25 Oct
1999
25 Oct
'99
6:03 a.m.
Chris Kennedy <chris(a)mainecoon.com> wrote:
I'm the last guy to defend IBM's architecture
for the PC, but IMHO there's
slightly more there than just laying out something from Intel data sheets.
Get out the schematics of the original 5150 PC and study them. You'll
realize that what IBM did was copy the 8088 application notes, and then
screw things up at nearly every opportunity.
The only detailss of the 5150 that don't fall right out of the application
notes are
1) The way that the 8259 interrupt controller is used: IBM botch this
severely.
2) The actual pinout of the bus connectors.
3) The keyboard and cassette interfaces.
When I hear people talking about the way the IBM PC was "designed" (or,
worse yet, "architected"), it makes me cringe.
However, given that it was a skunkworks project on a tight schedule,
with no intention of setting a standard that would be used by hundreds
of millions of systems in the future, I can't really blame them.