Milestone-Proposal talk:Colossus

Advocates’ Checklist

1. Is the proposal for an achievement rather than for a person? If the citation includes a person's name, have the proposers provided the required justification for inclusion of the person's name?
2. Was the proposed achievement a significant advance rather than an incremental improvement to an existing technology?
3. Were there prior or contemporary achievements of a similar nature? If so, have they been properly considered in the background information and in the citation?
4. Has the achievement truly led to a functioning, useful, or marketable technology?
5. Is the proposal adequately supported by significant references (minimum of five) such as patents, contemporary newspaper articles, journal articles, or citations to pages in scholarly books? At least one of the references should be from a peer-reviewed scholarly book or journal article. The full text of the material, not just the references, shall be present. If the supporting texts are copyright-encumbered and cannot be posted on the ETHW for intellectual property reasons, the proposers shall email a copy to the History Center so that it can be forwarded to the Advocate. If the Advocate does not consider the supporting references sufficient, the Advocate may ask the proposer(s) for additional ones.
6. Are the scholarly references sufficiently recent?
7. Does the proposed citation explain why the achievement was successful and impactful?
8. Does the proposed citation include important technical aspects of the achievement?
9. Is the proposed citation readable and understandable by the general public?
10. Will the citation be read correctly in the future by only using past tense? Does the citation wording avoid statements that read accurately only at the time that the proposal is written?
11. Does the proposed plaque site fulfill the requirements?
12. Is the proposal quality comparable to that of IEEE publications?
13. Are any scientific and technical units correct (e.g., km, mm, hertz, etc.)? Are acronyms correct and properly upper-cased or lower-cased? Are the letters in any acronym explained in the title or the citation?
14. Are date formats correct as specified in Section 6 of Milestones Program Guidelines? Helpful Hints on Citations, plaque locations
15. Do the year(s) appearing in the citation fall within the range of the year(s) included at the end of the title?
16. Note that it is the Advocate's responsibility to confirm that the independent reviewers have no conflict of interest (e.g., that they do not work for a company or a team involved in the achievement being proposed, that they have not published with the proposer(s), and have not worked on a project related to the funding of the achievement). An example of a way to check for this would be to search reviewers' publications on IEEE Xplore.

Reviewers’ Checklist

1. Is suggested wording of the Plaque Citation accurate?
2. Is evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?
3. Does proposed milestone represent a significant technical achievement?
4. Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?
5. Have proposers shown a clear benefit to humanity?

In answering the questions above, the History Committee asks that reviewers apply a similar level of rigor to that used to peer-review an article, or evaluate a research proposal. Some elaboration is desirable. Of course the Committee would welcome any additional observations that you may have regarding this proposal.

Submission and Approval Log

Submitted date: 2 May 2025
Advocate approval date: 6 May 2025
History Committee approval date:
Board of Directors approval date:

Expert Review from Brian Randell -- Bberg (talk) 22:54, 2 May 2025 (UTC)

1. Is suggested wording of the Plaque Citation accurate?
Yes.

1a. Since the citation includes a person's name, does the evidence presented support this, and is this the only person who should be so included?
The several quoted contemporary documents provide ample evidence that Tommy Flowers is the one person who should be identified as responsible for Colossus.

2. Is evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?
Yes. By now enough official documentation has been released, and carefully written analyses have been published, on Colossus and Flowers’ work, to provide ample support for the proposed wording of the Plaque Citation.

3. Does proposed milestone represent a significant technical achievement?
Absolutely! The speed with which Tommy Flowers, and his team successfully designed and produced the Colossus range is still awesome, as are the range’s technical success and impact.

4. Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?
The most similar competing achievement was ENIAC. The proposal provides a very good summary comparison of Colossus and ENIAC, and of the Atanasoff-Berry project.

5. Have proposers shown a clear benefit to humanity?
Bletchley Park’s Enigma and Colossus projects were very credibly assessed, by the Official Historian of British Intelligence in the Second World War (Professor Sir Harry Hinsley), as having helped to shorten the war by one or two years!

Short bio of Expert Reviewer
Brian Randell graduated in Mathematics from Imperial College, London, in 1957, and joined the English Electric Company where he and colleagues implemented the Whetstone KDF9 Algol compiler. From 1964-1969, he was with IBM in the United States, mainly at the IBM T.J. Watson Research Center, working on operating systems, the design of ultra-high speed computers, and computing system design methodology. With first Peter Naur and then John Buxton, he co-edited the two original NATO Software Engineering Reports. He then became Professor of Computing Science at Newcastle University, where in 1971 he set up the project that initiated research into the possibility of software fault tolerance.

He has been Principal Investigator on a succession of research projects in reliability and security funded by EPSRC, MoD, and the EU. Another, continuing, research interest has been the history of computing, especially the work of the Irish computer pioneer Percy Ludgate, and the Colossus Project. He has published over three hundred technical papers and reports, and is co-author or editor of eight books. He is now Emeritus Professor of Computing Science at Newcastle University. He is a Fellow of the BCS and the ACM, and was a Member of the Conseil Scientifique of the CNRS, France (2001-5), Chairman of the IEEE John von Neumann Medal Committee (2003-5), and a Member and then Chairman of the ACM A.M. Turing Award Committee (2005-9). He has received a D.Sc. from the University of London, and Honorary Doctorates from the University of Rennes, and the Institut National Polytechnique of Toulouse, France.

Expert Review from David A. Price -- Bberg (talk) 15:40, 4 May 2025 (UTC)

1. Is suggested wording of the Plaque Citation accurate?
Yes, the plaque citation is accurate.

1a. Since the citation includes a person's name, does the evidence presented support this, and is this the only person who should be so included?
Yes, it is appropriate that Tommy Flowers is named and that he is the only person named in this context. Mr. Flowers conceived this pioneering machine and was its lead designer.

2. Is evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?
Yes, the plaque citation is well supported by the evidence in the proposal.

3. Does proposed milestone represent a significant technical achievement?
Yes, the proposed milestone represents not only a significant achievement but an astonishing one for its time and circumstances.

4. Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?
No, there were not any contemporaneous similar or competing achievements. As noted in the proposal, the most comparable machine in conceptual terms, ENIAC, post-dated Colossus by two years and was not ready until after World War II was over.

5. Have proposers shown a clear benefit to humanity?
Yes, the proposal accurately documents that the Colossus machines were highly valuable to the war effort of the Allies during World War II.

Short bio of Expert Reviewer
David A. Price was educated at the College of William and Mary, where he received his degree in computer science, and at Harvard University and the University of Cambridge. He is a Fellow of the Royal Historical Society.

His 2021 book on Colossus titled Geniuses at War: Bletchley Park, Colossus, and the Dawn of the Digital Age was recognized by the IEEE History Committee in 2022 with its IEEE William and Joyce Middleton Electrical Engineering History Award. His book The Pixar Touch: The Making of a Company was named a Wall Street Journal "Best Book of the Year," a Fast Company "Best Business Book of the Year," and a Library Journal "Best Business Book of the Year." His book Love and Hate in Jamestown was a New York Times "Notable Book of the Year."

Citation as originally submitted -- Administrator4 (talk) 19:33, 7 May 2025 (UTC)

The Colossus Computers, 1944-1945

Six Colossus codebreaking computers operated in this building in 1944-1945. Designed by Thomas H. Flowers of the British Post Office, they enabled deciphering of encrypted radio messages transmitted between German Commands across occupied Europe, Russia and North Africa. The resulting military intelligence saved countless lives, and was critical in shortening World War II. As the first successful large-scale computing application of digital electronics, Colossus anticipated subsequent computer developments.

Expert Review from Jack Copeland -- Bberg (talk) 18:08, 12 May 2025 (UTC)

1. Is suggested wording of the Plaque Citation accurate?
The suggested wording of the plaque citation is accurate in every respect and very well chosen.

1a. Since the citation includes a person's name, does the evidence presented support this, and is this the only person who should be so included?
The citation names Thomas H. Flowers. The official 1945 report (declassified in 2000) of the Tunny-breaking operation states: “Colossus was entirely the idea of Mr Flowers of Dollis Hill” (General Report on Tunny, p. 35, TNA HW 25/4). Moreover, Colossus was not merely Flowers’ idea. It was Flowers’ tireless determination that made Colossus a reality. He received little or no support from Bletchley Park, who were critical of his idea. His faith in large-scale digital electronics, and his towering engineering skill, drove the project forward to its highly successful conclusion. Other engineers were certainly involved in the work, but it would be misleading to include other names in the plaque citation. Colossus was Tom Flowers’ invention.

2. Is evidence presented in the proposal of sufficient substance and accuracy to support the Plaque Citation?
The proposal is by and large accurate and it argues very adequately for each element of the suggested citation.

(1) There were six Colossus codebreaking computers operating in Block H in 1944-45. The best evidence for this (which is mentioned by the proposal) is the wartime floor-plan of Block H in General Report on Tunny. This shows the exact locations in Block H of the six Colossi, and also the space that had been reserved for Colossus XI.

(2) Colossus was designed by Thomas H. Flowers, as is made completely clear by (a) General Report on Tunny, (b) contemporaneous correspondence, and (c) the testimony of Flowers’ fellow engineers.

(3) That Colossus enabled the deciphering of encrypted radio messages transmitted between German Commands across occupied Europe, Russia and North Africa is made abundantly clear in General Report on Tunny, which the proposal cites regularly.

(4) That the resulting military intelligence saved countless lives, and was critical in shortening World War II is an accurate summary of the views of Sir Harry Hinsley, the official historian of British signals intelligence, and of other scholars who have written on the impact of the Colossi on the fighting.

(5) The proposal adequately summarizes the arguments of scholars that Colossus represented the first successful large-scale computing application of digital electronics, and anticipated subsequent computer developments.

3. Does the proposed milestone represent a significant technical achievement?
Colossus was undoubtedly a significant technical achievement. Prior to Colossus, electronic devices used relatively small numbers of vacuum tubes. Digital applications were uncommon. One well-known example of a digital application was the Atanasoff machine (the “Atanasoff-Berry Computer”), but this contained only a few hundred vacuum tubes. Flowers was the leading pioneer in the UK of large-scale electronics, and in this he was swimming against the tide—many were sceptical of the idea of employing large numbers of tubes in a single piece of equipment. As early as 1934, Flowers constructed an experimental installation containing three to four thousand tubes, for controlling connections between telephone exchanges by means of analog tones. A thousand telephone lines were controlled, each line having 3-4 valves attached to its end. While this equipment demonstrated that a large installation of tubes could run reliably for indefinitely long periods, Colossus was another quantum leap forward. In the exchange equipment, the handful of tubes attached to each telephone line operated independently of other tubes in the installation, whereas in the—digital—Colossus more than 2000 tubes worked in concert.

The scholarly literature details various additional engineering advances first seen in the Colossi. The proposal does a good job of summarizing the literature.

4. Were there similar or competing achievements? If so, have the proposers adequately described these and their relationship to the achievement being proposed?
As the proposal summarizes, there were no competing achievements at the time. The earlier Atanasoff–Berry machine was not of the same scale: it had an order of magnitude fewer tubes, and moreover was abandoned before becoming fully functional. The closest competitors to the Colossi were the large-scale electronic digital computers that went into service from 1946 onwards, beginning with ENIAC. However, ENIAC first ran in December 1945, almost two years after the first Colossus went into operation.

5. Have proposers shown a clear benefit to humanity?
The proposal does show a clear benefit to humanity. Most strikingly, this benefit was demonstrated in the Allied invasion of France and Germany during 1944–45, leading to the defeat of the Nazis. Colossus gave the Allies a window on the German armies and on the intentions of Hitler’s generals. By the time of the D-Day landings, information in decrypts had enabled the analysts to deduce the strength and disposition of German troops in the area of the Normandy beaches.

A few weeks before the invasion started, Colossus decrypted a crucial Tunny message, from Generaloberst Alfred Jodl, revealing that a very large Panzer force was going to be held in reserve and moved only on Hitler’s orders (message KV2388, 29 April 1944, TNA DEFE 3/44). This reserve included the Hitlerjugend SS Panzer Division, with around 150 tanks and over 22,000 men, and the crack Lehr Panzer Division, which in its recent move to France from Hungary required 84 trains to carry its infantry troops. Subsequent decrypts showed that the reserve was poised to deploy to the Calais region if necessary and was stationed as long as 24 hours away from the Normandy beaches. This was essential information for the Overlord commanders, who thanks to this intelligence knew that as the Allied troops landed, they would have a crucial breathing space before the German defences were at full strength in the Normandy area.

Even with the intelligence that the Colossi helped extract, it took the Allies almost a year to fight their way from the Normandy beaches to Berlin. In the absence of this intelligence, it might have taken them twice as long—or longer still. No one can say exactly. But if Colossus shortened the war by even 12 months, then at a conservative estimate this represents a saving of 7 million lives.

Bio of Expert Reviewer
Jack Copeland FRS NZ is Distinguished Professor in Humanities at the University of Canterbury in New Zealand. A Londoner by birth, he took his doctorate in mathematical logic at Oxford University, where he studied with Dana Scott and Robin Gandy. He has held the John Findlay Visiting Professorship of Philosophy at Boston University and the Royden B. Davis Visiting Chair of Interdisciplinary Studies in the Department of Psychology at Georgetown University, and a Dibner Fellowship in the History of Science at MIT, as well as numerous other Visiting Professorships and Fellowships at international centers such as ETH Zurich, Switzerland; Queensland University, Australia; Copenhagen University, Denmark; Renmin University, China; Beijing Normal University, China; Hebrew University of Jerusalem, Israel; Akita University, Japan; Plaksha University, India; and most recently RWTH-Aachen University, Germany.

He has received various prizes and honors internationally, including the American Philosophical Association Jon Barwise Prize, the Royal Society of New Zealand Aronui Medal, and the IACAP Covey Award. The citation for the APA Barwise Prize describes him as “the world-wide expert on Alan Turing and a leading philosopher of AI, computing and information”. Copeland’s books about Turing are: The Essential Turing (Oxford University Press), Colossus: The Secrets of Bletchley Park’s Codebreaking Computers (Oxford University Press), Alan Turing’s Automatic Computing Engine (Oxford University Press), Computability: Turing, Gödel, Church, and Beyond (MIT Press), Artificial Intelligence (Blackwell-Wiley), Turing: Pioneer of the Information Age (Oxford University Press) and, most recently, The Turing Guide (Oxford University Press).

Copeland has been script advisor and scientific consultant for a number of documentaries about World War II codebreaking. One of these, the BBC’s Code-Breakers, breaking the story of Flowers and Colossus, won two UK BAFTA awards and was listed as one of the year’s three best historical documentaries at the Media Impact Awards in New York City. Arte TV’s The Man Who Cracked the Nazi Codes, based on Copeland’s biography Turing, has been shown widely on TV networks around the world, and won the Best Documentary prize at the FIGRA European film festival.