Editing Colossus computer (section)

==Influence and fate==
Although the Colossus was the first of the electronic digital machines with programmability, albeit limited by modern standards,<ref>{{cite web|url=http://www.alanturing.net/turing_archive/pages/Reference%20Articles/BriefHistofComp.html#Col|title=A Brief History of Computing. Jack Copeland, June 2000|website=Alanturing.net|access-date=26 October 2017}}</ref> it was not a general-purpose machine, being designed for a range of cryptanalytic tasks, most involving counting the results of evaluating Boolean algorithms.

A Colossus computer was thus not a fully [[Turing complete]] machine. However, [[University of San Francisco]] professor Benjamin Wells has shown that if all ten Colossus machines made were rearranged in a specific [[Computer cluster|cluster]], then the entire set of computers could have simulated a [[universal Turing machine]], and thus be Turing complete.<ref>{{Cite conference | last = Wells | first = Benjamin |  title = Proceedings of the 8th International Conference on Unconventional Computation 2009 (UC09), Ponta Delgada, Portugal|contribution= Advances in I/O, Speedup, and Universality on Colossus, an Unconventional Computer  | series = Lecture Notes in Computer Science | volume = 5175 | pages = 247–261 | publisher = Springer-Verlag | location = Berlin, Heidelberg | date = 2009 | doi=10.1007/978-3-642-03745-0_27 | isbn = 978-3-642-03744-3  }}</ref>

Colossus and the reasons for its construction were highly secret and remained so for 30 years after the War. Consequently, it was not included in the [[history of computing hardware]] for many years, and Flowers and his associates were deprived of the recognition they were due. All but two of the Colossi were dismantled after the war and parts returned to the Post Office. Some parts, sanitised as to their original purpose, were taken to Max Newman's [[Royal Society]] [[Computing Machine Laboratory]] at [[Manchester University]].<ref>{{cite web | title = A Brief History of Computing | publisher = alanturing.net | access-date = 26 January 2010 | url = http://www.alanturing.net/turing_archive/pages/Reference%20Articles/BriefHistofComp.html#ACE }}</ref> Two Colossi, along with two Tunny machines, were retained and moved to [[GCHQ]]'s new headquarters at [[Eastcote]] in April 1946, and then to [[Cheltenham]] between 1952 and 1954.{{sfn|Copeland et al.|2006|pp=173–175}}{{sfn|GCHQ|2024}} One of the Colossi, known as ''Colossus Blue'', was dismantled in 1959; the other in the 1960s.{{sfn|Copeland et al.|2006|pp=173–175}} Tommy Flowers was ordered to destroy all documentation. He duly burnt them in a furnace and later said of that order:
{{blockquote|That was a terrible mistake. I was instructed to destroy all the records, which I did. I took all the drawings and the plans and all the information about Colossus on paper and put it in the boiler fire. And saw it burn.{{sfn|McKay|2010|pp=270–271}} }}The Colossi were adapted for other purposes, with varying degrees of success; in their later years they were used for training.<ref>{{cite AV media |last=Horwood |first=D.C. |title=A technical description of Colossus I: PRO HW 25/24 |year=1973 |url=https://www.youtube.com/watch?v=JF48sl15OCg |via=YouTube |access-date=16 March 2014 |archive-date=2 April 2014 |archive-url=https://web.archive.org/web/20140402160011/http://www.youtube.com/watch?v=JF48sl15OCg |url-status=dead }}</ref> [[I. J. Good|Jack Good]] related how he was the first to use Colossus after the war, persuading the US [[National Security Agency]] that it could be used to perform a function for which they were planning to build a special-purpose machine.{{sfn|Copeland et al.|2006|pp=173–175}} Colossus was also used to perform character counts on [[one-time pad]] tape to test for non-randomness.{{sfn|Copeland et al.|2006|pp=173–175}}

A small number of people who were associated with Colossus—and knew that large-scale, reliable, high-speed electronic digital computing devices were feasible—played significant roles in early computer work in the UK and probably in the US. However, being so secret, it had little direct influence on the development of later computers; it was [[EDVAC]] that was the seminal computer architecture of the time.<ref>{{cite journal |last1=Chodos |first1=Alan |title=August 1946: The Moore School Lectures |journal=APS News |date=2022 |volume=11 |issue=4 |url=https://www.aps.org/publications/apsnews/200208/history.cfm |access-date=25 January 2022}}</ref> In 1972, [[Herman Goldstine]], who was unaware of Colossus and its legacy to the projects of people such as Alan Turing ([[ACE (computer)|ACE]]), Max Newman ([[Manchester computers]]) and [[Harry Huskey]] ([[Bendix G-15]]), wrote that,

{{blockquote|Britain had such vitality that it could immediately after the war embark on so many well-conceived and well-executed projects in the computer field.{{sfn|Goldstine|1980|p=321}} }}

Professor [[Brian Randell]], who unearthed information about Colossus in the 1970s, commented on this, saying that:
{{blockquote|It is my opinion that the COLOSSUS project was an important source of this vitality, one that has been largely unappreciated, as has the significance of its places in the chronology of the invention of the digital computer.{{sfn|Randell|1980|p=87}} }}

Randell's efforts started to bear fruit in the mid-1970s. The secrecy about Bletchley Park had been broken when [[F. W. Winterbotham|Group Captain Winterbotham]] published his book ''The Ultra Secret'' in 1974.<ref>{{Citation | last = Winterbotham | first = F.W. | author-link = F.W. Winterbotham | title = The Ultra secret: the inside story of Operation Ultra, Bletchley Park and Enigma | place = London | publisher = Orion Books Ltd | orig-year = 1974 | year = 2000 | oclc = 222735270 | isbn = 9780752837512 }}</ref> Randell was researching the history of computer science in Britain for a conference on the history of computing held at the Los Alamos Scientific Laboratory, New Mexico on 10–15 June 1976, and got permission to present a paper on wartime development of the COLOSSI  at the [[Post Office Research Station]],  Dollis Hill (in October 1975 the British Government had released a series of captioned photographs from the Public Record Office).  The interest in the "revelations" in his paper resulted in a special evening meeting when Randell and Coombs answered further questions. Coombs later wrote that ''no member of our team could ever forget the fellowship, the sense of purpose and, above all, the breathless excitement of those days''. In 1977 Randell published an article ''The First Electronic Computer'' in several journals.{{efn| ''New Scientist'', 10 February 1977 & ''IBM UK News,'' 4 March 1967 }}<ref>''COLOSSUS and the History of Computing: Dollis Hill's Important Contribution'' by A.W.M. Coombs in The Post Office Electrical Engineers' Journal (POEEJ; Volume70, 1977/78 part 2, July 1977, pages 108-110)</ref>

In October 2000, a 500-page technical report on the Tunny cipher and its cryptanalysis—entitled ''General Report on Tunny''{{sfn|Good|Michie|Timms|1945}}—was released by GCHQ to the national [[Public Record Office]], and it contains a fascinating [[paean]] to Colossus by the cryptographers who worked with it:
{{blockquote|It is regretted that it is not possible to give an adequate idea of the fascination of a Colossus at work; its sheer bulk and apparent complexity; the fantastic speed of thin paper tape round the glittering pulleys; the childish pleasure of not-not, span, print main header and other gadgets; the wizardry of purely mechanical decoding letter by letter (one novice thought she was being hoaxed); the uncanny action of the typewriter in printing the correct scores without and beyond human aid; the stepping of the display; periods of eager expectation culminating in the sudden appearance of the longed-for score; and the strange rhythms characterizing every type of run: the stately break-in, the erratic short run, the regularity of wheel-breaking, the stolid rectangle interrupted by the wild leaps of the carriage-return, the frantic chatter of a motor run, even the ludicrous frenzy of hosts of bogus scores.{{sfn|Good|Michie|Timms|1945|loc = 5 Machines: 51 Introductory, (j) Impressions of Colossus, p. 327}} }}