCII character set; allowing, for example, use of non-Latin-based scripts or extended punctuation.

XML for graphical interface (XUL, XAML).

9) HISTORY OF SOFTWARE ENGINEERING

2009-05-30T13:56:00.000-07:00

by engr. AFAN BK

In the history of software engineering the software engineering has evolved steadily from its founding days in the 1940s until today in the 2000s. Applications have evolved continuously. The ongoing goal to improve technologies and practices, seeks to improve the productivity of practitioners and the quality of applications to users.

Overview

There are a number of areas where the evolution of software engineering is notable:

Emergence as a profession: By the early 1980s, software engineering had already emerged as a bona fide profession, to stand beside computer science and traditional engineering. See also software engineering professionalism.
Role of women: In the 1940s, 1950s, and 1960s, men often filled the more prestigious and better paying hardware engineering roles, but often delegated the writing of software to women. Grace Hopper, Jamie Fenton and many other unsung women filled many programming jobs during the first several decades of software engineering. Today, many fewer women work in software engineering than in other professions, a situation whose cause is not clearly identified and is often attributed to sexual discrimination, cyberculture or bias in education. Many academic and professional organizations are trying hard to solve this imbalance.
Processes: Processes have become a big part of software engineering and are hailed for their potential to improve software and sharply criticized for their potential to constrict programmers.
Cost of hardware: The relative cost of software versus hardware has changed substantially over the last 50 years. When mainframes were expensive and required large support staffs, the few organizations buying them also had the resources to fund large, expensive custom software engineering projects. Computers are now much more numerous and much more powerful, which has several effects on software. The larger market can support large projects to create commercial off the shelf software, as done by companies such as Microsoft. The cheap machines allow each programmer to have a terminal capable of fairly rapid compilation. The programs in question can use techniques such as garbage collection, which make them easier and faster for the programmer to write. On the other hand, many fewer organizations are interested in employing programmers for large custom software projects, instead using commercial off the shelf software as much as possible.

The Pioneering Era

The most important development was that new computers were coming out almost every year or two, rendering existing ones obsolete. Software people had to rewrite all their programs to run on these new machines. Programmers did not have computers on their desks and had to go to the "machine room". Jobs were run by signing up for machine time or by operational staff. Jobs were run by putting punched cards for input into the machine's card reader and waiting for results to come back on the printer.

The field was so new that the idea of management by schedule was non-existent. Making predictions of a project's completion date was almost impossible. Computer hardware was application-specific. Scientific and business tasks needed different machines. Due to the need to frequently translate old software to meet the needs of new machines, high-order languages like FORTRAN, COBOL, and ALGOL were developed. Hardware vendors gave away systems software for free as hardware could not be sold without software. A few companies sold the service of building custom software but no software companies were selling packaged software.

The notion of reuse flourished. As software was free, user organizations commonly gave it away. Groups like IBM's scientific user group SHARE offered catalogs of reusable components. Academia did not yet teach the principles of computer science. Modular programming and data abstraction were already being used in programming.

1945 to 1965: The origins

The term software engineering first appeared in the late 1950s and early 1960s. Programmers have always known about civil, electrical, and computer engineering and debated what engineering might mean for software.

The NATO Science Committee sponsored two conferences on software engineering in 1968 (Garmisch, Germany — see conference report) and 1969, which gave the field its initial boost. Many believe these conferences marked the official start of the profession of software engineering.

1965 to 1985: The software crisis

Software engineering was spurred by the so-called software crisis of the 1960s, 1970s, and 1980s, which identified many of the problems of software development. Many software projects ran over budget and schedule. Some projects caused property damage. A few projects caused loss of life[citation needed]. The software crisis was originally defined in terms of productivity, but evolved to emphasize quality. Some used the term software crisis to refer to their inability to hire enough qualified programmers.

Cost and Budget Overruns: The OS/360 operating system was a classic example. This decade-long[citation needed] project from the 1960s eventually produced one of the most complex software systems at the time. OS/360 was one of the first large (1000 programmers) software projects. Fred Brooks claims in The Mythical Man Month that he made a multi-million dollar mistake of not developing a coherent architecture before starting development.
Property Damage: Software defects can cause property damage. Poor software security allows hackers to steal identities, costing time, money, and reputations.
Life and Death: Software defects can kill. Some embedded systems used in radiotherapy machines failed so catastrophically that they administered lethal doses of radiation to patients. The most famous of these failures is the Therac 25 incident.
Peter G. Neumann has kept a contemporary list of software problems and disasters. The software crisis has been slowly fizzling out, because it is unrealistic to remain in crisis mode for more than 20 years. SEs are accepting that the problems of SE are truly difficult and only hard work[citation needed] over many decades can solve them.

1985 to 1989: No silver bullet

For decades, solving the software crisis was paramount to researchers and companies producing software tools. Seemingly, they trumpeted every new technology and practice from the 1970s to the 1990s as a silver bullet to solve the software crisis. Tools, discipline, formal methods, process, and professionalism were touted as silver bullets:

Tools: Especially emphasized were tools: Structured programming, object-oriented programming, CASE tools, Ada, Java, documentation, standards, and Unified Modeling Language were touted as silver bullets.
Discipline: Some pundits argued that the software crisis was due to the lack of discipline of programmers.
Formal methods: Some believed that if formal engineering methodologies would be applied to software development, then production of software would become as predictable an industry as other branches of engineering. They advocated proving all programs correct.
Process: Many advocated the use of defined processes and methodologies like the Capability Maturity Model.
Professionalism: This led to work on a code of ethics, licenses, and professionalism.
In 1986, Fred Brooks published the No Silver Bullet article, arguing that no individual technology or practice would ever make a 10-fold improvement in productivity within 10 years.

Debate about silver bullets raged over the following decade. Advocates for Ada, components, and processes continued arguing for years that their favorite technology would be a silver bullet. Skeptics disagreed. Eventually, almost everyone accepted that no silver bullet would ever be found. Yet, claims about silver bullets pop up now and again, even today.

Some interpret no silver bullet to mean that software engineering failed. The search for a single key to success never worked. All known technologies and practices have only made incremental improvements to productivity and quality. Yet, there are no silver bullets for any other profession, either. Others interpret no silver bullet as proof that software engineering has finally matured and recognized that projects succeed due to hard work.

However, it could also be said that there are, in fact, a range of silver bullets today, including lightweight methodologies (see "Project management"), spreadsheet calculators, customized browsers, in-site search engines, database report generators, integrated design-test coding-editors with memory/differences/undo, and specialty shops that generate niche software, such as information websites, at a fraction of the cost of totally customized website development. Nevertheless, the field of software engineering appears too complex and diverse for a single "silver bullet" to improve most issues, and each issue accounts for only a small portion of all software problems.

1990 to 1999: Prominence of the Internet

The rise of the Internet led to very rapid growth in the demand for international information display/e-mail systems on the world wide web. Programmers were required to handle illustrations, maps, photographs, and other images, plus simple animation, at a rate never before seen, with few well-known methods to optimize image display/storage (such as the use of thumbnail images).

The growth of browser usage, running on the HTML language, changed the way in which information-display and retrieval was organized. The wide-spread network connections led to the growth and prevention of international computer viruses on MS Windows computers, and the vast proliferation of spam e-mail became a major design issue in e-mail systems, flooding communication channels and requiring semi-automated pre-screening. Keyword-search systems evolved into web-based search engines, and many software systems had to be re-designed, for international searching, depending on Search Engine Optimization (SEO) techniques. Human natural-language translation systems were needed to attempt to translate the information flow in multiple foreign languages, with many software systems being designed for multi-language usage, based on design concepts from human translators. Typical computer-user bases went from hundreds, or thousands of users, to, often, many-millions of international users.

2000 to Present: Lightweight Methodologies

With the expanding demand for software in many smaller organizations, the need for inexpensive software solutions led to the growth of simpler, faster methodologies that developed running software, from requirements to deployment, quicker & easier. The use of rapid-prototyping evolved to entire lightweight methodologies, such as Extreme Programming (XP), which attempted to simplify many areas of software engineering, including requirements gathering and reliability testing for the growing, vast number of small software systems. Very large software systems still used heavily-documented methodologies, with many volumes in the documentation set; however, smaller systems had a simpler, faster alternative approach to managing the development and maintenance of software calculations and algorithms, information storage/retrieval and display.

Current trends in software engineering

Software engineering is a young discipline, and is still developing. The directions in which software engineering is developing include:

1- Aspects

Aspects help software engineers deal with quality attributes by providing tools to add or remove boilerplate code from many areas in the source code. Aspects describe how all objects or functions should behave in particular circumstances. For example, aspects can add debugging, logging, or locking control into all objects of particular types. Researchers are currently working to understand how to use aspects to design general-purpose code. Related concepts include generative programming and templates.

2- Agile

Agile software development guides software development projects that evolve rapidly with changing expectations and competitive markets. Proponents of this method believe that heavy, document-driven processes (like TickIT, CMM and ISO 9000) are fading in importance. Some people believe that companies and agencies export many of the jobs that can be guided by heavy-weight processes. Related concepts include Extreme Programming, Scrum, and Lean software development.

3- Experimental

Experimental software engineering is a branch of software engineering interested in devising experiments on software, in collecting data from the experiments, and in devising laws and theories from this data. Proponents of this method advocate that the nature of software is such that we can advance the knowledge on software through experiments only.

4- Model-driven

Model Driven Design develops textual and graphical models as primary design artifacts. Development tools are available that use model transformation and code generation to generate well-organized code fragments that serve as a basis for producing complete applications.

5- Software Product Lines

Software Product Lines is a systematic way to produce families of software systems, instead of creating a succession of completely individual products. This method emphasizes extensive, systematic, formal code reuse, to try to industrialize the software development process.
The Future of Software Engineering conference (FOSE), held at ICSE 2000, documented the state of the art of SE in 2000 and listed many problems to be solved over the next decade. The FOSE tracks at the ICSE 2000 and the ICSE 2007 conferences also help identify the state of the art in software engineering.

Software engineering today

The profession is trying to define its boundary and content. The Software Engineering Body of Knowledge SWEBOK has been tabled as an ISO standard during 2006 (ISO/IEC TR 19759).

In 2006, Money Magazine and Salary.com rated software engineering as the best job in America in terms of growth, pay, stress levels, flexibility in hours and working environment, creativity, and how easy it is to enter and advance in the field.

8) HISTORY OF LAPTOPS

2009-05-30T13:51:00.000-07:00

by engr. AFAN BK

Before laptop/notebook computers were technically feasible, similar ideas had been proposed, most notably Alan Kay's Dynabook concept, developed at Xerox PARC in the early 1970s. What was probably the first portable computer was the Xerox NoteTaker, again developed at Xerox PARC, in 1976. However, only ten prototypes were built.

Osborne 1

The first commercially available portable computer was the Osborne 1 in 1981, which used the CP/M operating system. Although it was large and heavy compared to today's laptops, with a tiny 5" CRT monitor, it had a near-revolutionary impact on business, as professionals were able to take their computer and data with them for the first time. This and other "luggables" were inspired by what was probably the first portable computer, the Xerox NoteTaker. The Osborne was about the size of a portable sewing machine, and more importantly, could be carried on commercial aircraft. However, it was not possible to run the Osborne on batteries: it had to be plugged into mains.

Kaypro II

In 1982 Kaypro introduced the Kaypro II, a CP/M-based competitor to the Osborne 1. The Kaypro II featured a display nearly twice as big as the Osborne's, at 9", and double-density floppy drives with twice the storage capacity. Following in the standard set by the Osborne 1, the Kaypro II also included a software bundle when purchased new.

Bondwell 2

Although it wasn't released until 1985, well after the decline of CP/M as a major operating system, the Bondwell 2 is one of only a handful of CP/M laptops. It used a Z-80 CPU running at 4 MHz, had 64 K RAM and, unusual for a CP/M machine, a 3.5" floppy disk drive built in. It had a 80×25 character-based LCD mounted on a hinge similar to modern laptops, one of the first computers to use this form factor.

Other CP/M laptops

The other CP/M laptops were the Epson PX-4 (or HX-40) and PX-8 (Geneva), The NEC PC-8401A, and the NEC PC-8500. These four units, however, utilized modified CP/M systems in ROM, and did not come standard with any floppy or hard disks.

Compaq Portable

A more enduring success was the Compaq Portable, the first product from Compaq, introduced in 1983, by which time the IBM Personal Computer had become the standard platform. Although scarcely more portable than the Osborne machines, and also requiring AC power to run, it ran MS-DOS and was the first true legal IBM clone (IBM's own later Portable Computer, which arrived in 1984, was notably less IBM PC-compatible than the Compaq.

Epson HX-20

Another significant machine announced in 1981, although first sold widely in 1983, was the Epson HX-20. A simple handheld computer, it featured a full-transit 68-key keyboard, rechargeable nickel-cadmium batteries, a small (120×32-pixel) dot-matrix LCD display with 4 lines of text, 20 characters per line text mode, a 24 column dot matrix printer, a Microsoft BASIC interpreter, and 16 KB of RAM (expandable to 32 KB).

GRiD Compass

However, arguably the first true laptop was the GRiD Compass 1101, designed by Bill Moggridge in 1979-1980, and released in 1982. Enclosed in a magnesium case, it introduced the now familiar clamshell design, in which the flat display folded shut against the keyboard. The computer could be run from batteries, and was equipped with a 320×200-pixel electroluminescent display and 384 kilobyte bubble memory. It was not IBM-compatible, and its high price (US$8,000–10,000) limited it to specialized applications. However, it was used heavily by the U.S. military, and by NASA on the Space Shuttle during the 1980s. The GRiD's manufacturer subsequently earned significant returns on its patent rights as its innovations became commonplace. GRiD Systems Corp. was later bought by the Tandy (now RadioShack) Corporation.

Ampere

The Ampere, a sleek clamshell design by Ryu Oosake, also debuted in 1983. It offered a MC68008 microprocessor dedicated to running an APL interpreter residing in ROM.

Sharp and Gavilan

Two other noteworthy early laptops were the Sharp PC-5000 and the Gavilan SC, announced in 1983 but first sold in 1984. The Gavilan was notably the first computer to be marketed as a "laptop". It was also equipped with a pioneering touchpad-like pointing device, installed on a panel above the keyboard. Like the GRiD Compass, the Gavilan and the Sharp were housed in clamshell cases, but they were partly IBM-compatible, although primarily running their own system software. Both had LCD displays, and could connect to optional external printers. The Dulmont Magnum, launched internationally in 1984, was an Australian portable similar in layout to the Gavilan, which used the Intel 80186 processor.

Kyotronic 85

The year 1983 also saw the launch of what was probably the biggest-selling early laptop, the Kyocera Kyotronic 85. Owing much to the design of the previous Epson HX-20, and although at first a slow seller in Japan, it was quickly licensed by Tandy Corporation, Olivetti, and NEC, who recognised its potential and marketed it respectively as the TRS-80 Model 100 line (or Tandy 100), Olivetti M-10, and NEC PC-8201. The machines ran on standard AA batteries. The Tandy's built-in programs, including a BASIC interpreter, a text editor, and a terminal program, were supplied by Microsoft, and are thought to have been written in part by Bill Gates himself. The computer was not a clamshell, but provided a tiltable 8 line × 40-character LCD screen above a full-travel keyboard. With its internal modem, it was a highly portable communications terminal. Due to its portability, good battery life (and ease of replacement), reliability (it had no moving parts), and low price (as little as US$300), the model was highly regarded, becoming a favorite among journalists. It weighed less than 2 kg with dimensions of 30×21.5×4.5 centimeters (12×8½×1¾ in). Initial specifications included 8 kilobytes of RAM (expandable to 24 KB) and a 3 MHz processor. The machine was in fact about the size of a paper notebook, but the term had yet to come into use and it was generally described as a "portable" computer.

Kaypro 2000

Possibly the first commercial IBM-compatible laptop was the Kaypro 2000, introduced in 1985. With its brushed aluminum clamshell case, it was remarkably similar in design to modern laptops. It featured a 25 line by 80 character LCD display, a detachable keyboard, and a pop-up 90 mm (3.5 inch) floppy drive.

IBM PC Convertible

Also among the first commercial IBM-compatible laptops was the IBM PC Convertible, introduced in 1986.

Toshiba T1000 and T1200

Two Toshiba models, the T1000 and T1200, were introduced in 1987. Although limited floppy-based DOS machines, with the operating system stored in ROM, the Toshiba models were small and light enough to be carried in a backpack, and could be run off lead-acid batteries. These also introduced the now-standard "resume" feature to DOS-based machines: the computer could be paused between sessions, without having to be restarted each time.

US Air Force

The first laptops successful on a large scale came in large part due to a Request For Proposal (RFP) by the U.S. Air Force in 1987. This contract would eventually lead to the purchase of over 200,000 laptops. Competition to supply this contract was fiercely contested and the major PC companies of the time; IBM Corporation, Toshiba, Compaq, NEC, and Zenith Data Systems (ZDS), rushed to develop laptops in an attempt to win this deal. ZDS, which had earlier won a landmark deal with the IRS for its Z-171, was awarded this contract for its SupersPort series. The SupersPort series was originally launched with an Intel 8086 processor, dual floppy disk drives, a backlit, blue and white STN LCD screen, and a NiCd battery pack. Later models featured an Intel 80286 processor and a 20 MB hard disk drive. On the strength of this deal, ZDS became the world's largest laptop supplier in 1987 and 1988. ZDS partnered with Tottori Sanyo in the design and manufacturing of these laptops. This relationship is notable because it was the first deal between a major brand and an Asian original equipment manufacturer.

Cambridge Z88

Another notable computer was the Cambridge Z88, designed by Clive Sinclair, introduced in 1988. About the size of an A4 sheet of paper as well, it ran on standard batteries, and contained basic spreadsheet, word processing, and communications programs. It anticipated the future miniaturization of the portable computer, and as a ROM-based machine with a small display, can — like the TRS-80 Model 100 — also be seen as a forerunner of the personal digital assistant.

Compaq SLT286

By the end of the 1980s, laptop computers were becoming popular among business people. The COMPAQ SLT286 debuted at the end of 1988, being the first battery-powered laptop to sport an internal hard disk drive and a VGA compatible LCD screen.

NEC UltraLite

The NEC UltraLite, released in mid-1989, was perhaps the first notebook computer, weighing just over 2 kg; in lieu of a floppy or hard drive, it contained a 2 megabyte RAM drive, but this reduced its utility as well as its size.

Compaq LTE

Additional light-weight notebook computers to include hard drives were those of the Compaq LTE series, introduced toward the end of 1989. Truly the size of a notebook, they also featured grayscale backlit displays with CGA resolution.

Apple Macintosh Portable

The first Apple Computer machine designed to be used on the go was the 1989 Macintosh Portable (although an LCD screen had been an option for the transportable Apple IIc in 1984). Unlike the Compaq LTE laptop released earlier in the year the Macintosh Portable was actually a "luggable" not a laptop, but the Mac Portable was praised for its clear active matrix display and long battery life, but was a poor seller due to its bulk. In the absence of a true Apple laptop, several compatible machines such as the Outbound Laptop were available for Mac users; however, for copyright reasons, the user had to supply a set of Mac ROMs, which usually meant having to buy a new or used Macintosh as well.

Apple Powerbook

The Apple PowerBook series, introduced in October 1991, pioneered changes that are now de facto standards on laptops, such as room for a palm rest, and the inclusion of a pointing device (a trackball). The following year, IBM released its ThinkPad 700C, featuring a similar design (though with a distinctive red TrackPoint pointing device).

Later PowerBooks introduced the first 256-color displays (PowerBook 165c, 1993), and first true touchpad, first 16-bit sound recording, and first built-in Ethernet network adapter (PowerBook 500, 1994).

IBM RS/6000 N40

In 1994, IBM released the RS/6000 N40 laptop based on a PowerPC microprocessor running the AIX operating system, a variant of UNIX. It was manufactured by Tadpole Technology (now Tadpole Computer), who also manufactured laptops based on SPARC and Alpha microprocessors, the SPARCbook and ALPHAbook lines, respectively.

Windows 95 operating system

The summer of 1995 was a significant turning point in the history of notebook computing. In August of that year Microsoft introduced Windows 95. It was the first time that Microsoft had placed much of the power management control in the operating system. Prior to this point each brand used custom BIOS, drivers and in some cases, ASICs, to optimize the battery life of its machines. This move by Microsoft was controversial in the eyes of notebook designers because it greatly reduced their ability to innovate; however, it did serve its role in simplifying and stabilizing certain aspects of notebook design.

Intel Pentium processor

Windows 95 also ushered in the importance of the CD-ROM drive in mobile computing, and initiated the shift to the Intel Pentium processor as the base platform for notebooks. The Gateway Solo was the first notebook introduced with a Pentium processor and a CD-ROM. Also featuring a removable hard disk drive and floppy drive, the Solo was the first three-spindle (optical, floppy, and hard disk drive) notebook computer, and was extremely successful within the consumer segment of the market. In roughly the same time period the Dell Latitude, Toshiba Satellite, and IBM ThinkPad were reaching great success with Pentium-based two-spindle (hard disk and floppy disk drive) systems directed toward the corporate market.

Improved technology

As technology improved during the 1990s, the usefulness and popularity of laptops increased. Correspondingly prices went down. Several developments specific to laptops were quickly implemented, improving usability and performance. Among them were:

Improved battery technology. The heavy lead-acid batteries were replaced with lighter and more efficient technologies, first nickel cadmium or NiCd, then nickel metal hydride (NiMH) and then lithium ion battery and lithium polymer.
Power-saving processors. While laptops in 1991 were limited to the 80286 processor because of the energy demands of the more powerful 80386, the introduction of the Intel 386SL processor, designed for the specific power needs of laptops, marked the point at which laptop needs were included in CPU design. The 386SL integrated a 386SX core with a memory controller and this was paired with an I/O chip to create the SL chipset. It was more integrated than any previous solution although its cost was higher. It was heavily adopted by the major notebook brands of the time. Intel followed this with the 486SL chipset which used the same architecture. However, Intel had to abandon this design approach as it introduced its Pentium series. Early versions of the mobile Pentium required TAB mounting (also used in LCD manufacturing) and this initially limited the number of companies capable of supplying notebooks. However, Intel did eventually migrate to more standard chip packaging. One limitation of notebooks has always been the difficulty in upgrading the processor which is a common attribute of desktops. Intel did try to solve this problem with the introduction of the MMC for mobile computing. The MMC was a standard module upon which the CPU and external cache memory could sit. It gave the notebook buyer the potential to upgrade his CPU at a later date, eased the manufacturing process somewhat, and was also used in some cases to skirt U.S. import duties as the CPU could be added to the chassis after it arrived in the U.S. Intel stuck with MMC for a few generations but ultimately could not maintain the appropriate speed and data integrity to the memory subsystem through the MMC connector.
Improved liquid crystal displays, in particular active-matrix TFT (Thin-Film Transistor) LCD technology. Early laptop screens were black and white, blue and white, or grayscale, STN (Super Twist Nematic) passive-matrix LCDs prone to heavy shadows, ghosting and blurry movement (some portable computer screens were sharper monochrome plasma displays, but these drew too much current to be powered by batteries). Color STN screens were used for some time although their viewing quality was poor. By about 1991, two new color LCD technologies hit the mainstream market in a big way; Dual STN and TFT. The Dual STN screens solved many of the viewing problems of STN at a very affordable price and the TFT screens offered excellent viewing quality although initially at a steep price. DSTN continued to offer a significant cost advantage over TFT until the mid-90s before the cost delta dropped to the point that DSTN was no longer used in notebooks. Improvements in production technology meant displays became larger, sharper, had higher native resolutions, faster response time and could display color with great accuracy, making them an acceptable substitute for a traditional CRT monitor.

mproved storage technology. Early laptops and portables had only floppy disk drives. As thin, high-capacity hard disk drives with higher reliability and shock resistance and lower power consumption became available, users could store their work on laptop computers and take it with them. The 3.5" HDD was created initially as a response to the needs of notebook designers that needed smaller, lower power consumption products. With continuing pressure to shrink the notebook size even further, the 2.5" HDD was introduced. One Laptop Per Child (OLPC) and other new laptops use Flash RAM (non volatile, non mechanical memory device) instead of the mechanical hard disk.
Improved connectivity. Internal modems and standard Serial port|serial, parallel, and PS/2 ports on IBM PC-compatible laptops made it easier to work away from home; the addition of network adapters and, from 1997, USB, as well as, from 1999, Wi-Fi, made laptops as easy to use with peripherals as a desktop computer. Many newer laptops are also available with built-in 3G Broadband wireless modems.

7) HISTORY OF PERSONAL COMPUTERS

2009-05-30T13:43:00.000-07:00

by engr. AFAN BK

This article covers the history of the personal computer. A personal computer is intended for individual use, as opposed to a mainframe where the end user's requests are filtered through operating staff, or a time sharing system in which one large processor is shared by many individuals. After the development of the microprocessor, individual personal computers were low enough in cost that they eventually became affordable consumer goods. Early personal computers - generally called microcomputers - were sold often in electronic kit form and in limited numbers, and were of interest mostly to hobbyists and technicians.

ETYMOLOGY

An early use of the term "personal computer" appeared in a November 3, 1962, New York Times article reporting John W. Mauchly's vision of future computing as detailed at a recent meeting of the American Institute of Industrial Engineers. Mauchly stated, "There is no reason to suppose the average boy or girl cannot be master of a personal computer".

Six years later a manufacturer took the risk of referring to their product this way, when Hewlett Packard advertised their "Powerful Computing Genie" as "The New Hewlett Packard 9100A personal computer". This advertisement was deemed too extreme for the target audience and replaced with a much drier ad for the HP 9100A programmable calculator.

Over the next seven years the phrase had gained enough recognition that when Byte magazine published its first edition, it referred to its readers as "[in] the personal computing field", and Creative Computing defined the personal computer as a "non-(time)shared system containing sufficient processing power and storage capabilities to satisfy the needs of an individual user." Two years later, when what Byte was to call the "1977 Trinity" of preassembled small computers hit the markets, the Apple II and the PET 2001 were advertised as personal computers, while the TRS-80 was a described as a microcomputer used for household tasks including "personal financial management". By 1979 over half a million microcomputers were sold and the youth of the day had a new concept of the personal computer.

THE BEGINNINGS OF THE PERSONAL COMPUTER INDUSTRY

Kenbak-1

The Kenbak-1 is considered by the Computer History Museum to be the world's first personal computer. It was designed and invented by John Blankenbaker of Kenbak Corporation in 1970, and was first sold in early 1971. Unlike a modern personal computer, the Kenbak-1 was built of small-scale integrated circuits, and did not use a microprocessor. The system first sold for US$750. Only around 40 machines were ever built and sold. In 1973, production of the Kenbak-1 stopped as Kenbak Corporation folded.

With only 256 bytes of memory, an 8-bit word size, and input and output restricted to lights and switches, the Kenbak-1 was most useful for learning the principles of programming but not capable of running application programs.

Datapoint 2200

A programmable terminal called the Datapoint 2200 is the earliest known device that bears some significant resemblance to the modern personal computer, with a screen, keyboard, and program storage. It was made by CTC (now known as Datapoint) in 1970 and was a complete system in a small case bearing the approximate footprint of an IBM Selectric typewriter. The system's CPU was constructed from a variety of discrete components, although the company had commissioned Intel to develop a single-chip processing unit; there was a falling out between CTC and Intel, and the chip Intel had developed wasn't used. Intel soon released a modified version of that chip as the Intel 8008, the world's first 8-bit microprocessor. The needs and requirements of the Datapoint 2200 therefore determined the nature of the 8008, upon which all successive processors used in IBM-compatible PCs were based. Additionally, the design of the Datapoint 2200's multi-chip CPU and the final design of the Intel 8008 were so similar that the two are largely software-compatible; therefore, the Datapoint 2200, from a practical perspective, can be regarded as if it were indeed powered by an 8008, which makes it a strong candidate for the title of "first microcomputer" as well.

Micral N

The French company R2E was formed by two former engineers of the Intertechnique company to sell their Intel 8008-based microcomputer design. The system was originally developed at the Institut National de la Recherche Agronomique to automate hygrometric measurements. The system ran at 500 kHz and included 16 kB of memory, and sold for 8500 Francs, about $1300US.

A bus, called Pluribus, was introduced that allowed connection of up to 14 boards. Boards for digital I/O, analog I/O, memory, floppy disk were available from R2E. The Micral operating system was initially called Sysmic, and was later renamed Prologue.

R2E was absorbed by Groupe Bull in 1978. Although Groupe Bull continued the production of Micral computers, it was not interested in the personal computer market, and Micral computers were mostly confined to highway toll gates (where they remained in service until 1992) and similar niche markets.

Xerox Alto and Star

The Xerox Alto, developed at Xerox PARC in 1973, was the first computer to use a mouse, the desktop metaphor, and a graphical user interface (GUI), concepts first introduced by Douglas Engelbart while at SRI International. It was the first example of what would today be recognized as a complete personal computer.

In 1981, Xerox Corporation introduced the Xerox Star workstation, officially known as the "8010 Star Information System". Drawing upon its predecessor, the Xerox Alto, it was the first commercial system to incorporate various technologies that today have become commonplace in personal computers, including a bit-mapped display, a windows-based graphical user interface, icons, folders, mouse, Ethernet networking, file servers, print servers and e-mail. It also included a programming language system called Smalltalk.

While its use was limited to the engineers at Xerox PARC, the Alto had features years ahead of its time. Both the Xerox Alto and the Xerox Star would inspire the Apple Lisa and the Apple Macintosh.

IBM 5100

IBM 5100 was a desktop computer introduced in September 1975, six years before the IBM PC. It was the evolution of a prototype called the SCAMP (Special Computer APL Machine Portable) that IBM demonstrated in 1973. In January 1978 IBM announced the IBM 5110, its larger cousin. The 5100 was withdrawn in March 1982.

When the PC was introduced in 1981, it was originally designated as the IBM 5150, putting it in the "5100" series, though its architecture wasn't directly descended from the IBM 5100.

Altair 8800

Development of the single-chip microprocessor was the gateway to the popularization of cheap, easy to use, and truly personal computers. It was only a matter of time before one such design was able to hit a sweet spot in terms of pricing and performance, and that machine is generally considered to be the Altair 8800, from MITS, a small company that produced electronics kits for hobbyists.

The Altair was introduced in a Popular Electronics magazine article in the January 1975 issue. In keeping with MITS's earlier projects, the Altair was sold in kit form, although a relatively complex one consisting of four circuit boards and many parts. Priced at only $400, the Altair tapped into pent-up demand and surprised its creators when it generated thousands of orders in the first month. Unable to keep up with demand, MITS eventually sold the design after about 10,000 kits had shipped.

The introduction of the Altair spawned an entire industry based on the basic layout and internal design. New companies like Cromemco started up to supply add-on kits, while Microsoft was founded to supply a BASIC interpreter for the systems. Soon after a number of complete "clone" designs, typified by the IMSAI 8080, appeared on the market. This led to a wide variety of systems based on the S-100 bus introduced with the Altair, machines of generally improved performance, quality and ease-of-use.

The Altair, and early clones, were relatively difficult to use. The machines contained no operating system in ROM, so starting it up required a machine language program to be entered by hand via front-panel switches, one location at a time. The program was typically a small driver for an attached paper tape reader, which would then be used to read in another "real" program. Later systems added bootstrapping code to improve this process, and the machines became almost universally associated with the CP/M operating system, loaded from floppy disk.

The Altair created a new industry of microcomputers and computer kits, with many others following, such as a wave of small business computers in the late 1970s based on the Intel 8080, Zilog Z80 and Intel 8085 microprocessor chips. Most ran the CP/M-80 operating system developed by Gary Kildall at Digital Research. CP/M-80 was the first popular microcomputer operating system to be used by many different hardware vendors, and many software packages were written for it, such as WordStar and dBase II.

Homebrew Computer Club

Although the Altair spawned an entire business, another side effect it had was to demonstrate that the microprocessor had so reduced the cost and complexity of building a microcomputer that anyone with an interest could build their own. Many such hobbyists met and traded notes at the meetings of the Homebrew Computer Club (HCC) in Silicon Valley. Although the HCC was relatively short-lived, its influence on the development of the modern PC was enormous.

Members of the group complained that microcomputers would never become commonplace if they still had to be built up, from parts like the original Altair, or even in terms of assembling the various add-ons that turned the machine into a useful system. What they felt was needed was an all-in-one system. Out of this desire came the Sol-20 computer, which placed an entire S-100 system - QWERTY keyboard, CPU, display card, memory and ports - into an attractive single box. The systems were packaged with a cassette tape interface for storage and a 12" monochrome monitor. Complete with a copy of BASIC, the system sold for US$2,100. About 10,000 Sol-20 systems were sold.

Although the Sol-20 was the first all-in-one system that we would recognize today, the basic concept was already rippling through other members of the group, and interested external companies.

PET

Chuck Peddle designed the Commodore PET (short for Personal Electronic Transactor) around his MOS 6502 processor. It was essentially a single-board computer with a new display chip (the MOS 6545) driving a small built-in monochrome monitor with 40×25 character graphics. The processor card, keyboard, monitor and cassette drive were all mounted in a single metal case. In 1982, Byte referred to the PET design as "the world's first personal computer".

The PET shipped in two models; the 2001-4 with 4 kB of RAM, or the 2001-8 with 8 kB. The machine also included a built-in Datassette for data storage located on the front of the case, which left little room for the keyboard. The 2001 was announced in June 1977 and the first 100 units were shipped in mid October 1977. However they remained back-ordered for months, and to ease deliveries they eventually canceled the 4 kB version early the next year.

Although the machine was fairly successful, there were frequent complaints about the tiny calculator-like keyboard, often referred to as a "Chiclet keyboard" due to the keys' resemblance to the popular gum candy. This was addressed in upgraded "dash N" and "dash B" versions of the 2001, which put the cassette outside the case, and included a much larger keyboard with a full stroke non-click motion. Internally a newer and simpler motherboard was used, along with an upgrade in memory to 8, 16, or 32 KB, known as the 2001-N-8, 2001-N-16 or 2001-N-32, respectively.

The PET was the least successful of the 1977 Trinity machines, with under 1 million sales.

Apple II

Steve Wozniak (known as "Woz"), a regular visitor to Homebrew Computer Club meetings, designed the single-board Apple I computer and first demonstrated it there. With specifications in hand and an order for 100 machines at US$666.66 each from the Byte Shop, Woz and his friend Steve Jobs founded Apple Computer.

About 200 of the machines sold before the company announced the Apple II as a complete computer. It had color graphics, full QWERTY keyboard, and internal slots for expansion mounted in a high build quality streamlined plastic case. The monitor and I/O devices were sold separately. The original Apple II operating system was only the built-in BASIC interpreter contained in ROM. Apple DOS was added to support the diskette drive; the last version was "Apple DOS 3.3".

Its higher price and lack of floating point BASIC, along with a lack of retail distribution sites, caused it to lag in sales behind the other Trinity machines until 1979, when it surpassed the PET; it was again pushed into 4th when Atari introduced its popular Atari 8-bit systems.

In spite of slow sales, the Apple II's lifetime was much greater than other machines and it ended up being the best seller among them; more than 4 million Apple IIs were shipped by the end of its production in 1993.

TRS-80

Tandy Corporation introduced the TRS-80, retroactively known as the Model 1 as improved models were introduced. The Model 1 combined the motherboard and keyboard into one unit with a separate monitor and power supply. Although the PET and especially the Apple II offered certain features that were greatly advanced in comparison, Tandy 3000+ Radio Shack storefronts ensured that it would have widespread distribution that neither Apple nor Commodore could touch.

The Model 1 used a Zilog Z80 processor clocked at 1.77 MHz (the later models were shipped with a Z80A). The basic model originally shipped with 4 kB of RAM, and later 16 kB. Its other strong features were its full stroke QWERTY keyboard, small size, well written Floating BASIC and inclusion of a monitor and tape deck all for US$599, a savings of US$600 over the Apple II. Its major drawback was the massive RF interference it caused in surrounding electronics, which caused it to run afoul of newer FCC regulations - a problem solved only by the Model I's retirement in favor of the TRS-80 Model III.

About 1.5 million of the TRS-80 line were sold before their cancellation in 1985.

HOME COMPUTER " Atari " 400/800

Atari was a well-known brand in the late 1970s, both due to their hit arcade games like PONG, as well as the hugely successful Atari VCS game console. Realizing that the VCS would have a limited lifetime in the market before a technically advanced competitor came along, Atari decided they would be that competitor, and started work on a new console design that was much more advanced.

While these designs were being worked on, the Trinity machines hit the market with considerable fanfare. Atari's management decided to re-purpose the work as home computers instead. Their knowledge of the home market through the VCS resulted in machines that were almost indestructible and just as easy to use as a games machine - simply plug in a cartridge and go. The new machines were first introduced as the 400 and 800 in 1978, but production problems meant widespread sales did not start until the next year.

At the time, the machines offered what was then much higher performance than contemporary designs and a number of graphics and sound features that no other microcomputer could match. They became very popular as a result, quickly eclipsing the Trinity machines in sales. In spite of a promising start with about 600,000 sold by 1981, the looming price war left Atari in a bad position. They were unable to compete effectively with Commodore, and only about 2 million machines were produced by the end of their production run.

TI-99

Texas Instruments (TI), at the time the world's largest chip manufacturer, decided to enter the home computer market with the Texas Instruments TI-99/4A. Announced long before its arrival, most industry observers expected the machine to wipe out all competition - on paper its performance was untouchable, and TI had enormous cash reserves and development capability.

When it was released in late 1979 TI took a somewhat slow approach to introducing it, initially focusing on schools. Contrary to earlier predictions, the TI-99's limitations meant it was not the giant-killer everyone expected, and a number of its design features were highly controversial. A total of 2.8 million units were shipped before the TI-99/4A was discontinued in March 1984.

VIC-20 and Commodore 64

Realizing that the PET could not easily compete with color machines like the Apple II and Atari, Commodore introduced the VIC-20 to address the home market. Limitations due to tiny 4 kB memory and its relatively limited display in comparison to those machines was offset by a low and ever falling price. Millions of VIC-20s were sold.

The best-selling personal computer of all time was released by Commodore International in 1982: the Commodore 64 (C64) sold over 17 million units before its end. The C64 name derived from its 64kb of RAM and it also came with a side mount ROM cartridge slot. It used the 6510 microprocessor CPU; MOS Technology, Inc. was then owned by Commodore.

The IBM PC

IBM responded to the success of the Apple II with the IBM PC, released in August, 1981. Like the Apple II and S-100 systems, it was based on an open, card-based architecture, which allowed third parties to develop for it. It used the Intel 8088 CPU running at 4.77 MHz, containing 29000 transistors. The first model used an audio cassette for external storage, though there was an expensive floppy disk option. The cassette option was never popular and was removed in the PC XT of 1983.[20] The XT added a 10MB hard drive in place of one of the two floppy disks and increased the number of expansion slots from 5 to 8. While the original PC design could accommodate only up to 64k on the main board, the architecture was able to accommodate up to 640KB of RAM, with the rest on cards. Later revisions of the design increased the limit to 256K on the main board.

The IBM PC typically came with PC-DOS, an operating system based upon Gary Kildall's CP/M-80 operating system. In 1980, IBM approached Digital Research, Kildall's company, for a version of CP/M for its upcoming IBM PC. Kildall's wife and business partner, Dorothy McEwen, met with the IBM representatives who were unable to negotiate a standard non-disclosure agreement with her. IBM turned to Bill Gates, who was already providing the ROM BASIC interpreter for the PC. Gates offered to provide 86-DOS, developed by Tim Paterson of Seattle Computer Products. IBM rebranded it as PC-DOS, while Microsoft sold variations and upgrades as MS-DOS.

The impact of the Apple II and the IBM PC was fully demonstrated when Time Magazine named the home computer the "Machine of the Year", or Person of the Year for 1982 (January 3, 1983, "The Computer Moves In"). It was the first time in the history of the magazine that an inanimate object was given this award.

APPLE LISA & MACINTOSH

In 1983 Apple Computer introduced the first mass-marketed microcomputer with a graphical user interface, the Lisa. The Lisa ran on a Motorola 68000 microprocessor and came equipped with 1 megabyte of RAM, a 12-inch (300 mm) black-and-white monitor, dual 5¼-inch floppy disk drives and a 5 megabyte Profile hard drive. The Lisa's slow operating speed and high price (US$10,000), however, led to its commercial failure. It also led to the decision by Steve Jobs to move to the Apple Macintosh team.

Drawing upon its experience with the Lisa, in 1984 Apple launched the Macintosh. Its debut was announced by a single broadcast during the 1984 Super Bowl XVIII of the now famous television commercial "1984" created by Ridley Scott and based on George Orwell's novel 1984. The intention of the ad was to equate Big Brother with the IBM PC and a nameless female action hero (portrayed by Anya Major), with the Macintosh.

The Mac was the first successful mouse-driven computer with a graphical user interface or 'WIMP' (Windows, Icons, Menus, and Pointers). Based on the Motorola 68000 microprocessor, the Macintosh included many of the Lisa's features at a price of US$2,495. The Macintosh was initially introduced with 128 kb of RAM and later that year a 512 kb RAM model became available. To reduce costs compared the Lisa, the year-younger Macintosh had a simplified motherboard design, no internal hard drive, and a single 3.5" floppy drive. Applications that came with the Macintosh included MacPaint, a bit-mapped graphics program, and MacWrite, which demonstrated WYSIWYG word processing.

While not an immediate success upon its release, the Macintosh was a successful personal computer for years to come. This is particularly due to the introduction of desktop publishing in 1985 through Apple's partnership with Adobe. This partnership introduced the LaserWriter printer and Aldus PageMaker (now Adobe PageMaker) to users of the personal computer. After Steve Jobs resigned from Apple in 1985 to start NeXT, a number of different models of Macintosh, including the Macintosh Plus and Macintosh II, were released to a great degree of success. The entire Macintosh line of computers was IBM's major competition up until the early 1990s.

GUIs spread

In the Commodore world, GEOS was available on the Commodore 64 and Commodore 128. Later, a version was available for PCs running DOS. It could be used with a mouse or a joystick as a pointing device, and came with a suite of GUI applications. Commodore's later product line, the Amiga platform, ran a GUI operating system by default. The Amiga laid the blueprint for future development of personal computers with its groundbreaking graphics and sound capabilities. Byte Magazine called it "the first multimedia computer... so far ahead of its time that almost nobody could fully articulate what it was all about.

In 1985, the Atari ST, also based on the Motorola 68000 microprocessor, was introduced with the first color GUI in the Atari TOS. It could be modified to emulate the Macintosh using the third-party Spectre GCR device.

In 1987, Acorn launched the Archimedes range of high-performance home computers in Europe and Australasia. Based around their own 32-bit ARM RISC processor, the systems initially shipped with a GUI OS called Arthur. In 1989, Arthur was superseded by a multi-tasking GUI-based operating system called RISC OS. By default, the mice used on these computers had three buttons.

6) HISTORY OF OPERATING SYSTEM

2009-05-30T13:42:00.000-07:00

by engr. AFAN BK

The history of computer operating systems recapitulates to a degree the recent history of computer hardware.

Operating systems (OSes) provide a set of functions needed and used by most application-programs on a computer, and the necessary linkages for the control and synchronization of the computer's hardware. On the first computers, without an operating system, every program needed the full hardware specification to run correctly and perform standard tasks, and its own drivers for peripheral devices like printers and card-readers. The growing complexity of hardware and application-programs eventually made operating systems a necessity.

BACKGROUND

Early computers lacked any form of operating system. The user had sole use of the machine and would arrive armed with program and data, often on punched paper and tape. The program would be loaded into the machine, and the machine would be set to work until the program completed or crashed. Programs could generally be debugged via a front panel using switches and lights. It is said that Alan Turing was a master of this on the early Manchester Mark 1 machine, and he was already deriving the primitive conception of an operating system from the principles of the Universal Turing machine.

Later machines came with libraries of support code, which would be linked to the user's program to assist in operations such as input and output. This was the genesis of the modern-day operating system. However, machines still ran a single job at a time; at Cambridge University in England the job queue was at one time a washing line from which tapes were hung with different colored clothes-pegs to indicate job-priority.

As machines became more powerful, the time to run programs diminished and the time to hand off the equipment became very large by comparison. Accounting for and paying for machine usage moved on from checking the wall clock to automatic logging by the computer. Run queues evolved from a literal queue of people at the door, to a heap of media on a jobs-waiting table, or batches of punch-cards stacked one on top of the other in the reader, until the machine itself was able to select and sequence which magnetic tape drives were online. Where program developers had originally had access to run their own jobs on the machine, they were supplanted by dedicated machine operators who looked after the well-being and maintenance of the machine and were less and less concerned with implementing tasks manually. When commercially available computer centers were faced with the implications of data lost through tampering or operational errors, equipment vendors were put under pressure to enhance the runtime libraries to prevent misuse of system resources. Automated monitoring was needed not just for CPU usage but for counting pages printed, cards punched, cards read, disk storage used and for signaling when operator intervention was required by jobs such as changing magnetic tapes.

All these features were building up towards the repertoire of a fully capable operating system. Eventually the runtime libraries became an amalgamated program that was started before the first customer job and could read in the customer job, control its execution, clean up after it, record its usage, and immediately go on to process the next job. Significantly, it became possible for programmers to use symbolic program-code instead of having to hand-encode binary images, once task-switching allowed a computer to perform translation of a program into binary form before running it. These resident background programs, capable of managing multistep processes, were often called monitors or monitor-programs before the term OS established itself.

An underlying program offering basic hardware-management, software-scheduling and resource-monitoring may seem a remote ancestor to the user-oriented OSes of the personal computing era. But there has been a shift in meaning. With the era of commercial computing, more and more "secondary" software was bundled in the OS package, leading eventually to the perception of an OS as a complete user-system with utilities, applications (such as text editors and file managers) and configuration tools, and having an integrated graphical user interface. The true descendant of the early operating systems is what is now called the "kernel". In technical and development circles the old restricted sense of an OS persists because of the continued active development of embedded operating systems for all kinds of devices with a data-processing component, from hand-held gadgets up to industrial robots and real-time control-systems, which do not run user-applications at the front-end. An embedded OS in a device today is not so far removed as one might think from its ancestor of the 1950s.

THE MAINFRAME ERA

It is generally thought that the first operating system used for real work was GM-NAA I/O, produced in 1956 by General Motors' Research division for its IBM 704. Most other early operating systems for IBM mainframes were also produced by customers.

Early operating systems were very diverse, with each vendor or customer producing one or more operating systems specific to their particular mainframe computer. Every operating system, even from the same vendor, could have radically different models of commands, operating procedures, and such facilities as debugging aids. Typically, each time the manufacturer brought out a new machine, there would be a new operating system, and most applications would have to be manually adjusted, recompiled, and retested.

SYSTEMS ON "IBM" HARDWARE

The state of affairs continued until the 1960s when IBM, already a leading hardware vendor, stopped the work on existing systems, and put all the effort into developing the System/360 series of machines, all of which used the same instruction architecture. IBM intended to develop also a single operating system for the new hardware, the OS/360. The problems encountered in the development of the OS/360 are legendary, and are described by Fred Brooks in The Mythical Man-Month—a book that has become a classic of software engineering. Because of performance differences across the hardware range and delays with software development, a whole family of operating systems were introduced instead of a single OS/360.[3][4]

IBM wound up releasing a series of stop-gaps followed by three longer-lived operating systems:

OS/MFT for mid-range systems. This had one successor, OS/VS1, which was discontinued in the 1980s.
OS/MVT for large systems. This was similar in most ways to OS/MFT (programs could be ported between the two without being re-compiled), but has more sophisticated memory management and a time-sharing facility, TSO. MVT had several successors including the current z/OS.
DOS/360 for small System/360 models had several successors including the current z/VSE. It was significantly different from OS/MFT and OS/MVT.
IBM maintained full compatibility with the past, so that programs developed in the sixties can still run under z/VSE (if developed for DOS/360) or z/OS (if developed for OS/MFT or OS/MVT) with no change.

OTHER MAINFRAME OPERATING SYSTEMS

Control Data Corporation developed the SCOPE operating system in the 1960s, for batch processing. In cooperation with the University of Minnesota, the KRONOS and later the NOS operating systems were developed during the 1970s, which supported simultaneous batch and timesharing use. Like many commercial timesharing systems, its interface was an extension of the Dartmouth BASIC operating systems, one of the pioneering efforts in timesharing and programming languages. In the late 1970s, Control Data and the University of Illinois developed the PLATO system, which used plasma panel displays and long-distance time sharing networks. PLATO was remarkably innovative for its time; the shared memory model of PLATO's TUTOR programming language allowed applications such as real-time chat and multi-user graphical games.

UNIVAC, the first commercial computer manufacturer, produced a series of EXEC operating systems. Like all early main-frame systems, this was a batch-oriented system that managed magnetic drums, disks, card readers and line printers. In the 1970s, UNIVAC produced the Real-Time Basic (RTB) system to support large-scale time sharing, also patterned after the Dartmouth BASIC system.

Burroughs Corporation introduced the B5000 in 1961 with the MCP (Master Control Program) operating system. The B5000 was a stack machine designed to exclusively support high-level languages with no machine language or assembler and indeed the MCP was the first OS to be written exclusively in a high-level language (ESPOL, a dialect of ALGOL). MCP also introduced many other ground-breaking innovations, such as being the first commercial implementation of virtual memory. MCP is still in use today in the Unisys ClearPath/MCP line of computers.

General Electric and MIT developed General Electric Comprehensive Operating Supervisor (GECOS), which introduced the concept of ringed security privilege levels. After acquisition by Honeywell it was renamed to General Comprehensive Operating System (GCOS).

Digital Equipment Corporation developed many operating systems for its various computer lines, including TOPS-10 and TOPS-20 time sharing systems for the 36-bit PDP-10 class systems. Prior to the widespread use of UNIX, TOPS-10 was a particularly popular system in universities, and in the early ARPANET community.

In the late 1960s through the late 1970s, several hardware capabilities evolved that allowed similar or ported software to run on more than one system. Early systems had utilized microprogramming to implement features on their systems in order to permit different underlying architecture to appear to be the same as others in a series. In fact most 360's after the 360/40 (except the 360/165 and 360/168) were microprogrammed implementations. But soon other means of achieving application compatibility were proven to be more significant.

MINICOMPUTERS & THE RISE OF "UNIX"

The beginnings of the UNIX operating system was developed at AT&T Bell Laboratories in the late 1960s. Because it was essentially free in early editions, easily obtainable, and easily modified, it achieved wide acceptance. It also became a requirement within the Bell systems operating companies. Since it was written in a high level C language, when that language was ported to a new machine architecture UNIX was also able to be ported. This portability permitted it to become the choice for a second generation of minicomputers and the first generation of workstations. By widespread use it exemplified the idea of an operating system that was conceptually the same across various hardware platforms. It still was owned by AT&T and that limited its use to groups or corporations who could afford to license it. It became one of the roots of the open source movement.

Other than that Digital Equipment Corporation created the simple RT-11 system for its 16-bit PDP-11 class machines, and the VMS system for the 32-bit VAX computer.

Another system which evolved in this time frame was the Pick operating system. The Pick system was developed and sold by Microdata Corporation who created the precursors of the system. The system is an example of a system which started as a database application support program and graduated to system work.

HOME COMPUTERS

Although most small 8-bit home computers of the 1980s, such as the Commodore 64, the Atari 8-bit, the Amstrad CPC, ZX Spectrum series and others could use a disk-loading operating system, such as CP/M or GEOS they could generally work without one. In fact, most if not all of these computers shipped with a built-in BASIC interpreter on ROM, which also served as a crude operating system, allowing minimal file management operations (such as deletion, copying, etc.) to be performed and sometimes disk formatting, along of course with application loading and execution, which sometimes required a non-trivial command sequence, like with the Commodore 64.

The fact that the majority of these machines were bought for entertainment and educational purposes and were seldom used for more "serious" or business/science oriented applications, partly explains why a "true" operating system was not necessary.

Another reason is that they were usually single-task and single-user machines and shipped with minimal amounts of RAM, usually between 4 and 256 kilobytes, with 64 and 128 being common figures, and 8-bit processors, so an operating system's overhead would likely compromise the performance of the machine without really being necessary.

Even the available word processor and integrated software applications were mostly self-contained programs which took over the machine completely, as also did video games.

VIDEO GAMES

Since virtually all video game consoles and arcade cabinets designed and built after 1980 were true digital machines (unlike the analog Pong clones and derivatives), some of them carried a minimal form of BIOS or built-in game, such as the ColecoVision, the Sega Master System and the SNK Neo Geo. There were however successful designs where a BIOS was not necessary, such as the Nintendo NES and its clones.

Modern day game consoles and videogames, starting with the PC-Engine, all have a minimal BIOS that also provides some interactive utilities such as memory card management, Audio or Video CD playback, copy protection and sometimes carry libraries for developers to use etc. Few of these cases, however, would qualify as a "true" operating system.

The most notable exceptions are probably the Dreamcast game console which includes a minimal BIOS, like the PlayStation, but can load the Windows CE operating system from the game disk allowing easily porting of games from the PC world, and the Xbox game console, which is little more than a disguised Intel-based PC running a secret, modified version of Microsoft Windows in the background. Furthermore, there are Linux versions that will run on a Dreamcast and later game consoles as well.

Long before that, Sony had released a kind of development kit called the Net Yaroze for its first PlayStation platform, which provided a series of programming and developing tools to be used with a normal PC and a specially modified "Black PlayStation" that could be interfaced with a PC and download programs from it. These operations require in general a functional OS on both platforms involved.

In general, it can be said that videogame consoles and arcade coin operated machines used at most a built-in BIOS during the 1970s, 1980s and most of the 1990s, while from the PlayStation era and beyond they started getting more and more sophisticated, to the point of requiring a generic or custom-built OS for aiding in development and expandability.
The personal computer era: Apple, PC/MS/DR-DOS and beyond

THE PERSONAL COMPUTER ERA: " APPLE, PC/MS/DR-DOS & beyond"

The development of microprocessors made inexpensive computing available for the small business and hobbyist, which in turn led to the widespread use of interchangeable hardware components using a common interconnection (such as the S-100, SS-50, Apple II, ISA, and PCI buses), and an increasing need for 'standard' operating systems to control them. The most important of the early OSes on these machines was Digital Research's CP/M-80 for the 8080 / 8085 / Z-80 CPUs. It was based on several Digital Equipment Corporation operating systems, mostly for the PDP-11 architecture. Microsoft's first Operating System, M-DOS, was designed along many of the PDP-11 features, but for microprocessor based system. MS-DOS (or PC-DOS when supplied by IBM) was based originally on CP/M-80. Each of these machines had a small boot program in ROM which loaded the OS itself from disk. The BIOS on the IBM-PC class machines was an extension of this idea and has accreted more features and functions in the 20 years since the first IBM-PC was introduced in 1981.

The decreasing cost of display equipment and processors made it practical to provide graphical user interfaces for many operating systems, such as the generic X Window System that is provided with many UNIX systems, or other graphical systems such as Microsoft Windows, the RadioShack Color Computer's OS-9 Level II/MultiVue, Commodore's AmigaOS, Apple's Mac OS, or even IBM's OS/2. The original GUI was developed at Xerox Palo Alto Research Center in the early '70s (the Alto computer system) and imitated by many vendors.

5) HISTORY OF COMPUTER SCIENCE

2009-05-30T13:40:00.000-07:00

by engr. AFAN BK

The history of computer science began long before the modern discipline of computer science that emerged in the twentieth century. The progression, from mechanical inventions and mathematical theories towards the modern concepts and machines, formed a major academic field and the basis of a massive world-wide industry.

EARLY COMPUTATION

The earliest known tool for use in computation was the abacus, and it was thought to have been invented in Babylon circa 2400 BCE. Its original style of usage was by lines drawn in sand with pebbles. This was the first known computer and most advanced system of calculation known to date - preceding Greek methods by 2,000 years. Abaci of a more modern design are still used as calculation tools today.

In 1115 BCE, the South Pointing Chariot was invented in ancient China. It was the first known geared mechanism to use a differential gear, which was later used in analog computers. The Chinese also invented a more sophisticated abacus from around the 2nd century BCE, known as the Chinese abacus.

In the 5th century BCE in ancient India, the grammarian Pāṇini formulated the grammar of Sanskrit in 3959 rules known as the Ashtadhyayi which was highly systematized and technical. Panini used metarules, transformations and recursions with such sophistication that his grammar had the computing power equivalent to a Turing machine. Between 200 BCE and 400 CE, Jaina mathematicians in India invented the logarithm. From the 13th century, logarithmic tables were produced by Muslim mathematicians.

The Antikythera mechanism is believed to be the earliest known mechanical analog computer. It was designed to calculate astronomical positions. It was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa 100 BC.

Mechanical analog computer devices appeared again a thousand years later in the medieval Islamic world and were developed by Muslim astronomers, such as the equatorium by Arzachel, the mechanical geared astrolabe by Abū Rayhān al-Bīrūnī, and the torquetum by Jabir ibn Aflah. The first programmable machines were also invented by Muslim engineers, such as the automatic flute player by the Banū Mūsā brothers and the humanoid robots by Al-Jazari. Muslim mathematicians also made important advances in cryptography, such as the development of cryptanalysis and frequency analysis by Alkindus.

When John Napier discovered logarithms for computational purposes in the early 17th century, there followed a period of considerable progress by inventors and scientists in making calculating tools. Around 1640, Blaise Pascal, a leading French mathematician, constructed the first mechanical adding device based on a design described by Greek mathematician Hero of Alexandria.

None of the early computational devices were really computers in the modern sense, and it took considerable advancement in mathematics and theory before the first modern computers could be designed.

ALGORITHMS

In the 7th century, Indian mathematician Brahmagupta gave the first explanation of the Hindu-Arabic numeral system and the use of zero as both a placeholder and a decimal digit.

Approximately around the year 825, Persian mathematician Al-Khwarizmi wrote a book, On the Calculation with Hindu Numerals, that was principally responsible for the diffusion of the Indian system of numeration in the Middle East and then Europe. Around the 12th century, there was translation of this book written into Latin: Algoritmi de numero Indorum. These books presented newer concepts to perform a series of steps in order to accomplish a task such as the systematic application of arithmetic to algebra. By derivation from his name, we have the term algorithm.

BINARY LOGIC

Around the 3rd century BC, Indian mathematician Pingala discovered the binary numeral system. In this system, still used today to process all modern computers, a sequence of ones and zeros can represent any number.

In 1703, Gottfried Leibniz developed logic in a formal, mathematical sense with his writings on the binary numeral system. In his system, the ones and zeros also represent true and false values or on and off states. But it took more than a century before George Boole published his Boolean algebra in 1854 with a complete system that allowed computational processes to be mathematically modeled.

By this time, the first mechanical devices driven by a binary pattern had been invented. The industrial revolution had driven forward the mechanization of many tasks, and this included weaving. Punch cards controlled Joseph Marie Jacquard's loom in 1801, where a hole punched in the card indicated a binary one and an unpunched spot indicated a binary zero. Jacquard's loom was far from being a computer, but it did illustrate that machines could be driven by binary systems.

BIRTH OF COMPUTER SCIENCE

Before the 1920s, computers (sometimes computors) were human clerks that performed computations. They were usually under the lead of a physicist. Many thousands of computers were employed in commerce, government, and research establishments. Most of these computers were women, and they were known to have a degree in calculus. Some performed astronomical calculations for calendars.

After the 1920s, the expression computing machine referred to any machine that performed the work of a human computer, especially those in accordance with effective methods of the Church-Turing thesis. The thesis states that a mathematical method is effective if it could be set out as a list of instructions able to be followed by a human clerk with paper and pencil, for as long as necessary, and without ingenuity or insight.

Machines that computed with continuous values became known as the analog kind. They used machinery that represented continuous numeric quantities, like the angle of a shaft rotation or difference in electrical potential.

Digital machinery, in contrast to analog, were able to render a state of a numeric value and store each individual digit. Digital machinery used difference engines or relays before the invention of faster memory devices.

The phrase computing machine gradually gave away, after the late 1940s, to just computer as the onset of electronic digital machinery became common. These computers were able to perform the calculations that were performed by the previous human clerks.

Since the values stored by digital machines were not bound to physical properties like analog devices, a logical computer, based on digital equipment, was able to do anything that could be described "purely mechanical." Alan Turing, known as the Father of Computer Science, invented such a logical computer known as the Turing Machine, which later evolved into the modern computer. These new computers were also able to perform non-numeric computations, like music.

From the time when computational processes were performed by human clerks, the study of computability began a science by being able to make evident which was not explicit into ordinary sense more immediate.

THE THEORETICAL GROUNDWORK

The mathematical foundations of modern computer science began to be laid by Kurt Gödel with his incompleteness theorem (1931). In this theorem, he showed that there were limits to what could be proved and disproved within a formal system. This led to work by Gödel and others to define and describe these formal systems, including concepts such as mu-recursive functions and lambda-definable functions.

1936 was a key year for computer science. Alan Turing and Alonzo Church independently, and also together, introduced the formalization of an algorithm, with limits on what can be computed, and a "purely mechanical" model for computing.

These topics are covered by what is now called the Church–Turing thesis, a hypothesis about the nature of mechanical calculation devices, such as electronic computers. The thesis claims that any calculation that is possible can be performed by an algorithm running on a computer, provided that sufficient time and storage space are available.

Turing also included with the thesis a description of the Turing machine. A Turing machine has an infinitely long tape and a read/write head that can move along the tape, changing the values along the way. Clearly such a machine could never be built, but nonetheless, the model can simulate the computation of any algorithm which can be performed on a modern computer.

Turing is so important to computer science that his name is also featured on the Turing Award and the Turing test. He contributed greatly to British code-breaking successes in the Second World War, and continued to design computers and software through the 1940s, but committed suicide in 1954.

At a symposium on large-scale digital machinery in Cambridge, Turing said, "We are trying to build a machine to do all kinds of different things simply by programming rather than by the addition of extra apparatus".

In 1948, the first practical computer that could run stored programs, based on the Turing machine model, had been built - the Manchester Baby.

In 1950, Britain's National Physical Laboratory completed Pilot ACE, a small scale programmable computer, based on Turing's philosophy.

SHANNON & INFORMATION THEORY

Up to and during the 1930s, electrical engineers were able to build electronic circuits to solve mathematical and logic problems, but most did so in an ad hoc manner, lacking any theoretical rigor. This changed with Claude Elwood Shannon's publication of his 1937 master's thesis, A Symbolic Analysis of Relay and Switching Circuits. While taking an undergraduate philosophy class, Shannon had been exposed to Boole's work, and recognized that it could be used to arrange electromechanical relays (then used in telephone routing switches) to solve logic problems. This concept, of utilizing the properties of electrical switches to do logic, is the basic concept that underlies all electronic digital computers, and his thesis became the foundation of practical digital circuit design when it became widely known among the electrical engineering community during and after World War II.

Shannon went on to found the field of information theory with his 1948 paper entitled A Mathematical Theory of Communication, which applied probability theory to the problem of how to best encode the information a sender wants to transmit. This work is one of the theoretical foundations for many areas of study, including data compression and cryptography.

WIENER & CYBERNETICS

From experiments with anti-aircraft systems that interpreted radar images to detect enemy planes, Norbert Wiener coined the term cybernetics from the Greek word for "steersman." He published "Cybernetics" in 1948, which influenced artificial intelligence. Wiener also compared computation, computing machinery, memory devices, and other cognitive similarities with his analysis of brain waves.

4) COMPUTING HARDWARE IN SOVIET COUNTRIES

2009-05-30T13:36:00.000-07:00

by engr. AFAN BK

The history of computing hardware in the former Soviet Bloc is somewhat different from that of Western countries. Computers were not imported in a large scale from the West. All computer hardware was either designed locally or tacitly studied and reproduced. This redevelopment led to some incompatibilities with Western standards, such as Integrated circuit pins on 2.5 mm spacing instead of 2.54 (0.1 inch) spacing. This made Soviet chips unsaleable on the world market, and made test machinery more expensive.

SOVIET COMPUTERS

1- MESM
2- Strela
3- Micro-80
4- Radio-86RK
5- Specialist
6- UT-88
7- Orion-128
8- Vector-06C

MESM

One of the first universally programmable computers in continental Europe was created by a team of scientists under the direction of Sergei Alekseyevich Lebedev from the Kiev Institute of Electrotechnology in the Soviet Union (now Ukraine).

The computer was known as MESM (МЭСМ, Малая Электронно-Счетная Машина, Small Electronic Calculating Machine), and became operational in 1950. It had about 6,000 vacuum tubes and consumed 25 kW of power. It could perform approximately 3,000 operations per minute.

Strela

The Strela computer 1953–1956, used 43-bit floating point words, with a signed 35-bit mantissa and a signed 6-bit exponent.

Seven Strelas were manufactured in Moscow by a factory in the Ministry of Instrument Making and Automation Means of the USSR; they were the primary debugging platforms for computing, and the most productive computers in the Soviet Union during this period. Strelas could process 2000 instructions per second. The last version of Strela used a 4096-word magnetic drum, rotating at 6000 rpm.

Micro-80

Micro-80 was the first DIY home computer. Schematics and information were published in the popular local DIY electronic magazine Radio in 1983. It was complex, using an Intel 8080-based system which contained about 200 ICs. This system gained low popularity, but set a precedent in getting attention of hobbyist for DIY computers, and later other DIY computers were published by Radio and other DIY magazines.

Radio-86RK

The Radio-86RK was the second DIY computer featured in Radio magazine, in an edition published in 1986. It was more popular than the Micro-80 because it was much simpler (29 IC's, i8080 @1.78 MHz with i8257 and i8275 based CRT terminal). Many factories started production of home computers based on this design (such as the Apogey BK-01, Mikrosha, Krista, Partner 01.01, and the Spektr-001). These computers had limited compatibility with the original software, although their schematics were very close to the original.

Specialist

The "Specialist" was the first DIY computer which was published in a magazine other than Radio; it was published in Modelist-Konstructor, a DIY magazine which was not exclusively focused on electronics. The computer was named the Specialist, and the magazine detailing its specifications was published in 1987, although it was developed by one hobbyist two years earlier. It was much more advanced than previous DIY computers, because it had a higher graphical resolution (384x256) and a "transparent" video system, which did not slow down the CPU when both the CPU and the video system tried to access the RAM simultaneously. It gained limited popularity with hobbyists, though some factories produced DIY kits.

UT-88

Yunij Technik (Young Engineer) magazine released details for one DIY home computer, the UT-88, which was published in 1988. It was a step back to the Micro-80 conception but was much simpler and used very widespread elements, which made it available for less skilled hobbyists. It was divided to few blocks, starting from single board microcomputer with LED display and HEX keyboard, and later adding more RAM, TV interface, and complete keyboard.

Orion-128

The Orion-128 was the last DIY computer published in Radio magazine and the last i8080-based DIY computer in Russia. It used the same concepts as the Specialist and had similar specifications, with both advances and flaws. It gained more popularity because it was supported by a more popular magazine, though it was never produced by factories in any form. Much of the software for the Orion-128 was ported by hobbyists from the Specialist and the ZX Spectrum.

Vector-06C

One of the last Soviet-designed, 8-bit home computers was the Vector-06C with an i8080 CPU clone @3 MHz, which is still used by some enthusiasts. It had color graphics (16 colors) with programmable palette, few resolutions. Some games were ported from MSX and ZX Spectrum computers (converting original code from Z80 to 8080 and replacing graphics output code).

EAST GERMAN COMPUTERS

In East Germany, the main manufacturer of computer hardware was VEB Robotron. They were involved in the ESER development of a standard across Comecon countries.

POLISH COMPUTERS

Odra

Some of the earliest computers created in Poland were the first Odra computers. They were manufactured in Wrocław, (the brand name comes from the Odra River that flows through the city of Wrocław) and exported to other communist countries. The production started in 1959–1960; the computers were built at the Elwro manufacturing plant, which was closed in 1989.

The last series of Odra computers, the Odra 1300, consisted of three models: the Odra 1304, 1305, and the 1325. Although the hardware was developed by Polish teams, the software for the above machines was provided by a British company called ICL (that is, the Odra was ICL 1900 compatible).

3) HISTORY OF COMPUTING HARDWARE AFTER 1960s

2009-05-30T13:30:00.000-07:00

by engr. AFAN BK

The history of computing hardware starting at 1960 is marked by the conversion from vacuum tube to solid state devices such as the transistor and later the integrated circuit. By 1959 discrete transistors were considered sufficiently reliable and economical that they made further vacuum tube computers uncompetitive. Computer main memory slowly moved away from magnetic core memory devices to solid-state static and dynamic semiconductor memory, which greatly reduced the cost, size and power consumption of computer devices. Eventually the cost of integrated circuit devices became low enough that home computers and personal computers became widespread.

THIRD GENERATION

The mass increase in the use of computers accelerated with 'Third Generation' computers. These generally relied on Jack St. Clair Kilby's invention of the integrated circuit (or microchip), starting around 1965. However, the IBM System/360 used hybrid circuits, which were solid-state devices interconnected on a substrate with discrete wires.

The first integrated circuit was produced in September 1958 but computers using them didn't begin to appear until 1963. Some of their early uses were in embedded systems, notably used by NASA for the Apollo Guidance Computer and by the military in the LGM-30 Minuteman intercontinental ballistic missile.

By 1971, the Illiac IV supercomputer, which was the fastest computer in the world for several years, used about a quarter-million small-scale ECL logic gate integrated circuits to make up sixty-four parallel data processors.

While large 'mainframes' such as the System/360 increased storage and processing capabilities, the integrated circuit also allowed the development of much smaller computers. The minicomputer was a significant innovation in the 1960s and 1970s. It brought computing power to more people, not only through more convenient physical size but also through broadening the computer vendor field. Digital Equipment Corporation became the number two computer company behind IBM with their popular PDP and VAX computer systems. Smaller, affordable hardware also brought about the development of important new operating systems like Unix.

Large scale integration of circuits led to the development of very small processing units, an early example of this is the processor was the classified CADC used for analyzing flight data in the US Navy's F14A Tomcat fighter jet. This processor was developed by Steve Geller, Ray Holt and a team from AiResearch and American Microsystems.

In 1966, Hewlett-Packard entered the general purpose computer business with its HP-2116, offering a computational power formerly found only in much larger computers. It supported a wide variety of languages, among them BASIC, ALGOL, and FORTRAN.

In 1969, Data General shipped a total of 50,000 Novas at $8000 each. The Nova was one of the first 16-bit minicomputers and led the way toward word lengths that were multiples of the 8-bit byte. It was first to employ medium-scale integration (MSI) circuits from Fairchild Semiconductor, with subsequent models using large-scale integrated (LSI) circuits. Also notable was that the entire central processor was contained on one 15-inch printed circuit board.

In 1973, the TV Typewriter, designed by Don Lancaster, provided electronics hobbyists with a display of alphanumeric information on an ordinary television set. It used $120 worth of electronics components, as outlined in the September 1973 issue of Radio Electronics magazine. The original design included two memory boards and could generate and store 512 characters as 16 lines of 32 characters. A 90-minute cassette tape provided supplementary storage for about 100 pages of text. His design used minimalistic hardware to generate the timing of the various signals needed to create the TV signal. Clive Sinclair later used the same approach in his legendary Sinclair ZX80.

FOURTH GENERATION

The basis of the fourth generation was Marcian Hoff's invention of the microprocessor.

Unlike Third generation minicomputers, which were essentially scaled down versions of mainframe computers, the fourth generation's origins are fundamentally different. Microprocessor-based computers were originally very limited in their computational ability and speed, and were in no way an attempt to downsize the minicomputer. They were addressing an entirely different market.

Although processing power and storage capacities have increased beyond all recognition since the 1970s, the underlying technology of LSI (large scale integration) or VLSI (very large scale integration) microchips has remained basically the same, so it is widely regarded that most of today's computers still belong to the fourth generation.

MICROPROCESSOR

On November 15, 1971, Intel released the world's first commercial microprocessor, the 4004. It was developed for a Japanese calculator company, Busicom, as an alternative to hardwired circuitry, but computers were developed around it, with much of their processing abilities provided by a single small microprocessor chip. Coupled with one of Intel's other products - the RAM chip, based on an invention by Robert Dennard of IBM, (kilobits of memory on a single chip) - the microprocessor allowed fourth generation computers to be smaller and faster than previous computers. The 4004 was only capable of 60,000 instructions per second, but its successors, the Intel 8008, 8080 (used in many computers using the CP/M operating system), and the 8086/8088 family (the IBM PC and compatibles use processors still backwards-compatible with the 8086) brought ever-increasing speed and power to the computers. Other manufacturers also produced microprocessors which were widely used in microcomputers.

SUPERCOMPUTERS

At the other end of the computing spectrum from the microcomputers, the powerful supercomputers of the era also used integrated circuit technology. In 1976 the Cray-1 was developed by Seymour Cray, who had left Control Data in 1972 to form his own company. This machine, the first supercomputer to make vector processing practical, had a characteristic horseshoe shape, to speed processing by shortening circuit paths. Vector processing, which uses a single instruction to perform the same operation on many arguments, has been a fundamental supercomputer processing method ever since. The Cray-1 could calculate 150 million floating point operations per second (150 megaflops). 85 were shipped at a price of $5 million each. The Cray-1 had a CPU that was mostly constructed of ECL SSI/MSI circuits

MAINFRAMES & MINICOMPUTERS

Before the introduction of the microprocessor in the early 1970s, computers were generally large, costly systems owned by large institutions: corporations, universities, government agencies, and the like. Users—who were experienced specialists—did not usually interact with the machine itself, but instead prepared tasks for the computer on off-line equipment, such as card punches. A number of assignments for the computer would be gathered up and processed in batch mode. After the jobs had completed, users could collect the output printouts and punched cards. In some organizations it could take hours or days between submitting a job to the computing center and receiving the output.

A more interactive form of computer use developed commercially by the middle 1960s. In a time-sharing system, multiple teletype terminals let many people share the use of one mainframe computer processor. This was common in business applications and in science and engineering.

A different model of computer use was foreshadowed by the way in which early, pre-commercial, experimental computers were used, where one user had exclusive use of a processor. Some of the first computers that might be called "personal" were early minicomputers such as the LINC and PDP-8, and later on VAX and larger minicomputers from Digital Equipment Corporation (DEC), Data General, Prime Computer, and others. They originated as peripheral processors for mainframe computers, taking on some routine tasks and freeing the processor for computation. By today's standards they were physically large (about the size of a refrigerator) and costly (typically tens of thousands of US dollars), and thus were rarely purchased by individuals. However, they were much smaller, less expensive, and generally simpler to operate than the mainframe computers of the time, and thus affordable by individual laboratories and research projects. Minicomputers largely freed these organizations from the batch processing and bureaucracy of a commercial or university computing center.

In addition, minicomputers were more interactive than mainframes, and soon had their own operating systems. The minicomputer Xerox Alto (1973) was a landmark step in the development of personal computers, because of its graphical user interface, bit-mapped high resolution screen, large internal and external memory storage, mouse, and special software.

MICROPROCESSOR & COST REDUCTION

The minicomputer ancestors of the modern personal computer used integrated circuit (microchip) technology, which reduced size and cost, but processing was carried out by circuits with large numbers of components arranged on multiple large printed circuit boards before the introduction of the microprocessor. They were consequently physically large and expensive to manufacture. After the "computer-on-a-chip" was commercialized, the cost to manufacture a computer system dropped dramatically. The arithmetic, logic, and control functions that previously occupied several costly circuit boards were now available in one integrated circuit which was very expensive to design but very cheap to manufacture in large quantities. Concurrently, advances in the development of solid state memory eliminated the bulky, costly, and power-hungry magnetic core memory used in prior generations of computers.

There were a few researchers at places such as SRI and Xerox PARC who were working on computers that a single person could use and could be connected by fast, versatile networks: not home computers, but personal ones.

ALTAIR 8800 & IMSAI 8080

Development of the single-chip microprocessor was an enormous catalyst to the popularization of cheap, easy to use, and truly personal computers. The Altair 8800, introduced in a Popular Electronics magazine article in the January 1975 issue, at the time set a new low price point for a computer, bringing computer ownership to an admittedly select market in the 1970s. This was followed by the IMSAI 8080 computer, with similar abilities and limitations. The Altair and IMSAI were essentially scaled-down minicomputers and were incomplete: to connect a keyboard or teletype to them required heavy, expensive "peripherals". These machines both featured a front panel with switches and lights, which communicated with the operator in binary. To program the machine after switching it on the bootstrap loader program had to be entered, without error, in binary, then a paper tape containing a BASIC interpreter loaded from a paper-tape reader. Keying the loader required setting a bank of eight switches up or down and pressing the "load" button, once for each byte of the program, which was typically hundreds of bytes long. The computer could run BASIC programs once the interpreter had been loaded.

The MITS Altair, the first commercially successful microprocessor kit, was featured on the cover of Popular Electronics magazine in January 1975. It was the world's first mass-produced personal computer kit, as well as the first computer to use an Intel 8080 processor. It was a commercial success with 10,000 Altairs being shipped. The Altair also inspired the software development efforts of Paul Allen and his high school friend Bill Gates who developed a BASIC interpreter for the Altair, and then formed Microsoft.

The MITS Altair 8800 effectively created a new industry of microcomputers and computer kits, with many others following, such as a wave of small business computers in the late 1970s based on the Intel 8080, Zilog Z80 and Intel 8085 microprocessor chips. Most ran the CP/M-80 operating system developed by Gary Kildall at Digital Research. CP/M-80 was the first popular microcomputer operating system to be used by many different hardware vendors, and many software packages were written for it, such as WordStar and dBase II.

Many hobbyists during the mid 1970s designed their own systems, with various degrees of success, and sometimes banded together to ease the job. Out of these house meetings the Homebrew Computer Club developed, where hobbyists met to talk about what they had done, exchange schematics and software, and demonstrate their systems. Many people built or assembled their own computers as per published designs. For example, many thousands of people built the Galaksija home computer later in the early 80s.

It was arguably the Altair computer that spawned the development of Apple, as well as Microsoft which produced and sold the Altair BASIC programming language interpreter, Microsoft's first product. The second generation of microcomputers — those that appeared in the late 1970s, sparked by the unexpected demand for the kit computers at the electronic hobbyist clubs, were usually known as home computers. For business use these systems were less capable and in some ways less versatile than the large business computers of the day. They were designed for fun and educational purposes, not so much for practical use. And although you could use some simple office/productivity applications on them, they were generally used by computer enthusiasts for learning to program and for running computer games, for which the personal computers of the period were less suitable and much too expensive. For the more technical hobbyists home computers were also used for electronics interfacing, such as controlling model railroads, and other general hobbyist pursuits.

MICRAL N

In France, the company R2E (Réalisations et Etudes Electroniques) formed by two former engineers of the Intertechnique company, André Truong Trong Thi and François Gernelle introduced in February 1973 a microcomputer, the Micral N based on the Intel 8008. Originally, the computer had been designed by Gernelle, Lacombe, Beckmann and Benchitrite for the Institut National de la Recherche Agronomique to automate hygrometric measurements. The Micral N cost a fifth of the price of a PDP-8, about 8500FF ($1300). The clock of the Intel 8008 was set at 500kHz, the memory was 16 kilobytes. A bus, called Pluribus was introduced and allowed connection of up to 14 boards. Different boards for digital I/O, analog I/O, memory, floppy disk were available from R2E. The Micral operating system was initially called Sysmic, and was later renamed Prologue. R2E was absorbed by Groupe Bull in 1978. Although Groupe Bull continued the production of Micral computers, it was not interested in the Personal Computer market. and Micral computers were mostly confined to highway toll gates (where they remained in service until 1992) and similar niche markets.

MICROCOMPUTER EMERGES

The advent of the microprocessor and solid-state memory made home computing affordable. Early hobby microcomputer systems such as the Altair 8800 and Apple I introduced around 1975 marked the release of low-cost 8-bit processor chips, which had sufficient computing power to be of interest to hobby and experimental users. By 1977 pre-assembled systems such as the Apple II, Commodore PET, and TRS-80 (later dubbed the "1977 Trinity" by Byte Magazine) began the era of mass-market personal computers; much less effort was required to obtain an operating computer, and applications such as games, word processing, and spreadsheets began to proliferate.

2) HISTORY OF COMPUTING HARDWARE BEFORE 1960

2009-05-30T13:25:00.000-07:00

by engr. AFAN BK

The history of computing hardware encompasses the hardware, its architecture, and its impact on software. The elements of computing hardware have undergone significant improvement over their history. This improvement has triggered worldwide use of the technology, performance has improved and the price has declined. Computers are accessible to ever-increasing sectors of the world's population. Computing hardware has become a platform for uses other than computation, such as automation, communication, control, entertainment, and education. Each field in turn has imposed its own requirements on the hardware, which has evolved in response to those requirements.

The von Neumann architecture unifies our current computing hardware implementations. Since digital computers rely on digital storage, and tend to be limited by the size and speed of memory, the history of computer data storage is tied to the development of computers. The major elements of computing hardware implement abstractions: input,output, memory, and processor. A processor is composed of control and datapath. In the von Neumann architecture, control of the datapath is stored in memory. This allowed control to become an automatic process; the datapath could be under software control, perhaps in response to events. Beginning with mechanical datapaths such as the abacus and astrolabe, the hardware first started using analogs for a computation, including water and even air as the analog quantities: analog computers have used lengths, pressures, voltages, and currents to represent the results of calculations. Eventually the voltages or currents were standardized, and then digitized. Digital computing elements have ranged from mechanical gears, to electromechanical relays, to vacuum tubes, to transistors, and to integrated circuits, all of which are currently implementing the von Neumann architecture.

Before computer hardware

The first use of the word "computer" was recorded in 1613, referring to a person who carried out calculations, or computations, and the word continued to be used in that sense until the middle of the 20th century. From the end of the 19th century onwards though, the word began to take on its more familiar meaning, describing a machine that carries out computations.

Earliest calculators

Devices have been used to aid computation for thousands of years, using one-to-one correspondence with our fingers. The earliest counting device was probably a form of tally stick. Later record keeping aids throughout the Fertile Crescent included clay shapes, which represented counts of items, probably livestock or grains, sealed in containers.

The abacus was used for arithmetic tasks. The Roman abacus was used in Babylonia as early as 2400 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money (this is the origin of "Exchequer" as a term for a nation's treasury).

A number of analog computers were constructed in ancient and medieval times to perform astronomical calculations. These include the Antikythera mechanism and the astrolabe from ancient Greece (c. 150–100 BC), which are generally regarded as the first mechanical analog computers. Other early versions of mechanical devices used to perform some type of calculations include the planisphere and other mechanical computing devices invented by Abū Rayhān al-Bīrūnī (c. AD 1000); the equatorium and universal latitude-independent astrolabe by Abū Ishāq Ibrāhīm al-Zarqālī (c. AD 1015); the astronomical analog computers of other medieval Muslim astronomers and engineers; and the astronomical clock tower of Su Song (c. AD 1090) during the Song Dynasty.

The "castle clock", an astronomical clock invented by Al-Jazari in 1206, is considered to be the earliest programmable analog computer. It displayed the zodiac, the solar and lunar orbits, a crescent moon-shaped pointer traveling across a gateway causing automatic doors to open every hour, and five robotic musicians who play music when struck by levers operated by a camshaft attached to a water wheel. The length of day and night could be re-programmed every day in order to account for the changing lengths of day and night throughout the year.

Scottish mathematician and physicist John Napier noted multiplication and division of numbers could be performed by addition and subtraction, respectively, of logarithms of those numbers. While producing the first logarithmic tables Napier needed to perform many multiplications, and it was at this point that he designed Napier's bones, an abacus-like device used for multiplication and division. Since real numbers can be represented as distances or intervals on a line, the slide rule was invented in the 1620s to allow multiplication and division operations to be carried out significantly faster than was previously possible. Slide rules were used by generations of engineers and other mathematically inclined professional workers, until the invention of the pocket calculator. The engineers in the Apollo program to send a man to the moon made many of their calculations on slide rules, which were accurate to three or four significant figures.

German polymath Wilhelm Schickard built the first digital mechanical calculator in 1623, and thus became the father of the computing era. Since his calculator used techniques such as cogs and gears first developed for clocks, it was also called a 'calculating clock'. It was put to practical use by his friend Johannes Kepler, who revolutionized astronomy when he condensed decades of astronomical observations into algebraic expressions. An original calculator by Pascal (1640) is preserved in the Zwinger Museum. Machines by Blaise Pascal (the Pascaline, 1642) and Gottfried Wilhelm von Leibniz (1671) followed. Leibniz once said "It is unworthy of excellent men to lose hours like slaves in the labour of calculation which could safely be relegated to anyone else if machines were used."

Around 1820, Charles Xavier Thomas created the first successful, mass-produced mechanical calculator, the Thomas Arithmometer, that could add, subtract, multiply, and divide. It was mainly based on Leibniz' work. Mechanical calculators, like the base-ten addiator, the comptometer, the Monroe, the Curta and the Addo-X remained in use until the 1970s. Leibniz also described the binary numeral system, a central ingredient of all modern computers. However, up to the 1940s, many subsequent designs (including Charles Babbage's machines of the 1800s and even ENIAC of 1945) were based on the decimal system; ENIAC's ring counters emulated the operation of the digit wheels of a mechanical adding machine.

In Japan, Ryoichi Yazu patented a mechanical calculator called the Yazu Arithmometer in 1903. It consisted of a single cylinder and 22 gears, and employed the mixed base-2 and base-5 number system familiar to users to the soroban (Japanese abacus). Carry and end of calculation were determined automatically.[28] More than 200 units were sold, mainly to government agencies such as the Ministry of War and agricultural experiment stations. Yazu invested the profits in a factory to build what would have been Japan's first propeller-driven airplane, but that project was abandoned after his untimely death at the age of 31.

1801: punched card technology

As early as 1725 Basile Bouchon used a perforated paper loop in a loom to establish the pattern to be reproduced on cloth, and in 1726 his co-worker Jean-Baptiste Falcon improved on his design by using perforated paper cards attached to one another for efficiency in adapting and changing the program. The Bouchon-Falcon loom was semi-automatic and required manual feed of the program. In 1801, Joseph-Marie Jacquard developed a loom in which the pattern being woven was controlled by punched cards. The series of cards could be changed without changing the mechanical design of the loom. This was a landmark point in programmability.

In 1833, Charles Babbage moved on from developing his difference engine to developing a more complete design, the analytical engine, which would draw directly on Jacquard's punched cards for its programming. In 1835, Babbage described his analytical engine. It was the plan of a general-purpose programmable computer, employing punch cards for input and a steam engine for power. One crucial invention was to use gears for the function served by the beads of an abacus. In a real sense, computers all contain automatic abacuses (the datapath, arithmetic logic unit, or floating-point unit). His initial idea was to use punch-cards to control a machine that could calculate and print logarithmic tables with huge precision (a specific purpose machine). Babbage's idea soon developed into a general-purpose programmable computer, his analytical engine. While his design was sound and the plans were probably correct, or at least debuggable, the project was slowed by various problems. Babbage was a difficult man to work with and argued with anyone who didn't respect his ideas. All the parts for his machine had to be made by hand. Small errors in each item can sometimes sum up to large discrepancies in a machine with thousands of parts, which required these parts to be much better than the usual tolerances needed at the time. The project dissolved in disputes with the artisan who built parts and was ended with the depletion of government funding. Ada Lovelace, Lord Byron's daughter, translated and added notes to the "Sketch of the Analytical Engine" by Federico Luigi, Conte Menabrea.

1930s–1960s: desktop calculators

By the 1900s, earlier mechanical calculators, cash registers, accounting machines, and so on were redesigned to use electric motors, with gear position as the representation for the state of a variable. The word "computer" was a job title assigned to people who used these calculators to perform mathematical calculations. By the 1920s Lewis Fry Richardson's interest in weather prediction led him to propose human computers and numerical analysis to model the weather; to this day, the most powerful computers on Earth are needed to adequately model its weather using the Navier-Stokes equations.

Companies like Friden, Marchant Calculator and Monroe made desktop mechanical calculators from the 1930s that could add, subtract, multiply and divide. During the Manhattan project, future Nobel laureate Richard Feynman was the supervisor of the roomful of human computers, many of them women mathematicians, who understood the differential equations which were being solved for the war effort. Even the renowned Stanisław Ulam was pressed into service to translate the mathematics into computable approximations for the hydrogen bomb, after the war.

In 1948, the Curta was introduced. This was a small, portable, mechanical calculator that was about the size of a pepper grinder. Over time, during the 1950s and 1960s a variety of different brands of mechanical calculator appeared on the market. The first all-electronic desktop calculator was the British ANITA Mk.VII, which used a Nixie tube display and 177 subminiature thyratron tubes. In June 1963, Friden introduced the four-function EC-130. It had an all-transistor design, 13-digit capacity on a 5-inch (130 mm) CRT, and introduced reverse Polish notation (RPN) to the calculator market at a price of $2200. The model EC-132 added square root and reciprocal functions. In 1965, Wang Laboratories produced the LOCI-2, a 10-digit transistorized desktop calculator that used a Nixie tube display and could compute logarithms.

1) BRIEF HISTORY OF THE COMPUTERS

2009-05-30T13:20:00.000-07:00

by engr. AFAN BK

Table of Contents

1) In The Beginning
2) Babbage
3) Use of Punched Cards by Hollerith
4) Electronic Digital Computers
5) The Modern “Stored Program” EDC

1- In The Beginnin

The history of computers starts out about 2000 years ago, at the birth of the abacus, a wooden rack holding two horizontal wires with beads strung on them. When these beads are moved around, according to programming rules memorized by the user, all regular arithmetic problems can be done. Another important invention around the same time was the Astrolabe, used for navigation. Blaise Pascal is usually credited for building the first digital computer in 1642. It added numbers entered with dials and was made to help his father, a tax collector. In 1671, Gottfried Wilhelm von Leibniz invented a computer that was built in 1694. It could add, and, after changing some things around, multiply. Leibniz invented a special stepped gear mechanism for introducing the addend digits, and this is still being used. The prototypes made by Pascal and Leibniz were not used in many places, and considered weird until a little more than a century later, when Thomas of Colmar (A.K.A. Charles Xavier Thomas) created the first successful mechanical calculator that could add, subtract, multiply, and divide. A lot of improved desktop calculators by many inventors followed, so that by about 1890, the range of improvements included:

•Accumulation of partial results
•Storage and automatic reentry of past results (A memory function)
•Printing of the results
Each of these required manual installation. These improvements were mainly made for commercial users, and not for the needs of science.

2- Babbage

While Thomas of Colmar was developing the desktop calculator, a series of very interesting developments in computers was started in Cambridge, England, by Charles Babbage (left, of which the computer store “Babbages, now GameStop, is named), a mathematics professor. In 1812, Babbage realized that many long calculations, especially those needed to make mathematical tables, were really a series of predictable actions that were constantly repeated. From this he suspected that it should be possible to do these automatically.

He began to design an automatic mechanical calculating machine, which he called a difference engine. By 1822, he had a working model to demonstrate with. With financial help from the British government, Babbage started fabrication of a difference engine in 1823. It was intended to be steam powered and fully automatic, including the printing of the resulting tables, and commanded by a fixed instruction program. The difference engine, although having limited adaptability and applicability, was really a great advance. Babbage continued to work on it for the next 10 years, but in 1833 he lost interest because he thought he had a better idea — the construction of what would now be called a general purpose, fully program-controlled, automatic mechanical digital computer. Babbage called this idea an Analytical Engine. The ideas of this design showed a lot of foresight, although this couldn’t be appreciated until a full century later. The plans for this engine required an identical decimal computer operating on numbers of 50 decimal digits (or words) and having a storage capacity (memory) of 1,000 such digits. The built-in operations were supposed to include everything that a modern general - purpose computer would need, even the all important Conditional Control Transfer Capability that would allow commands to be executed in any order, not just the order in which they were programmed. The analytical engine was soon to use punched cards (similar to those used in a Jacquard loom), which would be read into the machine from several different Reading Stations. The machine was supposed to operate automatically, by steam power, and require only one person there. Babbage’s computers were never finished. Various reasons are used for his failure. Most used is the lack of precision machining techniques at the time. Another speculation is that Babbage was working on a solution of a problem that few people in 1840 really needed to solve. After Babbage, there was a temporary loss of interest in automatic digital computers. Between 1850 and 1900 great advances were made in mathematical physics, and it came to be known that most observable dynamic phenomena can be identified by differential equations(which meant that most events occurring in nature can be measured or described in one equation or another), so that easy means for their calculation would be helpful. Moreover, from a practical view, the availability of steam power caused manufacturing (boilers), transportation (steam engines and boats), and commerce to prosper and led to a period of a lot of engineering achievements. The designing of railroads, and the making of steamships, textile mills, and bridges required differential calculus to determine such things as:

•center of gravity
•center of buoyancy
•moment of inertia
•stress distributions

Even the assessment of the power output of a steam engine needed mathematical integration. A strong need thus developed for a machine that could rapidly perform many repetitive calculations.

3- Use of Punched Cards by Hollerith

A step towards automated computing was the development of punched cards, which were first successfully used with computers in 1890 by Herman Hollerith (left) and James Powers, who worked for the US. Census Bureau. They developed devices that could read the information that had been punched into the cards automatically, without human help. Because of this, reading errors were reduced dramatically, work flow increased, and, most importantly, stacks of punched cards could be used as easily accessible memory of almost unlimited size. Furthermore, different problems could be stored on different stacks of cards and accessed when needed. These advantages were seen by commercial companies and soon led to the development of improved punch-card using computers created by International Business Machines (IBM), Remington (yes, the same people that make shavers), Burroughs, and other corporations. These computers used electromechanical devices in which electrical power provided mechanical motion — like turning the wheels of an adding machine. Such systems included features to:

•feed in a specified number of cards automatically
•add, multiply, and sort
•feed out cards with punched results
As compared to today’s machines, these computers were slow, usually processing 50 - 220 cards per minute, each card holding about 80 decimal numbers (characters). At the time, however, punched cards were a huge step forward. They provided a means of I/O, and memory storage on a huge scale. For more than 50 years after their first use, punched card machines did most of the world’s first business computing, and a considerable amount of the computing work in science.

4- Electronic Digital Computers

The start of World War II produced a large need for computer capacity, especially for the military. New weapons were made for which trajectory tables and other essential data were needed. In 1942, John P. Eckert, John W. Mauchly (left), and their associates at the Moore school of Electrical Engineering of University of Pennsylvania decided to build a high - speed electronic computer to do the job. This machine became known as ENIAC (Electrical Numerical Integrator And Calculator) The size of ENIAC’s numerical “word” was 10 decimal digits, and it could multiply two of these numbers at a rate of 300 per second, by finding the value of each product from a multiplication table stored in its memory. ENIAC was therefore about 1,000 times faster then the previous generation of relay computers. ENIAC used 18,000 vacuum tubes, about 1,800 square feet of floor space, and consumed about 180,000 watts of electrical power. It had punched card I/O, 1 multiplier, 1 divider/square rooter, and 20 adders using decimal ring counters, which served as adders and also as quick-access (.0002 seconds) read-write register storage. The executable instructions making up a program were embodied in the separate “units” of ENIAC, which were plugged together to form a “route” for the flow of information.

These connections had to be redone after each computation, together with presetting function tables and switches. This “wire your own” technique was inconvenient (for obvious reasons), and with only some latitude could ENIAC be considered programmable. It was, however, efficient in handling the particular programs for which it had been designed. ENIAC is commonly accepted as the first successful high - speed electronic digital computer (EDC) and was used from 1946 to 1955. A controversy developed in 1971, however, over the patentability of ENIAC’s basic digital concepts, the claim being made that another physicist, John V. Atanasoff (left) had already used basically the same ideas in a simpler vacuum - tube device he had built in the 1930’s while at Iowa State College. In 1973 the courts found in favor of the company using the Atanasoff claim

5- The Modern Stored Program EDC

Fascinated by the success of ENIAC, the mathematician John Von Neumann (left) undertook, in 1945, an abstract study of computation that showed that a computer should have a very simple, fixed physical structure, and yet be able to execute any kind of computation by means of a proper programmed control without the need for any change in the unit itself. Von Neumann contributed a new awareness of how practical, yet fast computers should be organized and built. These ideas, usually referred to as the stored - program technique, became essential for future generations of high - speed digital computers and were universally adopted.

The Stored - Program technique involves many features of computer design and function besides the one that it is named after. In combination, these features make very - high - speed operation attainable. A glimpse may be provided by considering what 1,000 operations per second means. If each instruction in a job program were used once in consecutive order, no human programmer could generate enough instruction to keep the computer busy. Arrangements must be made, therefore, for parts of the job program (called subroutines) to be used repeatedly in a manner that depends on the way the computation goes. Also, it would clearly be helpful if instructions could be changed if needed during a computation to make them behave differently.
Von Neumann met these two needs by making a special type of machine instruction, called a Conditional control transfer - which allowed the program sequence to be stopped and started again at any point - and by storing all instruction programs together with data in the same memory unit, so that, when needed, instructions could be arithmetically changed in the same way as data. As a result of these techniques, computing and programming became much faster, more flexible, and more efficient with work. Regularly used subroutines did not have to be reprogrammed for each new program, but could be kept in “libraries” and read into memory only when needed. Thus, much of a given program could be assembled from the subroutine library.

The all - purpose computer memory became the assembly place in which all parts of a long computation were kept, worked on piece by piece, and put together to form the final results. The computer control survived only as an “errand runner” for the overall process. As soon as the advantage of these techniques became clear, they became a standard practice.

The first generation of modern programmed electronic computers to take advantage of these improvements were built in 1947. This group included computers using Random - Access - Memory (RAM), which is a memory designed to give almost constant access to any particular piece of information. . These machines had punched - card or punched tape I/O devices and RAM’s of 1,000 - word capacity and access times of .5 Greek MU seconds (.5*10-6 seconds). Some of them could perform multiplications in 2 to 4 MU seconds.

Physically, they were much smaller than ENIAC. Some were about the size of a grand piano and used only 2,500 electron tubes, a lot less then required by the earlier ENIAC. The first - generation stored - program computers needed a lot of maintenance, reached probably about 70 to 80% reliability of operation (ROO) and were used for 8 to 12 years. They were usually programmed in ML, although by the mid 1950’s progress had been made in several aspects of advanced programming. This group of computers included EDVAC (above) and UNIVAC (right) the first commercially available computers.