[rescue] Wanted: SparcStation 20 and/or Parts

[Scott Quinn]

Quote:


Date: Thu, 24 Nov 2011 15:02:59 +0000
rom: mail at catsnest.co.uk
o: The Rescue List <rescue at sunhelp.org>
ubject: Re: [rescue] Wanted: SparcStation 20 and/or Parts
essage-ID:
<CAFWLKddzAOPmUOAZYDfJdOYQ5StTU2CjppG5kWbzAn4VMrDF+A at mail.gmail.com>
ontent-Type: text/plain; charset="us-ascii"
On Thu, Nov 24, 2011 at 2:48 PM, Andrew Reynolds
randrewreynolds at gmail.com>wrote:
> On Thu, Nov 24, 2011 at 10:35 AM, Michael-John Turner <mj at mjturner.net>
 wrote:
 > On Wed, Nov 23, 2011 at 01:59:24PM -0500, J. Alexander Jacocks wrote:
 >> Indeed I know that the SS20 can't use the second meg of cache.
 >> However, unless I find 2 more identical SM81s, I need a second SM81-2
 >> to be able to run 2 processors, as the SS20 requires identical CPUs to
 >> be installed for SMP.
 >
 > I'm not sure that's strictly true - officially, yes, but AFAIK it's
 > possible to mix modules. I think the key factor is that all CPUs must
 > either have cache or be cacheless.
 >
 My hand-me-down SS20 is running with an SM41 and an SM61, I'd have to
 fire it up to confirm hardware revisions. It's clunky, but it works. I
 seem to recall having to put the SM41 in the first MBUS slot.


oes it not then run them both as if there were SM41's?


Quote over, my personal drivel follows:

You can mix in MBus machines as long as the MBus speed is the same and the
MXCC controller is the same revision (don't know if minor rev counts, but
major rev does). Unlike the Sun4u series the multiplier is handled on the CPU
and can be different for each processor.  Michael's -20 needed the SM41 in the
first slot to set the MBus at 40MHz.