Oral-History:Heather Liddell

About Heather Liddell

Heather Liddell was born in 1940 in London. She grew up in Surrey and attended Royal Holloway College, University of London where she majored in mathematics. She received her PhD from Royal Holloway and began a post-doctoral fellowship at Queen Mary College in London. At Queen Mary, she worked in the Electronic Engineering department until becoming part of the new Computer Science department. Liddell has worked on optical filters in connection with lasers, ICL and Atlas computers, and IBM machines. Her work has mostly been concerned with numerical problems and numerical analysis with the aid of computers.

In this interview, Liddell talks about her experience with computers throughout college and as an academic. Her work on Distributed Array Processors (DAP) is also discussed. She also talks about her role at the college in developing algorithms. She goes into detail on her interests in parallel languages, applications, and algorithms.

About the Interview

HEATHER LIDDELL: An Interview Conducted by Janet Abbate for the IEEE History Center, 4 April 2001

Interview # 608 for the IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc.

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It is recommended that this oral history be cited as follows:

Heather Liddell, an oral history conducted in 2001 by Janet Abbate, IEEE History Center, Hoboken, NJ, USA.

Interview

INTERVIEW: Heather Liddell
INTERVIEWER: Janet Abbate
DATE: 4 April 2001
PLACE: Heather Liddell's office at Queen Mary College in London

Background and Education

Abbate:

This is an interview with Heather Liddell on April 4th. Can you tell me, first of all, what year you were born in?

Liddell:

1940.

Abbate:

Where did you grow up?

Liddell:

I grew up mostly in Surrey. I was actually born in London. It was wartime, and my father was killed in the war, in an accident, eleven months after I was born. So my mother was a war widow, and she went down to Surrey to be with her sisters, who were down there, and we lived there quite a number of years. And then, when I was eighteen, she remarried—actually the person who lived next door!

Abbate:

But not until you were grown up?

Liddell:

No; I was just less than 18 years old. He’d been around quite a while, so . . .

Abbate:

What did your parents do for a living?

Liddell:

Well, my father was in the army. Prior to that, I think he’d worked in the Meteorological office a bit; and after that I think he did something in the fur trade. You know, he was only 25 or 26 when he was killed, so he was still really finding his way when the war broke out. He had been at a public school, and had been in the Officers’ Training Corps, which is why he went into the army automatically. I said he was killed in an accident; it was in the Middle East, near Damascus. He’s buried in Damascus.

Abbate:

Ah. And did your mother work?

Liddell:

Yes, she worked in a bank for many years. I think she met my father when she was working somewhere in London, and that was before she was in banking; it was in some firm up there. Prior to the war, women weren’t employed in banks very much, but of course with all the men going off, they wanted to employ people, and she’d got quite good school certificates and things (the equivalent of GCSEs these days), so she was able to get a job in the bank.

Abbate:

Did she encourage you to have a career? Did you expect that you would be earning your own living?

Liddell:

Oh yes, I think so! Although her sisters didn’t work—they were married ladies—but she’d always had to work, and it never occurred to me I wouldn’t work, really. I went to a very good girls’ grammar school in Epsom, where, again, it was expected that people would pursue their careers, and were encouraged to go to university, which was quite unusual in those days.

Abbate:

Did she have any interest in math or science?

Liddell:

She was always pretty good at maths and, I suppose, numbers. I’m not sure that [she was interested in science]. She did some science, but she was also quite interested in art (in which I’ve got no interest) and music. I’ve always been interested in music.

Abbate:

Now, you were interested in mathematics from a fairly early age?

Liddell:

Yes, yes, I think so. I did relatively well when I went to grammar school in maths, and I was encouraged to study it, and to do maths and physics and so on. In fact, I did maths, physics, and music at school.

Abbate:

Those seem to go together.

Liddell:

Yes. And the reason I didn’t do chemistry or something like that—and I should probably have done it, because I think my father did quite a lot of chemistry, when he was taking his Higher School Certificate—was that we had an awful chemistry master, who used to throw chalk at us! It put me off completely! And it’s these stupid things that can change the course of a career.

Abbate:

Did you have any experience with computers in secondary school? Or not until later?

Liddell:

No, because they weren’t around then; this was in the ‘50s.

Abbate:

Pretty early.

Working with Computers at Royal Holloway College

Liddell:

The first experience was when I was at college, at Royal Holloway College. Computers were beginning to come in, and we attended some of the courses at an Institute in London.

Abbate:

Now, how did you choose that college?

Liddell:

I was actually on the waiting list for Oxford, but I wasn’t sure I was going to get there, and Royal Holloway was one of the colleges that our school recommended. It was, in fact, a women’s college. I knew they were quite strong on the mathematics side—some of my teachers, I think, had been there—and I did their entrance exams and was awarded a scholarship, so that automatically gave me a state scholarship and funding, so that was one of the reasons. Also it’s part of the University of London, as is this college [Queen Mary].

Abbate:

So that would have been 1958 or thereabouts?

Liddell:

Yes, I went to Royal Holloway in about 1959. I started school in 1951.

Abbate:

And you took a degree in maths?

Liddell:

Yes. But I did my Ph.D. in mathematical physics.

Abbate:

And was that also at Royal Holloway.

Liddell:

Yes. About the time we were doing our first degree, there’d been quite a lot of interesting research going on—it was quite a small college, so you got to know what was happening, and I had friends in the physics department who were starting to do work on lasers, which were very new then; and we all got very interested in this. Professor [Oliver] Heavens, who was my supervisor, had been working at Columbia University with Schawlow and Townes, who invented the laser, and he came back here to start things up. We got interested in it, and I got involved on the computational side.

Abbate:

Was that how you first got interested in computers?

Liddell:

Yes, I think it was, because a lot of computation was required to design the coatings for the laser mirrors.

Abbate:

So by the time you finished getting a degree in mathematical physics, you had been using computers a lot at that point.

Liddell:

Yes. In those days it was punch cards and paper tape, and you had to travel, taking them up to London to run them on the big machine—the Atlas—we had there. I also used the Atlas at Harwell, which was part of the Atomic Energy Authority, where we could get access.

Abbate:

So you would write the program, say on paper, and then punch the cards, and then travel somewhere to actually use the computer.

Liddell:

Yes, yes. It was a bit of a slow process, actually!

Abbate:

Well, typical for the time, I guess.

Liddell:

Yes.

Abbate:

So, using computers: Was that an area where there were many women involved, and it seemed natural? Or was it sort of unusual?

Liddell:

Well, I was in a women’s college, and it seemed natural; there were quite a number of us interested. I’ve never felt particularly at a disadvantage for being a woman. Perhaps it’s having been to a girls’ school and a women’s college! However, it wasn’t really particularly by choice I went to a women’s college; I would have preferred to go to a mixed university in some ways, but it’s just the way things worked out.

Abbate:

When you went to a place like Harwell, were there a lot of women running programs on the computer?

Liddell:

No, not a lot; they’d be mostly men, I guess, at that stage. And most of the people I worked with there—many of whom I’m still in touch with—were men.

Abbate:

So it was unusual, but it didn’t seem uncomfortable, particularly.

Liddell:

No, no. I was lucky, because I was always encouraged by my colleagues, and there was no sexist aspect to it.

Post-Doctoral Fellowship in Engineering at Queen Mary

Abbate:

After you took the Ph.D., you got some sort of post-doctoral fellowship?

Liddell:

Yes, which was here, at Queen Mary. It was in the Electronic Engineering department, because what I’d been working on was optical filters in connection with the lasers. These were the interference filters that you’d need for the reflecting coatings in the lasers. The work involved quite complex numerical optimization, which required the use of the computer. So I came here to work with a man called John Seeley, who was in Electronic Engineering. Then while I was here, I met my husband, who was in the Geology department here. And once there’s two of you working—and as you progress up the scale and get promoted—it’s quite difficult to move away and get two jobs. We did intend to, but it never happened!

Abbate:

So you stayed the entire time. Where would you have gone?

Liddell:

Well, at one stage, early in our career, Alan applied for a job at Durham University that seemed to be in his area, and I guess there would have been other opportunities for me up there—there were plenty of opportunities for people who did computing, so I think it would have been fairly easy. But as it turned out, they appointed somebody else; so in the end, we didn’t move.

Abbate:

Soon after you came to do the post-doc, you became a lecturer in computer science.

Liddell:

Yes, about a year after; in fact, less than a year.

Abbate:

1966 or thereabouts.

Becoming a Lecturer at Queen Mary

Liddell:

This is perhaps the only sexist thing that happened in my career—and it was in my favor! The Head of Department of Mathematics then was a lovely old gentleman called Professor Ferraro. My predecessor was a lady: Mary Pickering, but later she reverted to her maiden name, Mary Almond, and is at Manchester. I knew her when I was here in Electronic Engineering, and both she and Professor Ferraro suggested that I should apply for her job when she left. It was quite a good thing to move straight into a Lectureship—because in those days there was an Assistant Lectureship post—so I decided to accept.

Abbate:

And she had been doing computer courses?

Liddell:

Yes, she’d started doing some Introductory Programming courses here, and we had a little lab down in the basement of the main building.

Abbate:

Was she the only one?

Liddell:

They had a few Staff—I think there may have been a couple of programmers who used to work with her. The reason I’m hesitating is, about a year later, they decided to establish the Computer Centre here, and the director was Vic Green, who then employed quite a number of programmers. One of the people was Sandra Holloway, whose mother is a Professor of Maths in Canada; she’s been involved in computing all her life, too. She went back to Canada at one stage; her marriage over here wasn’t very successful, so she returned to work in Canada.

There were a number of people. There was a group that all worked together. At the time I got the Lectureship, they also appointed somebody else, Anthony Powell, to another Lectureship; and the other person who was keen to build it up at that time was a Reader, which is just below a Professor in grade in the English system. He had been a Reader in Numerical Analysis here. He was quite keen to build up the Computer Center and so on, so it was he who appointed me and also Anthony Powell, who was my colleague. The three of us took over from the work Mary had been doing, and then started to build up the subject.

Abbate:

And then you actually started a department in 1971?

Liddell:

Yes. At that stage, we were part of Mathematics; and then we split away into a completely separate department later on.

Becoming the Department of Computer Science

Abbate:

So that was in 1971 that the separate Computer Science department was founded? Or is that not right?

Liddell:

In October 1966, I was appointed Lecturer in Computer Science.

Abbate:

But it was sometime in the ‘70s that the department of Computer Science was founded.

Liddell:

Yes. In the early ‘70s. We were part of Mathematics for quite a long time, as a sort of sub-department, and then they decided to set up as a separate department.

Abbate:

Was that hard to set up? Did you have to argue that computer science deserved to be separate?

Liddell:

I think it was just the growth of interest in the subject. We had a large number of students who were interested in that area, and it became an obvious thing to do, you know, now that other Universities were beginning to have departments of Computer Science. For some time there had been in London an establishment called the Institute of Computer Science, where Jean [Dollimore] was based; also George [Coulouris], her partner, although George was partly attached to University College, I think. They came over here about that time, and George became a Professor of Computer Science fairly early on, and he was fairly instrumental in getting the department going, too, and separating us off from Mathematics; because he’s very much involved on the software engineering side, and he didn’t have the mathematical links that I have.

The other person we had, who’s probably our most famous person, is Peter Landis, who is now Professor of Theoretical Computation—he’s very well known in the Computer Science area.

Abbate:

And so he was there early on?

Liddell:

Yes, he was appointed as a Reader, too. So there were five or six of us, and the department gradually grew in size.

Abbate:

What kind of computers did you have?

Liddell:

We had mostly ICL computers, which were made by an English firm. We’d use the Atlas, which was an ICL Atlas, but we also had smaller versions of their computers—1905E and 1905S—that we used. At a later stage, at University College, they had an IBM machine, and George had been used to that. Then he went over to the States at the beginning of the UNIX era, and came back and started to get us interested in using networks of workstations.

Abbate:

These weren’t time-sharing machines at that point?

Liddell:

Well, the workstations weren’t, but after that we did use time-sharing machines. Jean can probably give you more details on that—I was a user, and they were much more involved in the system side. I’ve always been interested in the computer applications.

Abbate:

So, what sort of projects were you working on in the ‘70s?

Liddell:

I was mostly concerned with complex numerical problems that needed a computer to solve them—numerical analysis. So I was doing research on nonlinear optimization problems, and became involved with a numerical software company, the Numerical Algorithms Group, which is now a worldwide company; it has quite a big subsidiary company in the States, for instance. Its main base is in Oxford, and I’m still linked with them; we still do work with them. But they developed libraries of mathematical software for computer users to use, and I was very much involved in the development of those libraries.

Abbate:

Do you get royalties from them? Or just glory?

Liddell:

No, because it’s always been set up in such a way that it was run by the universities and the University Consortium, for the universities, so people didn’t pay—it was a sort of mutual benefit thing.

Abbate:

So people at universities could use it for free.

Liddell:

Yes. I did get royalties for my thin-film programs earlier, because I did some work for industry in that area. In fact, in the early days, I was very lucky, because at the time I started here, I’d been doing some work for a firm called Rank Optics, who were developing filters commercially, and they employed me as a consultant. I remember when Professor Ferraro employed me as a Lecturer, the Lecturer salary for a full-time post was about £1500 a year, but Rank Optics were paying me £500—and wanted to increase it to £750—as a consultancy fee, for just a few days’ consulting. He was very worried about this, and said, “Well, can’t you ask them to keep it at five?” These days, the College would say, “Oh good! We can get a big cut of that, since you work for us.”

Working on the Distributed Array Processor

Abbate:

You said in the article that, I guess it was around 1979, you were working in the DAP Support Unit. I don’t know what that means.

Liddell:

At the end of the ‘70s people started to get very interested in using many computers together, and the firm ICL, with whom we’d been connected, had this concept of what was called a Distributed Array Processor (DAP), where they used 6096 very, very simple processors, all working together.

Abbate:

Kind of like a Connection Machine or something?

Liddell:

Yes, it is. It was a precursor to the Connection Machine. And in fact, one of the people who worked on the DAP, Dennis Parkinson, worked for Thinking Machines for a while, also. So the DAP was used before the Connection Machine, but is a very similar sort of concept. The processors used in the DAP were simpler than those used in the Connection Machine. This involved a lot of new techniques, because one was using lots of these simple program processes all together, so there was a need for a different type of programming. One had to “think parallel,” as we used to try to persuade people—which is very natural in certain areas: things like image processing, for instance, where you’ve got lots and lots of images that all have to be analysed together; or solving large sets of differential equations, where you can perform much of the solution in parallel. Thus a lot of work was done developing techniques to use these parallel machines.

Abbate:

What was your role in this? Were you developing algorithms?

Liddell:

Mostly, yes, on the numerical side. I was particularly interested in linear algebra and in the nonlinear applications that I’d been studying previously.

Abbate:

Did you have a team of people you were managing?

Liddell:

Dennis Parkinson was brought in from industry as the overall Director, and I was the Project Manager, yes. There was a group of about seven of us, and then we increased the number as we got some more funding from the social science side and other sources. We gradually increased the team to about twelve or fifteen.

Abbate:

How did that project work out? Was the machine successful?

Liddell:

It wasn’t that successful commercially. I think it was a bit too far ahead of its time in some ways, and a bit like the Connection Machine: They were wonderful machines, but were big and very expensive. And of course, when workstations came along, people moved to a different way of exploiting parallelism, by using lots of workstations together. So that’s the way it progressed eventually. In fact, just towards the end of the DAP project, we got involved in a particular graphics workstation, called the PERQ.

Working on the PERQ

Abbate:

That’s “P-E-R-Q”?

Liddell:

Yes. They were taken over by ICL, but I can’t remember who the people were that originated the PERQs, now. But they were like the graphic workstations we have today, such as the Sun, and workstations.

Abbate:

And did that also involve parallel processing, or was that a separate thing?

Liddell:

It was involved with parallel processing. One of the things that ICL did was to develop what they called a “MiniDAP” attached to a PERQ. The PERQ was the host machine that performed the programming translation side and then sent instructions to the array of processors. By that stage it wasn’t 4096 processors, as we had on the ICL machines; it was 1024. Some of the UNIX workstations today do have components that are somewhat like that.

Abbate:

So these were pretty forward-thinking projects. It sounds like maybe there were technical spin-offs, or experience that got applied later on.

Liddell:

Yes, we’re applying them in lots of different areas. We’ve moved into some social science type problems; also database problems. There has always been emphasis on science and engineering problems, because that’s really what parallel machines were developed for initially. For instance, some very interesting fundamental physics was done on the DAP. One of our colleagues at Edinburgh, Professor Stuart Pawley, became a Fellow of the Royal Society partly because of the work he’d done using the DAPs. When we started using the PERQ, we had very good graphics, and one could look at the results. Now, when you’ve got thousands of results being produced, and you’re looking through paper results, it’s very difficult to judge exactly what’s happening; but as soon as we got the graphical display, he started seeing the hyper-fine structure in his fundamental physics problems.

Abbate:

So your user base was all over the country?

Liddell:

Yes.

Abbate:

It wasn’t just people here.

Liddell:

No, it was all over the country. I’d also started getting involved, in the ‘80s, in European projects. And if you look in my C.V., there’s quite a lot of European consortia we were very involved in—often involving image reading, and also some medical imaging, because that is very similar. Sometimes we were involved in computational chemistry and physics projects. So there were a number of different things. Computer Vision was a major area we got involved in. The person who owns this office is a Professor in computer vision. I worked with him for many years. His predecessor was Hilary Buxton, who is a Professor down at Sussex University: she was also involved in the DAPs in the early days, as one of our main users.

Abbate:

So the university started an actual Parallel Computing Centre. Did you initiate that? How did it get set up?

Liddell:

Well, yes. It was actually supported by the Research Councils, who support much of the research within the country. They decided to base it here, partly because we’d had previous experience with the Atlas Computer. The college made a case, and we’d been involved in the parallel processing early days, and that’s why they decided to put it here. We had strong links with ICL, who were the firm that was making the first of these computers, which was also one of the reasons they put it here. They put a second one into Edinburgh at a later stage, and then there was other work also going on with different sorts of parallel processing, some vector machines and so on, in places like Manchester and Cambridge. And it began to grow, until it’s almost a mainstream activity now.

Abbate:

Was this one of the first, though?

Liddell:

Yes, it was.

Abbate:

And were you the first Director of that?

Liddell:

I was the first Project Manager, yes. Dennis Parkinson was the Director. He’s still attached to the department here.

Abbate:

So what other sorts of projects did you work on? Were they all involved with parallel processing after that?

Liddell:

Pretty well, yes. At a later stage, after the DAP project, we were funded to continue by the Department of Trade and Industry, who established the Centre for Parallel Computing here at Queen Mary, and we were joined by a group from the Polytechnic of Central London—it’s now called University of Westminster—headed by Professor Yakup Paker, who was very much more interested on the computer systems side. And he’s still here, also.

Abbate:

You were doing more of the applications side, so it was complementary?

Liddell:

Yes. He’s more interested in the systems side.

Abbate:

In terms of funding, it sounds like you had industry support early on, and then government research support.

Liddell:

We had both, from the outset. I think there are probably some details in here of the funding; some was for equipment. It’s partly written for academic people, so it may not be altogether clear for somebody who doesn’t know the funding regime. A lot of it was funded by the Science Research Council (which became the Engineering and Physical Sciences Research Council), with a lot of industry funding as well. Also the Department of Trade and Industry, because they were interested in the industry side. We still get funding from those sources.

The current research I’m doing is on portfolio optimization.

Abbate:

Did you have to spend a lot of time applying for funding?

Liddell:

Quite a bit, yes.

Abbate:

Grant writing?

Liddell:

Yes, yes, it’s an ongoing thing one does.

Abbate:

And you’ve been teaching the whole time, as well?

Liddell:

I haven’t during the last two years, because I took semi-retirement in 1998. So I just do research now, which is rather nice, because I was Head of Department for three years, and that was a very arduous job—with teaching, research, and running a big department of about fifty staff, not all academics. I suppose there are about twenty-three academic staff and quite a lot of technical staff—you know, programmers; so there’s programming support, and hardware technical, and office staff. So there are many different groups, with all the problems that are associated with that.

Abbate:

It’s like running a company!

Liddell:

It is rather, yes. The trouble is, at university you’re not trained to do this. You’re just thrown into it and expected to know what to do!

Abbate:

Right: You’re chosen because you’re independent-minded, and then you’re [made responsible for managing people].

How did the teaching program develop? Was there some vision for what computer science should be?

Liddell:

Yes. We have people within the department here who are very interested in theory of programming and programming fundamentals, so that was one side of it. I was always more interested with the application side, but I got involved in some of the programming teaching. There’s quite an interest on the hardware side, and we taught the parallel computing course right from the beginning of the project, the DAP project. So we were trying to influence the students, if you like—i.e., pass on our experience to them; and quite a number of them got interested in projects, and sometimes they went on to do research, and went into that area themselves.

Abbate:

And this is graduate and undergraduate, as well?

Liddell:

Yes, yes. In fact, as I say somewhere here [looks at CV], there are various research students I’ve been involved with. There were a couple that I took over from other people. One of my colleagues died suddenly; I took over his student. Another, Hilary Buxton (whom I mentioned earlier), moved to another university, so I took over her student here, Aleka Psarrou, who’s actually married to Sean. So I’ve got Sean, who’s Chinese—his father was a Chancellor of Beijing University—and Aleka, who’s from Greece. They’re both in Britain, working here.

Abbate:

You mentioned you’d worked on some European projects? When did that start?

Liddell:

Let’s see: we started European projects with the beginning of the ESPRIT projects in the ‘80s. It was about ‘89 when we became involved in a number of our European projects. And I’m still involved, to a certain extent; I used to do some evaluation work for the European Commission. They have a series of postdoctoral fellowships called Marie Curie Fellowships, and I’ve been involved as an evaluator on some of those.

One of the big things we started in the ‘90s was the London Parallel Applications Centre, which was a consortium—there were four of them set up in the country; the London one was the biggest one. And in our case it was not just Queen Mary: it also involved Imperial College, City University, and University College—all big institutions—and we had quite a lot of government funding for that, plus funding from industry, up to about £13 million or so. The aim was to try and get parallel applications taken up by industry. That was quite an interesting area, and that involved us in contacts with Europe, also.

Abbate:

Who set the agenda for the European projects?

Liddell:

There are various committees that are set up by the European Commission, to look at the kind of work they think needs to be done. Now, their main interest is actually to help industry—as well as universities, but mostly industry—and it involves the Department of Trade and Industry quite a bit. A lot of academic people do get involved also, so you get again this picture of academics and industry working together quite strongly on these projects.

Abbate:

Is there some particular project that would be especially memorable for you, from those joint projects?

Liddell:

Oh, there are lots that are memorable, in different ways! I think some of the Computer Vision ones were particularly interesting. There was the one in which we first employed Sean. We worked with a big firm here called GEC, and with various German and Portuguese partners—we also had French and Belgian partners—where we were looking at the motion of vehicles and using computer vision to monitor this. We studied both aircraft and road vehicles: GEC was interested in the aircraft side, and some of the people in Germany at Wiesbaden and so on were interested in the road vehicle side. That was an interesting project.

Many of the medical imaging projects were very interesting, because we were working with a lot of medical people, and some of the people we worked with then are people who have become quite famous through the BSE [Mad Cow Disease] crisis, and so on! It was very interesting to have these people who had deep medical knowledge, but without very good computer knowledge. There was this particular man from Bart’s Hospital called Alec Colchester, who was very good on being able to combine the computer science and the medical side. He was very much a medical person. There was another person who worked also at Guy’s Hospital, David Hawkes, who was much more involved on the computer side, but he’d worked within the medical field. And then we got to know the European groups as well, and that was quite interesting.

Abbate:

So a lot of these things were directly applied.

Liddell:

Yes. In a way, the parallel computing has got lost within it now, because it’s just advanced techniques that were developed, and it so happened that the computers were useful for it. So as you see, I’ve always been applications-driven rather than systems-driven. When you talk to Jean [Dollimore], she’s much more systems-driven.

Abbate:

The other side.

Liddell:

Yes.

Reflection on Work with Computers, Professional Societies

Abbate:

What have you found to be the most satisfying aspects of working with computers?

Liddell:

I suppose the ability to combine teaching and research. It’s quite interesting, particularly with teaching research students and being involved in the real research side of things. And the interaction with people from industry and from other universities; I think that does broaden your horizons a lot.

Abbate:

Have you also been active in professional societies?

Liddell:

Yes. I was, for some years, Vice President of the Institute of Mathematics [and its Applications], with specific responsibility for the link with engineering mathematics. I think I became a member of the IMA Council in about 1992. I was on for about ten years, and then from about 1996 onwards, until the end of 2000 I was a Vice President. That was why they’ve put that profile of me in "Mathematics Today".

Abbate:

What sort of agendas did you have, or concerns that you were trying to work on through these societies?

Liddell:

Well, there are various types of mathematical society in this country. Some are “purer” than others, but we’ve got fairly strong links with them; there’s a very important society called the London Mathematical Society, whom we work with. But the Institute of Maths and its Applications is focused on the applications of mathematics, so that’s where we’re very much involved with industry, rather than with just academic mathematics. And, indeed, in publishing results in the press, also.

Abbate:

Have you been trying to bring those two sides together—the more academic and the industrial side?

Liddell:

Yes. The IMA is the U.K. equivalent of SIAM—I’m also a member of SIAM.

Abbate:

Which is . . . ?

Liddell:

The Society for Industrial and Applied Mathematics, in the States. So, the IMA is the U.K. equivalent of that.

Abbate:

Do you have close ties with the American societies?

Liddell:

Yes, to a certain extent. I mean, I’m not a terribly active member [of SIAM]; some of my colleagues are more active. I had more ties, I think, in the days when we were doing a lot more in the parallel computing projects. We used to go over there for conferences quite a bit.

Abbate:

I noticed, I guess from this article, that you were a Liveryman of the Worshipful Company of Engineers. What is that?

Liddell:

That is an old City of London tradition. That particular company isn’t an old institution, but the livery companies in the city are big—and very old—institutions, and they elect the Lord Mayor of London—not the mayor of the whole of London, but of the square mile that constitutes the City of London. And there’s a number of different companies. There is a Company of Information Technologists, but partly because of my background, I’m not a member of that; I’m a member of the Company of Engineers—which has been going a bit longer; it started in the early ‘50s. They are concerned with a wide range of issues; they’re quite interested in the public debate, the public side of engineering. For instance, at a dinner I was at recently, we had somebody who came to talk who was one of the experts on rail safety, and that was very interesting. In fact, he was on the radio a few days ago, too. That kind of looking at engineering, not just from the sort of academic sense, but also from the public sense, is quite interesting. My husband’s also very much involved with engineering applications. He was a geologist, but he’s involved in materials geology, and in engineering– and civil engineering–type applications. So I get to know a bit about that side, too.

Abbate:

Did he also work with computers?

Liddell:

Not a lot. We both fight for our laptop computer! We use them more as word processors, I think. But, yes, I first got to know him when we were running courses on programming. You know, he came along to one of them.

Reflection as a Woman in Computing

Abbate:

Have you ever felt, as a woman, that you’ve had any—that you always had equal access to jobs, promotions, and other kinds of perks?

Liddell:

Yes, I think so. The only constraint, as I say, was being married, with a son (who’s actually now 28). It constrains you a bit for moving to other universities—because you’re looking for two jobs, rather than one. But that isn’t particularly—I mean, it’s the same for Alan as for me. We would need to consider it together.

Abbate:

That’s sort of a different issue, I guess. But you never felt that you had experienced discrimination?

Liddell:

No, no. I think if anything, it’s been the opposite: it’s been helpful! You tended to be noticed, initially. Not so much now, but at one stage you tended to be noticed more as a woman.

Abbate:

And do you think the department is generally a welcoming place for women?

Liddell:

Oh yes, I mean we’ve always had quite a lot of women members from the outset. Occasionally you get a few abrasive types, but then you get that anywhere; both men and women.

Abbate:

So you haven’t had any problem recruiting women students here?

Liddell:

We certainly like to do so. I wouldn’t say we’ve had a problem. We certainly don’t discriminate against women, we’re quite keen. We’ve got quite a number of Muslim women, because of where we’re placed within London—there’s quite a big Muslim population—so we have quite a lot of Muslim women, and they do experience some difficulties sometimes, with respect to home ties.

Abbate:

But that’s not because they’re doing computer work?

Liddell:

No, no. I mean it’s just because they’re studying and trying to be independent, I think. I think they’re in a worse position than those of us that are Europeans. And we’ve also got, recently, and are very pleased to have, a number of European women who have joined the department as academic staff, which is nice.

Abbate:

Did you have important role models or mentors when you were starting your career?

Liddell:

Not particularly. I suppose there’s a number of people who influenced me: my research supervisors who got me interested in the physics side, and some of the Professors and things within the department, whom I’ve mentioned: Professor Ferraro, Professor Khabasa. But people have always been very supportive, so there’s nobody I’d really want to single out.

Abbate:

So you’ve had a whole community of support.

Liddell:

Yes, yes—which has been quite good!

Abbate:

That’s great.

Liddell:

I haven’t had to fight too much on that side. And it’s been the same with the professional societies. If anything, it’s been an advantage being a woman.

Abbate:

Are there women’s groups within the societies?

Liddell:

We don’t have one in the IMA, particularly, no. There was a lady—you said about mentors: There is a lady who was a Professor of Mathematics at Manchester for many years, whom I’ve always admired. She was also involved with the numerical algorithms group, and has done a lot of work in numerical analysis—not so much in computers, though, so much as on the pure mathematics side. She is Joan Walsh, who I think was Vice Chancellor of Manchester University at one stage. And she was probably quite influential at making sure that the computing within Manchester developed. You may hear her name mentioned if you’re going there.

Abbate:

I’ll ask.

How would you say the field has changed over the time that you’ve been involved in it? Either technically, socially, or broadly . . .

Liddell:

Well initially, of course, it was very much a new subject, with a very small number of people involved, and so one knew most of the people working on it within the country. And of course now Computer Science is very much a major discipline, rather than being a sort of specialist subject in one or two places. But that must have happened in the States, too.

Abbate:

One of my last questions: I always ask, Do you have any advice for young women considering a computer career today?

Liddell:

No—except to go for it!

[TAPE 1, SIDE 2]

Abbate:

So, we were in the middle of advice. You had said “Go for it . . .”

Liddell:

Yes. I think it’s also a career which can be flexible, because you can work from home a lot—as I’m doing now quite a bit, partly because we live further away from London. Once we sold our flat it made it more awkward to travel to London. And also, of course, if women have children, it’s easier to work from home sometimes. So it doesn’t preclude your having children.

Abbate:

Did you work at home before you retired?

Liddell:

Not a lot, no.

Abbate:

But you could have?

Liddell:

When my son was born, I had the statutory maternity leave, and that was it! We had a very good baby minder, so that was helpful. Now, I think Sylvia [Wilbur] will probably talk to you about that; she probably had time off for her children. And Jean, possibly; I can’t remember. You know, we’ve all had children, so being career people hasn’t excluded it.

Abbate:

But you felt it was flexible, and maybe if you wanted to do that, you could have?

Liddell:

I suppose in all our cases—and that might be important—we had support from partners and husbands and others, which is useful. It would be quite difficult if you have a not-very-understanding partner, I suspect—as happens with some of our Muslim women. They really have to fight to continue. But mostly, you know, it’s quite a good area to be in!

Abbate:

All right! Thank you very much!

[END OF RECORDING]