Looking for a big Unix box

[Neil Gorsuch]

In article <long-id at ucselx.sdsu.edu> nash at ucselx.sdsu.edu (Ron Nash) writes:
>I am throwing this to the collective net wisdom (:-).  I am asking for
>suggestions and any experiences good or bad to guide us in our search.
>The main uses of the computer will be teaching Unix and programming,
>and research.  We have Macsyma and Lisp users and neural-network
>research that can be quite a drain.
>We are looking for a Unix engine that will support at least 100
>concurrent users.  It would be nice if it could be expanded to support
>more users if needed.  The Unix should be BSD or be BSD compatible.  A
>major concern is compatability of BSD software.

Here's one way to do it that will definitely save you big bucks.
Instead of buying a single BIG machine for a BIG price, look to where
the best deal is in (MIPS+Mbytes/$), which is currently desktop
workstations, and buy some of those, TO BE USED AS MULTI-USER
MACHINES.  For instance, how about using 10 Sparcstations (or
substitute your own favorite brand) as multi-user machines.  Actually,
I would only put in 5 and put 20 users per machine, but you might want
to be more conservative and put in 10 with 10 users each.  If you make
each one a "dataless" client of an appropriate server, you will have a
VERY peppy 10 (20) user machine.  There's a nifty way to add a bunch
of serial ports to desktop workstations without using the ethernet, so
that shouldn't be a problem.  Each Sparcstation is 12.5 MIPS or so,
can have up to 64 Mbytes of memory, can have Gigabytes of 16 mS disk
storage, and is BSD ported/compatible, so they should handle your
needs.  And with recent/upcoming announcements, you will probably be
putting in 27 MIPS machines instead of 12.5 MIPS machines if you wait
a few months 8-).  Personally, I would even skip the server and
sprinkle the user's files amoungst the workstations, with various NFS
cross-mounts, while making sure to put as many user's files on the
workstations that they mostly log onto as is possible.  You should be
able to do that with a lot of the students and most of the professors.
You can be very creative in how you cross-mount user's home
directories, while still backing everyone up each night over the
network with a few Exabyte tapes.  The entire "system" will be much
more reliable, since you will have a number of machines so that one
machine going down will not cripple all of your users.  With the money
that you save on a maintanence contract for a big machine, you could
even have spare workstations lying around, and have users files
duplicated on more than one disk, with automatic nightly duplication,
so that in the event of a disk or workstations crash you could just
switch around your NFS mountings for fast "repair".  The system is
very easily expandible, just add more workstations.  In the case of
the Sparcstations, you can even have 2 ethernet interfaces in each for
ease of networking configuration.  When researchers clamor for a
workstation instead of a terminal, you can accomodate them without
bogging down your primary "system" ethernet backbone by putting the
private workstations on a second ethernet interface in the workstation
that was their "login" computer.
--
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