In other Unices (read: SYSV), I think that the
different designations are for different tape
densities (bits per inch).  "l" is low density,
"m" is medium density, and "a" is for, um,
asinine density.  There are usually "n" devices
also, for no-rewind.  I suppose that for newer
tape drives, density select could be used to
enable/disable compression.  mt in Linux has
a "datcompression" command that I use.

Also, in some Unices, they have two entirely
different sets of special files for interfacing
with tape drive drives.  One set is a SYSV-style
interface (ioctl?) and the other is a BSD-style
interface.  IIRC, Solaris and/or HP-UX is this
way.


HTH,

D

* On Thu, Aug 31, 2000 at 02:38:36PM -0700, der.hans wrote:
> Am 31. Aug, 2000 schwäzte Robert Ambrose so:
> 
> > 
> > COuld you shed a little more light on exactly what you're looking at?
> 
> I thought the different devices controlled what level of hardware
> compression was being involved.
> 
> /dev/st0 would be none or default
> /dev/st0l would be level 1
> /dev/st0m would be level 2
> /dev/st0a would be level 3
> 
> Or something like that. Driver has to support it and all that. Looks like
> I was wrong. It seems to me that the different devices was one way of
> controlling hardware compression under AIX, but I could be wrong.
> 
> I need to be able to find out what settings my tape drive has and then be
> able to change them :). I know how to do that in AIX, but that doesn't
> help me here.
> 
> Turns out that there is a closed source util from the drive
> manufacturer. It isn't working right for me and I'd prefer to have a
> generic solution regarding tape drives in general.
> 
> danke,
> 
> der.hans
> -- 
> H  der.hansOLuftHans.com   home.pages.de/~lufthans/   www.Opnix.com
> H  Help Jerry Lewis stamp out M$...oops that's MDA - der.hans
> 
> 
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