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First Transistorized Computer
Tom Kilburn (1921–2001), Richard Grimsdale (1929–2005), Douglas Webb (b. 1929), Jean H. Felker (1919–1994)
“With the invention of the transistor in 1947, the next step was to use it as a replacement for the vacuum tube. Tubes had a significant advantage compared to relays—they were a thousand times faster—but tubes required an inordinate amount of electricity, produced huge amounts of heat, and failed constantly. Transistors used a fraction of the power, produced practically no heat at all, and were more reliable than tubes. And because transistors were smaller than tubes, a transistorized machine would run inherently faster, because electrons had a shorter distance to move.
The University of Manchester demonstrated its prototype transistorized computer on November 16, 1953. The machine made use of the “point-contact” transistor, a piece of germanium that was in contact with two wires held in very close proximity to each other—the two “points.” The Manchester machine had 92 point-contact transistors and 550 diodes. The system had a word size of 48 bits. (Many of today’s microprocessors can operate on words that are 8, 16, 32, or 64 bits.) A few months later, Jean H. Felker at Bell Labs created the TRADIC (transistor digital computer) for the US Air Force, with 700 point-contact transistors and more than 10,000 diodes.
This point-contact transistor was soon replaced by the bipolar junction transistor, so named because it is formed by a junction involving two kinds of semiconductors. Manchester updated its prototype in 1955 with a new design that used 250 of these junction transistors. Called the Metrovick 950, that computer was manufactured by Metropolitan-Vickers, a British electrical engineering company.
In 1956, the Advanced Development Group at MIT Lincoln Lab used more than 3,000 transistors to build the TX-0 (Transistorized eXperimental computer zero), a transistorized version of the Whirlwind and the forerunner to Digital Equipment Corporation’s (DEC) PDP-1.”
Close-up of the prototype of the Manchester transistorized computer.