Xref: utzoo comp.sys.dec:2425 comp.unix.ultrix:2479 comp.os.vms:21357
Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!rutgers!cbmvax!grr
From: grr@cbmvax.commodore.com (George Robbins)
Newsgroups: comp.sys.dec,comp.unix.ultrix,comp.os.vms
Subject: Re: Exabyte--SCSI or Q-bus *or* BI-bus
Keywords: 8mm, SCSI, Q-BUS, BI-BUS, exabyte
Message-ID: <9246@cbmvax.commodore.com>
Date: 9 Jan 90 01:04:02 GMT
References: <9510@batcomputer.tn.cornell.edu> <5939@ncar.ucar.edu>
Reply-To: grr@cbmvax.commodore.com (George Robbins)
Distribution: na
Organization: Commodore, West Chester, PA
Lines: 37

In article <5939@ncar.ucar.edu> pack@acdpyr.UCAR.EDU (Dan Packman) writes:
> In article <9510@batcomputer.tn.cornell.edu> 
>     eric@geology.tn.cornell.edu writes:
> >We are contemplating the purchase of an Exabyte 8mm tape drive
> >for our system.  There is a choice about whether to connect it
> >to our VMS MicroVAX II (Q-bus) or to our DECstation 3100.
> 
> In a similar vein, we have an old VAX 8300 with both unibus and
> BI bus.  What are the relative performance hits with the uni-bus
> version of an 8mm unit versus a unibus version?

The main issue is that you have perhaps one vendor for the BI version
(Megatape?) and n-vendors for Q-bus/Unibus applications.  For this
incarnation, I don't think that any of the busses are going to have
performance problems. 

The most important thing is to get a commitment from the manufacturer
and/or distributor that the thing works with Ultrix and they they will
make it work if it doesn't or if it stops working with Ultrix x.y.
The main market still seems to be VMS and you may find Ultrix tech
support to be minimal...

Somone else asked about generic SCSI for Unibus/Q-bus machines.  I've
been looking for a while and never found anything.  Just about all the
SCSI boards have some kind of imbedded MSCP/TMSCP emulation and none
see to offer any generic or passthru mode.  Maybe the reference issue
of one of the Unix rags and a lot of phone calls would turn something
up.

I'd like to be able to hook up a cluster of 6 or so CD-ROM drives to
one of my systems, but it doesn't look like there's any way to do
this except perhaps with some DS3100 as a server...

-- 
George Robbins - now working for,	uucp: {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)