🚀 go-pugleaf

mjones@donald.aix.kingston.ibm.com (Mike Jones) writes:
>In article <970048@gore.com>, jacob@gore.com (Jacob Gore) writes:
>> / gnu.misc.discuss / mjones@donald.aix.kingston.ibm.com (Mike Jones) /Aug 1'91/
>> What does the width of the CPU external data bus have to do with the width
>> of peripheral buses???
>> Maybe you can explain...  I heard this the first time when working at IBM
>> eight years ago, and I still don't get it.
>Well, if (for instance) your CPU data bus is 16 bits wide, then you have the
>choice of either a) going with 16-bit peripherals, or b) multiplexing the
>16-bit CPU bus onto an 8-bit I/O bus.

Or c), having 8 bit peripherals ignore the upper 8 bits of the data bus,
an approach that works just fine on existing 68000 systems.

As I understand it, the problem was that Motorola wasn't shipping 68000s
in sufficient quantity when the little company which designed the PC before
being absorbed by IBM was doing their work, hence they went with the Intel
family by necessity.