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Von Neumann Architecture – Computerphile

Von Neumann Architecture – Computerphile

>>Sean: Professor Brailsford – a lot of people
talk about von Neumann architecture and we’ve talked about Babbage; we’ve talked
about Turing. Who was von Neumann ?!>>DFB: We’ve done a lot about Turing; we’ve
done a fair bit about Babbage, in the generation earlier. In fact a lot of
people, I guess, in the English-speaking world would regard Turing, in some way, as
being the Father of Computing. He came up with this very important result, in the
mid-thirties, about what was computable, and as we now know. to his credit. he
wasn’t at all afraid to burn himself with a soldering iron and try to create
hardware. Which he did at Bletchley Park during the war. So, yes, if he’s the Father,
if Babbage was the Grandfather and if Ada, Countess of Lovelace, was the Great-Aunt, then who on earth was John von Neumann?
And why is he mentioned alongside Turing? Well right at the outset let’s say John
von Neumann was the impossibly talented, impossibly charismatic, very wealthy,
Uncle to computing. It was he that, in the mid-1940s, in a way, made it all happen by
the force of his own personality. And kept it, not just in an enclosed
community, but encouraged all those who wanted to build general-purpose
computers to come along to this Summer School and do it. But that really, I guess,
is in the future. It’s where we’ve got to get to in the von Neumann story. But, yes,
you’re quite right Sean, to say that one of the first phrases that almost any
computer scientist hears about is The von Neumann Architecture for computers,
which to a large extent we still follow even now – all of, what 60-70 years later.
So, we’ve mentioned EDSAC before, we’ll be coming back to mention this very
important early computer again. But it is a von Neumann machine and all it’s
saying is [that] it’s very simple to build a computer. You need a Store, or Memory as
it’s more commonly called nowadays, to hold your instructions and your data.
You need a control unit, often called a CPU now. And
you need an arithmetic capability – the ALU, the arithmetic and logic unit. Again
many of you will know in modern chips those two are often combined into what
we just call “the CPU chip” nowadays. And you need input devices of various sorts
leading back to people’s Teletypes [with] input/output devices for backup storage,
disk and so on. You need to be able to do input and output. So there it is. It’s
just one, two, three, four, five boxes – that is the von Neumann architecture. And it’s
very, very similar today. There was a big debate at the time about that Store that
Memory. Shouldn’t you, for safety’s sake, put the instructions of your program in
a different sort of memory to your data? Wouldn’t it be safer to do that and
better in some ways? On the other hand, clearly, if you’ve got a good memory
technology, that works, the temptation might be just to put them [instructions and data]
in separate areas of that same technology and try and take some sort of precaution about
them not interfering with each other. In EDSAC the only way to get into a
subroutine and get back out of it again was to over-write part of your program
instructions! Let’s just return back to this incredible character John von
Neumann. How does he fit in alongside Alan Turing? Well, like I said, he’s the
older, impossibly talented, Uncle. Did Turing and von Neumann know each other?
Oh yes they did! They were both, basically, trained as mathematicians. Von Neumann –
it’s hard to know where to begin and where to end. You can’t exaggerate enough
about how good he was. He was Hungarian and his
Hungarian name – where they give surnames first – was, I think, Neumann Janos.
His father was very, very wealthy and when one was quite young the family
became ennobled in Hungary. [They] became basically at the level of Baron –
hereditary Baron I think over here. Janos was very talented; he was
a childhood prodigy. He could divide one eight-digit number by another eight
digit-number in a fraction of a second when he was aged about 6. He loved
history; he was a multi-talented polymath he easily came top of the class he
effortlessly took in detail. And that’s the first thing that all of his
mathematics contemporaries said about him was his sheer speed of picking up
new ideas and seeing the ramifications of them. So he was notorious even as a
teenager, and as a maths undergrad. He did his early education I think up to PhD
level in Budapest. He almost naturally ended up at a place we mentioned before
in connection with Godel and Hilbert. I’m talking, of course, about Gottingen
University in Germany. So Neumann Janos makes the journey, via a PhD, to becoming
effectively the research assistant to the superstar David Hilbert at
Gottingen. But because his family had been ennobled he’s not Janos Neumann
any more – Neumann Janos sorry – he’s Johann von Neumann
– impossibly talented. Hilbert his supervisor, at a seminar given by Johnny, John, Johann (!) asked who his tailor was.
Because his impossibly smart pinstripe suit was just a complete
knockout. So he was a legend almost the moment he got there and did some
fabulously important work there. It was obvious that for somebody of his talents
he was going to get a full Professorship very quickly indeed. I think he became
impatient, waiting for it to happen at any German university. So, in the late thirties
– ’37-’38? Somewhere around there anyway – Anyway he got an offer from Princeton, in
New Jersey. And that was, I don’t know, very timely. It all fitted in together
very well. As part of his tours of Europe, giving seminars, and on his way to
Princeton, I think he met Turing in the mid-thirties in Cambridge. Because he
gave seminars there and I think a lot of mutual respect grew
up. I mean, obviously, Turing being in awe of von Neumann wouldn’t be so exceptional.
But after that 1936 paper of Turing’s, about decidability, following on from
Godel and all that, von Neumann rated Turing – there was no question about that.
This was evidenced by the fact, you will recall – those of you who have seen my previous
videos – that Turing also took a sabbatical and worked with Alonzo Church at Princeton. Well, von Neumann was there by that time.
Von Neumann was such a superstar, they not only made him [full] Professor of Mathematics at
Princeton, at an absurdly early age – probably about 30, something like that.
But some of you will recall, right next door to Princeton – about a mile and a
half across the meadows – is the Institute for Advanced Study which had been
endowed in the early 1930s by a multi-millionaire. And this really was
the ultimate Club to be invited to join. You’ve got to be of the quality of
Einstein, who accepted the invitation. Hermann Weyl one of the founders of
quantum mechanics; Godel – we know about Godel. Godel was invited to just come
to IAS – Institute for Advanced Study at Princeton – stay as long as you like. Yes,
you’re a Professor; everything found: food accommodation; the lot. All we want is to
have the greatest minds here. Von Neumann was offered a professorship in that
community, I think at age 35 – maybe slightly younger. Unbelievably young. He’d
hardly been at Princeton a year or two, as an ordinary mathematics professor.
Everybody thought “This is a truly phenomenal person”. He reminded many
people of absolute superstars like Newton, Gauss, Euler, Einstein, Hilbert
himself. Even at early to mid- thirties they could see that potential
in him, there. So, yes, Turing visits Princeton in 1938 – worked with Alonzo
Church – but also of course had frequent interactions at seminars with von Neumann
And then came the big question, if you recall, for Alan Turing: “Should I
return to England and do my patriotic duty?” According to Andrew Hodges’
definitive biography of Turing, Turing’s father was all for Turing
staying in Princeton, you know: “Keep out of the war; get a prestigious mathematics
job”. And that was underlined by the fact that von Neumann offered Turing a job. He
basically said: “Turing, would you like to be my research assistant at the
Institute for Advanced Study?” Now Turing could see, straight away, that would
just make you as a mathematician. You were invited, by the great von Neumann,
to be his research assistant, at IAS! Only problem was, I think, first of all, I think
Alan Turing did feel a certain patriotism in wanting to come home and
do his bit. There was also the worry that at that time von Neumann had not
properly got into computing – he’d not turned his considerable talents to
considering it – and for the research assistantship he wanted Alan Turing to
do quantum mechanics, another of von Neumann’s great loves. And I don’t think
Turing was keen on that because he knew from experience, at Cambridge, where
he’d tried doing mathematical physics, it really wasn’t his arena at all. So he
politely declined with great thanks, came back to England and the rest, if you like,
is more or less history. Now there’s “Johnny”, as he’d now become. Johann von
Neumann speaker of four, five languages including Italian and English, once he’d
transferred from Gottingen to Princeton, wanted to become the all-American genius.
So he was … on more formal occasions he was just John von Neumann but to his
friends he was “Johnny”. You can’t exaggerate enough! I mean, his wife said: “He
can count everything but calories”. He was fond of food and drink; the champagne
parties! the glitz! the glamour! the girlfriends! Good old Johnny – he
absolutely was the antithesis of the shy mathematician. He was all-
encompassing and everybody who met him was just stunned by how he could see
his way through problems in no time flat. And just do
impossible things. And so he was there, in a very ,very nice position, Institute for
Advanced Study, even before the Americans joined the war. But he stayed
there throughout the war. But being who he was he was endlessly in demand to be
a consultant and, most famously, along with people like J Robert Oppenheimer he
was one of the consultants employed on the Manhattan Project – the atomic bomb and
the hydrogen bomb. But he was used by the Army, the US Navy, the Air Force
– everybody wanted Johnny as their consultant. And this even included, as the
war developed, the fact that one of the earliest computers which we have
mentioned in a previous video was University of Pennsylvania, Moore School
of Engineering. They helped develop the ENIAC which, if you remember, was a vacuum
tube computer running on decimal arithmetic and initially devoted to
gunnery trajectory calculations. It was a bit late in 1946 to be in direct
strategic use in gunnery, Actually Johnny, who by this time *of course* was a
consultant to the Moore School, devised a way, I think, to turn ENIAC into being a
general purpose computer, although it wasn’t a very efficient one, and I
believe he used it for some calculations relevant to the atomic bomb and all that
kind of thing. The natural question arising with everybody at the end of the
war went like this: “We all know – or even though it’s top-secret at Bletchley Park
we have heard gentle rumours – that computers are being developed all over
the place and you’ve always got to say: Are they special-purpose? Are they
general-purpose? Are they binary? Are they decimal? Are they fully
electronic? Or are they electromechanical? And literally there must have been at
least a dozen machines around that satisfied some of these criteria. If you
ask Germans about “Who’s the father of computing?”, they’ll say “Konrad Zuse”, He
developed electromechanical machines that were Turing-complete and
calculated things. But they never got beyond electromechanical. You get on to
electronic ones – you get Atanasoff and Berry’s electronic, valve driven,
thing – special purpose though! Could solve certain differential equations. And even
Tommy Flowers, and Colossus, we know, special purpose: could decrypt Tunny traffic –
Lorenz cipher as it later become known as. So, you’ve got everything
happening that if it’s general-purpose it’s not yet electronic; if it’s
special-purpose it is electronic but we want it to be general-purpose. So, at the
end of the war was the perfect time to get everybody together and say: “Look, now
that the war’s over we all want to find the way to do it correctly. To build
general-purpose, probably binary-based because they’re more reliable, all
electronic digital computers. How do we do it”? And who better to lead the charge and run a Summer School, and be associated
with it, than uncle Johnny of course! And the Moore School at Pennsylvania, to their
great credit, did this. They decided that the successor to ENIAC would be a thing
called EDVAC. They said, yeah, it’s going to take us three or four years to do
this but in the meantime here we are, 1946, why not all of you, all over the
world, who are interested in the quest to build general-purpose, all electronic,
digital computers, probably based on the binary system … we’ll hold a Summer School
in the Moore School of Engineering, 1946, welcome everybody. Did Turing go to it?
He was, I believe, at that time at the National Physical Laboratory in the UK
No he didn’t. Hated conferences did Turing. He wasn’t
a clubbable character. He couldn’t stand small-talk. Classic shy mathematician not
at all like von Neumann, right? So Turing wasn’t, if you
like, the UK representative there. And one wonders whether he would also been held
back by Bletchley Park and the Official Secrets Act because he’d only just left a
few years before. The representative from the UK was somebody who was Turing’s exact
contemporary. They had both done mathematics in the early 1930s, at
Cambridge. They had both got first-class degrees. Did they get on? Not very well!
But who’s this other person? His name is Maurice Wilkes – Maurice Vincent Wilkes – and
by the vagaries of job allocations around about World War II, he didn’t end
up at Bletchley Park, did Maurice, he ended up in radar. But he knew enough about
mathematics and electronics to be in a good position to do, or make, a von
Neumann machine in the UK in the period from about 1946 onwards. But we’d better
stop there because Maurice and his EDSAC is an extra story.

100 comments found

  1. Curious — could you ask Professor Brailsford if he had "recently" read, The Innovators by Isaac Walterson? All the references align up perfectly. 🙂

  2. But these subtitles are horrendously insulting to the poor 'mann's name! John von Neumann has been called everything from "monoi man" (8:42) through "Jana" (4:19) to "no mananas" (4:05). Also found several occurrences of lowercase "neumann" [sic] as if it's not a surname. For future reference: it's spelled either "John von Neumann" (properly capitalized) or "Neumann János" (Hungarian name). But I digress… At least there are subtitles. Thank you, +simdi ejinkeonye for getting everything else right. Your subtitles definitely help more than they hinder and I'm sure you intended no offense by getting his name wrong.

  3. Isn't Von Neumann's machine main memory made of 1024 memory locations (words) of 40 bit instead of 18 bit as shown in that book?

  4. Awesome discussion from Professor Brailsford… as always. It's interesting the concept for which he is most famous, the von Neumann Architecture, was originally put forth by Mauchly and Eckert. Both hated the fact they never got proper credit… but then Mauchly never gave Atanasoff his due credit either.

    I wonder if the professor ever crossed path Tommy Flowers and, if so, would he talk about him. He seems like one of the interesting and forward thinking characters in early computing. The fact that he was thinking about electronic circuit switching in the mid-30s while the rest of the world was content to innovate using relays attests to his prowess.

  5. There are many, many well-known stories about Johnny von Neumann (who in addition to all of this is consider the father of Game Theory, and the key figure in the development of US nuclear weapons strategy): stories of him showing up to lectures still tipsy, in the same tuxedo he'd gone to a cocktail party in the night before, and despite being up all night, being if anything an even better instructor for it; of him testing the performance of a new computer and only declaring it ready when it could compute a figure faster than he could; of his fury at a grad student who wrote an assembler, accusing the student of wasting the then-precious computer time (a serious problem at a time when the MTBF for hardware was rated in hours).

    But the favorite story for me is the impact he had on Feynman, whom he basically told, "Look, no matter what else, your first and foremost responsibility is to work on the problems you enjoy. If you aren't doing things that interest you, and spend too much time worrying about 'being responsible', you won't get anything done and you'll waste your potential, which is far more irresponsible than being irresponsible is."

    Which is why one of my personal titles is, "Episkipos of the Johnny von Neumann Memorial Floating Poker Game Cabal" (Hail Eris). I do rather amuse myself this way.

  6. Hi everyone! At some time last night (24 Feb. 2018 ) "Computerphile" reached 1,000,000 subscribers! Just wish Uncle Johnny could be here to buy endless bottles of champagne for all those who became subscribers as a result of watching this video 🙂

  7. It is a nice video but, I wished the Professor would have talked more about the von Neumann architecture than about von Neumann's life.

  8. I know it's not the point, but what great curtains!

    I think you make a strong argument that there are applications where you want to keep intstruction and storage memory very separate.

  9. You need to go read your computer history. John Mauchly & J. Presper Eckert created the stored program computer architecture. Von Neumann took notes and wrote a report, and then just kept quiet when it became clear that it wasn't his own work. A true travesty of history.

  10. Proud of this small bit of my hungarian heritage. There's indeed so much we've invented, things we use every day today. But hungarian scientists always left Hungary. Poverty and corruption.

  11. Professor Brailsford is by far my favorite in this channel. He is full of so much useful information. And no I'm not being sarcastic.

  12. Hey! Listening to professor Brailsford was like watching a documentary or living in that time. Very inspiring and fun stories about these mathematician, with a lot of extras. Thanks again! I hope that Computerphile makes more of these videos telling us how computers became what today we know about. Congratulations!

  13. why is it called 'von Neumann architecture'? Shouldn't it be called Zuse architecture? Since he came up with it first?

  14. I came here to learn about the architecture of von Neumann for my exams but I stumbled upon a gem that was this video

  15. Though this video was not particularly on Von Neumann Architecture, this video surely led me to learn more about computer architecture.

  16. Von Neumann had a photographic memory he could remember entire books just by reading them once, a prodigy beyond anything

  17. How many times does ProfDaveB call von Neumann "impossibly talented?" Okay! We get it! And we get it! And we get it!

  18. it was sure interesting, but where is the part about the von-Neuman architecture? :p perhaps change the title.

  19. Wow. So much knowledge he seems to have on the topic. Super interesting to learn more of these details.

  20. This is absolutely amazing, we are blessed to have a professor with such great knowledge available for everyone here on YouTube, thank you Professor Brailsford and Sean.

  21. So, now I know everything about 'uncle Johnny'…. When do you start talking about the architecture he developed?
    16 minutes of my life wasted to a clickbait.

    ps Loving most of the other videos you guys create, so please continue with whatever you please 🙂

  22. I don't get it firstly I am doing my GCSE and I am looking at the Von neumann architecture this has a CPU but what kind of CPU does it have? Because there are a lot of different CPUs?Does anyone know?

  23. today, parallel chips, or even graphic cards are not Von Neumann architecture, and we are moving swiftly away from this line of computing, as consciousness will never ever be achieved with this line, but with graphic card type designs.

  24. Von Neumann was very much indeed an international figure, but still, thanks for the effort for saying and pronouncing his name correctly in it's original Hungarian way as well. Respect, and great fan of the channel.

  25. What an amazing storyteller/historian the Professor is. I really enjoy listening to him, always very interesting.

  26. Gauss's intellect was considered to be the pinnacle of human thought, i.e. speed, capacity and depth of thought, even Newton, Euler and Archimedes were dwarfed by Gauss's sheer level of speed and perfection.
    It's often considered that in recorded human history von Neumann was the closest thing to Gauss's mental capacity and veracity.

  27. I built an IMSAI – Cromemco Z80 CPU from components. My soldering skills are industrial strength. So yeah. The desire for hardware.

  28. I’m pleased to see the ABC mentioned here, along with other early computers. One thing I like about Atanasoff was his view on priority. He said "I have always taken the position that there is enough credit for everyone in the invention and development of the electronic computer." That’s the right spirit. Remember people for their individual contributions without arguing about who should be considered the inventor.

  29. it seems to me the first von neumann machine was NOT EDSAC – but rather the ABC (atanasoff-berry computer) of 1928 – has all the right stuff you will find

  30. Professor Brailsford is real life Maestro from ''Once Upon a Time…' cartoon series. Once Upon a Time… Computer Science

  31. Remember when the Prof. said in an earlier video titled 'Why Use Binary' how he would be happy to buy a T-shirt with the binary algorithm printed on the front, if anyone ever made one.. well there he is in that very shirt :j

  32. Fascinating video, but very little on the Von Neumann architecture itself and it's consequences (programs as data and so on). I think you should do I video that's actually focused on Von Neumann architecture and contrast it to Harvard architecture. It can often be easier to understand something if you have something that's different as a reference point.

  33. Correction: He wasn't 35 when he was offered the IAS professorship. He wasn't 30 either, though he would celebrate his 30th birthday later that year in Princeton.

  34. I know von Neumann was an absolute genius, but how else would the architecture be structured, if not for those five or four boxes?  It was based the smartest computer of the time – human beings.

  35. Computerphile is one of my top-three sources of inspiration, Thank you!
    Greetings from:
    Sharif University of Technology, Iran,
    Royal Institute of Technology, KTH, Sweden,
    and now,
    Hamburg University, Germany.

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