Let me put in a word for The National Museum of Computing, www.tnmoc.org in Bletchley Park, where you can see the real thing (I can’t remember which state of refurbished/rebuilt/replica it is), along with a replica bombe, EDSAC (being built), the marvellously blinkenlicht-y WITCH, and (literal!) tons of other old computers. It’s an easy excursion by train from London, and you can combine it with a visit to bletchleypark.org.uk (it’s the same site).
The machine is a replica rebuilt from old photos of the original.
The level of secrecy around these machines at the time led to them all being destroyed, along with all of the plans! This is perhaps more understandable given the UK kept the fact it had cracked the encryption secret and continued to offer similar machines to other states so it could spy on them for many years after the war!
I was there yesterday, which is what led me to stumbling on the submitted link. The people in TNMOC are astonishing - their knowledge, experience, and passion was one of the best museum experiences I’ve ever had.
This was arguably the world's first electronic programmable computer. It used a form of frequency analysis looking at the frequency of the differences between characters rather than the frequency of the characters themselves. The ingenuity required to crack the code without seeing the actual encryption machine and then to build one of the first electronic computers ever made in order to automate it is almost unimaginable to me.
It's one of those special purpose devices that predated the stored-program general purpose electronic automatic digital computer. It was a key-tester, like a Bitcoin miner, not a general-purpose machine. It belongs to the era of "if only we had a good memory device". Eckert, at Columbia University, had been wiring together compute elements from IBM tabulators from the 1930s onward to get basic automatic computation. He went on to develop the UNIVAC I in the 1950s.
But things were kind of stuck on stored-program computing until somebody developed a useful memory device in which to store the program. Delay lines and Williams tubes were the first successes.
- Automatic electronic digital computer, but not general purpose or stored program - Colossus.
- General purpose automatic digital computer, but not stored program or electronic - Harvard Mark I,
- General-purpose electronic automatic digital computer, but not stored-program - ENIAC.
- Automatic general-purpose computer, but not digital or stored program - Bush Differential Analyzer.
There were many other special-purpose machines from that era that never quite made it to the general purpose computer stage. Teleregister [1] made special purpose systems for railroads, airlines, and the military.
Thanks for posting about my Virtual Colossus simulation! Glad you enjoyed trying it out :)
Feedback noted from replies, thanks - I'll add a mute button today. For those confused about controls, there's another mode that might help: Choose the option "Restart in Touch Mode" in the menu top right which will give you a cursor pad and camera direction pad which may help. I'll see if I can add a movement help tutorial or something like that.
If you're interested in Colossus & Bletchley Park, I also have many other machines for you to try out. Virtual Colossus is one of my first attempts at 3D in a browser!
Currently I'm working on a Hagelin M-209 cipher machine if you want to follow my work on Twitter/X: @VirtualColossus or Mastodon if you prefer: @virtualcolossus@infosec.exchange
There needs to be one more nav mode: mouse, but not POV movement. Touch mode doesn't seem to work with mouse, but I want to move the image like I would a 3D map instead of as if I'm viewing in VR goggles.
The Colossus Machine was a huge code-breaking computer built in the UK during World War 2. Multiple models were built but most were destroyed by the intelligence services at the end of the war. So far as I understand, it calculated possible keys being used on encrypted radio messages broadcast by the Nazis.
This is a 3D model I stumbled upon that shows how it works in intricate detail.
The whole story behind Colossus is fascinating. There is a replica in the National Museum of Computing in Bletchley Park.
I bet you were told that the code brakers at Bletchley Park only decrypted "Enigma" during WWII.
That is actually an old story, and is not entirely correct.
It turns out the Germans also had a much more advanced cypher called Lorenz, which required rather more advanced hardware, including the world's first programmable electronic computer. This was Colossus.
The biggest difference between enigma and Lorenz was Lorenz was broken without seeing a physical machine. It was broken as a very long message was transmitted twice with minor changes. That allowed recovery of of the plaintext and key stream
