Oral-History:Konrad Zuse
About Konrad Zuse
Konrad Zuse, born 1910, is a German pioneer in computer development. In 1934, when he was a student at Zuse began constructing mechanical computers and then relay computers. During World War II, Zuse founded a company, the Zuse Engineer Bureau. After the war, he received contracts from Remington Rand in Switzerland to build relay computers, and soon expanded into making computers for European companies and universities. After Zuse Engineer Bureau’s purchase by Siemens, Zuse continued consulting for that firm into the present day.
The interview describes Zuse’s progress from mechanical to electro-mechanical and then electronic computer work from the 1930s to the 1990s. Zuse discusses the formation of his company, the Zuse Engineer Bureau, which built computers for the Remington Rand company, other European businesses, and universities. He addresses his firm’s rise in the 1950s and its economic problems after losing the Remington Rand business. Zuse also describes the growth and development of the computer industry in the 1960s, and how his company fit into that phenomenon. He explains the reconstruction of the Z3 computer for the Deutsches Museum and his company’s early attempt to create a keyboard-notcher for computer punch cards. The interview ends with Zuse’s discussion of his firm’s business contacts with Russia and Eastern Europe.
About the Interview
KONRAD ZUSE:An Interview Conducted by Frederik Nebeker, IEEE Center for the History of Electrical Engineering, 28 August 1994
Interview #224 for the Center for the History of Electrical Engineering, The Institute of Electrical and Electronics Engineers, Inc.
Copyright Statement
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It is recommended that this oral history be cited as follows:
Konrad Zuse, an oral history conducted in 1994 by Frederik Nebeker, IEEE History Center, Piscataway, NJ, USA.
Interview
Interview: Konrad Zuse
Interviewer: Frederik Nebeker
Date: 28 August 1994
Place: Hamburg, Germany
Remington Rand research laboratories
Nebeker:
You were just telling me about your work for Remington Rand.
Zuse:
Perhaps you know the Remington Rand series of laboratories for advanced research in Norwalk.
Nebeker:
Yes.
Zuse:
We were invited there because we had made a model, a mechanical construction ... working a pipeline.
Nebeker:
This is a picture of what?
Zuse:
You had there the reading position. You took a card, and punched it, and between that time, this hardware read the punched values. Multiplication was established by running step by step through several additional units.
Nebeker:
This was all mechanical.
Zuse:
Yes, they were mechanical. I could handle several cards at the same time. I did not need to wait until the first was ready, and the values were flowing through this machine.
Nebeker:
Now is this what you built and took over to Norwalk?
Zuse:
This was a machine we built in Germany and showed in Norwalk.
Contacts at IBM
Nebeker:
You set up the company shortly after the war in 1947?
Zuse:
Yes. I had already begun as a private man in 1934 as a Ph.D. student. By then I began constructing mechanical computers, then computers with relays. During the war I had a firm called Zuse Engineer Bureau, and this was until the end of the war.
Nebeker:
Right.
Zuse:
At the end of the war conditions stopped this, and I couldn't continue with this work. I had a contact. It was in a small village in the Alps, and there was a man who had the opportunity already in 1947 to go to the United States, and he looked for contacts with President Watson of IBM. At that time, the firm had the name Hollerith here in Germany, until 1948 when they changed into IBM. We talked with this gentleman in Stuttgart. All things had to be decided in the United States, at that time in the United States. They were only interested in my patent applications; I had some.
Nebeker:
Right.
Zuse:
I was not interested only in building better contact with IBM. Perhaps it would be helpful for me later on. These patents got a great interest, yes. But I got soon in contact with Remington Rand, and Remington Rand was interested in the development of computers. They also had some people interested in making electronic machines. During the war and until around 1950, they were developing contacts with UNIVAC, and they prepared these machines for the market. But they liked to have a second horse in the stalls.
Nebeker:
Right.
Zuse:
We ourselves knew the future would be in electronics, but we got this order for making a fully mechanical machine. We did this.
Nebeker:
Had you built something similar to this before?
Zuse:
Yes, I had. My first computer I had already built in 1938. The first computer was fully mechanical.
Nebeker:
So they knew you had this experience.
Zuse:
I told them about the future trend, but they were interested in this mechanical development because in 1945 nearly all punch card machines were mechanical.
Zuse Engineer Bureau, development of relay computers
Nebeker:
In 1947, after the war, you were Zuse Engineer Bureau?
Zuse:
Yes. It was the year before my partner joined.
Nebeker:
Your intention was to build electronic calculators?
Zuse:
Not 1947.
Nebeker:
What was your intention in 1947?
Zuse:
We made relay computers. And mechanical special developments were a regular event. And we made relay computers. We tried to get that into the stores.
Nebeker:
What did you think would be your market for the relay computers? Who did you think would buy a relay computer in 1947?
Zuse:
Really, it was difficult in the years after the war for us. We put on a show about the machine and had people interested. Then came the first order from Germany, or the firm Leitz. You know Leitz optical?
Nebeker:
Yes.
Zuse:
They had good development at that time, 1950. They could give us an order for relay computers.
Nebeker:
Was that one of your first orders for the new company?
Zuse:
That was about 1949, yes. And for that we really worked on special development. First, we developed this for Leitz, and after that we went straight into this German surveying . That was the first years of the 1950s. We got interest there, and we had to develop a special machine and relay tape. From this here, the mechanical development, this was not electronic. Then we got contact with the Swiss part of Remington Rand. They were interested in relay work. We built a special machine for them. This was a relay computer combined with a Powers Remington punched card machine. This could make more sets of operations within one card. We developed about 40 machines for Switzerland.
Nebeker:
How many people worked for your small company from 1947 on?
Zuse:
Well, we began in 1949 with four people. Then we enlarged, and by 1963 we had a thousand people.
Nebeker:
It was a sort of steady growth?
Zuse:
Yes. That summer we made the machine we had forty people.
Nebeker:
That mechanical machine you built for Remington Rand, was that something that you contracted out to have the parts built, or did you build the parts yourself?
Zuse:
We made it in Germany.
Nebeker:
Your laboratory made the individual parts of that? So you had the necessary machine tools?
Zuse:
Yes, we had the machines, the stamps, and so on. We could organize this. It was fully fabricated in our laboratories, in my factory, in a little village in Hessen.
Nebeker:
How many people were working for you when you built that?
Zuse:
For this purpose, perhaps twenty. I don't know if it's exactly right.
Collaboration with international research community
Nebeker:
You said in your book that in 1948 you, along with others, were invited to England.
Zuse:
The British invited German scientists to London. We were living in a nice house there, and English gentlemen came there to interrogate us.
Nebeker:
This was voluntary, though? You didn't have to go?
Zuse:
This had no consequence at all. It had nothing to do with my company. They invited me as a private scientist.
Nebeker:
They wanted to know about your wartime work?
Zuse:
Yes, and at that time there were no secrets. I had no reason not to discuss it if they were interested, because at that time most people thought that the computer was an American invention, and there was little known about our German developments. So I was very interested that the British were learning something about the development.
Nebeker:
Was there someone in London who took special interest in your work?
Zuse:
Oh, no. There were interesting conversations, but nothing happened.
Contracts with IBM and Remington Rand, calculator development
Nebeker:
You said that you had an opportunity to work for IBM.
Zuse:
Yes. I had a contract with IBM, a so-called option contract. That means that they paid me some money and they had the patent rights, and at that time I could not make a contract with any other company. And that lasted for about nine or ten months.
Nebeker:
But did IBM want to employ you full-time? Did they make an offer of a job to you?
Zuse:
No. Then we didn't agree; they only liked to have my patent applications.
Nebeker:
Right.
Zuse:
I could have, perhaps, taken a job there, but they didn't promise me that I could work in the field of computers. They couldn't promise me that. I had some corporation papers with me, and I had to bring(?) these machines from Berlin , for the machine. Of course, it was working. They said, "You can work on the machines. We are not interested in them." Then I got a contract with Remington, who said, "Yes, we are interested in working with your cooperation." That was the reason. IBM did not offer me cooperation in any way. It was only that they would like my patent applications. They would like to have me as a co-operator in quite another field.
Nebeker:
You went to Norwalk, Connecticut, with Remington Rand there.
Zuse:
Yes.
Nebeker:
You mentioned that you met with Howard Aiken at Harvard University.
Zuse:
I met with Aiken, yes. I made a trip from Norwalk to Boston.
Nebeker:
Did you meet other computer pioneers at the time?
Zuse:
We met Presper Eckert. You know of Eckert because of the ENIAC.
Nebeker:
Right.
Zuse:
In Boston they were showing us the Whirlwind, which was under construction.
Nebeker:
Right, Jay Forrester's project.
Zuse:
They showed us this, and surely we had some conversations with them. It all was very interesting but there were no business consequences for us.
Nebeker:
Do you know how Remington Rand learned of your work? How did they know that your company would be able to build this calculator?
Zuse:
How did they know that? When I was in the small village in the Alps, Hildersheim, I had many visitors. In time my work became known, and there came people who were interested. I don't know how the connection came, how Remington Rand had heard of my work. But they came to see me.
Zuse Gesellschaft (Zuse KG), the Z4 computer
Nebeker:
In 1949 you founded Zuse KG.
Zuse:
Zuse Gesellschaft.
Nebeker:
What was the reason for that business move?
Zuse:
We had the order from the Swiss university, the technical university in Zurich, the Eidgenössische Teknische Hochschule Zurich. They had an interest in the machine they saw.
Nebeker:
Right.
Zuse:
We got a contract for five years, renting it to them. But there were a lot of changes they wanted to make, so we brought this machine. Mr. Eckert, he had [worked] there, his home was in Hessen, yes. It was a little village. We brought the machine here and at first we got it ready for the school. Then we got the contract with Remington Rand. We entered the agreement with them at the same time. We made the specialty developments for Remington Rand. Then came Leitz, and then came Remington Switzerland, and so on. Step by step we built a basis for our factory, and could enlarge step by step.
Nebeker:
When the Z4 went to Zurich, to the ETH, you maintained the computer while it was there, is that right? You kept it running?
Zuse:
We installed it, yes, and there were good people who maintained it. I myself was often in Zurich because at first, not all was going normally. After some time the machine was running so well that they let it run all night, without any people in there, in the whole building.
Nebeker:
But there were one or two people, normally, from your company?
Zuse:
No, no. We had installed it with our people. One or two people besides myself—I was the main person who installed it. They had good people who conserved the machine, and good co-operators. One was Dr. Speiser, who is a famous man in the field of computing. Sometimes he was President of IFIP. Then there was Dr. Gutteshalzer, who died very early, and who made very interesting investigations in computer programming. He was a very good mathematician. These men worked this machine. Dr. Speiser did maintenance.
Nebeker:
I see.
Zuse:
After some time the machine was very reliable.
Nebeker:
What was Professor Stiefel's interest? What did he want to use the computer for originally?
Zuse:
- Audio File
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(224 - zuse - clip 1.mp3)
He had the Institute of Mathematics, an institute at the Eidgenössische Teknische Hochschule. He had visited the United States and had heard of these new computers. We were happy to have such a machine in his institute. When he made this trip to the United States, he saw a lot of machines in construction, but never was he able to get the needed results. He gave them an equation and asked someone, "Can you calculate it?"
"Perhaps you can come back next week," they would say.
Nebeker:
Right.
Zuse:
Then he had heard of my machine, and he came to visit me. He gave me this equation, and I could calculate it quite easily. That was the reason, because he liked that. He was therefore very interested in my machine and made an offer. I don't know, some amount of money was given. At that time, a million dollars for a machine was odd, but there was nobody in ETH who could deliver that machine. So he bought my machine, which was ready. But they wanted to change this and enlarge it and so on, and we came to an agreement on how to do this. At first we made the enlargements on the machine in Hessen. Then we delivered the machine to Zurich.
Nebeker:
Right.
Zuse:
It was working very, very well, and made a series of famous calculations. We had many visitors.
Nebeker:
Stiefel, Speiser, and Rutishauser left your company and built a computer at ETH? Is that right?
Zuse:
They were not in my company. They were at the Institute at the ETH.
Nebeker:
I see. But then they went on to build their own computer, the R-MET?
Zuse:
R-MET, yes. When our five years were over, they made their own electronic machine. Meanwhile, it was clear that Zuse’s future lay in electronic machines. Mr. Speiser especially was a very good engineer in tubes and so on, and he made his own developments then.
Industry and the development of electronic computing machines
Nebeker:
You say here that except for the punched card companies, the computing machine companies didn't show an interest. The actual computing machine industry, with the exception of the punched card companies, played virtually no role in the development of electronic computing machines. What companies are you thinking of there?
Zuse:
Oh, it was purely whether you had the great recording tabulating machine industry...
Nebeker:
Right. Business calculators.
Zuse:
Before the war, for thirty or fifty years they had been buying these machines on the market, tens of thousands of them. It was a real industry for calculation machines.
Nebeker:
For business calculating machines?
Zuse:
Yes, but not only for business. For years I was an engineer in the aircraft industry. We made our technical calculations for the aircraft, and we used these machines too.
Nebeker:
The manufacturers didn't show any interest in the electronic computers?
Zuse:
No, I didn't even try to interest them. I had a contact with a man who owned a small factory. He made analog special computers. He was interested in my developments, and he helped me with some rather small project, today we would say [incomprehensible]. He didn't continue his labor after the war. His special machines were used mostly for military purposes.
Remington Rand stops its business with Zuse KG
Nebeker:
I see. You say at the start of Chapter 8 that, "It was an unwelcome surprise when one day the United States put an end to our good relationship with the Swiss.” How did that happen?
Zuse:
Remington Rand in Switzerland was subordinate to Remington Rand in the United States. They made the developments with our machines. The first they made on their own risk. This was good. But one day their people, the gentlemen in Remington Rand United States, said, "Stop with this. We have our own machines." They said, "So end the relationship."
Nebeker:
I see.
Zuse:
The Swiss people regretted this, but they couldn't change it, because they had to obey headquarters.
Nebeker:
You say that at that point your partners left the company. Eckert went to Ziemag.
Zuse:
Well, it was the main basis of our production, the orders from Remington Rand. You can imagine. When it was stopped, it wasn't quite clear what we would do then. We had to develop electronic machines, as it was now clear that there would be a gap in the development. We had to decide. We already had cooperation with Ziemag, a German firm, and they asked me, "Can you give us this Mr. Eckert?" At that time truly I could not promise he could stay here, and he would get quite a good job there.
Nebeker:
I see. You say that Stucken went to Brazil?
Zuse:
Yes.
Nebeker:
What job did he get there?
Zuse:
He met one time on the highway a nice girl, and this nice girl was a German-born Brazilian. Her parents had good factories in Brazil. Nothing to do with computers; I think in textiles . Then he went over to these companies, which had contacts with each other. He tried to be a co-operator in this firm with his wife. He saw that they were working under perfectly foolish conditions. They were functioning in a way fifty years out of date. He told them, "You must do that and that," and this caused trouble. Before long he was divorced, and he tried to make his own factory in Brazil. That's very difficult. You must know the laws there, and all the behavior are quite different than in Europe or the United States.
Nebeker:
I see.
Zuse:
He didn't succeed, but before the war his family were great merchants in coffee and salt, all over the world, millions in business, and so it was in his blood. He was ever the traveler. After he left Brazil he went to Ecuador, then he was in Spain.
Nebeker:
That's interesting.
Zuse:
It's quite a story. He wouldn’t like it, or I would write his story in my book. It was a very interesting story.
Nebeker:
Well, it must have been very hard for your company when you lost the Remington Rand Switzerland business. How much did your company shrink at that point? You said these two partners left you.
Zuse:
Two left me, yes, and I was the only owner, with my wife.
Nebeker:
How many employees did you have at that point?
Zuse:
At that time, perhaps two hundred.
Nebeker:
That many?
Development funds for software programs
Zuse:
One hundred or two hundred. Then came the development of the machines for universities, the tube machine, the twenty-three, the transistor machine. Then we could enlarge the factory. We were leaving this little village, and going to Bad Herzold. We had grown bigger and bigger. Then in the beginning of the 1960s there came a new situation in computer development. Until then the people who ordered the machines gave preliminary money.
Nebeker:
Development money.
Zuse:
Yes. Also we could get good credit from banks. But at the beginning of the 1960s, came IBM with these big developments. Then came another thing: the software programs.
Nebeker:
Yes.
Zuse:
It was very difficult to tell our German customers not only that the hardware costs money, but also that the software costs money too. We didn't like to say that. Only when the United States headed in this direction, could we convince our people that it was necessary. Therefore we had a lack of money for development.
Partnerships with Brown Boveri Company and Siemens
Zuse:
It was necessary to have a partner, and at first I truly hoped that it would be possible to get money and that I myself could continue to control the company. But my first partner was BBC, the Brown Boveri Company, and they made many mistakes. They lost a lot of money. I at that time was already excluded from the [incomprehensible] here. Then there came Siemens, and I was still a partner with BBC. Then Siemens took over the partnership of Brown Boveri, and they continued my factory, but, step by step, the development of new machines was stopped. It was a great concern, and they didn’t want to have a small department where they make their own machines. In my factory, they only wanted to make parts for machines and so on.
Nebeker:
I see.
Zuse:
And communications. For some years it was going well. Finally I left the company, and had a contract with [incomprehensible]. Even today I have a good relationship with Siemens. I have a contract of cooperation.
Nebeker:
Consulting for them?
Zuse:
Yes.
Nebeker:
How long was this period of partnership with Brown Boveri?
Zuse:
They was just only one year.
Nebeker:
Just one year. Before Siemens came in. When your company was acquired by Siemens, it gradually lost its identity, its separateness within Siemens. You said that Siemens no longer developed new computers of that type.
Zuse:
They didn't. I had hoped that we might make new developments. But Siemens was not interested in it.
Nebeker:
When you look back on it now, many years later, what is it that Siemens got out of acquiring Zuse KG? What did they gain?
Zuse:
Perhaps at the end there was some influence on a political basis. Somebody might have said, it should not happen that this German development is sold to the United States. It’s not going to another country perhaps America.
Nebeker:
Yes.
Zuse:
There were other American firms who were interested, and perhaps Siemens did not like that.
Nebeker:
I see. But they did not make great use of your engineers?
Zuse:
No, only the development contractors.
Reconstruction of Z3 computer for the Deutsches Museum
Nebeker:
It’s mentioned in this letter that you quote in the book, that in about 1962 the reconstructed model Z3 was installed in the Deutsches Museum.
Zuse:
They reconstructed this.
Nebeker:
How did the reconstruction of the Z3 come about? Did you take part in it? Did you help them reconstruct it?
Zuse:
Yes, I was the main man who could do this. At that time we were still working with relay machines. I had a good staff of clever people who were able to make relay machines, so it was possible. Today it would be difficult to make a reconstruction of the Z3. I would show this because this machine was rare.
Nebeker:
Yes.
Zuse:
It didn't exist anywhere, and to my opinion it was very important to us. So we reconstructed it.
Nebeker:
You worked with the Deutsches Museum?
Zuse:
We made it within my company, and then we donated it.
Nebeker:
So it was entirely built by the company and then sent to Munich?
Zuse:
The Deutsches Museum had nothing to do with it when I was constructing it.
Nebeker:
I see.
Zuse:
When we had delivered it to the Deutsches Museum it was working very well, and there were other gentlemen who could take care of the machine. For ten years it worked. If you go now to the Deutsches Museum, it is there. It should not be very difficult to put it in working order again.
Nebeker:
If they wanted to get the Z3 working, it would not be very difficult?
Zuse:
Yes, it is all there, and it works, though not fully. The arithmetical unit is working, as far as I know. It should be possible to get the whole machine working. I can't do it. We need clever and apt men to do that. It is difficult today.
Nebeker:
When you reconstructed the Z3 in 1962, did you have complete plans from the war years?
Zuse:
Yes. On this machine I based my patent application of 1941. I had not all the drawings, but the principal drawings were in this patent application. So I could reconstruct it.
Nebeker:
How exact a copy was the reconstruction to the original Z3?
Zuse:
The principle of all operations, the logic was all the same, practically the same.
Nebeker:
Were some of the parts different?
Zuse:
Yes, we made some differences that were not so important in the controlling unit, but all of the logic was consistent and all the capacity of the digits and so on were perfectly the same. How to make extractions of square roots, and the division, were also all the same methods.
Relay machine hardware
Nebeker:
You talked about this keyboard-notcher, this device to make these little notches in the side of a card—these cards that were sorted by putting the pins through them. You said that your company tried to develop a device, a keyboard-notcher, but it wasn't successful. Did any company build a successful machine to mechanize making those notches in the side of cards?
Zuse:
I don't know. My relay machines all had the keyboard, pushbuttons, lamps, and so on. It was for relay machines the best method. You could construct the parts that were familiar in the field of communications, telephones and so on. You could easily buy these parts.
Nebeker:
I wanted to ask about this Graphomat. You say that this multi-step gear drive.
Zuse:
Yes, there was a gear with twenty-five different velocities. I could change from one to the next within one twentieth of a second, so twenty times a second. I could make a special , and at first the people of Letzerwing were interested only in making the pin. Letzerwing was making cards very well, but they had a small circle, and within the circle you had a pin. This pin is a document. It is a legal document.
Nebeker:
I see.
Zuse:
They wanted to have a machine making this very exactly. Then they saw that this machine could be of interest for them, and some other people saw it could make full drawings.
Nebeker:
I see.
Zuse:
But at that time there were no good step motors. Only for some very slow and exact machine tools had they developed such things, and we couldn't get them. Before the war I had the idea to make such gears, which is a binary system. We were the first on the market with this machine. Then they thought, "Oh, that's good." By that time the step motors were made much better, and today you have step motors running exactly, very quick.
Zuse KG foreign business
Nebeker:
Your company, Zuse KG, had this major business with Switzerland, and you mentioned in your book other business within Germany, and you mentioned in one place that you had success in Czechoslovakia.
Zuse:
Yes.
Nebeker:
I'm wondering what foreign business you had besides Switzerland.
Zuse:
We had contracts in Germany and Switzerland, and in some years nearly all the optical firms in Europe were needing our machines.
Nebeker:
I see.
Zuse:
Then we got contracts with Czechoslovakia, because we could exhibit our machines at industrial show and could sell them. So we got good contact with Czechoslovakia.
Nebeker:
Was that also for an optical company?
Zuse:
I don't remember whether the Czechoslovakia has a famous optical firm. I can't remember. Reicher? Reicher-Wien in Austria had a famous factory for constructing microscopes and so forth. And then surely it was at that time we got contact with East Germany.
Nebeker:
You did some business with East Germany?
Zuse:
Yes, we delivered machines there. We had also delivered machines to Russia, because at that time they had a department for foreign trade. We got the order to make this machine. We never heard what they did with the machines. Perhaps the machines were installed for military purposes. We don't know that.
Nebeker:
You never knew what they were used for.
Zuse:
In Germany we sold several hundred machines, but only two of them were in the military field.
Nebeker:
I see.
Zuse:
We know that. We had direct contact with the military.
Nebeker:
Thank you very much.
