[rescue] challenge L backplane

[Sheldon T. Hall]

 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
CPU/memory.

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."

-Shel