chuck@coplex.UUCP (Chuck Sites) (09/02/88)
We have been living with a fairly nice 68020 based Unix system (actually
a Plexus P/75) which uses a Multibus backplane. Well, it seems that this
system is in need of a little more horse power in the CPU and we are looking
for some sort method to bring this CPU up to snuff with today's faster
processors and clock rates. I'm embarrassed to say, it's designed with a
12.5Mhz 0-wait CPU (not bad, but not great either). The questions I have
are several regarding this architecture:
How compatible are Multibus CPU boards when they maintain the same
CPU chip. (Basically I'm saying, If I purchase a vendor-X's 25Mhz 68020 board,
would the software remain binary compatible vendor-Y's 68020 12Mhz board.)
Do any standards exist regarding the CPU type and the multibus? How about
with the VME bus (Just out of curiosity of course.)
Does any one know of a plug-in board/or adapter which would change the
'020' to an '030' and still remain binary compatible regarding the OS and
it's device drivers? Hopefully with some speed gains from the dual
pipeline architecture (I could be way off base here since I havn't even
seen the spec sheets on an '030' yet.)
Or should I break out the schematics, and see if hacking the clock-speed
is the way to go? Anyway, I'm looking for advise and or recommendations for
vendors which might have a solution to this slow CPU problem on this Multibus
backplane, or if any Plexus owners have overcome this problem, please by
all means give me a call.
Chuck Sites Phone: (502)968-8495
chuck@coplex Copper Electronics Inc.
{mit-eddie!bloom-beacon!chuck}
[This maybe the wrong place to post this questions like this, so if it is,
please, by all means, drop me a hint as to the group which might know the
ends and outs of the various bus structures, VME, MULTIBUS, ect.]