An interview with Maurice Wilkes by Mike Hally in preparation of his book Electronic Brains

Transcript :

Maurice Wilkes Interviewed by Mike Halley

Transcribed and edited by Jon Hales, volunteer at CCH.

Mike Hally, checking recorder on Wednesday 25th February 2004 prior to trip to London and Cambridge to interview Professor Sir Maurice Wilkes.

INT: I'm just going to check the sound level first of all, so could you just introduce yourself please, say who you are? 

 Yes, I'm Maurice Wilkes, I'm now in the computer laboratory at Cambridge. I was once head for many years. 

INT: That's fine and your full title is Professor Sir Maurice Wilkes isn't it? 

MW: Yes, or just Sir Maurice Wilkes. 

INT: Right. Start with can you just tell me briefly about your early upbringing, where you were born, what school you went to, what sort of education you had? 

MW:  Yes, well I went to one of the old grammar schools. I was very fortunate I think in having my school education at a time when the school certificate, higher school certificate system was going strong, it was a wonderful system. We lost a lot I think by its dismantling and I went up that way. I went up to Cambridge. My father decided suddenly that he thought it was time I went to Cambridge, so I went. I only spent two years in sixth form but that didn't matter, school masters like to keep you at school. I came up to Cambridge, I took Mathematical Tripos, which is very much a misnamed examination, especially then because there wasn't much pure mathematics of the modern sort in it. It was mostly mathematical physics. Mind you, I suppose if you wanted to you could search out the pure mathematics but the compulsory course of pure mathematics was rather small. 

INT: Did you have a practical interest from an early age then? 

MW: Oh yes, I certainly did and I became a Radio Ham. I received encouragement there from the school master. The school had a transmitting licence, which is very unusual and cool, and he let me build a transmitter, operate it at home. We had two callsigns, a mobile one and a fixed one so that made it possible for me to have this equipment. Then I got my own licence when I was an undergraduate. When I say my own, you couldn't have a licence in your own name if you were under 21, so it was in my father's name. I learnt a great deal from that. Nothing like ham radio. It was a training in practical radio. 

INT: Did you pursue that interest at Cambridge? 

MW: Yes. When I came up, I kept away from the university transmitting section for a long time because I wanted to do other things, take full advantage of other opportunities in Cambridge. But I did in the end, I got involved with it. But of course I had my own licence at home and it was in the vacations that I did most of my ham work. Then when the war came, the local post office came and took all the equipment away, sealed it up, cancelled our licences and I never took it out again after the war. I learnt all I felt would get out of ham radio. 

INT: But you had this interest in the physics of the upper atmosphere. 

MW: Oh yes, that's right. My ambition then, I suppose you would say, was to be a practical experimental physicist. And I joined a group at the Cavendish which was concerned with propagation of radio waves in the upper atmosphere, what is called the ionosphere. And we use radio techniques, pulse techniques similar to radar, for exploring it. We were supposed to be doing physics, that's finding out about the upper atmosphere. But what attracted me was the technological work because I was very well qualified for that. But I did in fact, I think I was one of the few people in the group who managed to derive something physical. I had an estimate for the temperature of the atmosphere around 80 kilometres which I ... came directly from the work I was doing. 

INT: And did that bring you into contact with the early mechanical calculated machines, the differential analysers? 

MW: Yes, indeed. It was an interesting period, just the years immediately before the war. There was a widespread understanding of what could in principle be done in science by numerical computation. The only thing was all we got were desk machines. Punch cards were rather little used in Britain anyway. And I did my share of computing with a desk machine, solving differential equations, propagation equations. And I remember when I came to write my thesis, I very carefully listed [it] in an appendix I had done, because I had spent many, many hours doing that and I didn't want the examiners to feel it was just a sentence or two which is of course all it was in the end. But then came at that time the invention by Bush of the differential analyser. And it was a great fashion for analog computers. Leonard Jones, who was interested in what we now call computational chemistry, Professor, he took the lead and he got the funds together to order a full scale differential analyser. He had a Meccano model built, part of the propaganda. To everybody's surprise, it works remarkably well. This machine was not delivered until the war had broken out and I had gone off to do war work. But I was, he had, Leonard Jones had a great vision. He didn't say I want a differential analyser in the room to put it in. He said I want a university department. And so he established a complete university department. It only existed on paper. He was the director and I was the slave, the staff, with the lowest academic rank. And ..., but it was a properly qualified university department. 

INT: And this was the laboratory? 

MW: Yes, it was called the Mathematical Laboratory. It had been described as a computing laboratory but at the last moment they changed its name, an error we had to correct a good many years later. But it was called the Mathematical Laboratory. I came back after the war, after war service, Leonard Jones stayed on in government service. And anyway, I discovered much later that he had said that he didn't really want to go on being part-time head of the Mathematical Laboratory, that he felt it should have a full head. So that was an opening for me. And that's how I found, as a young man, I had this university department with its own finances and access to the general board of the faculties. And the top, you know, it wasn't buried in somebody else's laboratory. And that was a great bit of luck. 

INT: Pretty much your own man then? 

MW: Oh yes, yes, yes. 

INT: Just quickly going back to differential analyser, I was intrigued to read that they were, the early ones were to large part Meccano, which of course I played with like anyone else. 

MW: Oh you did. Oh of course. That was another thing we were lucky about, you know. Not only was the educational system good, but it was Meccano. Well the idea of building one of Meccano was Hartree's. Douglas Hartree, Manchester at that time. And he had one, a very crude one, built for, really for propaganda purposes. And it worked. I don't think it did much actual work. Leonard Jones had found just the right man, a man called Bratt, who had been a clockmaker, but had managed to get some funds to come to Cambridge, taken a degree, and he was available. And so Leonard Jones got a grant to employ him for two or three years to build a better Meccano machine. Better in the sense that those parts that needed to be precise were not made in Meccano. And that was the machine that did some quite useful work. Quite useful work. 

INT: Now then, moving on to your war work. You went into radar and I suppose what I'm really interested in is what, can you tell me about the war work that was useful to your computing work later on? 

MW: Well, of course I got a lot of experience, but it wasn't that I learnt electronic engineering,  or radio engineering during the war. In fact, I got, a lot of people got jobs. But I had, I brought with it, I brought technical knowledge, so that helped me in the very early stages. Sorry, I've forgotten what you asked. 

INT: No, I was just interested to know if there were things that you were learning or using in your war work, that you were later applying to computing.

 MW: Well, the answer must be yes, because radar didn't involve digital techniques in the sense we know them today, but it involved electronic techniques, as well as radio techniques. You see, you had radio, you had electronics coming along, which was non-communication stuff, and then finally you had computing. So out of radio grew these new disciplines. And so I did, oh yes, yes, it is of great value to me. But I think the most important thing was I learnt how to get things done. You see, we had good support, very good support, and one of the features of the times were crash programmes, particularly for the Air Force. In the latter part of the war, I was doing radar for the Air Force, and when some new radar, a new model of some of the radar equipment, airborne radar equipment, then the Air Staff immediately said, Well, could we have enough to equip a couple of squadrons as soon as possible? And these crash programmes were carried through quite independently of the production plans. I mean this thing was put in production, it was going to be manufactured, and that all went at a very high speed. But the crash programme was in addition to that. So I learnt how to do that. It was very valuable. And of course it was six years after all. And the six years when you, you see, I just got my first university job. I was just at the lowest rungs of the academic ladder. I was, let's see, I was born in 1913, so when the war broke out I was, how old was I?

INT: Twenty-six. 

MW: Twenty-six, that's right. I was twenty-six. So I was at an age when I could use experience, and I got that experience. 

INT: And I gather that the, just at the very end of the war, your visit to Germany was very interesting and very informative. 

MW: Oh yes, that was, yes, yes. I'd been cooped up in Britain all the war, you see. And I always like to put it this way, that a grateful government gave me six weeks holiday in Bavaria and Austria. It was a lovely summer. And we, I got there, I didn't, I learnt that you could volunteer for this intelligence work, interrogating German scientists. And I volunteered. The war was over before I actually got to Germany, but not very long. Everything was at a standstill in Germany. Nobody could move. The troops were all where they reached, points they'd reached. The civilians, no trains running or anything like that. But we could. We needed to, and there was a whole organisation set up. We were allowed, as it turned out, I mean, we could really choose our own intelligence targets. There were files of these targets, and we could choose them, and go off and do it. So it was really, and I discovered that radar, in a strict sense, was being ..., was fairly well covered. But that my old wartime, my pre-war field of ionosphere research, was not at all well covered. But there were a lot, they'd done a lot in the, during the war. So I was able to renew my interest in ionosphere work, and meet some of the people whose names I knew, and they knew my name[s] because of wartime, pre-war publications, or even wartime publications.  INT: And it also gave you a great interest in things American. 

MW: Well yes, I was in the American zone, that's right. I am very much an admirer of things American. And I always say that that was my first trip to America. The American zone was really like being in America. 

INT: So you came back. Perhaps you can explain that, how you came to get interested in making an electronic computer. What were the influences?

MW: Oh well, of course, you see, I came back and found myself head of the computer laboratory, with terms of reference to develop methods and equipment for doing computing. And of course I then began to learn about things that had gone on in the United States, the ENIAC, and the later ideas, which I had known nothing about, because I was working in something else doing war. I learned about those things, and one day I had a telegram from the Dean of the Moore School of Electrical Engineering in Philadelphia, M-O-O-R-E, inviting me to a course of lectures. And I accepted with alacrity. The university, through the Secretary General, agreed to underwrite my expenses, or most of them. I think they paid it all. And off I went. But it was not easy. Crossing the Atlantic wasn't easy then. I did get a passage and I arrived very late for the course. But nevertheless, I got the full message. And I met Eckert and Mauchly and their associates, and I went round to the other places, some of the other places, principal ones. 

INT: That seems remarkably generous, to run that Moore School. 

MW: Oh, wonderful. It was a wonderful, yes, wonderful piece of generosity. And I fully profited by it. 

INT: What did you make of John Mauchly and Presper Eckert? 

MW: Oh, I see. Oh, well, they remain my idols. Mauchly had some interests in meteorology, which I linked up a bit with my own, because I had got interested in tidal motion in the Earth's atmosphere. And my first book was on that subject. And Mauchly, we had something in common there. Eckert, of course, was a brilliant engineer. And he and I took to each other very much. I admired him. And of course, the ENIAC, the ENIAC was a crash program somewhere or other. Eckert says we built the ENIAC in something of a hurry. I knew exactly what he meant. I was doing the same with EDSAC at that time. He and ..., well, I made a speech when Eckert died. I had met him just a few weeks, quite a short time before, at the opening of the new ACM, Association for Computing Machinery, headquarters in New York. I was on the council of the ACM at that time. I had met him. So I had seen just not very long before he died. And I ..., one of the conferences, it was in Italy, North Italy, I made a kind of oration ..., a speech about Eckert in praise of Eckert. So that would provide you, I think, I give anecdotes there in support of my statement that he was really a brilliant engineer. And later on, I remember earlier, that's right, I always remember one occasion. He was a great talker, Eckert,  you know, he did most of the talking, if you weren't careful. And he had been, oh yes .., that's right, he'd been up to Cambridge to see what we were doing, but he was then, Remington Rand his employer to send him over to go to some dinner, something like that. I've forgotten when I arrived, when I arrived, I think before he did, as soon as he came into the room, he spotted me and came along. And we buttonholed in the corner and we talked, technicalities, you see. And after a while, I could see that his, the Remington Rand officials. We got a little anxious because there was the great man who was supposed to be entertaining the guests and whatnot. He was involved in the technical discussions. That was absolutely typical of Eckert. But as soon as he realised, and this again was also typical, as soon as he realised, you know, he then began to behave properly as a senior Remington Rand man and did his duty. But that was the sort of man he was. He was absolutely driven by engineering.

INT: A rather different character, I gather, was Howard Aitken.

MW: Oh yes.

INT: Quite a character.

MW: Yes. I wrote, let's see ..., there was a book about, the names escape me. I knew him very well. The man who was expert on Newton. It will come back. He produced a book about Aitken and I wrote one of the chapters giving my assessment of Aitken. So if you want any information there, that is available. Of course he was a great pioneer and one had, I mean, I respected him as such. But he was really rather, I suppose he'd got his mechanical thing going and then he discovered that in secrecy the ENIAC had been built. Anyway he is an example of a great pioneer becoming reactionary really. He was not, at least no longer a leader, no longer a leader and all the people who were building the early computers, they didn't listen to Aitken.

INT: And I was struck by, I'm sure it was something you said, that he saw a major use of his computer as being churning out lots and lots of mathematical tables.

MW: Yes, yes.

INT: Whereas you saw correctly that they would replace the tables.

MW: Yes, yes indeed. But still, I mean, I never lost my respect. I liked him as a man. I often told the story, I told it in my book I think possibly, that we were all, I mustn't say I was afraid of him, because Americans misunderstand that term, but you know what I mean, tried to avoid, he couldn't stand the binary system for example. But one day I was there and he was holding all forth about this and I took him on and he was delighted.

INT: He respected that?

MW: Oh yes, yes, oh yes. I think he was rather puzzled by the fact that people wouldn't argue with him. But I, anyway, we did, we went on hammer and tongs and he was delighted and he invited me to his home, his wife invited me to dinner, he fed me highballs and there were some other guests and I had a wonderful night. He could be very charming indeed.  INT: Well now getting back to the EDSAC, so you came back from the Moore School and you already had your ideas I think on the way back.

MW: That's right, I came back on the Queen Mary, one didn't fly the Atlantic in those days, one took boats, most people didn't. And in the Queen Mary on the way back I began to sketch out something that I might do. I was gradually beginning to realise that in spite of the enormous scale of the American activities, that one could get, I could get starting with resources that were available to me, as I did.

INT: Did you have the same wartime attitude of just do it?

MW: That's right..., yes, oh yes. And you see it was a, anything I think that you write or say about that period, you should remember that there was a country that had been at war for six years. A lot of us had been engaged in it and we were all heartily sick of that kind of thing. Moreover, everybody, government and everybody else, realised that we just had got to get civilian values and civilian activities re-established. And so that was what you were supposed to do in the university, if you had got some ideas then you got support. There was never any question of putting up a proposal, but then it was part of my terms of reference to do that kind of, but there was not, you didn't have to put up proposals for a project you see. I had sufficient resources in the lab to get started and then I could apply for further funding from the university. And then on my behalf, Secretary General of the faculties found out that the UGC [University Grants Committee] were willing to give some earmarked grants, which is a thing they hardly ever did. They were prepared to give earmarked grants for things that would help this effort of getting universities back into business and that one could apply for such grants for projects that were in existence, so some money came that way and I didn't really have to worry very much.

 INT: So technically what was the biggest problem or your first priority in this, in creating the answer? 

MW: Well, the ..., we ..., I think those of us who built the early computers felt that our knowledge of electronic engineering would stand us in good state and would provide all we needed. The first priority, however, was to get our memory working because that was a requirement that had never existed before and no memory existed. Eckert had made the crucial suggestion one might use mercury delay lines, mercury tanks, and well I tell the story in my book, that was the first thing to do to get pulses circulating and I met Tommy Gold who had experience of tanks for an entirely different purpose in radar and he gave me the essential data. So I, well the great rule about the EDSAC  was we, if we got something that worked that was it, not trying to make it better. Gold, whom I trusted, said this will work if you make it this way, I made it that way, it did work. That was a single tank, we needed the quantities so I made, designed a battery [of mercury delay line tanks]. But the essential important dimensions remained the same. That was the, so that was what we concentrated on and that. 

INT: And that was, I think it calls for one of your first celebrations in the Bun Shop. 

MW: Oh that's right, yes indeed. Indeed, in the Bun Shop, which of course was a pub. Yes I remember we, Gordon Stevens had joined us as an instrument maker and of course there weren't very many of us and it just, it was one of these celebrations whether it was that one or perhaps it wasn't. No, it was something else. And he found at the end of his first week he was dressed [inaudible] up to the pub to celebrate. This was very good for staff relations of course, naturally. The ..., I think we did have to learn though, electronic engineering was all very well, but we did have to learn one or two things. That transients must be properly handled. You see in a television set or a radar set, something happens, a flash on the screen, past history, doesn't matter. But in a computer which has memory, that kind of thing can lead to permanent error. For example, all the numbers in a, in the memory, if they were all zeros, they suddenly become all ones. That must be handled properly. And that was something we did have to learn. Everybody had to learn it, they'll tell you the story in different ways. But once it was understood, then the next generation of people, rather to my surprise, just took it in their stride.

INT: Was the, I've occasionally seen descriptions of EDSAC which imply it was your version of the EDVAC, but in fact, you didn't come back with a set of drawings, did you?

MW: Oh no, no no.

INT: You just did principles.

MW: Oh no, it resembled the EDVAC in that it was a serial machine, using mercury tanks. But that was all. I mean the instruction set was a single-address machine, whereas the EDVAC was three-address. I mean, everything was entirely different.

INT: All the detailed design was yours?

MW: And I, oh yes. No, but I don't think [...], the EDVAC design did not exist. I mean, except in Eckert's head. I don't think, I should be very surprised if there were any detailed designs. Of course the ENIAC designs and circuits were available when I got some of them, but they were not really relevant to the stored program computer. I suppose the name rhyming with EDVAC was a kind of compliment to the EDVAC.

INT: And your philosophy in building EDSAC, as understood it, was very much that it would be a working computer, a real service for the university.

MW: Oh, that's right. Well, yes. I had, fortunately, had experience of computing, bits I'd done myself before the war, and of course running the mathematical laboratory, where a lot of computing went on. And so I knew a lot about computing, and very few people in my position did. And so it was a feature of Cambridge that once we got the machine going, we immediately started using it. There was no question of a group, team of engineers, handing over to an entirely separate team of programmers or mathematicians or whatnot. So that was one of the reasons why we got going so quickly. But the idea was to make a machine that was practical, useful, could be used, not the best possible machine, not exploiting technology to the full, and there were certain specific decisions relating to that point, ... and cut corners. So we got a machine of some sort. Now that wouldn't have suited Eckert at all, because he had established a company with Mauchly, and they wanted to make a machine they could sell. Well, I mean, that's not our way. It was not the way to go about making a machine you could sell. But it would serve its purpose. And then we could get onto the second part of the game, which was learning how to program. And so we did some of the pioneering work in programming methodology, a term came into use later on, but didn't really appeal much to the other groups. And my experience made me realize that there were lots and lots of people like I was before the war, when I had been a student, who didn't want to do vast big problems like weather forecasting or something. They did that wretched integral that has got to be done, that would have meant weeks at a desk machine. These things were well within the power of the crudest sort of programming computer. And so the idea was to make a machine that would do that, but it was to be sensible design, nice to use as far as we could do that. Not the last word, not exploiting the technology fully.  INT: And in the midst of this, Lyons became involved. 

MW: Well, they got interested. They heard about us in America and came to see us. Well, you know that story as well. And they gave us a small sum of money, which [we] helped. And we helped them. That's right.

INT: Do you remember that first visit? Do you remember what sort of people they were like?

MW: Oh, yes. Yes, yes. They were university [...], people who had been recruited unusually [inaudible]. Simmons, one of the senior people, who was a member of my own college, had been. Thompson, well now Thompson surprised lots of people. He had in fact taken the Mathematical Tripos. And he had got the highest honours you can get. I mean, it was just to get a First and then what was called a B-star. He'd got that. So it had a curious effect later on when Lyons had some spare capacity and were selling the time. Because when people brought along a Matrix job to be done, Thompson took a look at it and said, Well, that's not the right way to do it.  It was a bit funny. Oh, yes. A very friendly firm. Informal, friendly, able.

INT: And very innovative.

MW: Oh, yes. Oh, yes. Oh, yes. They lent us the services of a young man, a technician really. They pulled him off the job he was working on, which was a slot machine that would put in your money and out would come a hot sausage, sizzling hot sausage. That was what he was working on. Diathermic heating, you see.

 INT: And can you say a bit about Pinkerton as well? You said that he'd perhaps been underrated in the story.

 MW: Yes. Well, only underrated because he did such a good job that the people who did the payroll programming just took it for granted. I knew him during the war at TRE [T... R... Establishment]. He was in the radar business as well. He came back younger than I was, took a PhD at the Cavendish, then wanted a job. And just at the moment when Lyons were looking for someone, of course, he applied. I supported him. And he ... built a somewhat re-engineered copy. But he said they had a rule, he said, that they didn't change anything in the EDSAC design unless they thoroughly understood why we had done it that way. That's the great words of wisdom from a great man.

INT: So it wasn't just a copy, though? He did detailed work to improve it, to make it reliable?

MW: Yes. Well, he didn't use the same, ... the vacuum tubes were similar, not the same. I forgot one there. We had EF-50 RL-7s and he had something else. So that was that change. But I don't know otherwise. And the mechanical form of the chassis was different. But circuit-wise, it was very much a copy. But here and there, he had ... he put it through the next stage of design, you see. If you build the first thing you build, throwing it together as we did, there were things that required a little further attention. But the logic, what we call the architecture, what we now call the architecture, that was exactly that.

INT: And I suppose he'd be responsible for the things like doing initial tests with the voltage a bit high and the voltage a bit low and so on?

MW: Well, that came from a TRE marginal checking.

INT: Did it?

MW: I pinched it from MIT and made quite a thing of it. He developed it further, I think. He was able to use it much more systematically. I mean, he had a much bigger, more powerful maintenance team than I had. Very necessary. And he made a more systematic use of the marginal checking, but it was a feature, yes. But that came from MIT.

INT: Presumably you were very pleased to see Lyons take this on and make a go of it.

MW: Oh, indeed. Oh, yes. Yes, yes, yes.

INT: Did you stay involved with their applications?

MW: Oh, yes. They were eventually taken over by English Electric and hence got absorbed into ICL. And he [Pinkerton] stayed to the end, the end of his career. The taking over of Lyons, by English Electric and others, that really brought an end to Pinkerton's innovative career as an engineer, unfortunately. Lyons was doing very well on their best machines. Their latest machines were very, very good. One ..., again, a name escapes me. There was one who became engineering director of the Post Office board responsible for electronic data processing. He said that the Lyons computer, for payroll purposes and such things, was by far the best of any machine available. And he bought up, when ICL stopped making it, he bought up all the second-hand ones he could. And then he used the power of the Post Office, in effect, to force ICL to reopen the line and make some more of these things, because they were so much better than anything else that was available. It would have been nice to have seen what Pinkerton would have done after that. But he didn't. He couldn't.

INT: Getting back to your own achievements, you came up with the idea of microprogramming, I think. Tell me about that.

MW: Yes, yes, yes. Well, that was a problem I identified and solved it. I saw that uniformity of design, regularity, was important. And you could do that for the memory. You could do it for the arithmetic unit, for parallel arithmetic unit. It was all very uniform, straightforward, repetitive units and so on. But the control was just done by someone taking a sheet of paper, sketching it out, throwing it in the waste paper basket and doing this. It was very, very unsystematic. I said, If we're going to get high reliability, let's try and systematise this. And so I came up with microprogramming. It was a conscious attack on a problem that was, I thought, sticking out.  INT: But at the time, nobody else was doing that. This was something that...

MW: Well, everything has its antecedents. It was Project Whirlwind. It was an MIT project, a government-supported project. That had a control matrix, but it was repetitive in a sense. But it was a first step, and I stood looking at that and was asking myself, Well, now, why doesn't this... Then I realised that we didn't want to have it churning out a fixed, just six or whatever it was, steps per instruction. We wanted to have a computer in miniature, a microcomputer, not in the modern sense of that term, running a microprogram. And that was it.  INT: So can you give me an example of what sort of things the microprogram would do at that time?

MW: It was just a way of building the control of what was otherwise a conventional machine. People did try and think of user microprogramming and so on, but that never really was important. But as a way of building a computer, it became virtually universal.  INT: Right. And this would make it much easier for the user?

MW: No, no, no, no. It was engineering.  INT: Purely in the engineering side.

MW: Yes, yes. As I say, there were movements to try and use a microprogram, but I don't regard that as important.

INT: Right.

MW: No, it was an engineering contribution. It made it much easier to design. I remember Pinkerton saying to me, he was showing me what he was doing. It was a remarkably easy way to design.

INT: You also got interested in Babbage's work, I believe.

MW: I did. INT: Yes. One of the first to go into it in detail.

MW: That's right.  INT: Look at his notes. Tell me a bit about that.

MW: Yes, yes, yes. This was the centenary of, let's see, it would be Babbage's death. Then I did go and look at the papers in the British Library and South Kensington Library. And I wrote a paper for that ... centenary meeting of the British Society. And that led me to, oh yes, I got hooked on historical research.

INT: What was your assessment then of Babbage's work, particularly on the analytical engine?

MW: Well, it was of course, he got a 'bee' in his bonnet about the difference engine. That was a very bad idea. You know there are two engines in different engines. The difference engine was a dud idea and he would never admit it, never appreciate it. But the analytical engine was [...] science of great originality. Unfortunately, he never published it. He talked about what it could do and that sort of thing in a not very comprehensible way, but sufficiently. But his notebooks contained a lot of stuff that would have been of great interest if they had been public knowledge just at that very brief period when people were still interested in mechanical computing devices. Of course by the time I came across them. But there I think that stuff was verging on genius.

INT: Because his use of programming through punch cards and conditional branching, there seemed to be all sorts of details that were almost a century ahead of their time really.

MW: I suppose so, except they weren't published. He would have said, Well I can't publish these things unless I have shown they work. But of course he was not a practical man. I mean he was not a go-getter. He was not good at crash programs. In fact, he was, as a project leader, he was abysmal and inaudible]. And he was a bit awkward, very vain of course. Still, yes, I very much enjoyed that historical research that they had done. I still come back to it occasionally.

INT: I forgot to ask you about what presumably must have been the great moment of EDSAC running the first time. MW: Yes it was.

INT: Can you tell me about that?

MW: Well ..., it was obviously Renwick, my colleague, Renwick, Bill Renwick, who was bearing most of the load then. And he was obviously making progress. Quite suddenly one day he did a program. And then, yes it was. But it was something we were expecting. But it was a great day.

INT: Presumably it was another trip to the bun shop?

MW: Another trip to the bun shop.

INT: And the previous year, when the Manchester Baby had run for the first time, was that a surprise or did you know that was going to happen?

MW: No. I mean, well, of course, as you will, this is brought up very clearly in this memoir that I mentioned at the Royal Society Biographical Memoirs about Tom Kilburn. They needed something to validate the cathode ray tube memory. And Tom ..., very well ahead of his time, realised the only proper way to test a computer memory is to run it on a computer. And so they built this very tiny one. Some people have said that it demonstrated the stored program principle, but I mean there was nothing to that after all. If a computer would work at all then the programs would run it. Though it was in fact, and this was a landmark, it was the first stored program device, computer, yes it was a genuine computer on a very small scale to run, yes, yes, yes. But no, I don't believe...

INT: I was just wondering how much you knew about each other's projects at the time.

MW: Oh, we were in touch. We were in touch, yes. But you see, you don't, when you're in the middle of a project, you're committed to everything. The last thing you want are new ideas. Because it would be incompatible with what you were doing. Our machines were very, very different. But we were friends and admirers. At least I admired him, I think perhaps he did. It was Williams, of course, in those days, not Kilburn. Kilburn hadn't yet assumed command. But nevertheless, the [Manchester] Baby I think was, even then, Kilburn's. And he realised its importance. And fortunately there is, on records, something he wrote which makes it perfectly clear that that was what it was all about. He got the idea of a train or something like that, you know, that kind of anecdotal thing that seems to give validity to it.

INT: And Turing, what did you make of Turing?

MW: He was a quiet, very quiet person. I liked Turing.  INT: Very different approach from yours.

MW: Yes, yes. He was really a mathematician. He liked dabbling in electronics, but that wasn't his forte. He wasn't the sort of man that one really had deep technical conversations with. I think he liked to teach more than he liked to learn.

INT: He was leaning towards artificial intelligence as well.

MW: Oh, he wrote a wonderful witty paper about that, partly with his tongue in his cheek. It's called 'Calculating Machinery Intelligence' in a journal called Mind. Very, very witty. He didn't regard it as the last one. In fact, when I wrote and asked him for a reprint, he sent me one, but remarked he didn't think it was very good paper. I just forget what the words he used were sent to that effect. There were some things in it that I think were ... witty ..., penetrating too.

INT: We're coming up to an hour, so looking back now, you got a knighthood a year or two ago, which presumably was because of your life in computing. Do you look back and you've really enjoyed it? It's been really interesting?

MW: Oh, yes, of course. But then I've been so extraordinarily lucky. Very, very lucky.

INT: Because really, your working life spans the whole of modern computing.

MW: It does. It does indeed. It does. Yes, yes. See, when I started on the EDSAC, I was in my early thirties. I mean I wasn't a baby. Yes, the whole thing spanned part of a man's life. And I was already established. I had a reputation in my work. I mentioned tidal motion in the atmosphere, that sort of thing. Yes. I always say you need luck, and I had plenty of it. You've got to use it wisely. I think for the most part I did use my luck wisely.

 INT: It's obviously kept the old brain cells working?

 MW: That's right. That's right. Yes.  

[BLANK_AUDIO] 

Provenance :
Created and collected by Mike Hally and donated to the LEO Computers Society

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