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Comments, Queries, and Debate: More on Wilkes, Whirlwind, and Microprogramming

IP.com Disclosure Number: IPCOM000129641D
Original Publication Date: 1990-Dec-31
Included in the Prior Art Database: 2005-Oct-06
Document File: 1 page(s) / 13K

Publishing Venue

Software Patent Institute

Related People

IEEE Computer Society: OWNER

Abstract

Comments, Queries, and Debate: More on Wilkes, Whirlwind, and Microprogramming At Professor Wilkes' suggestion, we are including the following excerpt from his memoirs, ";Memoirs of a Computer Pioneer"; published by MIT Press (1984), to show the relation between the Whirlwind design and his microprogramming concept, as he recalls it. It was during the trip [in 1950], and the few months that immediately followed it, that my ideas on the subject of microprogramming crystallized. We had tried to make the design of the control sections of the EDSAC as systematic as possible, but they contained a great deal of what is now called random logic. I felt that there must be a way of replacing this by something more systematic, perhaps along the lines of the configurations of diodes used for decoding the function digits and subsequently re-encoding them to drive various gates throughout the computer. My voyage across the Atlantic ... gave me the opportunity to do some quiet thinking on this subject and later, when I saw the Whirlwind computer, I found that it did indeed have a centralized control based on the use of a matrix of diodes. It was, however, only capable of producing a fixed sequence of eight pulses -- a different sequence for each instruction, but nevertheless fixed as far as a particular instruction was concerned. It was not, I think, until I got back to Cambridge that I realized that the solution was to turn the control unit into a computer in miniature by adding a second matrix to determine the flow of control at the microlevel and by providing for conditional micro-instructions. Sometime during the winter the ideas fell into shape and I gave an impromptu lecture to my colleagues. I subsequently wrote them up and included them in a lecture that I gave in July 1951 to a conference held at Manchester University to mark the completion of the Ferranti Mark I computer.

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Copyright ©; 1990 by the American Federation of Information Processing Societies, Inc. Used with permission.

Comments, Queries, and Debate: More on Wilkes, Whirlwind, and Microprogramming

At Professor Wilkes' suggestion, we are including the following excerpt from his memoirs, "Memoirs of a Computer Pioneer" published by MIT Press (1984), to show the relation between the Whirlwind design and his microprogramming concept, as he recalls it. It was during the trip [in 1950], and the few months that immediately followed it, that my ideas on the subject of microprogramming crystallized. We had tried to make the design of the control sections of the EDSAC as systematic as possible, but they contained a great deal of what is now called random logic. I felt that there must be a way of replacing this by something more systematic, perhaps along the lines of the configurations of diodes used for decoding the function digits and subsequently re-encoding them to drive various gates throughout the computer. My voyage across the Atlantic ... gave me the opportunity to do some quiet thinking on this subject and later, when I saw the Whirlwind computer, I found that it did indeed have a centralized control based on the use of a matrix of diodes. It was, however, only capable of producing a fixed sequence of eight pulses -- a different sequence for each instruction, but nevertheless fixed as far as a particular instru...