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From: chris@aivru.sheffield.ac.uk (Chris Brown)
Newsgroups: comp.sys.transputer
Subject: Re: SCSI Devices
Message-ID: <9009210908.AA08301@aivru.uucp>
Date: 21 Sep 90 09:08:35 GMT
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In response to Phillip Hallam-Baker's question about SCSI interfaces to
transputer arrays, I have never used a SCSI TRAM but I suspect they are
really intended to let you connect a disc to a transputer array; i.e.
there needs to be software already running on the TRAM to make the SCSI
i/face actually do anything. So I think it might be difficult or
impossible to make the TRAM emulate a SCSI peripheral (which presumably
is what you want), at least BEFORE it's been booted.

I endorse the point about cost savings; in the Sun world you pay dearly
for VME slots too. What we did was to (ab)use the SCSI port on a
diskless workstation by just treating it as a bidirectional bus and a
heap of control lines. We built a simple interface using a C011 (or was
it a C012, I can never remember which is which) a couple of bus
buffers, and a PAL. We have a very simple unix device driver to talk to
the workstation's SCSI port. This gives a very low cost connection. Of
course, you can't have a REAL scsi device co-existing with this
arrangement.

Chris Brown, A.I. Vision Research Unit, Sheffield University 
(chris@aivru.sheffield.ac.uk)