[rescue] SGI, Origin 200, and speed?

[Mike Meredith]

On Wed, 28 Apr 2004 16:56:49 -0400, Joshua Boyd wrote:
> On Wed, Apr 28, 2004 at 04:27:52PM -0400, Dave McGuire wrote:
> 
> >   Well no...you can connect a maximum of *two* Origin200 chassis 
> > together.  Origin2000s on the other hand...you can go up to sixteen 
> > chassis for a total of 128 processors.
> 
> You can do more.  You may need something custom from SGI to do so
> though.  Is it up to 128 processors, then the Meta router for more, or
> was it 32 processors, then the metarouter to connect blocks of 32...

If you increase an O2K beyond 32 processors, you lose the ability to
double up on the CrayLink cables (the extra ones are XpressLinks?) but
there's no need for a metarouter until you expand beyond 64 processors
(4 racks).

The original O2K could be expanded up to 128 processors with a
metarouter (and extra cache memory on the node boards and replacing
the router cards in each chassis). Later versions of the owner's guide
indicate that you can expand up to 256 processors. Given that NASA had
512 processor O2K's, the limit was probably something to do with the
metarouters (and the size of the cache memory?).

Trouble is that because SGI *really* didn't want you to cable these
things up yourself, information on the CrayLink cables, the routers, and
the metarouters is somewhat thin on the ground.