radar I didn’t know anything about
what was going on with mathematical
machines but I soon began to learn.
Did you have any help with your
education in computing machinery?
I learned a great deal from [Douglas]
Hartreec who was in touch with American people and one day I had a telegram out of the blue from the Moore
School at Philadelphia asking me to go
to a course. I got there with great difficulty as crossing the Atlantic in those
days was no simple matter. I missed
the early part of the course.
Did that cause you any
No, I had got a singular set of qualifications because I had done some computing as a student. I was one of the people
that worked a hand-operated calculating
machine. I was a thoroughly qualified
electronics person having done ham radio and all that sort of thing. I had the
mathematical background insofar as it
was necessary for computing.
[John Presper] Eckertd and [John]
Mauchlye were the instructors and
they put me absolutely and fully in the
picture. I heard them talking about
say the Von Neumannf computer, it’s
really the Eckert-Von Neumann computer and I thought I might have a shot
at building one.
Was that the first time that you
had encountered the notion of
c Douglas Rayner Hartree (1897–1958)
d John Presper Eckert Jr. (1919–1995)
e John William Mauchly (1907–1980)
f John von Neumann (1903–1957)
although there were
no digital computers
in the immediate
there was a lot of
the stored-program computer?
No, John Von Neumann wrote a report
on behalf of the group and [Leslie]
Comrieg was given a copy in America
and he showed it to me. He lent it to
me and I sat up all night reading it, so
it wasn’t the first time.
how did comrie come to
have a copy of the report?
They gave copies away to people who
visited. Comrie’s copy is now in the library of the Computer Laboratory.
What did you do next?
The first thing to do was to make sure
an ultrasonic memory would work and
we did that by January 1947 and then we
This was quite a departure from
the pre-war work of the laboratory.
Did you need any special
permission to start this work?
Cambridge is a very strange place,
there are little departments like mine,
and big ones like the Cavendish. But
from the administrative point of view
they are on a level. That meant I didn’t
have to ask anybody or make any proposals. I was able to just go ahead and
do it. There were some funds that went
with the lab in effect and I guessed that
more funds would become available in
Did you have a large staff
at your disposal?
No, no; very small. Most projects—in
industry and university—depend on a
small handful of three or four people
and we had less than that to provide
the drive. There were a lot of people
who were paid on the funds, mathematicians and other hangers-on and
there were also a number of assistants.
We had instrument makers and electronic people on the assistant level.
But I was the one who brought all the
information about computers into it
so there was no argument with me you
see; it all came from me. I had a very
loyal team and so we went ahead.
how long was it before you
achieved some success?
The EDSAC began to work in the summer of 1949 on May 6th. That was the
g Leslie John Comrie (1893–1950)
day we did the first program and we’d
all got little programs ready to run.
how was computer development
viewed at cambridge?
Oh I don’t know, I always like to make a
joke and say that they thought we were
mad and if, at a cocktail party, you enlarged on your enthusiasm you would
find people moving away from you!
You see, I never tried to do any proselytizing, I simply built a computer.
Did you have a clear sense
from the start of who your
users were likely to be?
They were all around me, they were
students who didn’t like spending
weeks, or a week, or more computing.
They rushed at a computer, even an
unsatisfactory experimental one, as
EDSAC was to begin with. And it was
through those students that the idea
spread. They went to their supervisors
and said “Look what I’ve done.” The
supervisors were duly impressed and
before very long important people in
Cambridge were saying that computers were important. It was very low-key, bottom-up, students-upward.
That’s not a bad way for ideas to
Did you have any concerns
about how the computer-building
work of the laboratory would
be funded going forward?
Well, I assumed it would all happen. We
were a very low-cost outfit because we
didn’t have a lot of the mathematicians
and people on the payroll for the sake
of the money and I was in 100% charge,
which made it very easy.
am i correct in thinking that
the initial capital budget or the
laboratory in 1936 was around
That was a very large
sum at the time.
It was. Lennard-Jones was a man of
enormous vision and although analog
computers were in the air the laboratory was not biased toward analog computers. We could drop them as soon as
it appeared that they didn’t work out
and I could go ahead and build a stored-program computer.