Experiences with 4D/2xx as timesharing systems?

[jim frost]

>     If you are not interested in graphics, why buy a SGI machine?
>Buy something from anybody else, it is bound to be better, cheaper,
>and better supported than a SGI machine.

The high-end 4D machines have very good price/performance even without
the graphics (so do the Personals but without graphics new offerings
from DEC etc are better apparently).  If they beat other systems in
price/performance (they beat quite a few), then the graphics is just a
bonus.  Operators can play flight while waiting for backups :-).

Seriously, I believe that a properly tuned/configured 4D/2xx would
make a fantastic multiuser machine for the money.  The biggest problem
is the lack of serial ports, which can be fixed by either a cheap
machine as a front-end or a standalone terminal server such as
encore's annex box.  Exactly how well this will perform is up in the
air; all of our SGI machines are obviously tuned to work
single-user/single application and perform rather poorly if you break
these constraints.  I haven't looked into correcting this because we
generally have one user, one or more machines.

Since the machines are mostly SysV and are intended to be
workstations, there are some real problems with using them as
multiuser:

	* 'tar' is not a backup program, no matter who thinks so.  We
	  copy entire filesystems between machines for redundancy and
	  back up from one of the Suns, but our data space is less
	  then a half-gigabyte in general, not the case on large
	  multiuser machines.

	* SysV "ps" is too painful to use when managing a system with
	  lots of things running.  Someone ought to build an "sps".
	  Funky shell scripts could fix this but when you need to know
	  what's going on, you usually are in too much trouble to
	  waste that kind of time and resources to find out (eg some
	  idiot accidentally spawned two hundred jobs and filled the
	  proc table; never done it myself :-).

	* There are several programs (ftp has given me trouble in the
	  past) which don't clean up utmp correctly, bothersome but
	  not fatal.

	* The filesystem does not appear to be BSD FFS, something
	  which becomes an issue real fast with a lot of users.  It
	  doesn't have the 14 character bugaboo that bothers me so
	  much though.

	* If you use Sun's yp, you're in for a lot of fun.  It's not
	  the default for getpwent etc.  Aside from the problems that
	  caused, we've had few problems with it.

	* The graphics is not in the least bit secure.  Neither is
	  anyone else's that I've worked with.

That's all I can think of at the moment.  Some of the above may have
been fixed; the OS version we use on most of our 4D's is out-of-date
and we've yet to see an update.  I'd be interested in hearing about
performance if someone has tuned a 4D for multiuser.

jim frost
madd at bu-it.bu.edu