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The Amdahl 470V/8 and the IBM 3033: A Comparison of Processor Designs

IP.com Disclosure Number: IPCOM000131489D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Nov-11
Document File: 11 page(s) / 40K

Publishing Venue

Software Patent Institute

Related People

Robert W. Doran: AUTHOR [+3]

Abstract

These implementations of the System 370 functional architecture both achieve high performance, yet their technologies, principles, and design philosophies are quite different. In 1975 Amdahl Corporation delivered the first of its 470V/6 computers and thereby initiated the era of the ";plug-compatible"; mainframe. Plug compatibles are intriguing to those interested in computer architecture because they allow us to make a sound comparison of the effectiveness of different designs. Before they were developed, one functional architecture was often implemented by the same manufacturer at different levels of performance, and different functional architectures were in competition at the same level of performance; but now, with plug compatibles, we have competing machines of the same functional architecture in the same performance range. This article compares the design architectures and use of technology in the largest computers currently available from Amdahl and IBM: the 470V/8 and the 3033. (Newer machines, the Amdahl 5860 and the IBM 3081, are just now becoming available.) While details of the 470V/8 included here are based on Amdahl documentation of a very detailed nature and have been checked by Amdahl engineering personnel, information concerning the 3033 is based entirely on its own theory of operations manual and other published literature. The 3033 details therefore have not been checked or approved by IBM.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

This record contains textual material that is copyright ©; 1982 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Contact the IEEE Computer Society http://www.computer.org/ (714-821-8380) for copies of the complete work that was the source of this textual material and for all use beyond that as a record from the SPI Database.

The Amdahl 470V/8 and the IBM 3033: A Comparison of Processor Designs

Robert W. Doran

Amdahl

These implementations of the System 370 functional architecture both achieve high performance, yet their technologies, principles, and design philosophies are quite different.

In 1975 Amdahl Corporation delivered the first of its 470V/6 computers and thereby initiated the era of the "plug-compatible" mainframe. Plug compatibles are intriguing to those interested in computer architecture because they allow us to make a sound comparison of the effectiveness of different designs. Before they were developed, one functional architecture was often implemented by the same manufacturer at different levels of performance, and different functional architectures were in competition at the same level of performance; but now, with plug compatibles, we have competing machines of the same functional architecture in the same performance range.

This article compares the design architectures and use of technology in the largest computers currently available from Amdahl and IBM: the 470V/8 and the 3033. (Newer machines, the Amdahl 5860 and the IBM 3081, are just now becoming available.) While details of the 470V/8 included here are based on Amdahl documentation of a very detailed nature and have been checked by Amdahl engineering personnel, information concerning the 3033 is based entirely on its own theory of operations manual and other published literature. The 3033 details therefore have not been checked or approved by IBM.

Each machine represents the latest in their respective lines of related machines (see Figure 1). Amdahl was founded in 1970 with the express goal of building a computer to compete with the IBM 370/165, which was first delivered in 1971. Before the Amdahl machine could be completed, however, IBM announced the replacement of the 165 by the "virtual-storage" 168. The Amdahl computer was then modified to make it compatible with the 168 and was first shipped in 1975. Both machines were upgraded to higher performance versions (the 168 III and the 470V/6 11) with 32K caches.

At this stage there was no question about the source of the Amdahl machine's performance advantage: The Amdahl technology was state-of-the-art, faster, and higher in density. That this analysis was too simplistic was shown by IBM's introduction of the 3033, which, though its technology did not seem to be a great advance over the 168, exceeded the V/6 in performance. However, Amdahl responded with the faster V/7 and later made further improvements (inclu...