Here we are at Bletchley Park but in a part of the
Bletchley Park site that's the National Museum of Computing
in the UK. And they've had the sense to have the siting here
for the rebuild of the Colossus machine
that was, as many of you know, the big feature
of Bletchley Park later on in the war, because it was involved in helping to
decrypt the
Lorenz cipher, which was a much much bigger challenge
than even Enigma.
[Is there much to see ?] Yes, there's quite a lot to see. You've got to remember this is
arguably the world's very first
electronic computer - it really is largely electronic.
It relies on thermionic valves -
that's vacuum tubes for those of you in North America.
So yes, the logic and the counting is done with vacuum tubes.
The feature, though, of computers of this
era - and it is a special-purpose computer remember - it's not general purpose,
and the one thing that was very difficult was to get them to have memory
because memory hadn't been invented. So the data that it has to analyze is
actually on a 5-hole paper tape
and you just have it spinning round at very high speed
and if you miss a particular piece of data you have to wait for it to come round
So that tape that you see there is going at five thousand
characters per second . [Let's get over there and have a look]. Five thousand characters per
second roughly, I think, corresponds to thirty miles an hour
and it is absolutely amazing that it does not fly apart.
There is one problem of joining the ends of the
tape and Phil, over there, who is the expert, tells me that whereas in the Second World War
they used to use a benzene-based Bostik sort of glue,
Health and Safety won't permit that any more and it's highly inflammable.
And so he's just been doing, he tells me, some experiments on what
the best substitute would be for joining tape ends.
Answer number one was brown parcel tape
which worked quite well. Answer number two, which he's just tried out I think, is Pritt Stick.
And Pritt Stick is just superb!
So there we are then - continuous read-out of data.
Quite a high latency because if you miss something you've got to
wait for it to come round again. But all of the
electronics here is dedicated, it's special-purpose.
It's recognizing patterns in the ciphertext
that came off the Lorenz cipher machine. And once you've specified what
sort of patterns you're looking for it will do the automatic counting for you.
The Lorenz machine was basically an adapter
that you could add on to a teleprinter. We've heard all about Enigma
which in many ways was a very low level very labour-intensive machine.
Hitler wanted something faster, more personal, more secure.
So the Lorenz machine was used by the High Command
to talk to each other. It was used by Hitler to give commands to his
generals. It was crucial round about D-day
to be able to decrypt the Lorenz traffic, because essentially
it did show that Hitler had been taken in
by an Allied plan to convince him
that D-day wasn't going to happen in Normandy but there was a whole -
how shall we say - `feint operation'- to say: "No! No! No!
let's try and convince the Germans that it's going to happen in Calais."
And they found out by decrypting Lorenz traffic using
Colossus Mk.II that, yes, Hitler had fallen
for this deception and kept on saying to his generals: "No! No! No! it's not going
to be in Normandy.
It's going to be in the Pas de Calais" That, according to
military people made a world of difference about the level of opposition they
faced and how quickly the advance across Germany could take place after D-day.
Well, what we'll find, in more detail later on, with all of these valves,
is this is why it really is thought of as one of the world's first
special-purpose, valve-driven, computers. Tommy Flowers
was its famous designer and people said to him
at the time "Flowers what are you proposing?
What's wrong with electromechanical technology - relays - you know, like in the Bombe?"
And basically Tommy said; "Look, for the job we have to do with the Lorenz cipher
it's not gonna be fast enough
I'll build it for you using valves" and then people said: "But how many
will you need Flowers, you know, six valves ? A dozen?" . And he said: "1500" and here we
have them !
And he was not afraid of valves, he didn't mind how many
he used. People when they said to him "But Flowers, come, come, come
we all know about thermionic valves they blow,
and they go `bang', and you have to replace them. They're not reliable enough!"
And he was basically a Post Office
telecoms engineer and he said: "Look I've worked in the research section -
I've led it - valves are fine so long as you never switch them off."
They've got heaters in there, of course, and
so long as, maybe, you know, when it's not working flat-out
you turn the heating voltage down, but DON'T
SWITCH IT OFF, you will be surprised how reliable
it can be. And he was proved right. It was tested out at Tommy's own place,
Dollis Hill,
in late '43. I think it's been established it was on
8th December 1943 at Dollis Hill. Testing
moved to Bletchley Park here in early 1944
and came into action pretty soon thereafter.
[This is a replica is it?]. This is a replica, Yes, as a result, I think, of the Freedom of
Information Act
in America, it was possible to get hold eventually
I think, of a complete set of drawings. [Wasn't Flowers very much an unsung hero ?]
Yes, he did suffer, because first of all people wouldn't believe him
then, when he did deliver, of course he was a hero
but effectively felt that he would never get his just
deserts of fame,
and all that, because of the secrecy. It's hard to believe now
how ultra, Ultra, ULTRA secret this was.
And i think it was very hard for Tommy
when later on, I think it was about 1946, there was an American
electronic special-purpose computer came along called ENIAC
which calculated gunnery trajectories.
Now of course since nobody knew anything about Colossus
this [ENIAC] has been widely reported as the world's first special-purpose
computer with valves. This [Colossus] was two years earlier than ENIAC,
but nobody could say a word about it. Not a word!
And I think a lot of people at Bletchley
still felt, at the end of the war, that frankly
Tommy Flowers, Max Newman, who was the head of the Newmanry here, which was in
charge of all this and
the guy who made one of the real initial
analyses that enabled Colossus to be built,
a chap called Bill Tutte, they should all have been knighted.
They weren't. They got various
sort of awards, and so on. The only good spin I can put on this, as to why they weren't
honoured more
is the secrecy again. I can just imagine a
Whitehall civil servant saying: "Look, if we start knighting all these people
they're going to start asking questions - the public - `Why?' "
"There's Flowers, superb engineer, but why a knighthood? Why?"
And don't forget this was in an era
up until about fairly recently, where the whole idea was that this
should be kept secret for ever. They didn't
want it ever to come out. Or I think Winston Churchill's compromise was something like a hundred years.
Can you imagine having to wait until
2045, or 2044, for this
to be made available. Anyway common sense has now prevailed, I'm glad to say.
And it's a wonderful thing to behold, it really is.
Flowers said: "One of the best days in my life was seeing all these
clever people
Alan Turing, Max Newman. Bill Tutte,
all of them with their mouths dropping open saying: "Flowers
what have you done?!" And I think he said
the worst bit, after that, was "This is wonderful! This is so quick!
Now we can really get working! Erm - Flowers we'd like four more
of these, preferably in two months time". And I don't think people said "Get real" in
early 1944
but that was the sentiment, effectively.