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From: juliane@belfast.dcd.wa.gov.au (Julian Elischer)
Newsgroups: comp.os.386bsd.questions,comp.os.386bsd.development
Subject: Re: SCSI tape questions
Date: 20 Sep 1993 10:19:00 +0800
Organization: Dept of Community Development, Perth, Australia
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Distribution: world
Message-ID: <27j3uk$k2l@belfast.dcd.wa.gov.au>
References: <27g4hp$uu@homer.cs.mcgill.ca>
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In article <27g4hp$uu@homer.cs.mcgill.ca> storm@cs.mcgill.ca (Marc WANDSCHNEIDER) writes:
>	1.  On the suns I used to work with, if the SCSI tape drive
>	was an Exabyte drive, nrst0 would be used for 8200s, and
>	nrst8 would be used for 8500s.  YOu could also use nrst0
>	for 8500s in 8200 mode (or whatever it's called).

>	Is there a similar mechanism in the BSD-du-jour code...?
>	How does this relate to 2GB DAT drives...?

yes, each of teh 4 groups of minor numbers can be assigned a different
density
e.g. 0-3, 4-7, 8-11, 12,15 can each have different densities..
(you have to have a resonably new scsi system, and I don't know what
teh density number for 2GB DAT is..  you can set the density using the
st(1) program (with man page!) distributed with teh scsi system.

>	2. In /usr/include/sys/mtio.h, there are  abunch of MT_IS*
>	constants indicating which tape drive one has.  However,	
>	there are a whole PILE Of drives not listed here.  Does
>	that mean that mt -fxxxx status is just going to barf saying
>	it doesn't know what the drive is, or will the system
>	just map it to the closest code possible....
since the driver does not return a type code.. (there are too many)
this can be ignored.. BTW st(1) is a superset of mt(1) and may replace it
some time (needs more work really).
st(1) can report back the densities presently active on the four virtual
devices associated with each device.

>	The reason I'm asking all these questions is that I plan to 
>	purchase a 2GB Sony or WangDAT DAT drive in the future and
>	do a bunch of fiddling with the dump, mt, and rmt commands...

I run a DAT at the moment (WangDAT 1300) and have no problems with it.

julian