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Date: Mon, 4 Nov 1996 13:04:09 +0600
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In-Reply-To: <199611041136.WAA09945@suburbia.net> (message from Julian Assange
	on Mon, 4 Nov 1996 22:36:56 +1100 (EST))
Subject: Re: scsi dat drive under freebsd
From: Tim Pierce <twpierce@midway.uchicago.edu>
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[shouldn't this be on freebsd-questions?]

> Will freebsd support 4mm DAT tape drives?

My WangTEK 6300-mumble series worked out of the box, as it were.
There were a few growing pains, but I now suspect a misconfigured
adapter rather than any kernel problems.

> The solaris st driver documentation has some magic-data for 4mm
> DATs using Helical scans, which seems to imply that they need specific
> support?

The Solaris st(7) page gives me the impression that `magic-data'
is a (poorly-chosen) dummy name used as an example; note that the
ficticious manufacturer of the dummy drive is `Magic DAT'.  It
should not be construed as evidence that 4mm drives necessarily
need `magic numbers' in order to run.

For example, here's the beginning of the st conf file on my
Solaris box:

    name="st" class="scsi"
	    target=0 lun=0;

    name="st" class="scsi"
	    target=1 lun=0;

    name="st" class="scsi"
	    target=2 lun=0;

    [ ... etc. ... ]

When I plugged the aforementioned WangTEK into this box, it worked
like a charm.  Presumably you need to add magic data for drives
which don't work precisely according to the SCSI spec, or which
can't be properly auto-sensed -- items which FreeBSD handles via a
`rogue list'.

I'd guess that if you're thinking of buying a 4mm DAT for your
FreeBSD system, don't worry too much about it, but check the
handbook and the SCSI driver source for a list of rogue drives
first to make sure you don't wind up with something that needs to
be babysat.