Re: Tape access with mtx/mt/tar

[Christopher McCrory <chrismcc pricegrabber com>]

On Thu, 2005-03-10 at 17:38 +0100, Arjan van de Ven wrote:
> On Thu, 2005-03-10 at 17:14 +0100, Jos Vos wrote:
> > On Thu, Mar 10, 2005 at 05:06:06PM +0100, Rainer Traut wrote:
> > 
> > > [root jupiter ~]# mt -f /dev/sg0 status
> > > /dev/sg0: Operation not permitted
> > 
> > You should use /dev/st0 or /dev/nst0 for the mt command, just like
> > you have a single tape drive (unless this is changed in RHEL4).
> > 
> > The /dev/sg0 device is only used for steering the autoloader.
> 
> not even that, you can steer the autoloader via /dev/st* too afaik.
> 

It depends on the auto loader.  Some are more integrated than others.
It depends on the vendor.  For the ones I have,  /dev/{n,}stX only
controls the tape itself.  /dev/sg$DependsOnScsiOrder controls the "Rube
Goldberg robot arm (*)".  Some units need a 'mt offline' before the
mechanism can remove a tape from the drive.


(*)  This is the technical term used by a friend of mine that writes
Novell Netware NLM and NT drivers for large cabinet size tape juke
boxes.



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Christopher McCrory
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