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Dead medium: the Zuse Ziffernrechner; the V1, Z1, Z2, Z3 and Z4 program-controlled electromechanical digital computers; the death of Konrad Zuse

(((Konrad Zuse, legendary computer pioneer, died December 18, 1995. The following obituaries and personal reminiscences cast several interesting sidelights on the birth of digital computation and the mishaps of Zuse's museum-piece computers.)))

From the Guardian newspaper in Britain:

FIRST ON THE DIGITAL TRACK by Jack Schofield

KONRAD ZUSE, who invented the digital computer while no one else was looking, has died in Berlin at the age of 85. He was born in Berlin-Wilmersdorf and built his first mechanical calculating machine in his parents' living room between 1936 and 1938.

In Britain and the US. similar but later developments were supported for their military significance, but Zuse's work was largely ignored. When he and his colleagues later proposed the construction of a 2,000-tube computer for special use in anti-aircraft defence, they were asked how long it would take. Zuse says they replied: "Around two years." The response to this was: "And just how long do you think it'll take us to win the war?"

Zuse started to develop his ideas about computing in 1934, a year before he graduated from the Technische Hochschule with a degree in civil engineering. He then went to work for the Henschel aircraft company as a design engineer or statiker. This involved solving tedious linear equations, which stimulated Zuse to apply his ideas and try to build a system to solve them automatically.

His first machine, the V1 (with hindsight renamed the Z1) was made of pins and steel plates, but it represented two dramatic advances. First. it was a general purpose machine, whereas most calculating machines were dedicated to specific tasks. Second, it used binary (on/off or stop/start) numbers instead of decimal ones, as Babbage's far earlier machines had done. This made Zuse's machine far easier to construct, although it was to remain somewhat unreliable.

Although both decisions seem obvious now, they were far from obvious at the time. Zuse's choice of a general purpose approach was based on his separation of the different elements: an arithmetic unit to do the calculations, a memory for storing numbers, a control system to supervise operations, plus input and output stages. This is still the basis of modern computers.

Babbage had taken the same line 100 years earlier with his analytical engine, but it proved too difficult to build. Zuse succeeded partly because he chose the binary numbering system instead of using decimals. Binary means counting in twos, which is far more long-winded than counting in tens. However, to count in twos you only need an on/off switch, which is very much easier to construct than the 10-position decimal equivalent. Each operation mav not do much work. but the speed of the simpler switching operation makes up for it.

Of course, mechanical switches are still somewhat primitive, and Zuse started to replace bulky mechanical ones in Z1 with second-hand electro-magnetic relays - the switches used in telephone systems. At the time, Zuse's college friend Helmut Schreyer "suddenly had the bright idea of using vacuum tubes. At first I thought it was one of his student pranks." Vacuum tubes, or valves, would work the same way but work at least a thousand times faster. Zuse was soon convinced it was the right approach, and this led to the design of the Z3, which was probably the first operational, general-purpose, programmable computer.

Zuse sold the idea to the Aerodynamics Research Institute, and set up a 15-man company to construct it. The machine was completed by December 1941, though it was later destroyed by Allied bombing. As Zuse recalled, the "construction of the Z3 was interrupted in 1939 when I was called up for military service. However, in my spare time, and with the help of friends, I was able to complete the machine."

Only one of Zuse's computers survived the war: the Z4. This was started in 1942, but it was becoming increasingly difficult to find parts, and in 1943,. the Berlin blitz began. The machine was moved around the city to avoid air raids, and then moved to Gottingen, before finally being shifted to Hinterstein, a small village in. Bavaria. After the end of the war, the Z4 was moved to Zurich in Switzerland, and in 1950, this Ziffernrechner, or number calculator, was installed at the Federal Polytechnical Institute.

Zuse's developments attracted the attention of IBM which seemed mainly interested in his patents - and Remington Rand, amongst others, but discussions came to nothing. In 1949, he founded his own computer company, Zuse KG, which developed a line of Z computers, and eventually employed about 1,000 people. However, short of capital, he gradually sold out to Siemens, the giant industrial conglomerate.and devoted himself to research.

In later life, Zuse received many honours, and in 1984 a research institute, the Konrad Zuse Centre for Information Technology (ZIB) was named after him. A copy of his first programme-controlled electro-mechanical digital computer, the Z3, was made in 1960 and put on display at the Deutsches Museum in Munich. A copy of the Z1 was constructed in 1989, and can be found in the Museum for Transport and Technology in Berlin.

Konrad Zuse, scientist and inventor, born June 2, 1910 died December 18, 1995.

(((janlee@VTOPUS.CS.VT.EDU) "J. A. N. Lee" offers a second Zuse obituary.)))

Subject: Konrad Zuse

The last of our great pioneers of the 1930's died Monday, December 18. Konrad Zuse, developer of the Z-1 through Z-4 machines was clearly one of those who foresaw the development of the computer and did something about it well before those whom we will acknowledge next year in Philadelphia. Zuse's image suffered from his location both in geography and time, since we now know that his work included in an elementary way many of the features of modern machines.

I had the pleasure of meeting with Dr. Zuse on several occasions, the last at the IFIP World Computer Congress in Hamburg in August 1994 where he drew standing room only audiences in a conference that was not that well attended elsewhere. I have only seen one obituary so far, and I am disappointed that it did not also mention his artistic capabilities also. His paintings were magnificent, and his recent portraits of German computer pioneers (prepared for the IFIP Congress) showed yet another side of this multi-talented pioneer. I was hoping that we could attract him to attend the ENIAC celebrations in February next, but sadly that opportunity is gone.

I for one will miss him. He was always the one with the joke and for greeting one with humor. I was in a meeting with him the day the Berlin Wall came down. I asked him what he felt about this, to which he replied "Now we can get on with our work!"

Subject: Konrad Zuse

I learned this morning of the death of Konrad Zuse, at age 85. As many of you know, Zuse conceived of the notion of a general purpose digital computer, using binary arithmetic, while a student in Berlin in the 1930s. With the help of his parents and a few friends he set out to build one in his parents' apartment.

At the outbreak of the Second World War he was released from service in the German army to work at the Henschel Aircraft Company, where he was a stress analyst. He continued working on his computing ideas, and in December 1941 he completed a machine that computed in binary, using floating point, with a 64-word memory, and which was programmed by paper tape. This machine is regarded as the first general purpose, functional digital computer in the world. It was destroyed during the war. Later on Zuse gave it the name "Z3," by which it is now known. In 1962 Zuse, now the head of a commercial computer company, built a reconstruction based on drawings that did survive. This computer, which I saw in operation at the Deutsches Museum a few years ago, is now itself one of the oldest operable computers in the world!

Zuse actively promoted his role as a computer pioneer, and he always stressed the historical claims of the Z3. I think that he felt less proud of the fact that he also founded a company, since it did not survive (it was eventually absorbed by Siemens). My guess is that as time goes on he may be more remembered for being one of the first "start-ups" as for his Z3.

Zuse was the last of the "first tier" of computer pioneers: Aiken, Stibitz, Eckert, Mauchly, Atanasoff, Turing. Incredible to think that so many of them were alive while all the madness of computering in the past couple of years has been going on. I knew him personally and will miss him very much.

There are some excellent resources about Conrad Zuse from his son Dr. Horst Zuse
Konrad Zuse and His Computers
Konrad Zuse CD-ROM