Tommy Flowers

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Thomas (Tommy) Harold Flowers, MBE (22 December 1905 – 28 October 1998) was a British engineer. During World War II, Flowers designed Colossus, an early electronic computer, to help solve encrypted German messages.

1 World War II
2 Post-war work
3 References
4 External links

Flowers was born in London's East End on 22 December 1905, the son of a bricklayer^[1]. After an apprenticeship in mechanical engineering, he earned a degree in electrical engineering at the University of London. In 1926, he joined the telecommunications branch of the General Post Office (GPO), moving to work at the research station at Dollis Hill on the northwest side of London in 1930. From 1935 onward, he explored the use of electronics for telephone exchanges. By 1939, he was convinced that an all-electronic system was possible. This background in switching electronics would prove crucial for his computer design in World War II.

[edit] World War II

Flowers's first contact with the wartime codebreaking effort came when he was asked for help by Alan Turing, who was then working at the government's Bletchley Park codebreaking establishment 50 miles north of London. Turing wanted Flowers to build a decoder for the relay-based Bombe machine, which Turing had developed to help decrypt the Germans' Enigma codes. Although the decoder project was abandoned, Turing was impressed with Flowers's work, and introduced him to Max Newman who was leading the effort to break a teletype-based cipher, called "Geheimschreiber" (secret writer) by the Germans and "Fish" by the English decoding team. This was a much more complex coding system than Enigma; the decoding procedure involved trying so many possibilities that it was impractical to do by hand. In February 1943, Flowers proposed an electronic system, which he called Colossus, using 1500 valves (vacuum tubes). Because the most complicated previous electronic device had used about 150 valves, some were skeptical that such a device would be reliable. Flowers countered that the British telephone system used thousands of valves and was reliable because the electronics were operated in a stable environment that included having the circuitry on all the time. The Bletchley Park management were not convinced, however, and merely encouraged Flowers to proceed on his own.

Flowers gained full backing for his project from the Director of Dollis Hill, W.G. Radley. With the highest priority for acquisition of parts, Flowers's extremely dedicated team at Dollis Hill built the first machine in 11 months. It was immediately dubbed 'Colossus' by the Bletchley Park staff for its immense proportions. It operated 5 times faster and was more flexible than the previous system, named Heath Robinson, which used electro-mechanical switches. Anticipating the need for additional computers, a redesign utilizing 2400 valves was begun before the first computer was finished. The Mark 2 operated 5 times faster than the first Colossus. Flowers estimated that they could be manufactured at a rate of about one per month. Years later, Flowers described the design and construction of these computers^[2].

Ten Colossi were completed and used during World War II in British decoding efforts, and an eleventh was ready for commissioning at the end of the war. All but two were dismantled at the end of the war. "The remaining two were moved to British secret service headquarters, where they may have played a significant part in the codebreaking operations of the Cold War".^[3] They were finally decommissioned in 1959 and 1960.

[edit] Post-war work

After the war, Flowers was awarded limited recognition through an Order of the British Empire at the lowest level of MBE (member) and £1,000. His work in computing was not properly acknowledged until the 1970s, because the project was restricted by the Official Secrets Act. His family had known only that he had done some 'secret and important' work^[4]. He remained at the Post Office Research Station where he was Head of the Switching Division. He and his group pioneered work on all-electronic telephone exchanges, completing a basic design by about 1950. He was also involved in the development of ERNIE^[5]. In 1964 he became Head of the Advanced Development Group at Standard Telephones and Cables Ltd., retiring in 1969^[6].