tjt (05/07/83)
I would be very surprised if the rest of the Apple II/Saybrook system could actually keep up with a 12.5MHz 68000. All but a very few instructions (MUL, DIV, shifts, and branches) are limited by memory speed. Tom Teixeira Massachusetts Computer Corporation (MASSCOMP) ...!decvax!genrad!masscom!tjt
tjt (05/07/83)
Anticipating flames in response to my previous followup ... The coprocessor board has its own memory which apparently is not accessible over the Apple II bus (the article said the 68000 could access the Apple II memory -- not vice versa). This should make it substantially easier to build sufficiently fast memory for a 12.5MHz processor. In particular, you can attach the memory more or less directly to the 68000 without bothering with bus drivers, arbiters, and the like. You can even punt a memory controller and refresh the RAM from software (a la SUN). In summary, I COULD be wrong about the 12.5MHz processor not being substantially faster than their 8MHz processor, but I would still be surprised. Tom Teixeira Massachusetts Computer Corporation (MASSCOMP) ...!decvax!genrad!masscom!tjt