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The Relay Calculator Z4

IP.com Disclosure Number: IPCOM000129348D
Original Publication Date: 1980-Jul-01
Included in the Prior Art Database: 2005-Oct-05
Document File: 6 page(s) / 28K

Publishing Venue

Software Patent Institute

Related People

A. P. SPEISER: AUTHOR [+2]

Abstract

The relay calculator Z4 was designed by Konrad Zuse in Berlin during the last years of World War IL It occupies a unique place in the family of earl digital computers. Some of the outstanding characteristics often Z4 were use of the binary system with floating point, mechanical 2048-bit memory, and provision for intermediate data storage on punched tape. Keywords end phones: relay calculator, mechanical memory, Konrad Zuse CR categories: 1.2, 6.0

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This is the abbreviated version, containing approximately 18% of the total text.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

Copyright ©; 1980 by the American Federation of Information Processing Societies, Inc. Used with permission.

The Relay Calculator Z4

A. P. SPEISER

(Image Omitted: © 1980 by the American Federation of Information Processing Societies, Inc. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the AFIPS copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the American Federation of Information Processing Societies, Inc. To copy t otherwise, or to republish, requires specific permission. Author's address: Brown, Boveri & Co., Ltd., CH-5401, Baden, Switzerland. © 1980 AFIPS 0164-1 239/80/030242-245S01.00/0)

The relay calculator Z4 was designed by Konrad Zuse in Berlin during the last years of World War IL It occupies a unique place in the family of earl digital computers. Some of the outstanding characteristics often Z4 were use of the binary system with floating point, mechanical 2048-bit memory, and provision for intermediate data storage on punched tape. Keywords end phones: relay calculator, mechanical memory, Konrad Zuse CR categories: 1.2,
6.0

In the history of instruments for digital processing, the relay computer Z4 stands out as a truly remarkable item. It has several unique characteristics, and in the family of early digital computers it occupies a place quite by itself. Unlike practically all other machines, it was developed essentially by one man who was the originator of the entire design.

It is deeply regrettable that no documentation has been published that would permit a full appreciation of this remarkable instrument. Hoffmann (1962), Speiser (1950), and Zuse (1970) have written about the Z4, but these descriptions are incomplete, and some of the most interesting characteristics of the Z4 are not to be found anywhere in the literature.

The author was associated with the Institute for Applied Mathematics at the Swiss Federal Institute of Technology (Eidgenossische Technische Hochschule -- ETH) in Zurich from 1949 to 1955. This paper is an attempt to give a description of the machine and to make a few remarks on its origin and its history.

Description of the Z4

The specifications of the Z4 are as follows: Relay calculator with 2200 telephone relays

Mechanical memory with 64 words

Binary number system, floating point, and well-developed algorithms for binary-to-decimal conversion and vice versa

Words of 32 bits (mantissa: 24 bits, including sign; exponent: 7 bits, including sign; special values: 1 bit); the exponent thus included values from -- 63 to +63

Programming in a machine language similar to what today is called "reverse Polish logic"

IEEE Computer Society, Jul 01, 1980 Page 1 IEEE Annals of the History of Computing Volume 2 Number 3, Pages 242-245

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The Relay Calculator...