Timeline of computing 1950–79
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|Sep 1950||GER||Konrad Zuse leased his Z4 machine to the ETH Zurich for five years. Z4 was a relay-based machine. The corresponding contract was signed in the fall of 1949, and the machine reassembled in Zurich after its arrival in July 1950.
The Z4 was replaced by ERMETH, a computer developed at the ETH in Switzerland from 1953 to 1956, one of the first electronic computers on the European continent.
|1950||UK||Turing Test – The British mathematician and computer pioneer Alan Turing published a paper describing the potential development of human and computer intelligence and communication. The paper would come later to be called the Turing Test.|
|1950||UK||The Pilot ACE computer, with 800 vacuum tubes, and mercury delay lines for its main memory, became operational on 10 May 1950 at the National Physical Laboratory near London. It was a preliminary version of the full ACE, which had been designed by Alan Turing.|
|1950||USA||TIME magazine cover story on the Harvard "Mark III: Can man build a superman?" includes a quote from Howard Aiken, commenting on "calculators" (computers) then under construction: "We'll have to think up bigger problems if we want to keep them busy."|
|1951||USA||EDVAC becomes operational.|
|30 Mar 1951||USA||The first commercially successful electronic computer, UNIVAC, was also the first general purpose computer – designed to handle both numeric and textual information. Designed by J. Presper Eckert and John Mauchly, whose corporation subsequently passed to Remington Rand. The implementation of this machine marked the real beginning of the computer era. Remington Rand delivered the first UNIVAC machine to the U.S. Bureau of Census. This machine used magnetic tape for input.|
|21 Apr 1951||USA||Whirlwind, the first real-time computer was built at MIT by the team of Jay Forrester for the US Air Defense System, became operational.
This computer is the first to allow interactive computing, allowing users to interact with it using a keyboard and a cathode-ray tube. The Whirlwind design was later developed into SAGE, a comprehensive system of real-time computers used for early warning of air attacks.
|17 Nov 1951||UK||J Lyons, a United Kingdom food company, famous for its tea, made history by running the first business application on an electronic computer. A payroll system was run on Lyons Electronic Office (LEO) a computer system designed by Maurice Wilkes who had previously worked on EDSAC.|
|Sep 1951||UK||The oldest known recordings of computer generated music were played by the Ferranti Mark 1 computer.|
|1951||USA||EDVAC (electronic discrete variable computer). The first computer to use Magnetic Tape.
EDVAC could have new programs loaded from the tape. Proposed by John von Neumann, it was installed at the Institute for Advance Study, Princeton, USA.
|1951||Australia||CSIRAC used to play music – the first time a computer was used as a musical instrument.|
|1951||USA||The A-0 high level compiler is invented by Grace Murray Hopper.|
|April 1952||USA||IBM introduces the IBM 701, the first computer in its 700 and 7000 series of large scale machines with varied scientific and commercial architectures, but common electronics and peripherals. Some computers in this series remained in service until the 1980s.|
|June 1952||USA||IAS machine completed at the Institute for Advanced Study, Princeton, USA (by Von Neumann and others).|
|1952||USSR||BESM-1 is completed. Only one BESM-1 machine was built. The machine used approximately 5,000 vacuum tubes.|
|1953||UK||The University of Manchester team complete the first transistorised computer.|
|1953||USA||Arthur Andersen was hired to program the payroll for General Electric (GE)'s Appliance Park manufacturing facility near Louisville, Kentucky. As a result, GE purchased UNIVAC I which became the first-ever commercial computer in the USA. Joe Glickauf was Arthur Andersen's project leader for the GE engagement.|
|1953||World||Estimate that there are 100 computers in the world.|
|1953||USA||Magnetic core memory developed.|
|1954||USA||FORTRAN (FORmula TRANslation), the first high-level programming language development, was begun by John Backus and his team at IBM
The development continued until 1957. It is still in use for scientific programming. Before being run, a FORTRAN program needs to be converted into a machine program by a compiler, itself a program.
|1954||USA||The IBM 650 is introduced. A relatively inexpensive decimal machine with drum storage, it becomes the first mass-produced computer, with some 2000 installations.|
|December 1954||USA||The NORC was delivered by IBM to the US Navy.|
|1956||USA||First conference on artificial intelligence held at Dartmouth College in New Hampshire.|
|1956||USA||The Bendix G-15 computer was introduced by the Bendix Corporation|
|1956||NED||Edsger Dijkstra invented an efficient algorithm for shortest paths in graphs as a demonstration of the abilities of the ARMAC computer. The example used was the Dutch railway system. The problem was chosen because it could be explained quickly and the result checked. Although this is the main thing many people will remember Dijkstra for, he also made important contributions to many areas of computing – in particular he should be remembered for his work on problems relating to concurrency, such as the invention of the semaphore.|
|1957||USA||First dot matrix printer marketed by IBM.|
|1957||USA||FORTRAN development finished. See 1954.|
|1958||USA||Programming language LISP (interpreted) developed, Finished in 1960. LISP stands for 'LISt Processing'. Used in A.I. development. Developed by John McCarthy at Massachusetts Institute of Technology.|
|1958||USSR||Setun, a balanced ternary computer developed in 1958 at Moscow State University.|
|12 Sep 1958||USA||The integrated circuit invented by Jack Kilby at Texas Instruments.
Robert Noyce, who later set up Intel, also worked separately on the invention. Intel later went on to perfect the microprocessor. The patent was applied for in 1959 and granted in 1964. This patent wasn't accepted by Japan so Japanese businesses could avoid paying any fees, but in 1989 – after a 30-year legal battle – Japan granted the patent; so all Japanese companies paid fees up until the year 2001 – long after the patent became obsolete in the rest of the World.
|1959||World||Computers introduced between 1959 and 1964, often regarded as Second Generation computers, were based on discrete transistors and printed circuits – resulting in smaller, more powerful and more reliable computers.|
|1959||USA||COBOL (COmmon Business-Oriented Language) developed by Grace Murray Hopper as the successor to FLOW-MATIC, finished in 1961.|
|1959||USSR||Minsk mainframe computer development and production begun in the USSR. Stopped in 1975.|
|ALGOL, first structured, procedural, programming language to be released.|
|1960||UK||Compiler compiler, first compiler compiler is released.|
|1960||YUG||CER-10, vacuum tube-based computer created by Mihajlo Pupin Institute of Yugoslavia, first computer in SFRY.|
|1960||ROM||[MECIPT-1 ro:MECIPT, vacuum tube-based computer created by Polytechnic University of Timisoara,first computer in Romania. The work was started in 1956 by Iosif Kaufmann, Wilhelm Loewenfeld and Vasile Baltac.|
|1961||USA||APL programming language released by Kenneth Iverson at IBM.|
|1962||UK||ATLAS is completed by the University of Manchester team.
This machine introduced many modern architectural concepts: spooling, interrupts, pipelining, interleaved memory, virtual memory and paging. It was the most powerful machine in the world at the time of release.
|1962||USA||Work begun on the Linc, the brainchild of the M.I.T. physicist Wesley A. Clark in May 1961. It was the first functional prototype of a computer scaled down to be optimized and priced for the individual user. Used for the first time at the National Institutes of Mental Health in Bethesda, Maryland in 1963, many consider it to be the first personal computer.|
|1962||USA||Spacewar!, the first computer game is written by MIT student Steve Russell.|
|1962||?||The AN/UYK-1 computer was designed with rounded edges to fit through the hatch of ballistic missile submarines, as part of the first satellite navigation system, Transit.|
|1963||USA||Mouse conceived by Douglas Engelbart
The Mouse was not to become popular until 1983 with Apple Computer's Lisa and Macintosh and not adopted by IBM until 1987 – although compatible computers such as the Amstrad PC1512 were fitted with mice before this date.
|1964||USA||Computers built between 1964 and 1972 are often regarded as 'Third Generation' computers, they are based on the first integrated circuits – creating even smaller machines. Typical of such machines was the IBM System/360 series mainframe, while smaller minicomputers began to open up computing to smaller businesses.|
|1964||USA||Programming language PL/I released by IBM.|
|1964||USA||Launch of IBM System/360 – the first series of compatible computers, reversing and stopping the evolution of separate "business" and "scientific" machine architectures; all models used the same basic instruction set architecture and register sizes, in theory allowing programs to be migrated to more or less powerful models as needs changed. The basic unit of memory, the "byte", was defined as 8 bits, with larger units such as "words" defined with sizes that were multiples of 8, with many consequences. Many competing computers at the time used word sizes that were multiples of 6. The marketing term "IBM Compatible" was often used, at this time, to indicate that the architecture used 8 bit bytes. Over 14,000 were shipped by 1968.|
|1964||USA||Project MAC begun at MIT by J.C.R. Licklider:|
|1964||YUG||CER-20 released by Mihajlo Pupin Institute of Yugoslavia as "electronic bookkeeping machine".|
|1965||USA||DEC PDP-8 Mini Computer. The first minicomputer, built by Digital Equipment (DEC). It cost $16,000.|
|1965||USA||Moore's law published by Gordon Moore. Originally suggesting processor complexity doubled every year.
It was published in the 35th Anniversary edition of Electronics magazine. The law was revised in 1975 to suggest a doubling in complexity every two years.
|1965||USA||Fuzzy logic designed by Lofti Zadeh (University of California, Berkeley), it is used to process approximate data – such as 'about 100'.|
|1965||USSR||BESM-6 mainframe computer was designed in the USSR.|
|1965||USA||Programming language BASIC (Beginners All Purpose Symbolic Instruction Code) developed at Dartmouth College, USA, by Thomas E. Kurtz and John George Kemeny.
BASIC was not implemented on microcomputers until 1975. This was the first language designed to be used in a time-sharing environment, such as DTSS (Dartmouth Time-Sharing System), or GCOS.
|1965||USA||Packet switching, funded by ARPA was developed. This makes reliable computer networking possible.
The first computer-to-computer login does not occur until November 21, 1969, between Stanford and UCLA.
|1965||USA||The first supercomputer, the Control Data CDC 6600, was developed.|
|1966||USA||Hewlett-Packard entered the general purpose computer business with its HP-2115 for computation, offering power formerly found only in much larger computers. It supported a wide variety of languages, among them ALGOL, BASIC, and FORTRAN.|
|1966||YUG||CER-200 released by Mihajlo Pupin Institute of Yugoslavia|
|1967||USA/CH||Development of programming language Pascal begun, continued in Switzerland from 1968 to 1971. Based on ALGOL. Developed by Niklaus Wirth as a pedagogic tool.|
|1967||USA||The floppy disk is invented at IBM by David Noble,|
|1967||YUG||CER-22 – first transistor-based computer created by Mihajlo Pupin Institute of Yugoslavia, SFRY.|
|1968||USA||Intel founded by Robert Noyce and a few friends.|
|1968||USA||Programming language LOGO developed by Seymour Papert and team at MIT.|
|2 Oct 1968||GER||First computer ball mouse offered by Telefunken. The device named Rollkugel RKS 100-86 is based on "reversing" an earlier trackball-like device (also named Rollkugel) embedded into radar flight control desks, which had been developed around 1965 by a team led by Rainer Mallebrein at Telefunken Konstanz for the German Bundesanstalt für Flugsicherung (de) as part of their TR 86 process computer system with its SIG 100-86 vector graphics terminal.|
|9 Dec 1968||USA||Douglas Engelbart demonstrates interactive computing,|
|1969||USA||ARPANET begun by the United States Department of Defense for research into networking.
It is the original basis for what now forms the Internet. It was opened to non-military users later in the 1970s and many universities and large businesses went on-line.
|7 Apr 1969||USA||The first Request for Comments, RFC 1 published. The RFCs (network working group, Request For Comment) are a series of papers which are used to develop and define protocols for networking; originally the basis for ARPANET, there are now thousands of them applying to all aspects of the Internet. Collectively they document everything about the way the Internet and computers on it should behave, whether its TCP/IP networking or how email headers should be written there will be a set of RFCs describing it.|
|1969||?||Introduction of the RS-232 (serial interface) standard by EIA (Electronic Industries Association), one of the oldest serial interfaces still in common use today.|
|1969||USA||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.|
|Oct 1970||USA||First dynamic RAM chip introduced by Intel. It was called the 1103 and had a capacity of 1 K-bit, 1024 bits.|
|1970||USA||Development of UNIX operating system begun.
It was later released as C source code to aid portability, and subsequently versions are obtainable for many different computers, including the IBM PC. It and its clones (such as GNU/Linux) are still widely used on network servers and scientific workstations. Originally developed by Ken Thompson and Dennis Ritchie.
|1970||USA||Programming language Forth developed. A simple, clean, stackbased design, which later inspired PostScript and the Java virtual machine.|
|Jun 1970||USA||Steve Geller, Ray Holt and a team from AiResearch and American Microsystems completed development of a 20-bit parallel microprocessor chip set for the US Navy's F-14A Tomcat fighter jet. The processor used LSI chips to produce a fast, powerful, and rugged programmable computer that fitted into the very tight space restrictions of the aircraft. The largest LSI chip contained the equivalent of 3268 transistors.|
|1971||USA||CTC ships the Datapoint 2200, a mass-produced programmable terminal. Its multi-chip CPU provided the basis for the Intel 8008. A monitor and cassette drives were built-in, and the entire system fit the approximate footprint of an IBM Selectric typewriter. Users quickly began to use the system as a standalone computer - one of the earliest to arguably qualify as a personal computer.|
|1971||USA||Kenbak-1 ships. This small, cheap ($750) personal computer, build using pre-microprocessor TTL technology, is one clear candidate for "first personal computer", and is so considered by the Computer History Museum and the American Computer Museum.|
|1971||USA||Ray Tomlinson develops the first program that can send email messages, via the Arpanet, between people using different computers. (Programs existed previously that could send emails between users all logged onto the same computer.)|
|15 Nov 1971||USA||First microprocessor, the 4004, developed by a team at Intel, was released.
It contains the equivalent of 2300 transistors and was a 4 bit processor. It is capable of around 60,000 instructions per second (0.06 MIPS), running at a maximum clock speed of 740 kHz.
|1971||USA||Texas Instruments releases the first easily portable electronic calculator.|
|1971||YUG||HRS-100, a hybrid computer system, released by Mihajlo Pupin Institute of Yugoslavia.|
|1972||USA||Atari founded by Nolan Bushnell and Ted Dabney, (see also 1972).|
|1972||USA||Pong released – widely recognised as the first popular arcade video game. It was invented by Allan Alcorn.|
|1972||?||Computers built after 1972 are often called 'fourth generation' computers, based on LSI (Large Scale Integration) of circuits (such as microprocessors) – typically 500 or more components on a chip. Later developments include VLSI (Very Large Scale Integration) of integrated circuits 5 years later – typically 10,000 components. The fourth generation is generally viewed as running right up until the present, since although computing power has increased the basic technology has remained virtually the same.|
|1972||USA||Programming language C developed at The Bell Laboratories in the USA by Dennis Ritchie
(one of the inventors of the Unix operating system), its predecessor was the B programming language – also from Bell. It is a very popular language, especially for systems programming – as it is flexible and fast. C was considered a refreshing change in the computing industry because it helped introduce structured programming. The successor to C, C++, was introduced in the 1980s, and in turn helped usher in the era of object-oriented programming.
|1972||USA||First handheld scientific calculator released by Hewlett-Packard, the engineer's slide rule is at last obsolete.|
|1 Apr 1972||USA||8008 microprocessor released by Intel.|
|1972||USA||The first international connections to ARPANET are established. ARPANET later became the basis for what we now call the Internet.|
|1972||NOR||Norsk Data launches the Nord-5, the first 32-bit supermini computer.|
|1973||USA||Development of the TCP/IP protocol suite by a group headed by Vinton Cerf and Robert E. Kahn. These are the protocols used on the internet.|
|1973||FRA||Programming language Prolog developed at the University of Luminy-Marseilles in France by Alain Colmerauer. It introduced the new paradigm of logical programming and is often used for expert systems and AI programming.|
|1973||USA||The TV Typewriter, designed by Don Lancaster, provided the first display of alphanumeric information on an ordinary television set. It used $120 worth of electronics components. 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.|
|1973||USA||Ethernet developed, this became a popular way of connecting PCs and other computers together – to enable them to share data, and devices such as printers. A group of machines connected together in this way is known as a LAN.|
|1974||?||CLIP-4, the first computer with a parallel architecture.|
|1974||CAN||MCM/70, the first personal computer to be commercially released, by Micro Computer Machines in Canada. Although it incorporated a plasma display, was programmable in the high level language APL, and weighed just 20 pounds, it failed commercially.|
|1 Apr 1974||USA||Introduction of the 8080. It ran at a clock frequency of 2 MHz and did 0.64 MIPS.|
|1974||USA||Motorola announces the MC6800 8 Bit Microprocessor. It is more easy to implement than the 8080 because it only needs a single power supply to operate and does not need support chips. Unlike the 8080 it is sold not as much as a general purpose "number cruncher / computer" CPU core but more as a control processor for industrial control and as a peripheral processor.|
|1974||USA||Engineers Chuck Peddle and Bill Mensch leave Motorola after completing work on the 6800 CPU and join MOS Technology, Inc.|
|9 Oct 1974||UK||ICL launches its New Range of mainframes, the ICL 2900 Series|
|Dec 1974||USA||The MITS Altair 8800, the third commercially available personal computer, is released. In December 1974, an article in Popular Electronics invited people to order kits for the computer. Despite the limited memory (256 bytes) and limited processing power, around 200 were ordered on the first day. 10,000 were shipped at a kit price of $397 each. The Altair bus later developed into an industry standard, the S-100 bus.|
|1975||USA||First microcomputer implementation of BASIC by Bill Gates and Paul Allen, it was written for the MITS Altair, this led to the formation of Microsoft later in the year.|
|1975||USA||Unix marketed (see 1970).|
|1975||NOR||Norwegian company Mycron releases its MYCRO-1, the first single-board computer.|
|1975||USA||Formation of Microsoft by Bill Gates and Paul Allen.|
|1975||USA||MOS Technology, Inc. releases their 6501 CPU. which is pin compatible with Motorola's 6800, who soon starts a lawsuit against them. The 6501 is quickly withdrawn from sale and replaced with the 6502 which has a "lawsuit-compatible" design, but is otherwise nearly identical to the 6501.
The 6502 becomes one of the most popular CPUs for the next 10 years and is used in many computers and game consoles (most notably the Atari 2600, Apple II, the Commodore PET, VIC-20 and Commodore 64, the Acorn Electron/BBC Microcomputer, and the Nintendo Entertainment System/NES).
|1975||USA||IBM 5100 computer released; with integrated keyboard, display, and mass storage on tape, it resembles the personal computers of a few years later, although it does not use a microprocessor.|
|Nov 1975||USA||Zilog is founded by ex-Intel employees.|
|1 Apr 1976||USA||Apple Computer, Inc. founded, to market the Apple I single-board computer designed by Steve Wozniak and Steve Jobs.
It uses the MOS Technology 6502 microprocessor.
|1976||USA||First laser printer introduced by IBM – the IBM 3800.
The first colour versions came onto the market in 1988.
|1976||USA||Introduction of the Intel 8085 chip. An improved version of the 8080, with a superset of the 8080s instruction set (only a couple of extra instructions). Single 5V power supply (while the 8080 needed several different voltages).|
|1976||USA||Z80 chip released by Zilog. It was a superset of the 8080 chip with additional registers and instructions, and using only one power supply voltage. CP/M was originally written for the 8080, but many implementations used the Z80. The Z80 was the processor for home computers like the Tandy TRS-80 of 1977, the Sinclair ZX Spectrum of 1982 and many others.|
|1976||USA||MOS Technology, Inc introduces the KIM-1 microcomputer system as a demonstrator for its 6502 CPU.|
|1976||USA||Cray-1 supercomputer was invented by Seymour Cray.
He left Control Data in 1972 to form his own company. This machine was known as much for its horseshoe-shaped design as it was for being the first supercomputer to make vector processing practical. 85 were shipped at a cost of $5 million each.
|1976||USA||Commodore buys MOS Technology, Inc in a stock trade. MOS is valued at $12 million. Chuck Peddle joins Commodore as chief engineer. With the purchase of MOS, Commodore begins work on the Commodore PET.|
|1977||USA||Commodore introduces the Commodore PET. It comes with 4KB or 8KB of RAM, and an integrated cassette deck and 9" monochrome monitor.|
|5 Jun 1977||USA||Apple II computer introduced based on an 8 bit MOS Technology 6502 microprocessor running at 1 MHz with 4 KB of RAM. It had an open architecture, used color graphics, and an audio cassette interface for loading programs and storing data. Later, in July 1978, a floppy disk drive was made available with an elegantly designed interface. One of the first examples of a "killer app" (for the business world) was released for it—the VisiCalc spreadsheet program—in 1979.|
|Aug 1977||USA||Tandy brought out the TRS-80 with "Level I BASIC". Although the TRS-80 had a primitive 4K BASIC (a stripped down version of the public domain "Li-Chen Wang Basic") and abysmal graphics it still became a bestseller quickly.|
|Sep 1977||USA||Heathkit made the H8 Home computer kit available. It was based on an Intel 8080a processor and shipped with HDOS a Heathkit Disk Operating System and Benton Harbor BASIC.|
|1978||USA||Tandy upgraded the TRS-80 with a much improved Microsoft 8K "Level II BASIC", and an "expansion interface" which added 32KB RAM, A floppy disk and a printer interface. With these extras the TRS-80 became a viable small business computer.|
|8 Jun 1978||USA||Introduction of the 16-bit Intel 8086, the first x86 microprocessor. The available clock frequencies were 5, 8 and 10 MHz, with an instruction set of about 300 operations. At its introduction, the fastest 8086 available was the 8 MHz version which achieved 0.8 MIPS and contained 29,000 transistors. Over three decades later, x86 remains the most popular and commercially successful instruction set architecture in the history of personal computing.|
|1978||JAP||The Arcade Video game 'Space Invaders' is released, sparking a video game craze. In 1979, Atari's Asteroids would prove to be incredibly popular.|
|1979||USA||Programming language Ada introduced by Jean Ichbiah and team at Honeywell for the US Department of Defense.|
|1 Jun 1979||USA||Introduction of the Intel 8088, compatible with the 8086 with an 8-bit data bus – but this makes it cheaper to implement in computers. Chosen for the IBM PC, Intel processors were found in millions of IBM-PC compatible computers.|
|1979||UK||Commodore PET released in the United Kingdom. Based on a 1 MHz 6502 processor it displayed monochrome text and had just 8 KB of RAM. Priced £569. For £776 you could purchase a version with 16 KB of RAM, while for £914 you could get a 32 KB of RAM.|
|Compact disc was invented.|
|1979||USA||The 68000 Microprocessor launched by Motorola, the first of the 68k family. 5+ years later it was used in machines such as the Apple Macintosh, the Atari ST and the Commodore Amiga.|
|1979||USA||Shortly after the release of V7 Unix, which included UUCP, a protocol for communication over standard telephone lines, Tom Truscott and Jim Ellis created Usenet, a global discussion group system. Nowadays, it uses Internet protocols and is still popular.|
|1979||USA||Four disgruntled Atari programmers leave and form Activision, the first third-party video game software publisher. Activision promotes both the game and the programmer, changing the way software is marketed.|
|1979||USA||The IBM PC. IBM saw its computer market dominance being eroded by the new personal computers, such as the Apple II and the Commodore PET. IBM therefore began work on its own personal computer. When finished, this computer was released as the IBM PC on 12 August 1981.|
|1979||USA||Texas Instruments releases the TI-99/4 microcomputer. This system generally used audio cassettes to store information, along with ROM modules, similar to gaming units, to hold commercial software. Additionally, TI made available a speech synthesizer, based on their own chip, for the TI-99/4 and its successor, the 4A.|
|Nov 1979||USA||Atari released the Atari 400/800 home computer. Atari 400/800 computer is gaming-based home computer. This computer is based on 6502 microprocessor.|
- Stefan Betschon: Der Zauber des Anfangs - Schweizer Computerpioniere. In: Ingenieure bauen die Schweiz. Franz Betschon et al. (editors), pp. 376-399, Verlag Neue Zuercher Zeitung, Zurich 2013, ISBN 978-3-03823-791-4
- "Auf den Spuren der deutschen Computermaus" [In the footsteps of the German computer mouse] (in German). Heise Verlag. 2009-04-28. Retrieved 2013-01-07.
- "Telefunken's 'Rollkugel'". oldmouse.com.
- "SIG-100 video terminal and mouse".
- see 6502 microprocessor history
- Steven Weyhrich (28 December 2001). "Apple II History Chapter 5, The Disk II". Retrieved 27 November 2008.