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

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.