
That photo of Colossus - sohkamyung
http://www.tnmoc.org/news/notes-museum/wrens-meet-70-years
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mathieuh
I'm not sure of the prior history, which may affect my appreciation for it,
but as far as I know, what happened with Colossus was that they were aware the
cipher seeds changed each day, and they obtained an Enigma machine so they
could decipher Enigma codes, it was the fact there was a reliance on
intercepting the day’s seeds, or having a spy/double agent leak them which
meant cracking Enigma messages was usefully impossible within the timeframe in
which military strategies could be formulated and altered.

So Colossus brute-forced every combination of Enigma symbols and seeds until
it got something that made sense.

Colossus did this in hours, instead of the weeks waiting for code breakers
with brain-power and persistence alone, and to my knowledge this was the first
application of computers as we recognise them today.

I find it amazing that Turing sat and thought to himself, in the 1940s, "I bet
I can make a machine that does this", and built the thing, and built it so
well it deciphered the codes within the day, before the seeds changed. I'm
sure a brute force on paper existed before Colossus, but Colossus is a
stunning, visceral machine to watch.

Seeing Colossus operating is an absolute experience for computerphiles.
There's something more soulful (in the laïc sense) in seeing a big wall of
spinning disks and tape and reassuring thuds and whirs than in modern solid-
state computers.

~~~
josst
Small correction, Colossus was designed to break the Lorenz cypher (which was
considerably more complex than Enigma). The machine itself was designed by
Tommy Flowers (not Turing), who was a post office worker who had previously
worked with vacuum tubes and thought it would be possible to build a
programmable computer with them. After the war Flowers applied for funding to
build a similar machine (Colossus being top secret) and was denied on account
of the idea being impractical.

The machine Turing is famous for his work on was Bombe, which was designed to
crack Enigma.

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mathieuh
Can't edit my comment now that it has children (I think that's how the logic
works) so upvoting you for visibility.

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julianz
That's a fantastic story. At my grandfather's funeral (he was an electronic
and medical researcher who developed early foetal pulse monitors as well as
the respirators now used to treat sleep apnoea) it gradually became apparent
that I was chatting with two of the people who'd installed one of New
Zealand's first computer systems. Incredible conversation but it only lasted
half an hour and then off they went. I wish I'd had a chance to record some of
it.

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tokyodude
I guess one of my favorite movies took its name from this?

[https://www.imdb.com/title/tt0064177/](https://www.imdb.com/title/tt0064177/)

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mirimir
Damn, high-speed paper-tape! I used an early DNA sequencer controlled by paper
tape, and it's touchy to keep the tape from breaking. I think that they
migrated the mechanism from looms. The belt drives also remind me of the
water- and steam-powered eras.

~~~
skookumchuck
Paper tape is indeed a descendant of the Jacquard Loom.

[https://en.wikipedia.org/wiki/Jacquard_loom#Mechanical_Jacqu...](https://en.wikipedia.org/wiki/Jacquard_loom#Mechanical_Jacquard_looms)

~~~
ngcc_hk
First thing i think of. In fact the Ibm for quite a while can be considered as
a punch paper card company (and their first antitrust is about their use of
that to meter the computer use)

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mirimir
Paper tape was even more of a pain than cards were. Or at least, in different
ways. Cards jammed, it's true. But you could easily replace damaged cards.
Repairing damaged tape was iffy. On the other hand, one might drop a stack of
cards. So some of us would number the cards in pencil. Carefully, and lightly.

~~~
Animats
Colossus had an endless loop of paper tape zipping by to present patterns for
matching. It wasn't a general purpose computer. It was a key-tester, like a
Bitcoin miner.

~~~
mirimir
Ah. So they could have many copies of those tapes, and quickly replace ones
that broke, right?

~~~
lb1lf
I seem to recall reading in either Kahn's or Sebag-Montefiore's book on
Bletchley Park that one early failure mode of the tape was that it was run
through the reader at a fast enough pace to occasionally catch fire.

Oops.

~~~
Animats
Basic problem of early computing: no good memory devices. IBM had electronic
arithmetic before WWII, as an experimental tube multiplier. But nobody had a
memory device that didn't require lots of parts per digit or bit. Hence cards
and paper tape.

~~~
mirimir
I had an old friend who worked with 60s era mainframes. You had a decent
enough CPU, but no memory. And very slow storage.

So you worked out some set of instructions with total execution time
comparable to storage I/O. And put that into ~firmware. Then you read data
from one device, and wrote data to another device. And kept repeating that,
with other instruction sets, until you were done.

That's not very different from current usage. Except that most intermediate
results go into various sorts of memory. Or /tmp devices, if there's too much
data for memory. And at the CPU level, instruction sets are just about as
small.

But the point is that one could process ~huge amounts of data. Many GiB, as I
recall. Just very slowly, with lots of thrashing tape.

And now one can use the same approach, except with clusters. And process
humongous amounts of data.

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someguydave
I’ve seen the Colossus replica running at Bletchley Park. It was quite
impressive to see.

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W-Stool
Let us also not forget the Forbin Project.

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opless
I came here for exactly this comment.

Thank you.

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escherplex
If interested in WW2 Allied code breaking you may want to watch the BBC
documentary _Station X - The Code Breakers of Bletchley Park_ on _Acorn tv_

~~~
kevin_thibedeau
Simon Singh's "Code" also has an approachable description of the decoding
process.

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jtms
Both museums at Bletchley are just fantastic... can’t wait to get back there
sometime again in the future!

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aarondotcom
Where’s the new photo?

~~~
KSS42
It's in the Photo Gallery to the right of the main photo.

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ngcc_hk
“D. Well I was quite angry as we had kept it a secret for so long. There is me
now in all the books. I didn’t like that!” Cannot stop laughing. Rip Dorothy.
Uk has a fighting chance with you girls working in that industry. Would have
to play a visit.

Guess no one would catch me as a chinese spy to copy that ba.

