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ETHistory 1855-2005 | Living memory | Departements | D-INFK | Research | D-INFK | ERMETH - Electronic Calculating Machine of the ETH | 
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ERMETH - Electronic Calculating Machine of the ETH

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Shortly after the foundation of the Institute for Applied Mathematics in 1948, the planning to build an own computer started. At the beginning of the 1950s, though, programmable machines with storage that could be used for solving scientific calculations were not commercially available yet. Therefore, the idea of building an own machine from scratch was taken up. The concept of the ERMETH owed a lot to knowledge that Eduard Stiefel, Ambros Speiser and Heinz Rutishauser gathered on study trips around Europe and the USA. During the year of 1949, Speiser and Ruthishauser had been in Harvard meeting Howard Aiken, and lateron in Princeton with John von Neumann.
Speiser, the technical leader of the project, was responsible for the construction of the ETH computer together with five engineers and three mechanics. The electronic circuits were strongly based on Aiken's Mark III computer, but revised and enhanced by Hans Schlaeppi. The electronic as well as most of the mechanic parts were manufactured by Hasler in Bern.
The main problem at ETH was the construction of the main storage system, a magnetic drum which rotated at a speed of 6000 rpm. The ERMETH was a digital computer with 2000 electronic tubes and 6000 germanium diodes. At that time, diodes have just been newly developed, but it soon became clear that they worked reliably enough. Although the transistor had been invented in 1948 already, hardly anyone in Zurich had ever been able to work with one or even seen one.

After Speiser left and went to IBM in 1955, his successor Alfred Schai supervised the assembling and start-up operations of the ERMETH. In the same year, the ETH celebrated its centenary, and a demonstration of the ERMETH was intended to prove the progressiveness of the institution. Literally, the computation of Pi was shown: The slow displaying of one digit after the other was not based on calculations but on previous manual inputs. The machine was not finished yet, but at least the input and output worked.

The programming of the ERMETH was done using the so-called "automatic creation of calculation schemes", a development by Rutishauser. For the Mark III there already existed a "coding machine", and the Z4 offered extensive capabilities with its "Plankalkül". Rutishauser then reached the conclusion "that it ought to be possible to use the programmable calculating machine itself with its versatility to create calculation schemes. This would mean that one could not only solve numerical problems with these calculating machines, but also «calculate» the calculation schemes." The term "programming language" did not exist then, and the commands of the program were still in German and not in English. Shortly afterwards, H. R. Schwarz developed the ALGOL compiler for the ERMETH.

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© 2005 ETH Zurich | April 14, 2005 | !!! This document is stored in the ETH Web archive and is no longer maintained !!!