21 Jun
2012
21 Jun
'12
10:22 p.m.
On Jun 21, 2012, at 5:11 PM, Chuck Guzis wrote:
On 21 Jun 2012 at 12:20, Eric Smith wrote:
In a way, yes, but no one else was making chipsets for 68K or PPC
machines (or if they were, they were using their own custom logic,
too). In the PC world, the market was big enough to sustain lots
of chipset vendors (though only VIA seems to have survived, and
I think SIS did in name only), but it's not like IBM was using
commodity chipsets for RS6000 machines.
Of course, Apple is still using a fair amount of custom logic for
its chipsets, last I checked.
As far as info on the custom LSI, I get the impression that info
is available for some of the chipsets in developer tech notes that
were shipped on the developer program CDs. I'd love to see some
of those, but I've never come across a source (and I suspect it
wouldn't be strictly legal to distribute). The brief overview
tech note on machines like the 9500 mentions the existence of
such documentation, but it's unclear how detailed that might be.
I'd be interested in trying them if you can
read them and post the
JEDEC files as some point. I suspect probably a few other people
would be interested as well.
Did Apple ever publish any information on their custom LSI on the
Power Mac series? IMOHO, that's what makes these machines
essentially throwaway for anything but trivial problems. You've got
these big quad flatpacks with Apple house numbers and no clue
whatsoever what's in them. But maybe that's the idea--toss and get a new one
if the old one
doesn't work. I wonder how many Macs ended up in the landfill
because of a dead PRAM battery...
I dunno. I think it was more or less necessary once you passed
the complexity of an original 68000 if you wanted to keep the
machine small enough to fit on a desktop. It does make them
more or less disposable in a way, but I've never found an old
Mac logic board where chipset failure was the problem unless
an exploded PRAM battery had corroded it off.
- Dave