Vax 11/780 performance vs Sun 4/280 performance

[Barry Shein]

Although I don't disagree with the original claim of Suns having knees
(related to NeXT being pronounced Knee-zit? never mind) the discussion
can lose sight of reality here.

A 780 cost around $400K* and supported around 20 logins, a Sun4 or
even Sun3/280 probably comes close to that in support for around 1/5
the price or less, and the CPU is much faster when a job gets it. If
your Vax was horribly overloaded and had 32 users just buy more than
one system and split the community, you'll also double the I/O paths
that way and probably have at least one system up almost all the time
(we NFS'd everything between our Suns in Math/Computer Science and
Information Technology here so they can log into any of them although
that does mean that if your home dir is on a down system you lose.)

Also the cost of things like memory is so much lower that you can
cheat like hell on getting performance. Who ever had a 32MB 780?
That's practically a minimum config for a Sun4 server.

The best use for a Sun server as a time-sharer is if a) you don't
expect rapid growth in the number of logins (eg. doubling in a year)
that will outgrow the machine and b) you expect a lot of the community
using the system to migrate from dumb terminals to workstations in the
reasonably near future, that way voila, you have the server,
especially if each new workstation means one less time-sharer and it
converges fairly rapidly. It's a nice way to give them time to get
their financial act together to buy workstations. For example, for our
CS and Math Faculty here having 3 servers worked out very well, many
of the users have now grown into workstations and the server
facilities were "just there".

Another rationale of course is that you're looking for just a little
system for perhaps a dozen or so peak load people, I don't know any
system off-hand that can do that as nicely as a system like the above
for the money.

If your needs are much more in the domain of traditional time-sharing
(eg. hordes of students that never ceases growing term to term, dumb
terminals and staying that way for the next few years [typically, if
you ever get them workstations you'll put an appropriate, separate,
server in *that* budget]) then you probably want to look at something
more expandable/upgradeable. I find Encores and (no direct experience
but I hear good things) Sequents pretty close to perfect for that kind
of usage. I'm sure there are others that will suffice but we don't use
them so I can't comment (we have 7 Encores and over 100 Suns here.)

Anyhow, seat-of-the-pants systems analysis on the net is probably a
precarious thing at best, I hope I've pointed out the issues are
several and small differences in two groups' needs can make any
recommendation inapplicable.

All I can say is we have quite a few Sun 3 servers here doing
something resembling traditional time-sharing and everyone seems very
happy with it. Given the right conditions it works out well, given the
wrong ones no doubt it would be a nightmare, so what else is new?

	-Barry Shein, Boston University

P.S. I have no vested interest in any of the above mentioned companies
although I am on the Board of Directors of the Sun Users Group, I
doubt that would be considered "vested".

* Yes I realize that it's been almost 10 years since the 780 came out,
but that was the original question.