Error message...

[Jeff Ross <jross@openvistas.net>]

I'm trying to implement a backup system using DVD+RW.  Currently I'm 
backing up about 3 GBs of data, although it was over 4GBs a little while 
ago.

To do this I'm using 2 scripts called from root's cron.  The first 
blanks the disk:

#!/bin/sh
umount -f /dev/cd0c
growisofs -use-the-force-luke -overburn -Z /dev/rcd0c=/dev/zero

The second does the backup:

#!/bin/sh
/sbin/umount -f /dev/cd0c
#burn the dvd
cd /
growisofs -use-the-force-luke -overburn  -Z /dev/rcd0c -R samba home


I'm getting the following error message with either script on a pretty 
frequent basis, especially when this script is called from root's cron:

WARNING: /dev/rcd0c already carries isofs!
About to execute 'builtin_dd if=/dev/zero of=/dev/rcd0c obs=32k seek=0'
 :-(  unable to GET PERFORMANCE: Input/output error
 :-(  falling down to SET CD SPEED
 :-[  WRITE@LBA=0h failed with SK=6h/ASC=29h/ACQ=00h]:Input/output error
 :-(  write failed: Input/output error

If I call this script from the command line, though, it works just fine.


OS is OpenBSD 3.5,  cdrtools-2.01.01, dvd+rw-tools-5.21.4.10.8.
Hardware is (from dmesg) cd0 at scsibus0 targ 0 lun 0: <HP, DVD Writer 
300c, 7H29> SCSI0 5/cdrom removable.

According to HP's web site, there is a firmware update for this unit, 
but it requires both Windows and the Veritas recording software to 
install.  I don't see that as an option.

I'd appreciate any insight into this problem.

Thanks,

Jeff Ross