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