IBM 8100

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See also: IBM 8000 series, canceled in 1961

The IBM 8100 was at one time IBM’s principal distributed processing engine, providing local processing capability under two incompatible operating systems – DPPX and DPCX.

In 1978 IBM announced the 8100 Information System and the Distributed Programming Processing Executive (DPPX). These products were intended to provide turnkey distributed processing capabilities in a centrally controlled and managed network.

It never saw much success, and became moribund when host-based networks went out of fashion. This, coupled with IBM's recognition that they had too many hardware and software systems with similar processing power and function, led to announcement in March 1986 that the 8100 line would not be expanded and a new System/370 compatible processor line, ES/9370, would be provided to replace it. In March 1987, IBM announced that it intended to provide in 1989 a version of DPPX/SP that would run on the new ES/9370. A formal announcement followed in March 1988 of DPPX/370, a version of DPPX that executed on the ES/9370 family of processors. DPPX/370 was made available to customers in December 1988.

[edit] Architecture

The 8100 was a 32-bit processor, but its instruction set reveals its lineage as the culmination of a line of so-called Universal Controller processors internally designated UC0 (8-bit), UC.5 (16-bit) and UC1 (32-bit). Each processor carried along the instruction set and architecture of the smaller processors, allowing programs written for a smaller processor to run on a larger one without change.

The 8100 had another interesting distinction in being one of the first commercially available systems to have a network with characteristics of what we now call local area networks. It was called the "8100 Loop" and it supported various attached terminals, printers and other devices.

The 8100 also supported a terminal called the 8775 which was the first to ship with the ability to download its functionality from the host computer to which it was attached.

[edit] Further reading

Porting DPPX from the IBM 8100 to the IBM ES/ 9370: Feasibility and overview[1]; by R. Abraham, B. F. Goodrich; IBM Systems Journal, Volume 29, Number 1, Page 90 (1990)