A transistor computer is a computer which uses discrete transistors instead of vacuum tubes. The "first generation" of electronic computers used vacuum tubes, which generated large amounts of heat, were bulky, and were unreliable. A "second generation" of computers, through the late 1950s and 1960s featured boards filled with individual transistors and magnetic memory cores (see History of computing hardware). These machines remained the mainstream design into the late 1960s, when integrated circuits started appearing and led to the "third generation" machines.

First transistor computerEdit

The University of Manchester's experimental Transistor Computer was first operational in November 1953 and it is widely believed to be the first transistor computer to come into operation anywhere in the world. There were two versions of the Transistor Computer, the prototype, operational in 1953, and the full-size version, commissioned in April 1955. The 1953 machine had 92 point-contact transistors and 550 diodes, manufactured by STC. It had a 48-bit machine word.[1] The 1955 machine had a total of 200 point-contact transistors and 1300 point diodes,[1] which resulted in a power consumption of 150 watts. There were considerable reliability problems with the early batches of transistors and the average error free run in 1955 was only 1.5 hours. The Computer also used a small number of tubes in its clock generator, so it was not the first fully transistorized machine.[2]

The design of a full-size Transistor Computer was subsequently adopted by the Manchester firm of Metropolitan-Vickers, who changed all the circuits to more reliable types of junction transistors.[1] The production version was known as the Metrovick 950 and was built from 1956 to the extent of six[1] or seven machines,[3] which were "used commercially within the company"[3] or "mainly for internal use".[1]

Other early machinesEdit

In Japan, the ETL Mark III began development as a transistorized computer in 1954,[4] and was completed in 1956. In Canada, the DRTE Computer was completed in 1957. In Austria, the Mailüfterl was completed in May 1958.[5] The ETL Mark III and DRTE were the first transistorized computers in Asia and mainland Europe, respectively.

First transistorized stored-program computerEdit

In Japan, the ETL Mark III began development as a transistorized computer in 1954,[4] and was completed in 1956. It was created by the Electrotechnical Laboratory, with design finished in March 1956, followed by fabrication in April and operation beginning in July.[6][5] It was the first transistorized stored-program computer,[6][7][8] and used ultrasonic delay line memory.[6] It was also the first transistorized computer in Asia.

The ETL Mark III's successor, the ETL Mark IV, began development in 1956 and was completed in 1957. It used high-speed magnetic drum memory.[9][8] A modified version, the ETL Mark IV A, was introduced in 1958, as a fully transistorized computer with magnetic-core memory and an index register.[8][10]

Schools and hobbyistsEdit

First generation computers were largely out of reach of schools and hobbyists who wished to build their own, largely because of the cost of the large number of vacuum tubes required (though relay-based computer projects were undertaken[11]). The fourth generation (VLSI) was also largely out of reach, too, due to most of the design work being inside the integrated circuit package (though this barrier, too, was later removed[12]). So, second and third generation computer design (transistors and SSI) were perhaps the best suited to being undertaken by schools and hobbyists.[13]

See alsoEdit


  1. 1.0 1.1 1.2 1.3 1.4 David P. Anderson, Tom Kilburn: A Pioneer of Computer Design, IEEE Annals of the History of Computing - Volume 31, Number 2, April–June 2009, p. 84
  2. Cooke-Yarborough, E.H. (June 1998). "Some early transistor applications in the UK.". Engineering and Science Education Journal (London, UK: IEE) 7 (3): 100–106. Error: Bad DOI specified. ISSN 0963-7346. Retrieved 2009-06-07. 
  3. 3.0 3.1 1953 - Transistorized Computers Emerge, Computer History Museum
  4. 4.0 4.1 Martin Fransman (1993), The Market and Beyond: Cooperation and Competition in Information Technology, page 19, Cambridge University Press
  5. 5.0 5.1 Blackman, Nelson M. (June 1961). "The state of digital computer technology in Europe". Communications of the ACM (ACM) 4 (6): 256–265. Error: Bad DOI specified. Retrieved 2009-06-07. 
  6. 6.0 6.1 6.2 Early Computers, Information Processing Society of Japan
  7. 【Electrotechnical Laboratory】 ETL Mark III Transistor-Based Computer, Information Processing Society of Japan
  8. 8.0 8.1 8.2 Early Computers: Brief History, Information Processing Society of Japan
  9. 【Electrotechnical Laboratory】 ETL Mark IV Transistor-Based Computer, Information Processing Society of Japan
  10. 【Electrotechnical Laboratory】 ETL Mark IV A Transistor-Based Computer, Information Processing Society of Japan
  11. A.B.Bolt (1966). We Built our own Computers, SMP Handbooks, UK; re-released in 2010 by Cambridge University Press, Cambridge, UK, ISBN 978-0-521-09378-1
  12. C.Mead and L.Conway (1980). Introduction to VLSI Systems, Addison-Wesley, Reading, USA, ISBN 0-201-04358-0
  13. A.Wilkinson (1968). Computer Models, Edward Arnold, UK, SBN 7131 1515 X

External linksEdit

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