Timeline of Computer History
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The Z3, an early computer built by German engineer Konrad Zuse working in complete isolation from developments elsewhere, uses 2,300 relays, performs floating point binary arithmetic, and has a 22-bit word length. The Z3 was used for aerodynamic calculations but was destroyed in a bombing raid on Berlin in late 1943. Zuse later supervised a reconstruction of the Z3 in the 1960s, which is currently on display at the Deutsches Museum in Munich.

After successfully demonstrating a proof-of-concept prototype in 1939, Professor John Vincent Atanasoff receives funds to build a full-scale machine at Iowa State College (now University). The machine was designed and built by Atanasoff and graduate student Clifford Berry between 1939 and 1942. The ABC was at the center of a patent dispute related to the invention of the computer, which was resolved in 1973 when it was shown that ENIAC co-designer John Mauchly had seen the ABC shortly after it became functional.

The legal result was a landmark: Atanasoff was declared the originator of several basic computer ideas, but the computer as a concept was declared un-patentable and thus freely open to all. A full-scale working replica of the ABC was completed in 1997, proving that the ABC machine functioned as Atanasoff had claimed. The replica is currently on display at the Computer History Museum.

The US Army asked Bell Laboratories to design a machine to assist in testing its M-9 gun director, a type of analog computer that aims large guns to their targets. Mathematician George Stibitz recommends using a relay-based calculator for the project. The result was the Relay Interpolator, later called the Bell Labs Model II. The Relay Interpolator used 440 relays, and since it was programmable by paper tape, was used for other applications following the war.

Designed by British engineer Tommy Flowers, the Colossus is designed to break the complex Lorenz ciphers used by the Nazis during World War II. A total of ten Colossi were delivered, each using as many as 2,500 vacuum tubes. A series of pulleys transported continuous rolls of punched paper tape containing possible solutions to a particular code. Colossus reduced the time to break Lorenz messages from weeks to hours. Most historians believe that the use of Colossus machines significantly shortened the war by providing evidence of enemy intentions and beliefs. The machineâs existence was not made public until the 1970s.

An inspiring summer school on computing at the University of PennsylvaniaÂ´s Moore School of Electrical Engineering stimulates construction of stored-program computers at universities and research institutions in the US, France, the UK, and Germany. Among the lecturers were early computer designers like John von Neumann, Howard Aiken, J. Presper Eckert and John Mauchly, as well as mathematicians including Derrick Lehmer, George Stibitz, and Douglas Hartree. Students included future computing pioneers such as Maurice Wilkes, Claude Shannon, David Rees, and Jay Forrester. This free, public set of lectures inspired the EDSAC, BINAC, and, later, IAS machine clones like the AVIDAC.

During World War II, the US Navy approaches the Massachusetts Institute of Technology (MIT) about building a flight simulator to train bomber crews. Under the leadership of MIT's Gordon Brown and Jay Forrester, the team first built a small analog simulator, but found it inaccurate and inflexible. News of the groundbreaking electronic ENIAC computer that same year inspired the group to change course and attempt a digital solution, whereby flight variables could be rapidly programmed in software. Completed in 1951, Whirlwind remains one of the most important computer projects in the history of computing. Foremost among its developments was Forresterâs perfection of magnetic core memory, which became the dominant form of high-speed random access memory for computers until the mid-1970s.

Started in 1943, the ENIAC computing system was built by John Mauchly and J. Presper Eckert at the Moore School of Electrical Engineering of the University of Pennsylvania. Because of its electronic, as opposed to electromechanical, technology, it is over 1,000 times faster than any previous computer. ENIAC used panel-to-panel wiring and switches for programming, occupied more than 1,000 square feet, used about 18,000 vacuum tubes and weighed 30 tons. It was believed that ENIAC had done more calculation over the ten years it was in operation than all of humanity had until that time.

University of Manchester researchers Frederic Williams, Tom Kilburn, and Geoff Toothill develop the Small-Scale Experimental Machine (SSEM), better known as the Manchester "Baby." The Baby was built to test a new memory technology developed by Williams and Kilburn -- soon known as the Williams Tube â which was the first high-speed electronic random access memory for computers. Their first program, consisting of seventeen instructions and written by Kilburn, ran on June 21st, 1948. This was the first program in history to run on a digital, electronic, stored-program computer.

The Selective Sequence Electronic Calculator (SSEC) project, led by IBM engineer Wallace Eckert, uses both relays and vacuum tubes to process scientific data at the rate of 50 14 x 14 digit multiplications per second. Before its decommissioning in 1952, the SSEC produced the moon position tables used in early planning of the 1969 Apollo XII moon landing. These tables were later confirmed by using more modern computers for the actual flights. The SSEC was one of the last of the generation of 'super calculators' to be built using electromechanical technology.

While many early digital computers were based on similar designs, such as the IAS and its copies, others are unique designs, like the CSIRAC. Built in Sydney, Australia by the Council of Scientific and Industrial Research for use in its Radio physics Laboratory in Sydney, CSIRAC was designed by British-born Trevor Pearcey, and used unusual 12-hole paper tape. It was transferred to the Department of Physics at the University of Melbourne in 1955 and remained in service until 1964.

The first practical stored-program computer to provide a regular computing service, EDSAC is built at Cambridge University using vacuum tubes and mercury delay lines for memory. The EDSAC project was led by Cambridge professor and director of the Cambridge Computation Laboratory, Maurice Wilkes. Wilkes' ideas grew out of the Moore School lectures he had attended three years earlier. One major advance in programming was Wilkes' use of a library of short programs, called âsubroutines,â stored on punched paper tapes and used for performing common repetitive calculations within a larger program.

MADDIDA is a digital drum-based differential analyzer. This type of computer is useful in performing many of the mathematical equations scientists and engineers encounter in their work. It was originally created for a nuclear missile design project in 1949 by a team led by Fred Steele. It used 53 vacuum tubes and hundreds of germanium diodes, with a magnetic drum for memory. Tracks on the drum did the mathematical integration. MADDIDA was flown across the country for a demonstration to John von Neumann, who was impressed. Northrop was initially reluctant to make MADDIDA a commercial product, but by the end of 1952, six had sold.

Built by a team led by engineers Frederick Williams and Tom Kilburn, the Mark I serves as the prototype for Ferrantiâs first computer â the Ferranti Mark 1. The Manchester Mark I used more than 1,300 vacuum tubes and occupied an area the size of a medium room. Its âWilliams-Kilburn tubeâ memory system was later adopted by several other early computer systems around the world.

One of the first commercially produced computers, the companyÂ´s first customer was the US Navy. The 1101, designed by ERA but built by Remington-Rand, was intended for high-speed computing and stored 1 million bits on its magnetic drum, one of the earliest magnetic storage devices and a technology which ERA had done much to perfect in its own laboratories. Many of the 1101âs basic architectural details were used again in later Remington-Rand computers until the 1960s.

Based on ideas from Alan Turing, BritainÂ´s Pilot ACE computer is constructed at the National Physical Laboratory. "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," Turing said at a symposium on large-scale digital calculating machinery in 1947 in Cambridge, Massachusetts. The design packed 800 vacuum tubes into a relatively compact 12 square feet.

The hobbyist magazine Radio Electronics publishes Edmund Berkeley's design for the Simon 1 relay computer from 1950 to 1951. The Simon 1 used relay logic and cost about $600 to build. In his book Giant Brains, Berkeley noted - âWe shall now consider how we can design a very simple machine that will think. Let us call it Simon, because of its predecessor, Simple Simon... Simon is so simple and so small in fact that it could be built to fill up less space than a grocery-store box; about four cubic feet.â

The Standards Eastern Automatic Computer (SEAC) is among the first stored program computers completed in the United States. It was built in Washington DC as a test-bed for evaluating components and systems as well as for setting computer standards. It was also one of the first computers to use all-diode logic, a technology more reliable than vacuum tubes. The world's first scanned image was made on SEAC by engineer Russell Kirsch in 1957.

The NBS also built the Standards Western Automatic Computer (SWAC) at the Institute for Numerical Analysis on the UCLA campus. Rather than testing components like the SEAC, the SWAC was built using already-developed technology. SWAC was used to solve problems in numerical analysis, including developing climate models and discovering five previously unknown Mersenne prime numbers.

The title of âfirst commercially available general-purpose computerâ probably goes to Britainâs Ferranti Mark I for its sale of its first Mark I computer to Manchester University. The Mark 1 was a refinement of the experimental Manchester âBabyâ and Manchester Mark 1 computers, also at Manchester University. A British government contract spurred its initial development but a change in government led to loss of funding and the second and only other Mark I was sold at a major loss to the University of Toronto, where it was re-christened FERUT.

The Univac 1 is the first commercial computer to attract widespread public attention. Although manufactured by Remington Rand, the machine was often mistakenly referred to as âthe IBM Univac." Univac computers were used in many different applications but utilities, insurance companies and the US military were major customers. One biblical scholar even used a Univac 1 to compile a concordance to the King James version of the Bible. Created by Presper Eckert and John Mauchly -- designers of the earlier ENIAC computer -- the Univac 1 used 5,200 vacuum tubes and weighed 29,000 pounds. Remington Rand eventually sold 46 Univac 1s at more than $1 million each.

Modeled after the Cambridge University EDSAC computer, the president of Lyons Tea Co. has the LEO built to solve the problem of production scheduling and delivery of cakes to the hundreds of Lyons tea shops around England. After the success of the first LEO, Lyons went into business manufacturing computers to meet the growing need for data processing systems in business. The LEO was Englandâs first commercial computer and was performing useful work before any other commercial computer system in the world.

The Institute of Advanced Study (IAS) computer is a multi-year research project conducted under the overall supervision of world-famous mathematician John von Neumann. The notion of storing both data and instructions in memory became known as the âstored program conceptâ to distinguish it from earlier methods of instructing a computer. The IAS computer was designed for scientific calculations and it performed essential work for the US atomic weapons program. Over the next few years, the basic design of the IAS machine was copied in at least 17 places and given similar-sounding names, for example, the MANIAC at Los Alamos Scientific Laboratory; the ILLIAC at the University of Illinois; the Johnniac at The Rand Corporation; and the SILLIAC in Australia.

During three years of production, IBM sells 19 701s to research laboratories, aircraft companies, and the federal government. Also known inside IBM as the âDefense Calculator," the 701 rented for $15,000 a month. Programmer Arthur Samuels used the 701 to write the first computer program designed to play checkers. The 701 introduction also marked the beginning of IBMâs entry into the large-scale computer market, a market it came to dominate in later decades.

The Johnniac computer is one of 17 computers that followed the basic design of Princeton's Institute of Advanced Study (IAS) computer. It was named after John von Neumann, a world famous mathematician and computer pioneer of the day. Johnniac was used for scientific and engineering calculations. It was also repeatedly expanded and improved throughout its 13-year lifespan. Many innovative programs were created for Johnniac, including the time-sharing system JOSS that allowed many users to simultaneously access the machine.

At MIT, researchers begin experimenting with direct keyboard input to computers, a precursor to todayÂ´s normal mode of operation. Typically, computer users of the time fed their programs into a computer using punched cards or paper tape. Doug Ross wrote a memo advocating direct access in February. Ross contended that a Flexowriter -- an electrically-controlled typewriter -- connected to an MIT computer could function as a keyboard input device due to its low cost and flexibility. An experiment conducted five months later on the MIT Whirlwind computer confirmed how useful and convenient a keyboard input device could be.

Physicist Stan Frankel, intrigued by small, general-purpose computers, developed the MINAC at Caltech. The Librascope division of defense contractor General Precision buys Frankelâs design, renaming it the LGP-30 in 1956. Used for science and engineering as well as simple data processing, the LGP-30 was a âbargainâ at less than $50,000 and an early example of a âpersonal computer,â that is, a computer made for a single user.

The TX-0 (âTransistor eXperimental - 0â) is the first general-purpose programmable computer built with transistors. For easy replacement, designers placed each transistor circuit inside a "bottle," similar to a vacuum tube. Constructed at MITÂ´s Lincoln Laboratory, the TX-0 moved to the MIT Research Laboratory of Electronics, where it hosted some early imaginative tests of programming, including writing a Western movie shown on television, 3-D tic-tac-toe, and a maze in which a mouse found martinis and became increasingly inebriated.

DEC is founded initially to make electronic modules for test, measurement, prototyping and control markets. Its founders were Ken and Stan Olsen, and Harlan Anderson. Headquartered in Maynard, Massachusetts, Digital Equipment Corporation, took over 8,680 square foot leased space in a nineteenth century mill that once produced blankets and uniforms for soldiers who fought in the Civil War. General Georges Doriot and his pioneering venture capital firm, American Research and Development, invested $70,000 for 70% of DECâs stock to launch the company in 1957. The mill is still in use today as an office park (Clock Tower Place) today.

The 501 is built on a 'building block' concept which allows it to be highly flexible for many different uses and could simultaneously control up to 63 tape drivesâvery useful for large databases of information. For many business users, quick access to this huge storage capability outweighed its relatively slow processing speed. Customers included US military as well as industry.

The first large-scale computer communications network, SAGE connects 23 hardened computer sites in the US and Canada. Its task was to detect incoming Soviet bombers and direct interceptor aircraft to destroy them. Operators directed actions by touching a light gun to the SAGE airspace display. The air defense system used two AN/FSQ-7 computers, each of which used a full megawatt of power to drive its 55,000 vacuum tubes, 175,000 diodes and 13,000 transistors.

IBMÂ´s 7000 series of mainframe computers are the companyÂ´s first to use transistors. At the top of the line was the Model 7030, also known as "Stretch." Nine of the computers, which featured dozens of advanced design innovations, were sold, mainly to national laboratories and major scientific users. A special version, known as HARVEST, was developed for the US National Security Agency (NSA). The knowledge and technologies developed for the Stretch project played a major role in the design, management, and manufacture of the later IBM System/360--the most successful computer family in IBM history.

The LINC is an early and important example of a âpersonal computer,â that is, a computer designed for only one user. It was designed by MIT Lincoln Laboratory engineer Wesley Clark. Under the auspices of a National Institutes of Health (NIH) grant, biomedical research faculty from around the United States came to a workshop at MIT to build their own LINCs, and then bring them back to their home institutions where they would be used. For research, Digital Equipment Corporation (DEC) supplied the components, and 50 original LINCs were made. The LINC was later commercialized by DEC and sold as the LINC-8.

A joint project of Englandâs Manchester University, Ferranti Computers, and Plessey, Atlas comes online nine years after Manchesterâs computer lab begins exploring transistor technology. Atlas was the fastest computer in the world at the time and introduced the concept of âvirtual memory,â that is, using a disk or drum as an extension of main memory. System control was provided through the Atlas Supervisor, which some consider to be the first true operating system.

The Control Data Corporation (CDC) 6600 performs up to 3 million instructions per second âthree times faster than that of its closest competitor, the IBM 7030 supercomputer. The 6600 retained the distinction of being the fastest computer in the world until surpassed by its successor, the CDC 7600, in 1968. Part of the speed came from the computerÂ´s design, which used 10 small computers, known as peripheral processing units, to offload the workload from the central processor.

The Canadian Chalk River Nuclear Lab needed a special device to monitor a reactor. Instead of designing a custom controller, two young engineers from Digital Equipment Corporation (DEC) -- Gordon Bell and Edson de Castro -- do something unusual: they develop a small, general purpose computer and program it to do the job. A later version of that machine became the PDP-8, the first commercially successful minicomputer. The PDP-8 sold for $18,000, one-fifth the price of a small IBM System/360 mainframe. Because of its speed, small size, and reasonable cost, the PDP-8 was sold by the thousands to manufacturing plants, small businesses, and scientific laboratories around the world.

System/360 is a major event in the history of computing. On April 7, IBM announced five models of System/360, spanning a 50-to-1 performance range. At the same press conference, IBM also announced 40 completely new peripherals for the new family. System/360 was aimed at both business and scientific customers and all models could run the same software, largely without modification. IBMâs initial investment of $5 billion was quickly returned as orders for the system climbed to 1,000 per month within two years. At the time IBM released the System/360, the company had just made the transition from discrete transistors to integrated circuits, and its major source of revenue began to move from punched card equipment to electronic computer systems.

A large parallel processing computer, the ILLIAC IV does not operate until 1972. It was eventually housed at NASAÂ´s Ames Research Center in Mountain View, California. The most ambitious massively parallel computer at the time, the ILLIAC IV was plagued with design and production problems. Once finally completed, it achieved a computational speed of 200 million instructions per second and 1 billion bits per second of I/O transfer via a unique combination of its parallel architecture and the overlapping or "pipelining" structure of its 64 processing elements.

Designed by scientists and engineers at MITâs Instrumentation Laboratory, the Apollo Guidance Computer (AGC) is the culmination of years of work to reduce the size of the Apollo spacecraft computer from the size of seven refrigerators side-by-side to a compact unit weighing only 70 lbs. and taking up a volume of less than 1 cubic foot. The AGCâs first flight was on Apollo 7. A year later, it steered Apollo 11 to the lunar surface. Astronauts communicated with the computer by punching two-digit codes into the display and keyboard unit (DSKY). The AGC was one of the earliest uses of integrated circuits, and used core memory, as well as read-only magnetic rope memory. The astronauts were responsible for entering more than 10,000 commands into the AGC for each trip between Earth and the Moon.

Initially designed for internal use by HP employees, co-founder Bill Hewlett issues a challenge to his engineers in 1971: fit all of the features of their desktop scientific calculator into a package small enough for his shirt pocket. They did. Marketed as âa fast, extremely accurate electronic slide ruleâ with a solid-state memory similar to that of a computer, the HP-35 distinguished itself from its competitors by its ability to perform a broad variety of logarithmic and trigonometric functions, to store more intermediate solutions for later use, and to accept and display entries in a form similar to standard scientific notation. The HP-35 helped HP become one of the most dominant companies in the handheld calculator market for more than two decades.

Xerox PARC physicist Gary Starkweather realizes in 1967 that exposing a copy machineâs light-sensitive drum to a paper original isnât the only way to create an image. A computer could âwriteâ it with a laser instead. Xerox wasnât interested. So in 1971, Starkweather transferred to Xerox Palo Alto Research Center (PARC), away from corporate oversight. Within a year, he had built the worldâs first laser printer, launching a new era in computer printing, generating billions of dollars in revenue for Xerox. The laser printer was used with PARCâs Alto computer, and was commercialized as the Xerox 9700.

Under the direction of engineer Dr. Paul Friedl, the Special Computer APL Machine Portable (SCAMP) personal computer prototype is developed at IBM's Los Gatos and Palo Alto, California laboratories. IBMâs first personal computer, the system was designed to run the APL programming language in a compact, briefcase-like enclosure which comprised a keyboard, CRT display, and cassette tape storage. Friedl used the SCAMP prototype to gain approval within IBM to promote and develop IBMâs 5100 family of computers, including the most successful, the 5150, also known as the IBM Personal Computer (PC), introduced in 1981. From concept to finished system, SCAMP took only six months to develop.

Based on the Intel 8008 microprocessor, the Micral is one of the earliest commercial, non-kit personal computers. Designer Thi Truong developed the computer while Philippe Kahn wrote the software. Truong, founder and president of the French company R2E, created the Micral as a replacement for minicomputers in situations that did not require high performance, such as process control and highway toll collection. Selling for $1,750, the Micral never penetrated the U.S. market. In 1979, Truong sold R2E to Bull.

Designed by Don Lancaster, the TV Typewriter is an easy-to-build kit that can display alphanumeric information on an ordinary television set. It used $120 worth of electronics components, as outlined in the September 1973 issue of hobbyist magazine Radio Electronics. The original design included two memory boards and could generate and store 512 characters as 16 lines of 32 characters. A cassette tape interface provided supplementary storage for text. The TV Typewriter was used by many small television stations well in the 1990s.

The first commercially advertised US computer based on a microprocessor (the Intel 8008,) the Scelbi has 4 KB of internal memory and a cassette tape interface, as well as Teletype and oscilloscope interfaces. Scelbi aimed the 8H, available both in kit form and fully assembled, at scientific, electronic, and biological applications. In 1975, Scelbi introduced the 8B version with 16 KB of memory for the business market. The company sold about 200 machines, losing $500 per unit.

The Alto is a groundbreaking computer with wide influence on the computer industry. It was based on a graphical user interface using windows, icons, and a mouse, and worked together with other Altos over a local area network. It could also share files and print out documents on an advanced Xerox laser printer. Applications were also highly innovative: a WYSIWYG word processor known as âBravo,â a paint program, a graphics editor, and email for example. Appleâs inspiration for the Lisa and Macintosh computers came from the Xerox Alto.

For its January issue, hobbyist magazine Popular Electronics runs a cover story of a new computer kit â the Altair 8800. Within weeks of its appearance, customers inundated its maker, MITS, with orders. Bill Gates and Paul Allen licensed their BASIC programming language interpreter to MITS as the main language for the Altair. MITS co-founder Ed Roberts invented the Altair 8800 â which sold for $297, or $395 with a case â and coined the term âpersonal computerâ. The machine came with 256 bytes of memory (expandable to 64 KB) and an open 100-line bus structure that evolved into the âS-100â standard widely used in hobbyist and personal computers of this era. In 1977, MITS was sold to Pertec, which continued producing Altairs in 1978.

Chuck Peddle leads a small team of former Motorola employees to build a low-cost microprocessor. The MOS 6502 was introduced at a conference in San Francisco at a cost of $25, far less than comparable processors from Intel and Motorola, leading some attendees to believe that the company was perpetrating a hoax. The chip quickly became popular with designers of early personal computers like the Apple II and Commodore PET, as well as game consoles like the Nintendo Entertainment System. The 6502 and its progeny are still used today, usually in embedded applications.

The fastest machine of its day, The Cray-1's speed comes partly from its shape, a "C," which reduces the length of wires and thus the time signals need to travel across them. High packaging density of integrated circuits and a novel Freon cooling system also contributed to its speed. Each Cray-1 took a full year to assemble and test and cost about $10 million. Typical applications included US national defense work, including the design and simulation of nuclear weapons, and weather forecasting.

Designed by Sunnyvale, California native Steve Wozniak, and marketed by his friend Steve Jobs, the Apple-1 is a single-board computer for hobbyists. With an order for 50 assembled systems from Mountain View, California computer store The Byte Shop in hand, the pair started a new company, naming it Apple Computer, Inc. In all, about 200 of the boards were sold before Apple announced the follow-on Apple II a year later as a ready-to-use computer for consumers, a model which sold in the millions for nearly two decades.

Sold complete with a main logic board, switching power supply, keyboard, case, manual, game paddles, and cassette tape containing the game Breakout, the Apple-II finds popularity far beyond the hobbyist community which made up Appleâs user community until then. When connected to a color television set, the Apple II produced brilliant color graphics for the time. Millions of Apple IIs were sold between 1977 and 1993, making it one of the longest-lived lines of personal computers. Apple gave away thousands of Apple IIs to school, giving a new generation their first access to personal computers.

Performing far better than the company projections of 3,000 units for the first year, in the first month after its release Tandy Radio ShackÂ´s first desktop computer â the TRS-80 â sells 10,000 units. The TRS-80 was priced at $599.95, included a Z80 microprocessor, video display, 4 KB of memory, a built-in BASIC programming language interpreter, cassette storage, and easy-to-understand manuals that assumed no prior knowledge on the part of the user. The TRS-80 proved popular with schools, as well as for home use. The TRS-80 line of computers later included color, portable, and handheld versions before being discontinued in the early 1990s.

The first of several personal computers released in 1977, the PET comes fully assembled with either 4 or 8 KB of memory, a built-in cassette tape drive, and a 'chiclet' keyboard. The PET was popular with schools and for use as a home computer. It used a MOS Technologies 6502 microprocessor running at 1 MHz. After the success of the PET, Commodore remained a major player in the personal computer market into the 1990s.

Beginning with the VAX-11/780, the Digital Equipment Corporation (DEC) VAX family of computers rivals much more expensive mainframe computers in performance and features the ability to address over 4 GB of virtual memory, hundreds of times the capacity of most minicomputers. Called a âcomplex instruction set computer,â VAX systems were backward compatible and so preserved the investment owners of previous DEC computers had in software. The success of the VAX family of computers transformed DEC into the second-largest computer company in the world, as VAX systems became the de facto standard computing system for industry, the sciences, engineering, and research.

Shortly after delivery of the Atari VCS game console, Atari designs two microcomputers with game capabilities: the Model 400 and Model 800. The 400 served primarily as a game console, while the 800 was more of a home computer. Both faced strong competition from the Apple II, Commodore PET, and TRS-80 computers. Atari's 8-bit computers were influential in the arts, especially in the emerging DemoScene culture of the 1980s and '90s.

Based around the Texas Instruments TMS 9900 microprocessor running at 3 MHz, the TI 99/4 has one of the fastest CPUs available in a home computer. The TI99/4 had a wide variety of expansion boards, with an especially popular speech synthesis system that could also be used with TI's Speak & Spell educational game. The TI 99/4 sold well and led to a series of TI follow-on machines.

This very small home computer is available in the UK as a kit for Â£79 or pre-assembled for Â£99. Inside was a Z80 microprocessor and a built-in BASIC language interpreter. Output was displayed on the userâs home TV screen through use of an adapter. About 50,000 were sold in Britain, primarily to hobbyists, and initially there was a long waiting list for the system.

The British Broadcasting Corporationâs Computer Literacy Project hoped âto introduce interested adults to the world of computers.â Acorn produces a popular computer, the BBC Microcomputer System, so viewers at home could follow along on their own home computers as they watched the program. The machine was expandable, with ports for cassette storage, serial interface and rudimentary networking. A large amount of software was created for the âBBC Micro,â including educational, productivity, and game programs.

IBM's brand recognition, along with a massive marketing campaign, ignites the fast growth of the personal computer market with the announcement of its own personal computer (PC). The first IBM PC, formally known as the IBM Model 5150, was based on a 4.77 MHz Intel 8088 microprocessor and used MicrosoftÂ´s MS-DOS operating system. The IBM PC revolutionized business computing by becoming the first PC to gain widespread adoption by industry. The IBM PC was widely copied (âclonedâ) and led to the creation of a vast âecosystemâ of software, peripherals, and other commodities for use with the platform.

The C64, as it is better known, sells for $595, comes with 64 KB of RAM and features impressive graphics. Thousands of software titles were released over the lifespan of the C64 and by the time it was discontinued in 1993, it had sold more than 22 million units. It is recognized by the 2006 Guinness Book of World Records as the greatest selling single computer of all time.

Created almost five years after the original Apple II, Franklin's Ace 1000 main logic board is nearly identical to that in the Apple II+ computer, and other models were later cloned as well. Franklin was able to undercut Apple's pricing even while offering some features not available on the original. Initially, Franklin won a court victory allowing them to continue cloning the machines, but in 1988, Apple won a copyright lawsuit against Franklin, forcing them to stop making Apple II âclones.â

When Xerox PARC loaned the Stanford Engineering Department an entire Alto Ethernet network with laser printer, graduate student Andy Bechtolsheim re-designed it into a prototype that he then attached to Stanfordâs computer network. Sun Microsystems grows out of this prototype. The roots of the companyâs name came from the acronym for Stanford University Network (SUN). The company was incorporated by three 26-year-old Stanford alumni: Bechtolsheim, Vinod Khosla and Scott McNealy. The trio soon attracted UC Berkeley UNIX guru Bill Joy, who led software development. Sun helped cement the model of a workstation having an Ethernet interface as well as high-resolution graphics and the UNIX operating system.

Lisa is the first commercial personal computer with a graphical user interface (GUI). It was thus an important milestone in computing as soon Microsoft Windows and the Apple Macintosh would soon adopt the GUI as their user interface, making it the new paradigm for personal computing. The Lisa ran on a Motorola 68000 microprocessor and came equipped with 1 MB of RAM, a 12-inch black-and-white monitor, dual 5.25-inch floppy disk drives and a 5 MB âProfileâ hard drive. Lisa itself, and especially its GUI, were inspired by earlier work at the Xerox Palo Alto Research Center.

Advertised as the first 100% IBM PC-compatible computer, the Compaq Portable can run the same software as the IBM PC. With the success of the clone, Compaq recorded first-year sales of $111 million, the most ever by an American business in a single year. The success of the Portable inspired many other early IBM-compatible computers. Compaq licensed the MS-DOS operating system from Microsoft and legally reverse-engineered IBMâs BIOS software. Compaq's success launched a market for IBM-compatible computers that by 1996 had achieved an 83-percent share of the personal computer market.

Apple introduces the Macintosh with a television commercial during the 1984 Super Bowl, which plays on the theme of totalitarianism in George OrwellÂ´s book 1984. The ad featured the destruction of âBig Brotherâ â a veiled reference to IBM -- through the power of personal computing found in a Macintosh. The Macintosh was the first successful mouse-driven computer with a graphical user interface and was based on the Motorola 68000 microprocessor. Its price was $2,500. Applications that came as part of the package included MacPaint, which made use of the mouse, and MacWrite, which demonstrated WYSIWYG (What You See Is What You Get) word processing.

The PC Jr. is marketed as a home computer but is too expensive and limited in performance to compete with many of the other machines in that market. Itâs âchicletâ keyboard was also criticized for poor ergonomics. While the PC Jr. sold poorly, the PC/AT sold in the millions. It offered increased performance and storage capacity over the original IBM PC and sold for about $4,000. It also included more memory and accommodated high-density 1.2-megabyte 5 1/4-inch floppy disks.

In 1984, Michael Dell creates PC's Limited while still a student of the University of Texas at Austin. The dorm-room headquartered company sold IBM PC-compatible computers built from stock components. Dell dropped out of school to focus on his business and in 1985, the company produced the first computer of its own design, the Turbo PC, which sold for $795. By the early 1990s, Dell became one of the leading computer retailers.

Commodoreâs Amiga 1000 is announced with a major event at New York's Lincoln Center featuring celebrities like Andy Warhol and Debbie Harry of the musical group Blondie. The Amiga sold for $1,295 (without monitor) and had audio and video capabilities beyond those found in most other personal computers. It developed a very loyal following while add-on components allowed it to be upgraded easily. The inside of the Amiga case is engraved with the signatures of the Amiga designers, including Jay Miner as well as the paw print of his dog Mitchy.

Compaq beats IBM to the market when it announces the Deskpro 386, the first computer on the market to use IntelÂ´s new 80386 chip, a 32-bit microprocessor with 275,000 transistors on each chip. At 4 million operations per second and 4 kilobytes of memory, the 80386 gave PCs as much speed and power as older mainframes and minicomputers.

The 386 chip brought with it the introduction of a 32-bit architecture, a significant improvement over the 16-bit architecture of previous microprocessors. It had two operating modes, one that mirrored the segmented memory of older x86 chips, allowing full backward compatibility, and one that took full advantage of its more advanced technology. The new chip made graphical operating environments for IBM PC and PC-compatible computers practical. The architecture that allowed Windows and IBM OS/2 has remained in subsequent chips.

Daniel Hillis of Thinking Machines Corporation moves artificial intelligence a step forward when he develops the controversial concept of massive parallelism in the Connection Machine CM-1. The machine used up to 65,536 one-bit processors and could complete several billion operations per second. Each processor had its own small memory linked with others through a flexible network that users altered by reprogramming rather than rewiring. The machineÂ´s system of connections and switches let processors broadcast information and requests for help to other processors in a simulation of brain-like associative recall. Using this system, the machine could work faster than any other at the time on a problem that could be parceled out among the many processors.

The first IBM system to include IntelÂ´s 80386 chip, the company ships more than 1 million units by the end of the first year. IBM released a new operating system, OS/2, at the same time, allowing the use of a mouse with IBM PCs for the first time. Many credit the PS/2 for making the 3.5-inch floppy disk drive and video graphics array (VGA) standard for IBM computers. The system was IBM's response to losing control of the PC market with the rise of widespread copying of the original IBM PC design by âcloneâ makers.

Steve Jobs, forced out of Apple in 1985, founds a new company â NeXT. The computer he created, an all-black cube was an important innovation. The NeXT had three Motorola microprocessors and 8 MB of RAM. Its base price was $6,500. Some of its other innovations were the inclusion of a magneto-optical (MO) disk drive, a digital signal processor and the NeXTSTEP programming environment (later released as OPENSTEP). This object-oriented multitasking operating system was groundbreaking in its ability to foster rapid development of software applications. OPENSTEP was used as one of the foundations for the new Mac OS operating system soon after NeXT was acquired by Apple in 1996.

VTech, founded in Hong Kong, had been a manufacturer of Pong-like games and educational toys when they introduce the Laser 128 computer. Instead of simply copying the basic input output system (BIOS) of the Apple II as Franklin Computer had done, they reversed engineered the system and sold it for US $479, a much lower price than the comparable Apple II. While Apple sued to remove the Laser 128 from the market, they were unsuccessful and the Laser remained one of the very few Apple âclonesâ for sale.

Intel released the 80486 microprocessor and the i860 RISC/coprocessor chip, each of which contained more than 1 million transistors. The RISC microprocessor had a 32-bit integer arithmetic and logic unit (the part of the CPU that performs operations such as addition and subtraction), a 64-bit floating-point unit, and a clock rate of 33 MHz.

The 486 chips remained similar in structure to their predecessors, the 386 chips. What set the 486 apart was its optimized instruction set, with an on-chip unified instruction and data cache and an optional on-chip floating-point unit. Combined with an enhanced bus interface unit, the microprocessor doubled the performance of the 386 without increasing the clock rate.

Apple had initially included a handle in their Macintosh computers to encourage users to take their Macs on the go, though not until five years after the initial introduction does Apple introduce a true portable computer. The Macintosh Portable was heavy, weighing sixteen pounds, and expensive (US$6,500). Sales were weaker than projected, despite being widely praised by the press for its active matrix display, removable trackball, and high performance. The line was discontinued less than two years later.

Based on the Touchstone Delta computer Intel had built at Caltech, the Paragon is a parallel supercomputer that uses 2,048 (later increased to more than four thousand) Intel i860 processors. More than one hundred Paragons were installed over the lifetime of the system, each costing as much as five million dollars. The Paragon at Caltech was named the fastest supercomputer in the world in 1992. Paragon systems were used in many scientific areas, including atmospheric and oceanic flow studies, and energy research.

Apple enters the handheld computer market with the Newton. Dubbed a âPersonal Digital Assistantâ by Apple President John Sculley in 1992, the Newton featured many of the features that would define handheld computers in the following decades. The handwriting recognition software was much maligned for inaccuracy. The Newton line never performed as well as hoped and was discontinued in 1998.

The Pentium is the fifth generation of the âx86â line of microprocessors from Intel, the basis for the IBM PC and its clones. The Pentium introduced several advances that made programs run faster such as the ability to execute several instructions at the same time and support for graphics and music.

Be, founded by former Apple executive Jean Louis GassÃ©e and a number of former Apple, NeXT and SUN employees, releases their only product â the BeBox. Using dual PowerPC 603 CPUs, and featuring a large variety of peripheral ports, the first devices were used for software development. While it did not sell well, the operating system, Be OS, retained a loyal following even after Be stopped producing hardware in 1997 after less than 2,000 machines were produced.

Officially known as the Track Write, the automatically expanding full-sized keyboard used by the ThinkPad 701 is designed by inventor John Karidis. The keyboard was comprised of three roughly triangular interlocking pieces, which formed a full-sized keyboard when the laptop was opened -- resulting in a keyboard significantly wider than the case. This keyboard design was dubbed âthe Butterfly.â The need for such a design was lessened as laptop screens grew wider.

Palm Inc., founded by Ed Colligan, Donna Dubinsky, and Jeff Hawkins, originally created software for the Casio Zoomer personal data assistant. The first generation of Palm-produced devices, the Palm 1000 and 5000, are based around a Motorola microprocessor running at 16MHz, and uses a special gestural input language called âGraffiti,â which is quick to learn and fast. Palm could be connected to a PC or Mac using a serial port to synchronize â âsyncâ â both computer and Palm. The company called it a âconnected organizerâ rather than a PDA to emphasize this ability.

Sony had manufactured and sold computers in Japan, but the VAIO signals their entry into the global computer market. The first VAIO, a desktop computer, featured an additional 3D interface on top of the Windows 95 operating system as a way of attracting new users. The VAIO line of computers would be best known for laptops were designed with communications and audio-video capabilities at the forefront, including innovative designs that incorporated TV and radio tuners, web cameras, and handwriting recognition. The line was discontinued in 2014.

The Advanced Strategic Computing Initiative (ASCI) needed a supercomputer to help with the maintenance of the US nuclear arsenal following the ban on underground nuclear testing. The ASCI Red, based on the design of the Intel Paragon, was built by IBM and delivered to Sandia National Laboratories. Until the year 2000, it was the world's fastest supercomputer, able to achieve peak performance of 1.3 teraflops, (about 1.3 trillion calculations per second).

The first supercomputer using the Linux operating system, consumer, off-the shelf parts, and a high-speed, low-latency interconnection network, was developed by David A. Bader while at the University of New Mexico. From this successful prototype design, Bader led the development of âRoadRunnerâ, the first Linux supercomputer for open use by the national science and engineering community via the National Science Foundation's National Technology Grid. RoadRunner was put into production use in April 1999. Within a decade this design became the predominant architecture for all major supercomputers in the world.

Apple makes a splash with its Bondi Blue iMac, which sells for about $1,300. Customers got a machine with a 233-MHz G3 processor, 4GB hard drive, 32MB of RAM, a CD-ROM drive, and a 15" monitor. The machine was noted for its ease-of-use and included a 'manual' that contained only a few pictures and less than 20 words. As Appleâs first new product under the leadership of a returning Steve Jobs, many consider this the most significant step in Apple's return from near-bankruptcy in the middle 1990s.

Japan's SoftBank introduces the first camera phone, the J-Phone J-SH04; a Sharp-manufactured digital phone with integrated camera. The camera had a maximum resolution of 0.11 megapixels a 256-color display, and photos could be shared wirelessly. The J-Phone line would quickly expand, releasing a flip-phone version just a month later. Cameras would become a significant part of most phones within a year, and several countries have even passed laws regulating their use.

Developed by the Japanese government to create global climate models, the Earth Simulator is a massively parallel, vector-based system that costs nearly 60 billion yen (roughly $600 million at the time). A consortium of aerospace, energy, and marine science agencies undertook the project, and the system was built by NEC around their SX-6 architecture. To protect it from earthquakes, the building housing it was built using a seismic isolation system that used rubber supports. The Earth Simulator was listed as the fastest supercomputer in the world from 2002 to 2004.

With a distinctive anodized aluminum case, and hailed as the first true 64-bit personal computer, the Apple G5 is the most powerful Macintosh ever released to that point. While larger than the previous G4 towers, the G5 had comparatively limited space for expansion. Virginia Tech used more than a thousand PowerMac G5s to create the System X cluster supercomputer, rated #3 in November of that year on the worldâs TOP500 fastest computers.

Harkening back to the hobbyist era of personal computing in the 1970s, Arduino begins as a project of the Interaction Design Institute, Ivrea, Italy. Each credit card-sized Arduino board consisted of an inexpensive microcontroller and signal connectors which made Arduinos ideal for use in any application connecting to or monitoring the outside world. The Arduino used a Java-based integrated development environment and users could access a library of programs, called âWiring,â that allowed for simplified programming. Arduino soon became the main computer platform of the worldwide âMakerâ movement.

Nearly a quarter century after IBM launched their PC in 1981, they had become merely another player in a crowded marketplace. Lenovo, China's largest manufacturer of PCs, purchased IBM's personal computer business in 2005, largely to gain access to IBM's ThinkPad line of computers and sales force. Lenovo became the largest manufacturer of PCs in the world with the acquisition, later also acquiring IBM's server line of computers.

Named in honor of the space shuttle which broke-up on re-entry, the Columbia supercomputer is an important part of NASA's return to manned spaceflight after the 2003 disaster. Columbia was used in space vehicle analysis, including studying the Columbia disaster, but also in astrophysics, weather and ocean modeling. At its introduction, it was listed as the second fastest supercomputer in the world and this single system increased NASA's supercomputing capacity 10-fold. The system was kept at NASA Ames Research Center until 2013, when it was removed to make way for two new supercomputers.

At the 2006 World Economic Forum in Davos, Switzerland, the United Nations Development Program (UNDP) announces it will create a program to deliver technology and resources to targeted schools in the least developed countries. The project became the One Laptop per Child Consortium (OLPC) founded by Nicholas Negroponte, the founder of MIT's Media Lab. The first offering to the public required the buyer to purchase one to be given to a child in the developing world as a condition of acquiring a machine for themselves. By 2011, over 2.4 million laptops had been shipped.

Many companies have attempted to release electronic reading systems dating back to the early 1990s. Online retailer Amazon released the Kindle, one of the first to gain a large following among consumers. The first Kindle featured wireless access to content via Amazon.com, along with an SD card slot allowing increased storage. The first release proved so popular there was a long delay in delivering systems on release. Follow-on versions of the Kindle added further audio-video capabilities.

Apple introduces their first ultra notebook â a light, thin laptop with high-capacity battery. The Air incorporated many of the technologies that had been associated with Apple's MacBook line of laptops, including integrated camera, and Wi-Fi capabilities. To reduce its size, the traditional hard drive was replaced with a solid-state disk, the first mass-market computer to do so.

The Roadrunner is the first computer to reach a sustained performance of 1 petaflop (one thousand trillion floating point operations per second). It used two different microprocessors: an IBM POWER XCell L8i and AMD Opteron. It was used to model the decay of the US nuclear arsenal, analyze financial data, and render 3D medical images in real-time. An offshoot of the POWER XCell8i chip was used as the main processor in the Sony PlayStation 3 game console.

Originally a Cray XT3 system, the Jaguar is a massively parallel supercomputer at Oak Ridge National Laboratory, a US science and energy research facility. The system cost more than $100 million to create and ran a variation of the Linux operating system with up to 10 petabytes of storage. The Jaguar was used to study climate science, seismology, and astrophysics applications. It was the fastest computer in the world from November 2009 to June 2010.

Since the release of the Macintosh in 1984, Apple has placed emphasis on high-resolution graphics and display technologies. In 2012, Apple introduced the Retina display for the MacBook Pro laptop and iPad tablet. With a screen resolution of up to 400 pixels-per-inch (PPI), Retina displays approached the limit of pixel visibility to the human eye. The display also used In Plane Switching (IPS) technology, which allowed for a wider viewing angle and improved color accuracy. The Retina display became standard on most of the iPad, iPhone, MacBook, and Apple Watch product lines.

With a peak speed of over a petaflop (one thousand trillion calculations per second), the Tianhe 1 (translation: Milky Way 1) is developed by the Chinese National University of Defense Technology using Intel Xeon processors combined with AMD graphic processing units (GPUs). The upgraded and faster Tianhe-1A used Intel Xeon CPUs as well, but switched to nVidia's Tesla GPUs and added more than 2,000 Fei-Tang (SPARC-based) processors. The machines were used by the Chinese Academy of Sciences to run massive solar energy simulations, as well as some of the most complex molecular studies ever undertaken.

The iPad combines many of the popular capabilities of the iPhone, such as built-in high-definition camera, access to the iTunes Store, and audio-video capabilities, but with a nine-inch screen and without the phone. Apps, games, and accessories helped spur the popularity of the iPad and led to its adoption in thousands of different applications from movie making, creating art, making music, inventory control and point-of-sale systems, to name but a few.

The Nest Learning Thermostat is an early product made for the emerging âInternet of Things,â which envisages a world in which common everyday devices have network connectivity and can exchange information or be controlled. The Nest allowed for remote access to a userâs homeâs thermostat by using a smartphone or tablet and could also send monthly power consumption reports to help save on energy bills. The Nest would remember what temperature users preferred by âtrainingâ itself to monitor daily use patterns for a few days then adopting that pattern as its new way of controlling home temperature.

Conceived in the UK by the Raspberry Pi Foundation, this credit card-sized computer features ease of use and simplicity making it highly popular with students and hobbyists. In October 2013, the one millionth Raspberry Pi was shipped. Only one month later, another one million Raspberry Pis were delivered. The Pi weighed only 45 grams and initially sold for only $25-$35 U.S. Dollars.

The University of Michigan Micro Mote is the smallest computer in the world. The motes, measuring just over 1 cubic millimeter, were powered by a tiny battery and could collect sunlight through a photocell, enough to supply the tiny amount of energy a mote consumes -- about one trillionth of a watt. Three types of mote were initially introduced: two that measure temperature or pressure, and one that could take images. Since then, motes that recognize different sounds, measure light, track position, and record brain activity have been developed.

Motes are also known as "smart dust," since their tiny size and low cost make them inexpensive enough to "sprinkle" in the real world as sensors. An ecologist, for example, could sprinkle thousands of motes from the air onto a field and measure soil and air temperature, moisture, and sunlight, yielding accurate real-time data about the environment.

Building a computer into the watch form factor has been attempted many times but the release of the Apple Watch leads to a new level of excitement. Incorporating a version of Apple's iOS operating system, as well as sensors for environmental and health monitoring, the Apple Watch was designed to be incorporated into the Apple environment with compatibility with iPhones and Mac Books. Almost a million units were ordered on the day of release. The Watch was received with great enthusiasm, but critics took issue with the somewhat limited battery life and high price.