Subject: DSSI disk support on 3400s
To: None <port-vax@NetBSD.ORG>
From: Jay Maynard <>
List: port-vax
Date: 07/21/1998 14:16:18
I tried mailing this reply to John Rogers, but it bounced...

   ----- The following addresses had permanent fatal errors -----

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... while talking to
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On Mon, Jul 20, 1998 at 10:17:20AM -0400, wrote:
>      I saw on the port-vax mailing list that you are planning on working on
> supporting DSSI disks in the future.  I have a uVax 3400 and wanted to work
> on the EDA640 driver, so I bought a copy of the KA640 technical manual.
> It's pretty good for describing the linking
> of buffers together in the interface memory, but completely empty of any
> content on the data to be stored into the buffers.  Would you have any
> documentation that you could share about DSSI and its packet structures?

As far as I understand, the data sent over the DSSI bus is straight MSCP,
which NetBSD already knows how to talk to. Therefore, a DSSI disk driver
should be as simple as hooking the existing ra driver to a new driver for
the DSSI port, instead of the uda driver. That was the path I was planning
to take, at least for the KA6[6-9]0 DSSI ports.