SPARCserver 390s - user experiences?

[Philip Leverton]

This is a request for user experiences with SPARCserver 390's.  I would
like to know how people have found these machines, and what uses they are
putting them to (compute server, network server, a combination of both
etc.). Also, what sort of applications are run (e.g. ditroff, TeX,
compiling [cc/f77], NFS serving, X client appls., databases, graphics)

SUN advertising says that they can support up to 68 users and 15-30
diskless NFS clients. But how many active users can they actually support?
This is why I am interested in people's actual load they have on these
machines. (I have heard that SUN4's get a slowdown after about 16 users'
are active - I don't know whether I believe this or not - it seems
implausible, and I hope very fictional for SPARCserver 390's.) For IPI
disk/controllers, what sort of I/O rate can you hope to achieve (peak or
averaged)?

Related to this is something I read recently in a UNIX mag that said that
some implementations of SPARC have memory management units with eight
contexts, and performance drops after more than eight jobs are being
scheduled round-robin. Is this for real and exactly what SPARC
implementations suffer from this? 

Please mail replies to me; I will summarise for the net.

Thanks.

Philip Leverton
Computing Services, University of Melbourne
pal at murdu.ucs.unimelb.edu.au
pal at murdu.mu.oz.au
{uunet,hplabs,mcvax,ukc,nttlab}!munnari!murdu.oz!pal