tape support

tape support

[Dietmar Maurer]

Is there a way to use a scsi tape? I tried -drive file=/dev/sg0, but
that does not work (eject, rewind works, but read/write fails - no date
is written - no errors)

- Dietmar

Re: tape support

[Laurent Vivier]

Le jeudi 11 septembre 2008 à 12:54 +0200, Dietmar Maurer a écrit :
> Is there a way to use a scsi tape? I tried -drive file=/dev/sg0, but
> that does not work (eject, rewind works, but read/write fails - no date
> is written - no errors)

try "-drive file=/dev/sg0,if=scsi"

Laurent
-- 
----------------- Laurent.Vivier@bull.net  ------------------
  "La perfection est atteinte non quand il ne reste rien à
ajouter mais quand il ne reste rien à enlever." Saint Exupéry

RE: tape support

[Dietmar Maurer]

I already tried that - it does not work (the tape is seen as st0 as expected, but read/write operation does not work).

- Dietmar

> -----Original Message-----
> From: Laurent Vivier [mailto:Laurent.Vivier@bull.net]
> Sent: Donnerstag, 11. September 2008 13:01
> To: Dietmar Maurer
> Cc: kvm@vger.kernel.org
> Subject: Re: tape support
> 
> Le jeudi 11 septembre 2008 à 12:54 +0200, Dietmar Maurer a écrit :
> > Is there a way to use a scsi tape? I tried -drive file=/dev/sg0, but
> > that does not work (eject, rewind works, but read/write fails - no
> date
> > is written - no errors)
> 
> try "-drive file=/dev/sg0,if=scsi"
> 
> Laurent
> --
> ----------------- Laurent.Vivier@bull.net  ------------------
>   "La perfection est atteinte non quand il ne reste rien à
> ajouter mais quand il ne reste rien à enlever." Saint Exupéry
> 

Re: tape support

[Soren Hansen]

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On Thu, Sep 11, 2008 at 01:24:20PM +0200, Dietmar Maurer wrote:
> I already tried that - it does not work (the tape is seen as st0 as expected, but read/write operation does not work).

Does the user running kvm have read/write access to the tape device on
the host?

-- 
Soren Hansen               | 
Virtualisation specialist  | Ubuntu Server Team
Canonical Ltd.             | http://www.ubuntu.com/

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Re: tape support

[Avi Kivity]

Laurent Vivier wrote:
> Le jeudi 11 septembre 2008 à 12:54 +0200, Dietmar Maurer a écrit :
>   
>> Is there a way to use a scsi tape? I tried -drive file=/dev/sg0, but
>> that does not work (eject, rewind works, but read/write fails - no date
>> is written - no errors)
>>     
>
> try "-drive file=/dev/sg0,if=scsi"
>   

How would that work?  Won't qemu attempt to show the tape as a disk?  Or
does it detect this special case and passes-through the scsi device?

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

Re: tape support

[Laurent Vivier]

Le samedi 13 septembre 2008 à 07:51 +0300, Avi Kivity a écrit :
> Laurent Vivier wrote:
> > Le jeudi 11 septembre 2008 à 12:54 +0200, Dietmar Maurer a écrit :
> >   
> >> Is there a way to use a scsi tape? I tried -drive file=/dev/sg0, but
> >> that does not work (eject, rewind works, but read/write fails - no date
> >> is written - no errors)
> >>     
> >
> > try "-drive file=/dev/sg0,if=scsi"
> >   
> 
> How would that work?  Won't qemu attempt to show the tape as a disk?  Or
> does it detect this special case and passes-through the scsi device?

Yes, Qemu detects it's SCSI interface and passes the SCSI commands to
devices. But qemu ignores the type of the device but OS (linux) detects
this as a tape (with INQUIRY).

It works well for CD/DVD and disk, but I'm working with Dietmar to make
it working with tape (commands encoding differs)... and I found some
devices to test.

Regards,
Laurent
-- 
----------------- Laurent.Vivier@bull.net  ------------------
  "La perfection est atteinte non quand il ne reste rien à
ajouter mais quand il ne reste rien à enlever." Saint Exupéry

Re: tape support

[Avi Kivity]

Laurent Vivier wrote:

  

>> How would that work?  Won't qemu attempt to show the tape as a disk?  Or
>> does it detect this special case and passes-through the scsi device?
>>     
>
> Yes, Qemu detects it's SCSI interface and passes the SCSI commands to
> devices. But qemu ignores the type of the device but OS (linux) detects
> this as a tape (with INQUIRY).
>
> It works well for CD/DVD and disk, but I'm working with Dietmar to make
> it working with tape (commands encoding differs)... and I found some
> devices to test.
>   

Neat...

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.