Posted by baruchel 5 days ago
super interesting place and worth the short trip out of london! also i believe the term they used was "semi-programmable digital computer." bombes were mechanical search machines that i believe operated on short ciphertext sequences and i believe the big innovation with the colossus was having the ciphertext live on a long optical tape that would be re-read at thousands of characters per second, thus enabling a high speed processing loop of longer sequences. but i am no expert on this!
If you consider the NMC "just up the road" then the Bletchley Park site you're thinking of is also "jump up the road" from er, Bletchley Park, a stately home that's less interesting to a nerd than either the NMC or Bletchley Park museum about war era "intelligence" but might be fascinating if period furniture is more interesting to you than the world's first (for many different values of first, the museum has several options, but not all of them) programmable computer.
although i just looked. critically they have different ticket offices. it was a long time ago! either way, worth a visit of both and they make up an excellent way to spend a day.
Don't ask me how I know...
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
It's like you've seen an article about the Knicks winning a basketball game and you ask why it doesn't mention Igor Shesterkin - who plays ice hockey.
The house is part of the museum these days, so a ticket for the museum covers the house (which is, yes, basically just one of a great many English stately homes you might visit and not by any means the most interesting) as well as numerous huts and exhibits about the larger intelligence operation in WW2 and what else was done on that site beyond simple "breaking Enigma" (the most famous thing) and Lorenz (which is why Colossus exists)
The first digital circuits with vacuum tubes and gas tubes had been designed also in UK, during the decade preceding WWII, when most of them had been used in nuclear physics, e.g. in electronic counters for ionizing radiation, because the mechanical counters commonly used at that time were too slow for counting radiation events.
The earlier publications about such electronic counters were the inspiration both in UK for Flowers and the other people who contributed to the design of Colossus, and also in USA for the Atanasoff-Berry Computer, the first computer with vacuum tubes made in USA, whose electronic circuits were in turn an inspiration for the designers of ENIAC.
The first electronic computers were designed bottom-up, without much thinking about the high-level structure, until von Neumann handled that. The designers of those computers struggled mostly with the detailed schematic design of the digital blocks made with vacuum tubes, like flip-flops and gates, in order to make them work reliably, because before WWII there was very little experience with such circuits.
Definitely programmable, definitely capable of computing, but not a ‘stored program’ in the sense we know it today.
I think “around a tonne” is very light for “room-size”, so I googled, and found https://www.tnmoc.org/news-releases/2019/2/5/colossus-decryp..., which says:
“Standing 2m high, 5 m wide and almost 4 m deep (7 ft by 17 ft by 11 ft), Colossus weighed five tonnes, and used 8 kW of power. Colossus Mark II, which arrived at Bletchley Park in May 1944, had 2,500 valves and 7 km of wiring, and was able to read 5000 characters per second (faster than anything ever produced commercially).”
But this should be what you're looking for?
https://publish.fid-media.de/entities/book/f1548ef2-2420-4c9...
How far we have come :-p