What happened to DVD writing?

[Zaphod Beeblebrox]

On Sun, Sep 20, 2009 at 9:47 AM, Warren Block <wblock at wonkity.com> wrote:

> Recording data DVDs worked a few weeks/months ago on this system with a
> PATA Lite-On DVD recorder:
>
> FreeBSD lightning 7.2-STABLE FreeBSD 7.2-STABLE #0: Sun Sep 20 07:25:58 MDT
> 2009      root at lightning:/usr/obj/usr/src/sys/LIGHTNING  i386
>
> Now growisofs starts, but appears to never manage to write to the DVD. It's
> a DVD-R, one from the same batch that has worked before:
>
>  0.77% done, estimate finish Sun Sep 20 07:55:57 2009
>
> and there it stops.  Rebooting is needed, and the machine can't quite bring
> itself to shut down after syncing buffers.  /var/log/messages:
>
> Sep 20 07:42:44 lightning kernel: acd0: FAILURE - READ_BUFFER ILLEGAL
> REQUEST as c=0x24 ascq=0x00
> Sep 20 07:42:46 lightning kernel: acd0: FAILURE - MODE_SELECT_BIG ILLEGAL
> REQUEST asc=0x24 ascq=0x00
> Sep 20 07:42:56 lightning kernel: acd0: FAILURE - READ_TOC ILLEGAL REQUEST
> asc=0x24 ascq=0x00
> Sep 20 07:43:25 lightning kernel: acd0: WARNING - TEST_UNIT_READY taskqueue
> time out - completing request directly
> Sep 20 07:43:36 lightning kernel: acd0: WARNING - TEST_UNIT_READY freeing
> taskqueue zombie request
> Sep 20 07:45:26 lightning kernel: acd0: WARNING - PREVENT_ALLOW taskqueue
> timeout - completing request directly
> Sep 20 07:45:26 lightning kernel: acd0: WARNING - PREVENT_ALLOW freeing
> taskqueue zombie request
>
>
I recently upgraded from 7.0 to 7.2-p3.  I just last night cut a dual layer
DVD with growisofs.  It appears to have cut fine.

When growisofs stops in the middle like that, it's often caused by media
defects.  Have you tried another disk?

Another possibility is that the drive is worn out.  DVD writers have a
limited lifespan largely measured by the number of disks they cut.