Commodore's Z80 in the 128 was due to unnecessary fear that they might lose
market share to CP/M, when IBM should have been their big worry.
I don't know all of the details of the ST/Amiga technology swap, but BOTH
were too late, if the primary goal was competing with IBM.
That might be Commodore marketing - Bil Herd said that he threw the Z-80
into the design essentially because he could. :) He's done a few talks on
how the C-128 came about. It's pretty interesting.
It also saved the 100% compatibility problem (in this case, with Commodore's
CP/M cartridge by designing it onto the board, and with Commodore Magic Voice,
which fouled banking by altering the memory configuration lines in realtime:
the 8502 would crash, but the Z80's activity would not be detected and the
C= key could be checked to force a C64 memory map).
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Cameron Kaiser * Floodgap Systems *
www.floodgap.com * ckaiser at
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