[rescue] challenge L backplane

Sheldon T. Hall shel at cmhcsys.com
Sat May 8 21:28:22 CDT 2004

 Charles Shannon Hendrix writes ...
> Fri, 07 May 2004 @ 14:59 -0400, Sheldon T. Hall said:
> > Geoff Koehler writes ...
> > >
> > > In a nutshell, a deskside onyx backplane will support up to IR
> > > graphics, but only has a slot for 1 CPU board (up to 4CPU's),
> > > and 1 MC3
> > > board (2 G??).  The Challenge L backplane has no graphics support, but
> > > has more memory and CPU slots.
> >
> > Heh.  The Challenge L can't take enough CPU or memory boards to
> > suit me as
> > it is.  The doco says you can get 8-way memory interleaving if
> > you have four
> > memory boards, but the L only has room for three.  On the other
> > hand, it you
> > can have something like 15 or 20 SCSI busses....
> Hmmm... there aren't slots for 3 CPU boards and one memory board?

There are 5 total EBUS slots ... one has to be a processor, one has to be an
IO4, and one has to be memory.  So you have two left for some combination of

One MC3 memory board will hold 32 SIMMs, and supports either 16 MB or 64 MB
SIMMs, so you can have up to 2 GB on one MC3 board.  In theory, it's faster
if you use 2 MC3 boards, since that allows memory interleaving.  I don't
know how much diffo it's supposed to make.

One processor board can have up to 4 processors.

> A friend has a Challenge L I thought about trying to max out, and I was
> counting on being able to do 3 CPU and 1 memory board.  I could have
> sworn when I looked in there it had room.

Yep ... 3 processor boards, 1 MC3, and 1 IO4.  12 processors, 2 GB RAM, and
more SCSI disks that you can afford.  That single IO4 board can support 5 FW
SCSI controllers, I think.  Izzat 5x15=75 drives?  Something like that.

> If not, oh well... hard to complain for free.

Well, of course, it won't be free for long ... gotta have some more
processors, more RAM, bigger disks, a DLT for backup, VME for 100baseT
networking, etc....

Still, a Challenge makes a pretty studly "home computer."


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