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The Life and Work of Konrad Zuse (by Horst Zuse) |
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As Konrad Zuse's oldest son, I have tried to present his work as a mixture of new technical aspects of his machines along with other themes, such as the concepts of the stored program computer, pipelined computers, the Zuse KG company, his paintings, and so forth.
Konrad Zuse founded the Zuse KG in order to build computers for engineers and scientists. Unfortunately the role of this company from 1949 in post-war Germany is still neglected and not well known. In particular, Konrad Zuse's achievements during this time are not well understood or accepted to this today. It is remarkable to me that my father considered the problem of programming computers with his high level language Plankalkül so early in the evolution of computers. There is no question that the modern computer needed many brilliant scientists to create it. However, considering Konrad Zuse's computers in detail shows an amazing similarity with today's machines. In 1998, a journalist in Hoyerswerda in Germany asked me whether the acknowledgement of my fathers work is justified. I replied that I also am a computer scientist and that I therefore have to be very critical and unbiased with respect to my father's work, but that I have tremendous respect for his achievements. I will summarize these achievements based on the statements of Speiser [SPEI98] and Bauer [ROJA98a]. Both scientists say that Konrad Zuse must be credited with the following fundamental inventions in the area of computing development, where most of these inventions were implemented in the Z1 (1938), Z3 (1941), and Z4 (1945), with the exception of the Plankalkül: |
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The use of the binary number system for numbers and the circuits. |
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The use of floating point numbers, along with the algorithms for the translation between binary and decimal and vice versa. |
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An algorithm for the non-restoring calculation of the square-root. With this algorithm, the square-root can be calculated with n steps, if n is the number of digits. This technique was not known in the US in 1949. |
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The carry-look ahead circuit for the addition operation. |
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Look-Ahead: The program is read two instructions in advance, and it is tested to see whether memory instructions can be performed ahead of time. |
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Pseudo-memory: In case the look-ahead mechanism finds that a number that is to be restored is needed again within the next two instructions, the number is placed in a register of mechanical contacts where it is available with no access time. For this purpose, the memory has two registers of reading contacts. |
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Special values (Sonderwerte): If a result exceeds the capacity of the arithmetic unit, it is designed as Sonderwert. This principle guarantees that the machine always calculates correctly. |
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The most unusual feature was undoubtedly the mechanical binary cells that made up the memory. The memory has 64 words with 32 bits (Z1 and Z4). These devices were completely different from mechanisms in contemporary cash registers or desk-top calculators. The elements could be used not only for storage, but also for calculation, for example for address coding. A relay memory would have required about 2500 relays, which would have more than doubled the size and the weight of the Z4 computer. |
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The Plankalkül as the world's first complete high-level language in 1945/46 (final edition). |
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All of these ideas were Konrad Zuse's personal achievements. In one or two cases he was perhaps not the first inventor, but he certainly had no knowledge of work being performed elsewhere. Until 1950 he lived in complete isolation from the world outside Germany. I think that Giloi [GILO97] writes very correctly: Through Brian Randells book [RAND73], an English translation of Zuses first patent application of 1936 [ZUSE36] has become more widely known, proving that Zuse had already developed many of the major concepts of the digital computer years before John von Neumann, Arthur Burks, and Herman Goldstine wrote their famous report [BURK46].
In conclusion, I hope that this article will help scientists, students, and other interested persons, especially in US and Canada, to better understand Konrad Zuse's contributions to computing. |
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