System Industries "SIMACS"

[Ken Shoemaker]

We had this beastie on two of our VAXes about a year ago that I had
the misfortune of working on.  At the time, they didn't have unix
support (not that it would have made much difference) so the machines
were running VMS.  There were a couple of problems, none the least
of which I could attribute to our VMS crew not quite knowing how
to configure the systems to which it was attached.  However one
of the really fundamental problems I'm not sure Unix can approach
any better, and it was a real performance killer.  Consider two
machines having write access for a single disk.  For normal
files perhaps it wouldn't cause too many problems, but for
directory files you could have some nasty problems.  With
the kernel running on a single machine it has just one
place where disks are cached, but with two machines doing
the same thing, it can get kinda funky.  As a result (at least
for the VMS machines) one machine would hit the other machine
to dump out its disk buffers whenever it wanted to do anything,
and semaphores were kept on the disk itself.  Anyway, high
performance it ain't.

In addition to these problems, I would make sure that the unix
support is available.  They were promising this last year, but
last I heard, it was still "vaporware" (not that I'm casting
aspersions, but a word to the wise....)
-- 
I've got one, two, three, four, five senses working overtime, 
	trying to take this all in!

Ken Shoemaker, Intel, Santa Clara, Ca.
{pur-ee,hplabs,amd,scgvaxd,dual,idi,omsvax}!intelca!kds
	
---the above views are personal.  They may not represent those of Intel.