--- title: The Computer That Helped Win World War II | daily.dev description: Colossus, the world's first large-scale programmable electronic digital computer, was built by engineer Tommy Flowers during World War II to break Germany's... canonical: https://daily.dev/posts/the-computer-that-helped-win-world-war-ii-fgb5ueerp twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: The Computer That Helped Win World War II | daily.dev og:description: Colossus, the world's first large-scale programmable electronic digital computer, was built by engineer Tommy Flowers during World War II to break Germany's... og:url: https://daily.dev/posts/the-computer-that-helped-win-world-war-ii-fgb5ueerp og:image: https://api.daily.dev/og/posts/fGB5uEeRp.png og:image:alt: The Computer That Helped Win World War II og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # The Computer That Helped Win World War II **[Hacker News](https://daily.dev/sources/hn)** · 11 min read · 0 upvotes · 0 comments ## Summary Colossus, the world's first large-scale programmable electronic digital computer, was built by engineer Tommy Flowers during World War II to break Germany's Lorenz cipher (codenamed 'Tunny'), which was far more advanced than Enigma. After codebreakers John Tiltman, Bill Tutte, and Alan Turing cracked the theoretical basis of the Tunny machine, Flowers built Colossus in secret over 10 months, delivering it to Bletchley Park in January 1944. Running on ~2,000 vacuum tubes kept continuously powered for reliability, it processed ciphertext at 25,000 characters per second. Ten Colossi were operational by war's end, providing the Allies with unprecedented intelligence on German military strategy. Most were destroyed after the war to maintain secrecy. Colossus is now being recognized as an IEEE Milestone, with a dedication ceremony planned for 29 September at Bletchley Park. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community take How the wider developer community reacted, aggregated from 3 discussions and 72 comments across lobsters, hackernews (as of 2026-07-27). **TL;DR:** Commenters are broadly enthusiastic about Colossus and its historical significance, debating its classification as a 'stored program' computer versus a special-purpose machine, praising the engineers behind it (especially Tommy Flowers), and recommending visits to Bletchley Park and the National Museum of Computing. A side thread debates Nazi-era corporate sympathies and conspiracy theories with more skepticism. **Sentiment:** 55% positive · 30% mixed · 15% skeptical **The case for** - Tommy Flowers and the Colossus team achieved a remarkable engineering feat using only valve technology and mathematics available at the time. - The National Museum of Computing at Bletchley Park is highly recommended as an accessible, fascinating day trip from London with working replicas. - Colossus represented a genuine leap beyond the Bombe by tackling a stream cipher (Lorenz/Tunny) with a more general computational approach. - The distinction between Enigma and Lorenz ciphers is important context that many people miss, and the article helps clarify it. **The pushback** - The article reportedly understates Colossus's physical size, citing ~1 tonne when sources suggest it was actually ~5 tonnes. - The article apparently ignores Polish mathematicians' contributions — though commenters note this conflates Enigma with Lorenz, which are separate systems. - Conspiracy-style documentaries about WWII funding muddle real historical context by being too conspiratorial rather than grounding claims in evidence. - Tommy Flowers was never fully reimbursed for funding Colossus out of his own pocket, and was later refused a loan to build a computer because he couldn't disclose his prior work. **By community** - lobsters (mixed): No substantive comments available to assess sentiment. - hackernews (positive): Commenters are enthusiastically engaged with the history of Colossus, debating its technical classification, praising its engineers, and recommending Bletchley Park visits, with a skeptical side thread on WWII conspiracy theories. **Hottest debate:** Whether Colossus qualifies as a true 'stored program' computer or merely a programmable special-purpose digital machine. **Open questions** - Was the program in Colossus effectively 'stored' in the paper tape loop? - Why didn't earlier civilizations with sufficient complexity (e.g., Romans, Egyptians) develop computing — what was the actual prerequisite? - Are there more technical books on Colossus's design beyond the Copeland essay collection? **Highlights** > They weren't all destroyed, some were moved to what became GCHQ (UK's equivalent to the NSA) See Influence and Fate: https://en.wikipedia.org/wiki/Colossus_computer It's Tommy Flowers I always felt sorry for, after the war he wanted a loan to build a computer was refused on the grounds that what he wanted to build was impossible. He knew it was possible but couldn't disclose that due to secrecy laws > — [youngtaff on hackernews · 1 comments](https://news.ycombinator.com/item?id=49071966) > ‘Stored program’ is where the debate is. Colossus was ‘programmable’ but the program was not a series of instructions executed in a sequence - it was a single data process executed on the input data against a set of stored registers. Definitely programmable, definitely capable of computing, but not a ‘stored program’ in the sense we know it today. > — [jameshart on hackernews · 1 comments](https://news.ycombinator.com/item?id=49072565) > Flowers had to begin building Colossus out of his own pocket. The British government eventually repaid him, but not in full. > — [RachelF on hackernews · 1 comments](https://news.ycombinator.com/item?id=49074392) > I have a major problem with that article, it completely ignores Polish mathematicians' contributions who literally GAVE the brits the codes 5 weeks BEFORE the start of WWII. https://en.wikipedia.org/wiki/Marian_Rejewski > — [kubatyszko on hackernews · 1 comments](https://news.ycombinator.com/item?id=49072496) > Appended is a walkaround video of the Colossus at the National Museum of Computing next to Bletchley Park which is, FYI, a much better and far more interesting place to visit than Bletchley Park itself on the same site - and much cheaper. They have a bombe that cracked enigma, the colossus and some other German encoding machines and they are incredible to see. The lectures were absolutely fascinating. https://www.youtube.com/shorts/W7w6YXaNvt8 > — [t43562 on hackernews](https://news.ycombinator.com/item?id=49073949) **Source threads** - [lobsters](https://lobste.rs/s/u821ri/computer_helped_win_world_war_ii_colossus) · 1 points · 0 comments - [hackernews](https://news.ycombinator.com/item?id=49012309) · 56 points · 72 comments - [hackernews](https://news.ycombinator.com/item?id=49019986) · 3 points · 0 comments ## Similar posts on daily.dev - [ENIAC, the General-Purpose Digital Computer, Is 80](https://daily.dev/posts/eniac-the-general-purpose-digital-computer-is-80-4tgarj8js) · Hacker News · 0 upvotes · 0 comments - [War Hero that Inspired NLP and worlds first AI model.](https://daily.dev/posts/war-hero-that-inspired-nlp-and-worlds-first-ai-model--gqutipqwd) · Medium · 0 upvotes · 0 comments - [Alan Turing’s Remarkable, Nearly-Forgotten Voice Encryption Device](https://daily.dev/posts/alan-turing-s-remarkable-nearly-forgotten-voice-encryption-device-cokbuuslj) · Hackaday · 1 upvotes · 0 comments - [Schneier on Security](https://daily.dev/posts/schneier-on-security-zj3msmhrk) · Schneier on Security · 1 upvotes · 0 comments - [Enigma Cipher Device Still Holds Secrets for Cyber Pros](https://daily.dev/posts/enigma-cipher-device-still-holds-secrets-for-cyber-pros-buiazknbz) · Dark Reading · 0 upvotes · 0 comments --- Tags: [#encryption](https://daily.dev/tags/encryption), [#computing-history](https://daily.dev/tags/computing-history) [View this post on daily.dev](https://daily.dev/posts/the-computer-that-helped-win-world-war-ii-fgb5ueerp) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"The Computer That Helped Win World War II","url":"https://daily.dev/posts/the-computer-that-helped-win-world-war-ii-fgb5ueerp","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/the-computer-that-helped-win-world-war-ii-fgb5ueerp"},"datePublished":"2026-07-27T16:37:13.021Z","dateModified":"2026-07-27T21:23:35.179Z","description":"Colossus, the world's first large-scale programmable electronic digital computer, was built by engineer Tommy Flowers during World War II to break Germany's...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/f65364aa62ad371129714ebca601ec93?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/f65364aa62ad371129714ebca601ec93?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Hacker News","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Hacker News","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/hn","url":"https://daily.dev/sources/hn"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/the-computer-that-helped-win-world-war-ii-fgb5ueerp","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"encryption,computing-history","timeRequired":"PT11M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Hacker News","item":"https://daily.dev/sources/hn"},{"@type":"ListItem","position":3,"name":"The Computer That Helped Win World War II"}]} ```