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From: luiten@arizona.edu (John Luiten)
Newsgroups: comp.periphs
Subject: VAXs sharing a 9900 controller
Message-ID: <1822@megaron.arizona.edu>
Date: Mon, 20-Jul-87 13:07:10 EDT
Article-I.D.: megaron.1822
Posted: Mon Jul 20 13:07:10 1987
Date-Received: Wed, 22-Jul-87 03:42:10 EDT
Organization: U of Arizona CS Dept, Tucson
Lines: 31
Keywords: System Industries, 9900 controller, performance




We currently have a System Industries 9900 disk controller attached
to a VAX 780 using the SBI interface.  The controller supports two 
Fujitsu Eagle drives and the 780 is lightly used.  Another machine 
we have is a VAX 8650 with a 9900 disk controller and four Fujitsu 
Eagle drives.  The 8650 is currently short of disk space and we are 
hesitant to put any more drives on the 9900 controller. 

We are exploring the possibility of dual porting the 9900 controller
on the 780 such that it drives one Eagle in support of the 780 and
one (possibly up to three) Eagles on the 8650.  The single Eagle drive
on the 780 would support both the operating system and user files while
the additional 8650 drive would most likely be for user files only.

We have pretty well figured out the configuration with System Industries, 
but would feel better if we were able to talk to someone who has 
experience in using a shared 9900 controller between two VAXen.  The 
operating system of both machines is Mt. Xinu BSD 4.3 with NFS.

Has anyone else tried this sort of thing?  If so, what sort of software
problems and/or performance impacts did you experience?

Please mail replies directly to me and if there are enough to warrant, 
I'll summarize and post.



John Luiten / Computer Science Dept. / U of Arizona / Tucson, AZ  85721
+1 602 621 6610 / luiten@arizona.edu / {noao,ihnp4,allegra}!arizona!l (swou