Transistor computer
Encyclopedia
A transistor computer is a computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 which uses discrete transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

s instead of vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...

s. 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
Magnetic core memory
Magnetic-core memory was the predominant form of random-access computer memory for 20 years . It uses tiny magnetic toroids , the cores, through which wires are threaded to write and read information. Each core represents one bit of information...

. These machines remained the mainstream design into the late 1960s, when integrated circuits started appearing and led to the "third generation" machines.

The first transistor computer

The University of Manchester
University of Manchester
The University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...

'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 transistor
Point-contact transistor
A point-contact transistor was the first type of solid-state electronic transistor ever constructed. It was made by researchers John Bardeen and Walter Houser Brattain at Bell Laboratories in December 1947. They worked in a group led by physicist William Bradford Shockley...

s and 550 diode
Diode
In electronics, a diode is a type of two-terminal electronic component with a nonlinear current–voltage characteristic. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material connected to two electrical terminals...

s, manufactured by STC
STC
- Education :* S. Thomas' College, Mt Lavinia, a private school in Sri Lanka* South Texas College* South Thames College* Sha Tin College, Hong Kong* Saint Theresa's College, Philippines- Organizations :* Scarborough Town Centre* Space Transport Corporation...

. It had a 48-bit
48-bit
Computers with 48-bit words include CDC 1604 and BESM-6.The IBM AS/400, in its CISC variants, is a 48-bit addressing system. The address size used in logical block addressing was increased to 48 bits with the introduction of ATA-6....

 machine word. The 1955 machine had a total of 200 point-contact transistors and 1300 point diodes, 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.

The design of a full-size Transistor Computer was subsequently adopted by the Manchester
Manchester
Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...

 firm of Metropolitan-Vickers
Metropolitan-Vickers
Metropolitan-Vickers, Metrovick, or Metrovicks, was a British heavy electrical engineering company of the early-to-mid 20th century formerly known as British Westinghouse. Highly diversified, they were particularly well known for their industrial electrical equipment such as generators, steam...

, who changed all the circuits to more reliable types of junction transistor
Bipolar junction transistor
|- align = "center"| || PNP|- align = "center"| || NPNA bipolar transistor is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons...

s. The production version was known as the Metrovick 950
Metrovick 950
The Metrovick 950 was a transistorized computer, built from 1956 onwards by British company Metropolitan-Vickers, to the extent of six or seven machines, which were "used commercially within the company" or "mainly for internal use"...

 and was built from 1956 to the extent of six or seven machines, which were "used commercially within the company" or "mainly for internal use".

Other early machines

During the mid-1950s a series of similar machines appeared. These included the Bell Laboratories TRADIC
TRADIC
The TRADIC was the first transistorized computer in the USA, completed in 1954....

, completed in January 1954 also incorporated a single high-power output vacuum-tube amplifier to supply its 1-MHz clock power.

The first fully transistorised computer was either the Harwell CADET
Harwell CADET
The Harwell CADET was the first fully transistorised computer in Europe, and may have been the first fully transistorised computer in the world....

 which first operated in February 1955, although the price paid for this was that it only operated at the slow speed of 58 kHz, or the prototype IBM 604
IBM 604
The IBM 604 was a control panel programmable Electronic Calculating Punch introduced in 1948, and was a machine on which considerable expectations for the future of IBM were pinned and in which a corresponding amount of planning talent was invested...

 transistor calculator, described in the next section. The Burroughs Corporation claimed the SM-65 Atlas ICBM / THOR ABLE guidance computer (MOD 1) that it delivered to the US Air Force at the Cape Canaveral
Cape Canaveral
Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.It is part of a region known as the...

 missile range in June 1957 was "the world's first operational transistorized computer".

In Japan the ETL Mark III began operation in July 1956; the Canadian DRTE Computer
DRTE Computer
The DRTE Computer was a transistorized computer built at the Defence Research Telecommunications Establishment , part of the Canadian Defence Research Board. It was one of the earlier fully transistorized machines, running in prototype form in 1957, and fully developed form in 1960...

 in 1957, while in Austria, the Mailüfterl
Mailüfterl
Mailüfterl is an Austrian nickname for the first transistorized computer on the European mainland. The first computers of this kind were TRADIC, Harwell CADET and TX-0.It was built in 1955 at the Vienna University of Technology by Heinz Zemanek...

 was completed in May 1958, being the first transistorised computers in Asia and mainland Europe.

The first commercial fully transistorised computer

In April 1955, IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

 announced the IBM 608
IBM 608
The IBM 608 was the first IBM product to use transistor circuits without any vacuum tubes and is believed to be the world's first all-transistorized calculator to be manufactured for the commercial market.Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H.; . IBM's 360 and early 370 systems. MIT...

 transistor calculator which was first shipped in December 1957. IBM and several historians thus consider the IBM 608 the first all solid-state computing machine commercially marketed. The development of the 608 was preceded by the prototyping of an experimental all-transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

 version of the 604. This was built and demonstrated in October 1954, but was not commercialized.

In Italy, Olivetti
Olivetti
Olivetti S.p.A. is an Italian manufacturer of computers, printers and other business machines.- Founding :The company was founded as a typewriter manufacturer in 1908 in Ivrea, near Turin, by Camillo Olivetti. The firm was mainly developed by his son Adriano Olivetti...

's first commercial fully transistorised computer was the Olivetti
Olivetti
Olivetti S.p.A. is an Italian manufacturer of computers, printers and other business machines.- Founding :The company was founded as a typewriter manufacturer in 1908 in Ivrea, near Turin, by Camillo Olivetti. The firm was mainly developed by his son Adriano Olivetti...

Elea 9003, being sold from 1959.

Schools and Hobbyists

First generation computers where 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). The third and fourth generations were 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). So, the second generation computer was really the best suited to being undertaken by schools and hobbyists.

External links

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