 | |
| Developer | Tommy Flowers, assisted by Sidney Broadhurst, William Chandler and for the Mark 2 machines, Allen Coombs |
|---|---|
| Manufacturer | Post Office Research Station |
| Type | Special-purpose electronic digital programmable computer |
| Generation | First-generation computer |
| Release date |
|
| Discontinued | 1960 |
| Units shipped | 12 |
| Media |
|
| CPU | Custom circuits using thermionic valves and thyratrons. A total of 1,600 in Mk 1 and 2,400 in Mk 2. Also relays and stepping switches |
| Memory | None (no RAM) |
| Display | Indicator lamp panel |
| Input | Paper tape of up to 20,000 × 5-bit characters in a continuous loop |
| Power | 8.5 kW[b] |
Colossus was a set of computers developed by British codebreakers in the years 1943–1945[1] to help in the cryptanalysis of the Lorenz cipher. Colossus used thermionic valves (vacuum tubes) to perform Boolean and counting operations. Colossus is thus regarded[2] as the world's first programmable, electronic, digital computer, although it was programmed by switches and plugs and not by a stored program.[3]
Colossus was designed by General Post Office (GPO) research telephone engineer Tommy Flowers[1] based on plans developed by mathematician Max Newman at the Government Code and Cypher School (GC&CS) at Bletchley Park.
Alan Turing's use of probability in cryptanalysis (see Banburismus) contributed to its design. It has sometimes been erroneously stated that Turing designed Colossus to aid the cryptanalysis of the Enigma.[4] (Turing's machine that helped decode Enigma was the electromechanical Bombe, not Colossus.)[5]
The prototype, Colossus Mark 1, was shown to be working in December 1943 and was in use at Bletchley Park by early 1944.[1] An improved Colossus Mark 2 that used shift registers to run five times faster first worked on 1 June 1944, just in time for the Normandy landings on D-Day.[6] Ten Colossi were in use by the end of the war and an eleventh was being commissioned.[6] Bletchley Park's use of these machines allowed the Allies to obtain a vast amount of high-level military intelligence from intercepted radiotelegraphy messages between the German High Command (OKW) and their army commands throughout occupied Europe.
The existence of the Colossus machines was kept secret until the mid-1970s.[7][8] All but two machines were dismantled into such small parts that their use could not be inferred. The two retained machines were eventually dismantled in the 1960s. In January 2024, new photos were released by GCHQ that showed re-engineered Colossus in a very different environment from the Bletchley Park buildings, presumably at GCHQ Cheltenham.[9] A functioning reconstruction of a Mark 2 Colossus was completed in 2008 by Tony Sale and a team of volunteers; it is on display in The National Museum of Computing at Bletchley Park.[10][11][12]
Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).
- ^ a b c "Colossus". The National Museum of Computing. Retrieved 25 January 2021.
- ^ Copeland "Introduction" 2006, p. 2.
- ^ Sale 2000.
- ^ Golden, Frederic (29 March 1999), "Who Built The First Computer?", Time, vol. 153, no. 12, archived from the original on 6 January 2006
- ^ Copeland, Jack, "Colossus: The first large scale electronic computer", Colossus-computer.com, retrieved 21 October 2012
- ^ a b Flowers 1983, p. 246.
- ^ Barber, Nicola (21 December 2015). Who Broke the Wartime Codes?. Capstone. ISBN 9781484635599. Retrieved 26 October 2017 – via Google Books.
- ^ Cite error: The named reference
lorenzwas invoked but never defined (see the help page). - ^ GCHQ 2024.
- ^ "coltalk_2". Codesandciphers.org.uk. Retrieved 26 October 2017.
- ^ Campbell-Kelly, Martin (31 August 2011). "Tony Sale obituary". The Guardian. Retrieved 26 October 2017.
- ^ Colossus – The Rebuild Story, The National Museum of Computing, archived from the original on 18 April 2015, retrieved 13 May 2017