bavarikon4UDescription
Originally called V 4, work on the system was started around 1942 due to the good experience with the Z 3 and was completed in 1945. In contrast to the Z 3, which was destroyed in a bombing raid in December 1943, it was rescued from Berlin and presented to a group of scientists in Göttingen for the first time in March 1945. From there, it was moved by adventurous means to Allgäu. In 1946, it was provisionally set up in Hopferau in Allgäu. From 1950 to 1955, it was rented (at a rent of 30,000 francs for five years) to the Swiss Federal Institute of Technology (ETH) in Zurich. It was then sold to the Laboratoire de Recherches Techniques de Saint-Louis in Weil am Rhein. In 1959 it was bought back by ZUSE KG, Bad Hersfeld, and given to the Deutsches Museum in 1960.
Binary floating point numbers with 22 bits for the mantissa and 8 bits for the exponent (plus 1 bit each for the special character and exponent sign) are used, so the word length is 32 bits. There are two simultaneously working arithmetic units for the mantissa or the exponent. The addition takes place in parallel. In addition to the four basic arithmetic operations, squaring and root extraction are realised, as well as multiplications with certain constants. The main memory is mechanical, designed for 64 words, expandable up to 500. It was destroyed by transport damage around 1970. Data and programme entry is made using the control panel and/or the film strip scanner. This is a rigid programme with a maximum of 2 loops.
It was improved in 1950: Now it was possible to skip commands, there was also a second scanner. The working speed averaged 30 operations per minute. Addition took 0.5 seconds, multiplication 3.5 seconds.
Among other things, an increase in the number of programme scanners from 2 to a maximum of 6, output via a maximum of 2 tape punches, conditional programme jumps and an index register for address conversion were planned for later expansion, but no longer realised. (Source: Bauer 2004)