Konrad Zuse. Biography. Contributions. Zuse-Companies. Z3r. Tour-Zuse-Computer. Z23 Crosses Altlantic. Early Computers. Neumann vs Konrad Zuse. Impressum and Contact. Professor Dr.-Ing. habil.
Horst Zuse

Zuse-Companies and Computers from 1936 to 1949

In the Methfesselstraße 7 and 10 and from 1944 in the Oranienstraße 6, Konrad Zuse built the following computers:

* Z1 - thin metal sheets (Privately financed)

* Z2 - relays and thin metal sheets (Privately financed)

* Z3 - relays (Support by the government),

* S1 - relays (Support by the government),

* S2 - relays (Support by the government),

* Z4 - relays, memory consisting of thin plates (Support by the government).

In 1945 the Zuse Apparatebau were destroyed by allied airraids and only the Machine Z4 survived the attacks by the allied airraids.

Konrad Zuse fled from Berlin in March 1945 and arrived in Hinterstein (Allgäu, Bavaria) in April 1945. There, Konrad Zuse met Wernher von Braun in the Haus Ingeborg. It was the first and last time in his life that he met Wernher von Braun. He left the group of Wernher von Braun and went to Hinterstein and hided parts of the Z4 in a shed of the Alpenhotel Steinadler. The French and American troops looked for the Z4, but they did not find it.

In this barn (right) of the Hotel Steinadler in Hinterstein (Allgäu, Bavaria) the Z4 was hidden. At this time the Z4 was the only one computer in Europe.

From 1945 till 1947 it was almost impossible to restore the not finished and slightly damaged Z4. At this time, the Z4 was the only one computer in Europe. Konrad Zuse used tins from the allies to repair parts of the mechanical memory of the Z4. The first problem was to survive the years after the war. In order to get some food, Konrad Zuse made woodcuts and sold them to the farmers and the American troops. The next picture (DIN A4) shows a woodcut by Konrad Zuse, which shows Hinterstein (Allgäu, Bavaria). The Computer Z4 was hidden close to the church.

In 1945 he made woodcuts of the surroundings of Hinterstein in order to sell these cuts to the farmers to get some food. The following picture is a color woodcut of the Zipfelsfälle (Zipfel waterfall) in Hinterstein (DIN A3) by Konrad Zuse. He used three separate wood plates, one for the yellow, one for blue and one for red color. Each wood plate was pressed on the same paper.

In a paper from 1947 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.


The problems in this context are so extensive, that a generation of scientists, engineers and economists will be necessary, to process them sufficiently.

With problems Konrad Zuse 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 from his view the problems of algebraic computers are solved.

In 1948 the Z4 was build up in a former flour mill in Hopferau (Allgäu, Bavaria). Some calculations could be done, but it was very difficult to keep the machine working. Electrical power was only available for some hours a day and mostly it was not sufficient for the Z4.

In 1949 Prof. Stiefel from the ETH (Eidgenössische Technische Hochschule Zürich) visited Konrad Zuse in Hopferau and wanted to see the Z4. Till today it is not clear from whom he heard about this Machine Z4 in Hopferau.

Prof. Stiefel gave Konrad Zuse a differential equation as a problem to solve. Konrad Zuse formulated the program for the Z4, created a punch tape and the Z4 began to work. The result was correct. Later, a contract was made between the ETH and the Zuse KG, although Prof. Stiefel visited the machines ENIAC, MARK I and MARK II in the USA.

The major reasons to lease the Z4 for 5 years were:

* It was the only one available computer in Europe.

*It was a reliable relay computer although there was a bad feeling about the mechanical memory of the Z4. The reliability of relays was well known. However, a memory such as of the Z4 nobody had seen at any time before.

* The Planfertigungteil, which was a feature to write programs in a very easy way.

* Konrad Zuse promised to make some extensions with the Z4.

* The US computers were not available.

In order to fulfil the contract with the ETH, Konrad Zuse founded the Zuse KG.

Zuse KG

From top to bottom: Methfesselstraße 7 in Berlin-Kreuzberg, where Konrad Zuse constructed the Z3 and started in 1942 the construction of the Z4. After the escape from Berin on March 16, 1945 he arrived with his wife Hinterstein (Hotel Steinadler). There in the shed in the rear of hotel the Z4 was holed up and covered with hay. Konrad Zuse wanted to avoid that the allies (French and later US-Troops could find the Z4.