<Perhaps not in a PC, but other micros have used asynchronous buses (like
<the native bus of the 68000, and VME bus).
I think you got that backwards. VME and 68k were synchronous. The PC
bus is async (as is s100, Multibus, U and Q busses)!
The sync/async bus thing is a fundemental moto/intel difference!
On the similarity plane... ISA is basically multibus with a few breakages
like the interrupt edge/level thing.
Allison