Why Build Colossus? (Bill Tutte) - Computerphile

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Peter Johnson : I'd listen to Brailsford talking about pretty much anything. Keep him on as long as possible :)

Man from Mars : Look how times have changed: from "Never turn off the computer" to "Have you tried turning it off and on again?"

LetsDoRedstone : I love all the videos with professor Brailsford!

Daporan : Professor Brailsford is the boss!

Kizmet Mars : Because building Colossus increases trade?

Mohamed Agoumi : Such an interesting topic and such a calm and intelligent man

Ben786 : I've just realized why I love hearing Professor Brailsford speak — he sounds just like Winnie the Pooh!

TheBigFat : You shouldn't, they get easily countered by the zerg's corruptors.

Jiyva : could just have droped the double leters in their mesages

Haze H : well they shut down hydra bane all-ins pretty effectively I believe.

Micai Askauss : I like this guy

B3ll3r0ph0nt3s : Professor Brailsford is a pleasure to listen to. Please give us more! =)

Neil Roy : I always love listening to him, doesn't matter what the topic is. Such a treasure.

Keex11 : Why? To play Numberwang, of course.

Martijn Heeroma : Thanks again Professor Brailsford

rchandraonline : This is one thing assembly language programmers usually learn. Back in the 8 bit microprocessor days, you used to look at how many bytes an immediate load used to take, like LD A, 0 on the Z80, and how long it took to execute, and compare that with a similar operation like XOR A, A, a lot of times it took less time (clock cycles) or less space or both to do the XOR. As long as you knew this as an idiom, or made code comments, it didn't reduce readability/intelligibility.

artemonstrick : I can listen to this guy forever

Nathan : Imagine the change that would have happened if someone took a simple Raspberry Pi back in time to the scientists/arithmeticians working on this stuff.

Mouse-Floof : heh, I have something to attest to the power of tubes being gently heated and kept at slow-ish smoulder... The Hammond Novachord :3

Jun Yang Tye : Because they are good against light units

Julian Weinert : Wow. I mean they could've simply prohibited double characters. You would be able to properly understand the whole message once decrypted but would get rid of this weakness by the cost of an order...

Peter Frencken : When i was an industrial electrician in a factory that ran 24/7 365 days a year, we used to hate shutting down equipment for maintenace. There was about a 50/50 chance that one of the electromechanical parts in the system would fail on startup.

Zadster : Interestingly, in all the books I have read about Alan Turing, Bletchley Park and so on, there is very little connection mentioned between Alan Turing and Tommy Flowers, and I believe Turing had long moved on to Hanslope Park (early 1943) to work on voice encryption by the time Colossus actually became "Turing Complete" and properly programmable with decision branches and loops. So we end up with the man who defined what a computer is, and the "first" (yes, Konrad Zuse etc, I know) programmable electronic computer in the same place, but with seemingly no link between them.

Steve Evans : Legend... And Tommy Flowers, being a practical man, not just theoretical, was spot on... Valve last for years if you just leave them running.

nab 6215 : I love the WWII and code breaker talk. Please keep him talking about this.

Rohan Dvivedi : I Love all of computerphile videos

S0chan : That's NUMBERWANG!

EddyGurge : I love listening to him.

Naughty Robot : Did you never even see The Forbin Project, you fools? You've killed us all

AustrianAnarchy : Dr. Forbin's answer was quite sufficient, thankyouverymuch.

Youthure : Interesting!

Marques Jozefowicz : 1st

Mob Mentality : would the Germans have known character doubling was an inherent flaw in encryption? perhaps a "drop one letter from all double letter words" directive should have been implemented!

Ronny-san : It is really funny that I saw the your Enigma Videos about a year ago, decided to make it the topic of my seminar paper (the exact Topic is 'deciphering machines at Bletchley park') and just when i came to the chapter about the Tunny and Colossus I found this video uploaded not long ago xD

A Lee Wade : Awesome video as always. From the video, "Tommy said to them, I've been doing research on use of thermionic valves in telephone exchanges..." Valves had been used for since 1915 to amplify long distance calls. The genius of Tommy Flowers was his research into _switching_ calls electronically. He was way ahead of his time... and sadly under-recognized for his contributions.

ThePharphis : This is similar to X-Ray sources for crystallography (Cu, Mo, etc.) There is a working-voltage and a standby-voltage and these instruments (to be used by researchers) is only to be turned off for maintenance or long pauses in work schedules

Dave L : Is there anything better than a Brailsford video?

11Kralle : We should never have insisted on 'stickstofffreie Schifffahrtsspeziallagerrechte'!

Jeongheon Lee : I could never wrap my head around that code could be cracked by statistics. but now i can thanks to him!

Christopher Lee : Please interview Brailsford on Apple. Just want to hear his thoughts. Leaving this comment here, barrel completely unloaded. You know it's the right thing to do.

dosmastrify : ... To crack the code... Duh...

Yaddlezap : If only the Germans had been broadcasting in lipograms excluding double letters, lol.

Hrnek Bezucha : For our yank friends, thermionic valve is a vacuum tube.

Daniel Jensen : I wonder what the clock speed was for that thing. A few Hertz? 100?

MaxSantos : And now... you could probably do it in a crappy Arduino, let alone a Raspberry!

Stay EZ My Friends : Wow, I know a lot about ww2 but I was oblivious about this machine and it's counterpart it was built to crack. Thanks for the upload.

MaxSantos : What? So if they "transmited" the "mesage" with purpose "mispeling" by removing the double chars... the "mesage" would be readable but not crackable?

Chel Viz : So how did they go about estimating which letter the exclusive ORs represented? A neophyte here, thanks a lot!

Lordious : Pizza! 2 Z