PC/370 implementation - test-drb@ccmp.vtda.org

12 Apr 2007

Jim Battle wrote:

...
 Are you sure about that?  Nick Tredennick, the
architect (or maybe co 
architect) of the 68000 left Motorola, went to work for IBM, and was the 
architect of the "micro 370".  The design and its evolution were 
described in a book Tredennick wrote, Microprocessor Logic Design: The 
Flowchart Method. 

The source for my information is the IBM Systems Journal, Vol 23, No 3 from 1984. 
...
 From page 245: "After studying several types
of microprocessors to identify one architecturally suitable as a base for System/370, IBM
selected the Motorola MC68000 microprocessor and began working with Motorola engineers to
develop a customized microprocessor. At IBM's site in Endicott, New York, a group in
the engineering organization wrote the internal microcode which allowed the device to
directly execute a large subset of the commercial System/370 instructions."

Later in the article, they just call it the "custom" processor.

It sounds like the same part could be an MC68000 or the S/370 depending on microcode load;
when they say 'the device,' I believe they are referring to the aforementioned
MC68000.

Thanks,

Mike