Problem with growisofs: How do I disable autodetection of DVDs?

[Kenneth P. Turvey]

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I'm trying to automate a daily backup to DVD-RW, DVD+RW, or DVD-R.  I'm
running int a problem though.  When I run the command:

kt at volkswagon:~$ tar --create --bzip2 \ 
      --exclude ./subversion \
      --exclude-from=./.backup.daily.exclude \
      --sparse . | sudo nice -n -20 \
      growisofs -use-the-force-luke \ 
      -Z /dev/dvdrw=/proc/self/fd/0

I get the following output:

Executing 'builtin_dd if=/proc/self/fd/0 of=/dev/dvdrw obs=32k seek=0' /dev/dvdrw:
FEATURE 21h is not on, engaging DAO... /dev/dvdrw: "Current Write Speed" is 2.0x1385KBps.
:-! "COMMAND SEQUENCE ERROR"@LBA=0h. Is media being read? 
:-! the LUN :appears to be stuck at 0h, retrying in 5 secs...
         0/4707319808 ( 0.0%) @0x, remaining ??:??


The error message just keeps repeating until I kill it.  

It looks like the way Ubuntu is autodetecting my DVD and displaying that
it is empty or what its status is might be causing me a problem doing
the backup.  So, unless someone out there has a better idea what is
going on, I would like to disable the autodetection of this device. How
do I go about doing that?

I should note that the command line presented above has worked on 
numerous occasions, so it isn't that.  

Thank you. 

- -- 
Kenneth P. Turvey <kt-usenet at squeakydolphin.com> 
http://kt.squeakydolphin.com (not much there yet)
Jabber IM: kpturvey at jabber.org
Phone: (314) 255-2199
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