Colossus & Bletchley Park - Computerphile

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 a 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 it supposed to see yes there's quite a lot to see you 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 to those of you in North America so yes the 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 five whole paper tape and you just have it spinning around at very high speed and if you miss a particular piece of data you have to wait for it to come round again so that tape that you see there is going at five thousand characters per second let's get over there earlier five thousand characters per second roughly I think corresponds to 30 miles an hour and this is absolutely amazing that it does not fly apart there is one problem of joining the ends of the tape and Phil over there as the expert tells me that whereas in the Second World War they used to use a benzene based Bostic sort of glue health and safety won't permit that anymore 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 that Brown parcel tape which worked quite well answer number two which is try it out I think is pretty sick and Princeton just superb so there we are then continuous readout of data quite a high latency because if you miss something you've got to wait for it to come around 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 lots of the 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 labor-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 IED plan to convince him that d-day wasn't going to happen in Normandy but there was a whole how should we say feint operation to say no no no let's try and convince the Germans it's going to happen in Calais and they found out by decrypting Lorenz traffic using Colossus mark 2 that yes Hitler had fallen for this deception and kept on sentry General's no no no you know it's not going to be a 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 they advanced the question it could take place after d-day well what we'll find in more detail later on but all of these valves is this is why it really is thought of as one of the world's first special-purpose valve driven computer Tommy flowers as its famous designer and people said to him at the time flowers proposing what's wrong with electromechanical technology relays you know I can the bomb and basically Tommy so look for the job we have to do with a Laurent cipher it's not going to be fast enough I'll build it for you using vowels and then people said but how many will you need flowers you know six hours a dozen he said 1500 may we have him and he was not afraid of vowels he didn't mind how many we used people when they set him but hours 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 as long as you never switch them off there they've got heaters in miracles and so long as maybe it 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 at how reliable it can be and he was pretty riot it was tested out at Tommy's own clays Dollis Hill in late 43 I think it's been established it was on 8th of December 1943 dollars hill testing moved to Bletchley Park here in early 1944 and came into action pretty soon thereafter this is a replica of 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 was it fair is 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 was effectively felt that he would never get his just deserts of fame and all out 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 was about 1946 there was an American electronic special-purpose computer came along called ENIAC which calculated gunnery trajectories now of course new engine mail Colossus this is being widely reported as the world's first special-purpose computer with valves this was two years earlier than any AK 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 Newman rehear which was in charge of all this and the guy who made the real one of the really initial analyses that enable classic should we build built chuck or built at 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 all over more is the secrecy again I can just imagine the Whitehall civil servant say looking for some lighting all these people they're gonna start asking questions in public why this flowers superb engineer but why night on fire you know and don't forget this was in an era up into about fairly recently where the whole idea was that this should be kept secret forever they didn't want it ever to come out or I think Winston Churchill's compromise was something like I had forgive there could you imagine having to wait until 2045 on 2044 for this to be made available anyway common sense is now prevailed and glad to say and it's a wonderful thing to behold flowers said one of the best days of my life was seeing all these clever people Alan Turing max Newman built art all of them with their mouths dropping off saying flowers what have you done and I think you said the worst bit after that was this is wonderful this is so quick now we can really get working flowers we like for 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 effect zero to one and so on and the important thing about this is by doing this we're going to get a huge list of North's all in a row and that is very easily compressed by Huffman encoding

Channel: Computerphile

Views: 217,868

Keywords: computers, computerphile, colossus, Colossus Computer (Invention), Bletchley (City/Town/Village), Bletchley Park (House), university of nottingham, professor david brailsford, computer science, enigma, code, ciphers, tnmoc, The National Museum of Computing, lorenze, tunny

Id: 9HH-asvLAj4

Length: 8min 42sec (522 seconds)

Published: Thu May 28 2015

Reddit Comments

[u/sigma914]

Built by the extremely underappreciated Tommy Flowers, a decent chunk of it from his own pocket. After the war he went to the bank to try and get a loan to build another one, but they wouldn't lend him the money because noone believed it would work.