SUMMARY: 256Mb RAM in a Sparc 2?

From: Carlo L. Tiana (carlo@vision.arc.nasa.gov)
Date: Thu Nov 14 1991 - 20:13:50 CST


A late summary, and unfortunately still an inconclusive one.
I was hoping that, by waiting long enough, a consensus of replies
would be reached, but I guess not.

The original posting:
---------------------
> We have a bunch of Sparc 2's with 64Mb RAM in them (16x4Mb SIMMs)
> and, surprise surprise, we would like to stuff more in. Has any-
> one tried to do so? Has anyone found a supplier of 16Mb SIMMs?
> Are there ways to get more than even 256Mb RAM in these machines?
> (like, one could imagine some sort of SBus based memory expansion
> card with 16 SIMM slots - bringing the total possible amount of
> RAM to 512Mb if 16Mb SIMMs were ok). Your experience would be, as
> usual, appreciated.
> Thanks,
> Carlo Tiana
> NASA Ames Research Center
> (415) 604-0001

Thanks to:
----------
From: Mike Raffety <miker@sbcoc.com>
From: kpc!kpc.com!cdr@uunet.UU.NET (Carl Rigney)
From: michael@hal.com (Michael Coxe)
From: Hans van Staveren <sater@cs.vu.nl>
From: ohnielse@ltf.dth.dk (Ole Holm Nielsen)
From: pbg@cs.brown.edu (Peter Galvin)
From: Ian Daniel <Daniel@europarc.xerox.com>
From: Kanthan Pillay <svpillay@Princeton.EDU>
From: liz@isis.cgd.ucar.EDU (Liz Coolbaugh)
From: "Ric Anderson" <ric@cs.arizona.edu>
From: poffen@sj.ate.slb.com (Russ Poffenberger)
From: Tad Guy <tadguy@ab00.larc.nasa.gov>
From: evans@c4west.eds.com (Bill Evans)
From: bmskc!moe!paul@uunet.UU.NET (Paul Evan Matz)
From: wjb@cogsci.cog.jhu.edu
From: Steve Hanson <hanson@pogo.fnal.gov>
From: mmm@yardbird.wpd.sgi.com (Mike Murray)
From: "Kevin C. McMahon" <kevin@saber.com>

The findings:
-------------
-Sun and Clearpoint or Dataram sell a 32 Mb board that can be plugged on
 the SBus, although it may not be a true SBus board, maybe it just draws
 power from it, and has a special connection to the motherboard. Brings
 the total to 92Mb (with 64Mb on the motherboard, in 4Mb SIMMs). Someone
 mentioned the board and the piggyback are ~$3100 each from 3rd party.
-It seems that it is possible to attach a piggyback board to the above for
 another 32Mb, bringing the total to 128Mb.
-16Mb SIMMs are available. But: can they be used? Some say yes, some say:

 "As far as I know, the maximum RAM address space for the Sparc II is 128 mb"

 "You cannot put 16Mb SIMMS in, there just is no address space there."

 "Clearpoint has 16MB SIMMs. They are not supported by Sun though..." (this
 has not meant much in the past - we have plenty of stuff around that's not
 supported by Sun and works like a charm - maybe *because* it isn't :-)

 ...vendors saying 16Mb SIMMs are ok in a SS2, and they can supply...

 "The Simm slots in the Sparc-2's only support 4MB simms. The 16MB
 wonders take a different connector as I understand it. Not surprising,
 since a 16MB Simm would need 2 more address lines than a 4MB Simm."

 "Sun only acknowledges that an SS-2 can go up to 128Mb. I don't think that it
 supports 16Mb SIMM's. (Certainly not the kind found in the IPX, these are 32
 data bit wide, as opposed to 8 bit wide on SS-2)."

 "You can't use 16 MB SIMMS in this machine. 16 MB SIMMS are available
 for the IPX, ELC, etc from a number of suppliers (clearpoint, etc)."

If the 16Mb SIMMs work, prices have been quoted from $875/SIMM to $2200/SIMM.

Comments:
---------
So. I am still confused as to whether 16Mb SIMMs (for various reasons, the
most desirable solution) would work, although if I were to take a vote from
the replies they wouldn't. I would be amazed if the address space were the
limitations. Macs can take 256Mb of RAM these days, it would be very
short-sighted of Sun to build in this limitation...
If someone mails me irrefutable facts, I will post a followup summary.



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