Gene Amdahl - The IBM & Amdahl Years

The IBM & Amdahl Years

At IBM, Amdahl worked on the IBM 704, the IBM 709, and then the Stretch project, the basis for the IBM 7030. He left IBM in December 1955 but returned in September 1960 (after working at Ramo Wooldridge and at Aeronutronic). On his return he worked on the System/360 family architecture and became an IBM Fellow in 1965, and head of the ACS Laboratory in Menlo Park, California. He left IBM again in September 1970, after his ideas for computer development were rejected, and set up Amdahl Corporation in Sunnyvale, Calif. with aid from Fujitsu.

Competing with IBM in the mainframe market, the company manufactured "plug-compatible" mainframes, shipping its first machine in 1975 – the Amdahl 470V/6, a less expensive, more reliable and faster replacement for the System 370/168. By purchasing an Amdahl 470 and plug-compatible peripheral devices from third-party manufacturers, customers could now run S/360 and S/370 applications without buying actual IBM hardware. Amdahl's software team developed VM/PE, software designed to optimize the performance of IBM's MVS operating system when running under IBM's VM operating system. By 1979 Amdahl Corporation had sold over a US $1 billion of V6 and V7 mainframes and had over 6,000 employees worldwide. The corporation went on to distribute an IBM-plug-compatible front-end processor (the 4705) as well as high-performance disk drives, both jointly developed with Fujitsu engineers.

At the Spring Joint Computer Conference, Amdahl along with three other computer architects, most notably Dan Slotnick, ILLIAC IV architect, engaged in a discussion on future architectural trends. Amdahl argued, verbally and in three written pages, for performance limitations in any special feature or mode introduced to new machines. This resulted in two, major and lesser, "laws" of computer performance regarding sequential vs. parallel processing. These arguments continue to this day.