Colossus the world's first electronic computer

[JazHaz]

Watch a short film made by Google about it, here.

[SandJ]

It is important to understand every word in the following is significant: Colossus was the world's first electronic, digital, programmable computer. It was not a general purpose computer. Change any of those words and the claim-to-fame differs. Its existence was a national secret until the 1990s, when many of the computing history books had to be revised.

Colossus and its successors were used by British code breakers to help read encrypted German messages during World War II. It was one of the code-breaking tools / systems / facilities / services that helped change the course of the war. "The prototype, Colossus Mark 1, was shown to be working in December 1943 and was operational at Bletchley Park by February 1944. An improved Colossus Mark 2 first worked on 1st June 1944, just in time for the Normandy Landings. Ten Colossus computers were in use by the end of the war."

The Computer Conservation Society in the UK holds regular meetings in Manchester and London. If you intend to visit any of the Manchester meetings, PM me and I'll meet you there and buy you a beer.

Bletchley Park is where the polymath Alan Turning worked. This year would have been his 100th birthday but I think you've missed your chance to attend this year's Turing Lecture.

There is a logical progression from Bletchley Park to GCHQ, part of the international collaborative service "Keeping our society safe and successful in the Internet age" that reads everything you post on here.

[Greyth]

I was utterly gobsmacked when I learned that a rebuilt Colossus achieved a processing speed 5.18 ghz!

[Gimbal Locke]

It is important to understand every word in the following is significant: Colossus was the world's first electronic, digital, programmable computer. It was not a general purpose computer. Change any of those words and the claim-to-fame differs.

The first working programmable computer was Konrad Zuse's Z3 in 1941. Fortunately, the Nazis did not understand its importance. The Allied however did: they bombed it in 1943.

The Colossus was based on a Polish prototype which was transported to England when Germany attacked Poland. The Polish had cracked the Enigma codes, based on information from the French secret service. During the war, the Germans made their codes more complex, and consequently the Polish "bombe" evolved into the British Colossus.

Bletchley Park is where the polymath Alan Turning worked. This year would have been his 100th birthday but I think you've missed your chance to attend this year's Turing Lecture.

There are other upcoming celebrations of Turing's 100th birthday, such as http://events.cs.bham.ac.uk/turing12/index.php

[Greyth]

There is a petition floating about to exonerate him from the stigma that caused him to end his life so tragically. It would certainly open a can of worms for the UK government if it achieved it's ultimate aim.

http://epetitions.direct.gov.uk/

[JensAyton]

The Colossus was based on a Polish prototype

It really wasn’t. Colossus was unrelated to the Bombes, doing a different type of computation for a different type of cypher. Colossus was a fully-electronic version of a machine called “Heath Robinson”.

I was utterly gobsmacked when I learned that a rebuilt Colossus achieved a processing speed 5.18 ghz! :shock:

Er… are you sure you’re not confusing it with this completely different Colossus? :-)

The real Colossus Mk II ran at around 5 kHz (highly approximate, as the clock was based on counting sprocket holes in a paper tape run by an unclocked motor). The speed was chosen because the paper tape was shown to explode at a little less than 10 kHz.¹ It did more in one “cycle” than a modern computer does, and had five processors working in parallel, but not a million times more.

¹ “The various sections of tape did their best to obey Newton’s first law and travel in a straight line in the direction they happened to be going with an initial velocity of nearly 60 miles per hour, and thus found all sorts of curious places in which to come to rest.” — Tommy Flowers

[Greyth]

Er… are you sure you’re not confusing it with this completely different Colossus?

I don't think so Ahruman, here is one account although it differs from the account that I originally read in some details. I suspect that their estimate of 5.8 ghz is in error... from memory approx 5.2 ghz is the ceiling for valve switching... above that and it becomes unreliable.

http://theinstitute.ieee.org/technology ... crypted148

[Commander McLane]

Er… are you sure you’re not confusing it with this completely different Colossus?

I don't think so Ahruman, here is one account although it differs from the account that I originally read in some details. I suspect that their estimate of 5.8 ghz is in error... from memory approx 5.2 ghz is the ceiling for valve switching... above that and it becomes unreliable.

http://theinstitute.ieee.org/technology ... crypted148

From the linked article:

“If you scale the CPU frequency, you get an equivalent clock speed of 5.8 megahertz for Colossus,” says Schüth. “That is a remarkable speed for a computer built in 1944.”

That's MHz, not GHz.

[SandJ]

“If you scale the CPU frequency, you get an equivalent clock speed of 5.8 megahertz for Colossus,” says Schüth. “That is a remarkable speed for a computer built in 1944.”

I refer to my earlier post:

It is important to understand every word in the following is significant: Colossus was the world's first electronic, digital, programmable computer. It was not a general purpose computer.

ENIAC was the first general-purpose digital programmable computer (although it was not the first stored-program computer, so still not a fully-fledged computer). Colossus was not general-purpose, it was built to solve a very specific kind of problem. Schüth's laptop was built to run Windows, not run cryptographic analysis. Hence his winning PC was fairly crap at solving the problems. Colossus was designed and built specifically to crack Lorenz codes.

This difference in design made Colossus relatively very efficient; hence the "equivalent clock speed" seeming to be so high. That is, for the Colossus to solve Lorenz codes, and be running NetBSD in the background and servicing network card, graphics card, keyboard and mouse interrupts, it would have needed to be a faster machine.

BTW, the Bombe machines, used to crack Enigma-type codes, were not electronic digital programmable computers.

[Greyth]

Thanks guys for sorting me out again. You have the patience of saints.

[SandJ]

Thanks guys for sorting me out again.

No worries. There's a lot of confusion about the period anyway.

The whole period was covered by the Official Secrets Act so the computing history books, when they started coming out, were wrong and credited ENIAC with being the first computer. When Bletchley Park was shut down at the end of the war, everything was destroyed to keep it a secret. Amazingly, around 10,000 people worked there during the war, and not one said anything about it publicly until (I think) The Ultra Secret was published in 1974. Try keeping a secret like that these days!

However, it is said by the tour guides that not everything was destroyed: one of the code-breaking machines may have gone 'astray' in the general direction of Cheltenham. And post-war Soviet Russia was using similar encryption methods to the Germans. And then, surprise, surprise, GCHQ appeared in Cheltenham. Not that there is any evidence remaining of any of this, after all, the Official Secrets Act still applies...

So all this history was under a security blanket.

And then the movie industry told their versions of the story where the US Navy captured an Enigma machine (U-571 in 2000) and the only reference to the Polish contribution was a fictitious pro-Nazi Polish spy (Enigma in 2001).

That misinformation doesn't help either.

[Greyth]

I remember that many Polish laid down their lives to deliver a machine to the Allies. Well, gave up their lives full stop. There are entire cemeteries dedicated to Polish war dead. I used to pass one on the way to a client site. Whenever there was a one way ticket mission the Polish would be in the queue.

[JensAyton]

I remember that many Polish laid down their lives to deliver a machine to the Allies. Well, gave up their lives full stop. There are entire cemeteries dedicated to Polish war dead. I used to pass one on the way to a client site. Whenever there was a one way ticket mission the Polish would be in the queue.

This is certainly true. The Polish government-in-exile (first in France, then in Britain) controlled military forces across the European fronts, in Africa and the Middle East, as well as within Poland, throughout the war. The Polish Air Force reformed as a number of highly-regarded units within the RAF. Polish intelligence cracked the Enigma cypher before the war started, and constructed the first “bombe” (high-speed Enigma simulator) to help with the process. (Polish intelligence also uncovered the Holocaust; [wp]Witold Pilecki[/wp] voluntarily spent two an a half years in Auschwitz.) Poles achieved a great many things during WWII, many of which were suppressed by the Communist regime. Colossus happens not to be among them.

[NigelJK]

I was told a few years ago that the British has cracked the Japanese Naval code (anyone have any idea by whom and how?) near the start of WWII. Churchill was informed of the Attack on Pearl Harbour before it happened, and declined to let the US know it was on it way, apparently to 'help' the US into the War effort.

[Disembodied]

I was told a few years ago that the British has cracked the Japanese Naval code (anyone have any idea by whom and how?) near the start of WWII. Churchill was informed of the Attack on Pearl Harbour before it happened, and declined to let the US know it was on it way, apparently to 'help' the US into the War effort.

Doesn't sound very likely to me ... given such British naval disasters as the sinking of the Prince of Wales and the Repulse by the Japanese Navy in 1941, it doesn't sound like the British were getting much in the way of useful intelligence back then. It would also seem to be an unusual way to bring an ally into a war: NOT telling them about an attack? What happens if they find out later? Why not, instead, tell your ally about the imminent attack, and not only make sure that they are extremely grateful to you, but also make sure that when your enemy makes the attack, they walk into an ambush and get creamed?

Plus, according to wikipedia:

The British, Australians, Dutch and Americans cooperated on attacks against JN-25 [the chief code used by the Imperial Japanese Navy during and slightly before World War II] beginning well before the Pearl Harbor attack. The Japanese Navy was not engaged in significant battle operations until late 1941, so there was little traffic available with which to work. Before then, IJN discussions and orders could generally travel by more secure routes than encrypted broadcast, such as courier or direct delivery by an IJN vessel. Publicly available accounts differ, but the most credible agree that the JN-25 version in use before December 1941 was not more than perhaps 10% broken at the time of the attack, and that primarily in stripping away its superencipherment.