Kathleen Mauchly: We knew that there was a big project going on at the Moore School. The whole back section of the first floor was devoted to this construction project that was going on there. Not only that, but when Fran and I first came to Moore School, with the exception of the girls—I think there were about four of them who had been sent up from Aberdeen—and Dean Pender’s secretary, there were no women in the Moore School at all. But gradually, as the project of the ENIAC construction went on, the Moore School hired more and more women. So it was very obvious that there were very very many more women, and they were working at the wiring jobs that were going on. And I don’t know where they had recruited the girls from, but they weren’t all college graduates or anything like that. But it did fill up Moore School, pretty much, and they would tell us that they were working on this project. We never did get into see it in the actual construction phases, that I know of.
Fran Bilas and I worked on opposite shifts all during the war. And toward the spring of 1945, it became pretty obvious that the war was ending and I can’t remember exactly whether it was Lieutenant Goldstine or John Holberton who came to me one day while I was working on my shift and asked if I would be at all interested in working on a new computer that was being constructed upstairs.
So with nothing else looming big in my future at that time, I said I thought that’d be interesting to learn how to do that. So evidently they had approached about six girls who were working in the unit at the time and asked them if they’d be interested in learning this. So there were six of us chosen from those who decided they would like to, and we were sent around the first week in June, I suppose, to Aberdeen for a three‐month study of how to operate all the different computing machines that were down there. That is, the IBM‐type card‐handling machines, because we weren’t at all familiar with that type of operation.
So we went down there and we learned how to wire up tabulator boards and how to wire up their automatic relay multipliers which they had down there. And the six of us spent the summer in Aberdeen leaning how to operate all the IBM machines. The reason for this was that the input and the output of the ENIAC was going to be by way of IBM machines. So if we were going to operate the machine, the people in charge figured that we would have to know how to work IBM cards.
Well, when we came back that Fall, this is now in the Fall of 1945, the ENIAC was already pretty much constructed. As a matter of fact, all the panels were up. Some of the parts were not quite finished. I think the divider/square rooter was not in operation, but otherwise everything else was.
Then we were told we had to learn how to operate this machine. Well, how do you go about that? And somebody from Moore School, I just don’t remember just who the person was, gave us a whole stack of blueprints, and these were the wiring diagrams for all the panels. And they said, “Here, you can figure out how the machine works and then figure out how to program it.” Well, this was a little bit hard to do, knowing nothing about anything. So Dr. [Arthur] Burks at that time was one of the people assigned to explain to us how various parts of the computer worked, how an accumulator worked. Well, once you knew how an accumulator worked, you could pretty well be able to trace the other circuits for yourself and figure this thing out.
So we then proceeded to program a trajectory to go onto this machine. And we had barely begun to think that we had enough knowledge of the machine to program a trajectory when we were told that two people were coming from Los Alamos to put a problem on the machine and Fran and I were asked to help these two people from Los Alamos to put their problem on the machine.
Well, as I understood… I didn’t understand it too well at that time, but now I know from things I’ve learned later, that was Nick Metropolis and Stan Frankel, both from Los Alamos laboratory, had already been to the Moore School in July at the invitation of Captain Goldstine and they had worked with Captain and Mrs. Goldstine and had gotten the general idea of how the ENIAC was going to work. And they had programmed their problem, which was supposed to be a Top Secret problem, and then they had left, gone back to Los Alamos. When they appeared again about October, I think it was, they had the problem pretty much programmed onto sheets of paper and we were to help them set up the machine for this. And that was our first real time on the computer itself. We went downstairs into that room and that was when all the fun began, because no one knew how many bad joints there were and how many bad tubes there were and so on, til we actually started testing the machine.
Well, John [Mauchly] and Pres [Eckert] at that time were like mother hens. Oh, they were mother hens, of course they were. They stayed with that computer night and day. Whatever went wrong, they were in there—there were a couple engineers assigned to do the work, but they just were completely involved in every aspect of that operation of the computer. Not in the problem itself. I’m not even sure that they were told what the problem was, because it was supposedly a Top Secret problem. But they certainly knew and wanted to know what each little single part of that computer was going to do.
So Fran and I worked…sometimes I would come in the morning at a quarter of eight and work until five or six or seven. And Fran would come in for the evening shift, and she would sometimes work up til three AM. And then on alternate weeks, the reverse would happen. So we got to know everybody attached to the Moore School, to the ENIAC project very very well.
Nick and Stan’s problem went on in November and December, I think. Then during January, we heard that there was going to be a public demonstration of the ENIAC, and Captain and Mrs. Goldstine were in charge of this public demonstration. So they picked Betty Bartik (and maybe Betty Holberton, but I’m not quite sure about that.) to work with them in working up some demonstration problems. And that demonstration took place in February and was highly successful. It was very good.
Well, shortly after that, I think Nick Metropolis came back to work again on his problem, and this time with him came Tony Turkevich from the University of Chicago. They worked for a few weeks, and they had no sooner left when Dr. Hartree came from England and I was assigned to work with Dr. Hartree.
So Dr. Hartree had also been here once before and had had the operation of the machine explained to him, and he had also evidently had some blueprints or some description of the machine before he arrived to put his problem on. So I went over, worked with him, and ironed the bugs out of the setup that he had worked out, and together we set up the machine and started to work Dr. Hartree’s problem. And that went on most of the month of July of 1946, we’re talking about now.
So, I had a lot of fun working on that machine. Just absolutely wonderful time. So that Fall when the machine was moved to Aberdeen, I went to Aberdeen with the machine. I wasn’t down there very long when I found out that the mother hen was anxious to see how that machine was getting along. So John would come down to see how they were getting along on that machine.
Well, when I first married John, and that was, he said, a great emergency. His mother was sick, his wife had previously died two years before that, and his mother was not well. His children didn’t have anybody much looking after them. And the housekeeper that he had hired to look after the children was about to have a baby and she was going to leave, and oh, he had so many compelling reasons why we should get married. So, anyway, we did.
John Mauchly: You had none, of course.
Kathleen: Well…I don’t know. I felt that there were so many women then that were looking for a husband just to have somebody look after them. And I felt that here was a man I really loved, I may as well marry him. That was a good reason.
It’s on the tape, but I just wanted it on a side, was that my parents did not like the idea of my marrying John, at all.
John: I was too old for her.
Kathleen: There were many complications [crosstalk]
John: Besides, I didn’t have the right religion.
Kathleen: …and the religion, yeah, was a difference and so on.
John: Oh, everything was wrong.
Kathleen: Everything was wrong, so they were not about to either give me a wedding or even come to the wedding. So my sister was my bridesmaid and Pres Eckert was our best man at our wedding.