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The Design of a Control Unit Reflections on Reading Babbage's Notebooks

IP.com Disclosure Number: IPCOM000129365D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Oct-05
Document File: 6 page(s) / 29K

Publishing Venue

Software Patent Institute

Related People

M V. WILKES: AUTHOR [+2]

Abstract

Babbage published very little on the detailed design of the control system for the Analytical Engine. In this paper the author puts forward a possible reason for this and discusses the relationship between Babbage's ideas as revealed in his unpublished work and modern concepts. Keywords: Babbage, control unit CR Category: 1.2

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

Copyright ©; 1981 by the American Federation of Information Processing Societies, Inc. Used with permission.

The Design of a Control Unit Reflections on Reading Babbage's Notebooks

M V. WILKES

(Image Omitted: © 1981 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 otherwise, or to republish, requires specific permission. Author's Address: Digits Equipment Corporation, 146 Main Street, Maynard, MA 01754. © 1981 AFIPS 0164-1239/31 /020116-120

The Design of a Control Unit Reflections on Reading Babbage's Notebooks

M V. WILKES .00/0)

Babbage published very little on the detailed design of the control system for the Analytical Engine. In this paper the author puts forward a possible reason for this and discusses the relationship between Babbage's ideas as revealed in his unpublished work and modern concepts. Keywords: Babbage, control unit CR Category: 1.2

I had long known of the existence of Babbage's notebooks, but it was not until I began to prepare an address for delivery on the 100th anniversary of his death (Wilkes 1971) that I made a detailed examination of them. When I did so, I was taken very much by surprise at the quantity and quality of the information they contained. It was like becoming aware, for the first time, of the bulk and size of the submerged part of an iceberg. Babbage's world, into which I found myself projected, was entirely mechanical, but it was not dissimilar with regard to some of the problems studied to the world of the late 1940s and 1950s.

Mechanical desk calculating machines existed in Babbage's time, although they were little used. The design of an arithmetic unit, or mill, for a fully automatic computer was, however, a virgin field, and Babbage had to do much pioneering research. He also had to decide how the control of the machine was to be organized, and it is with this aspect of the subject that I am primarily concerned in the present paper.

The sharp demarcation that exists in respect of subject matter between what was published about Babbage's work and what is to be found in his unpublished writings is striking, and I found it, at first, surprising. It is almost as though a security barrier had existed. Anyone unacquainted with Babbage's character might conclude that he kept certain matters to himself with a view, one day, to exploiting them for profit. It is true that he had something of the inventor in him and was apt to complain that his work, on which he had spent much time and money, had brought him little recognition or reward. But, very much more th...