Hardware question on 4D/20
Dave Olson
olson at anchor.esd.sgi.com
Wed Jul 4 03:27:33 AEST 1990
jcmiller at hydra.unm.edu (Jeff Miller) writes:
| Hello fellow SGI users!!
|
| I have a couple of hardware questions for all of you GURU's out there:
|
| (1) What is involved in upgrading a 4D/20 to a 4D/25? I am willing to perform
| the surgery myself. I believe that it involves replacing the R3000 and R3010
| CPU and FPU with faster components and, of course, faster RAM. In addition,
| there seems to be room to install 64Kb of cache RAM in place of the existing
| 8Kb cache. Is there any special hardware swith to tell the CPU that it has
| more cache?
| ( Yes, I know the proceding proposal definitely voids my warranty-- if I
| still had one :-)
I won't speak to the rest, but some other things that you get with a
4D25 are a faster SCSI chip, and a new I/O controller chip. The
combination boosts disk throughput considerably. Since the I/O chip is
an SGI chip, you can't just buy one. The SCSI chip is the WD 33C93A,
instead of the 33C93. Just changing the SCSI chip won't help a whole
lot without the new I/O chip (I seem to recall about 10% improvement
with just the 93A). The types of the I/O and SCSI chips are determined
independently of each other.
I also seem to recall that there was some minor board layout required
to accomodate the higher clock rate, and some PAL changes.
The cache is sized at boot time; I don't know if the 4D20 cpu board
really supports more cache than is present; I am not a hardware
person.
And, as you note, you have completely violated your warranty, and if
you blow it, you lose...
--
Dave Olson
Life would be so much easier if we could just look at the source code.
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