IBM 801

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The 801 was a RISC microprocessor from IBM . It was developed in the 1970s and used in various versions until the 1980s .

Development of the 801 began as a pure research project, led by John Cocke at the Thomas J. Watson Research Center in Building 801. Ways to improve the performance of the existing systems were looked for by examining traces of programs on System / 370 mainframes and the compiler code. In this project, the idea arose that it would be possible to make a very small and very fast CPU core that could be used to execute code for any machine. The instruction set was reduced to the most important and fastest instructions.

The project produced the design in a prototype CPU that was functional in 1980. Motorola's MECL-10K technology was used on large circuit boards. The CPU was clocked at 66 ns cycles (about 15.15 MHz) and was able to handle an incredible 15 MIPS at that time  . The prototype was a 24-bit implementation with no virtual memory. The 801 architecture was used in various IBM devices, including channel controllers for the 370 systems, as well as likely for the IBM 9370 mainframe core and the IBM RT .

In the early 1980s, the lessons learned from the 801 were incorporated into the America Project . This later led to the IBM POWER architecture and the RS / 6000 workstations to mainframes.

John Cocke later won the Turing Award and the Presidential Medal of Science for his work on the 801.

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