Looking for a big Unix box

[Paul Graham]

In article <1990Feb25.075337.22513 at zardoz.cpd.com>,
neil at uninet (Neil Gorsuch) writes:
|In article <long-id at ucselx.sdsu.edu> nash at ucselx.sdsu.edu (Ron Nash) writes:
|>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.
[ and proceeds to describe a cluster of workstations acting as a timesharer]

last semester we went looking for a timeshare machine.  when we
settled on a SPARC compatible system it was suggested that we consider
purchasing a roomful of 4/60s rather than spend the money on a 4/490
and a solbourne 5/802.  my answer then and even more so now is bzzzzt,
wrong and no prize for you ;-).  i wouldn't think for a second of putting
10 users on anything like a 4/60 let alone 20 (my workstation is a
4/60, with 12MB and the fast disk).  i also think such a cluster would
be nightmare to manage without having the users files on a server.
now i do think the idea of multiple cpus is a good one and my
experience with the 2 cpus in our solbourne has been very good (the
machine can do almost 6000 context switches per second.  this only the
first semester we've encouraged a few people to run classes on it but
it's been quite snappy with 60-70 users most of whom are running emacs
and many of which are running ibcl) some hardware problems not
withstanding.  sunOS is, of course, BSD similar.  you can also get
macsyma et.al. for sparc machines.  other reasonable sounding
solutions would be an encore (too pricey for us) or perhaps a
multi-cpu 5000 from dec, assuming ultrix still looks more like bsd
than sysV.  these alternatives are dependent on software of course.

i've become a big fan of shared-memory multi-cpu boxes.  i think
they're clearly the wave of future.  why even sun will have one
someday.  one just needs to make sure that each cpu is big enough and
that the system design doesn't make peripheral/memory access a bottleneck.

impertinent details: our budget was $250k (we came pretty close) we
bought a 4/490 and 5/802 each with 64MB and about 2G of disk.  we
don't use serial ports and we didn't have to pay for terminal servers
or maintenance (someone else's budget).  we spent about the same
amount of money on each machine and yes the solbourne is (with two
cpus) twice as fast as the 4/490.  we don't like putting all our eggs
in one basket.  all prices were for last summer.  oh yah, 64 pty's
isn't nearly enough and you have to teach rlogin/telnet about the rest.