|
The Life and Work of Konrad Zuse (by Horst Zuse) |
| Part 6 (continued): The Z4 after the War |
|
During the period from 1945 to1947 it was almost impossible to fully restore the damaged Z4. However Konrad Zuse used tin cans he obtained from the allies to repair parts of the Z4s mechanical memory.
Unfortunately there was nowhere in Hinterstein that was suitable for Konrad Zuse to set up the Z4. Thus, in 1947, Konrad Zuse, his wife Gisela, and their son (myself Horst) moved to Hopferau (Bavaria), which is about 30 km north of Hinterstein. By 1948, the Z4 was reassembled in a former flour store in Hopferau. Some calculations could be performed, but the electrical power was only available for a few hours each day, and it was generally not sufficient to accomodate the Z4s power consumption. In 1948 Eduard Stiefel from the ETH-Zürich wanted to set up a new Institute for Applied Mathematics. Stiefels declared goal was to advance numerical analysis. Accordingly he was looking for a way to gain access to computing power beyond the level that could be performed by simple desktop calculators. |
In [ZUSE47] Konrad Zuse wrote the following statement related to computers in the future: Die in diesem Zusammenhang auftretenden Probleme sind so umfangreich, daß eine Generation von Wissenschaftlern, Technikern und Wirtschaftlern erforderlich sein wird, um sie erschöpfend zu bearbeiten.
Translation: The problems in this context are so extensive, that a generation of scientists, engineers and economists will be necessary, to process them sufficiently. By "problems" my father meant the introduction of computers in science and companies. His plan was to build logistic computers. These computers were extended algebraic computers, like the Z4, in order to solve problems of the engineers. These problems should be formulated in the Plankalkül, which today is accepted as the first programming language of the world. Already in 1943 he wrote, that the problems of algebraic computers are solved. |
|
|
Stiefel quickly realized that commercial punched card machines were not suited for mathematical work, and that the electronic computer projects under way, mainly in the US, but also in Britain, would not fill the gap for several years to come. He thus decided that ETH should build his own electronic computer. For this purpose, he delegated two of his assistants, Heinz Rutishauser and Ambros Speiser, to visit US. Their assignment was to study the state-of-the-art in US computing and then to start a suitable project at the ETH.
Rutishauser and Speiser spent most of 1949 at Havard with Howard Aiken and at Princeton with John von Neumann, but they also visited a number of other computer installations, including the ENIAC at Aberdeen and the MARK II at Dahlgren. In 1949, Stiefel was informed about the existence of the Z4 and he was told that the machine may possibly be for sale. To this day it is not clear from whom he had heard about the Z4 in Hopferau. |
||
|
|
|
|
| Fig.59 (Left). Konrad Zuses workshop in Hopferau (Allgäu) in 1947, where he installed the Z4. The Z4 stood at the right-hand side of the workshop. Fig.60 (Middle). The Z4s input and output devices and the Planfertigungsteil (program construction unit) in Hopferau. Fig.61 (Right). Prof. Eduard Stiefel from the ETH-Zürich, who purchased the Z4 for 50,000 DM and transported it from Hopferau to Zürich in 1949. | ||
|
Prof. Stiefel inspected the Z4 computer in Hopferau in 1949. Konrad Zuse explained the specifications of the Z4, which were very convincing. Stiefel then gave Konrad Zuse a differential equation to solve. My father formulated the program for the Z4, created a punch tape, and the Z4 began to work. The result was correct. Thus, despite the fact that the Z4 was only barely in operational condition, Stiefel decided that the idea of transferring it to the ETH Zürich should by all means be studied.
Stiefel wrote a letter to Rutishauser and Speiser who were in Havard at this time. Although Aiken dissuaded Speiser and Rutishauser from a relay machine (he proposed to build and use electronic machines) Rutishauser and Speiser wrote to Stiefel that the idea of taking the Z4 should not be flatly rejected. Stiefel also persuaded the ETH President, Hans Pallmann, to make the necessary funds available for renting the Z4. Stiefel must therefore receive credit for a wise decision [SPEI98], because there were enough reservations that have could made him shy away from this step. Among these reservations were: |
|
|
|
Relays were a technology of the past, electronics could do the job 100 or even 1000 times faster, as Aiken stated. |
 |
The condition of the Z4 and its demonstration to Stiefel were not fully convincing. It was uncertain whether the small group around Zuse would be able to bring the machine up to a reliable operating level. |
 |
The mechanical memory was most unusual and nobody had ever seen anything similar. An informed prediction of the Z4s operating performance seemed to be impossible. A failure of the memory would have rendered the entire machine useless. |
 |
Installation and operation of the Z4 would absorb all the efforts of Stiefels small group. |
Ambros Speiser, who was a scientist working with the Z4 in Zürich in 1950, said in an interview to Horst Zuse in 1998 [ZUSE98]:
For this reason the speed of the computer was not the most important thing. Amongst other aspects, the simplicity of programming was very important to Stiefel. The Z4s attached Planfertigungsteil (program construction unit) convinced him to take the Z4, because it allowed scientists how to enter programs in less than three hours. Also the powerful arithmetic unit with its exception handling capability was an ideal prerequisite for the calculations Stiefel wanted to make. In 1948, representatives from IBM visited Konrad Zuse in Hopferau. However, they were more interested in my fathers patents than in his future ideas. IBM did not want to guarantee Konrad Zuse that he could work on computing in the future. For this reason only a short option contract was concluded between Konrad Zuse and IBM. |
|
|
|
|
| Return to EPE Online Home Page | |
