Subject: disabling tape drive compression
To: None <current-users@netbsd.org>
From: Simon J. Gerraty <sjg@quick.com.au>
List: current-users
Date: 10/27/1998 08:59:51
The consensus from my amanda question was to disable compression on
the tape drive and let amanda do it....

So I'd like to setup a tape device that will always turn off
compression.

The man page for st(4) says:

     There are several different `operation' modes. These are controlled by
     bits 2 and 3 of the minor number and are designed to allow users to easi-
     ly read and write different formats of tape on devices that allow multi-
     ple formats.  The parameters for each mode can be set individually by
     hand with the mt(1) command.  When a device corresponding to a particular

does this mean that I can create say:

crw-rw----  1 root  operator  14, 5 Oct 26 10:44 /dev/nrnst0

and use mt -f /dev/nrnst0 compress 0

to associate no-compression with that device permanently? (until
next reboot).  The fact that mt fails unless there is a tape in the
drive suggests perhaps not.

Can this be encoded in the quirks table?

Otherwise I guess I can hack amanda's pre-dump checks to do the deed.

--sjg