[TriLUG] more DVD-burning questions

[Brian Henning]

Pat Regan wrote:
> There is nothing preventing you from burning an ext2 image to a DVD.
> The only problem you will cause yourself is that you will be limiting
> the machines that will be able to read the DVD.
 > <snip>
> 
> If you want to create an ext2 image, you'll have to use dd to create an
> empty file, format it, then mount it.  You can create your image
> directly on the loopback drive.

Okay, still no luck.  Here's what I did this time:

% dd if=/dev/zero of=staging.ext2 bs=1024 count=7000k

% mke2fs -m 0 staging.ext2
...tell mke2fs to proceed even though target isn't block special device

% mount -t ext2 staging.ext2 staging_mountpoint/ -o loop

% df -h staging_mountpoint
Filesystem            Size  Used Avail Use% Mounted on
staging.ext2          6.8G   16M  6.8G  97% staging_mountpoint/

% dd if=6.5GBfile.gz of=staging_mountpoint/6.5GBfile.gz bs=1024
...this seemed to be slightly faster than cp

% umount staging_mountpoint

% cdrecord -dev=/dev/cdrom1 -verbose -dao -driveropts=burnfree staging.ext2
...no errors.  But again, fixating seemed to take a terribly short time.

% mount -t ext2 /dev/cdrom1 /cdrom
mount: block device /dev/cdrom is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/cdrom,
        missing codepage or other error
        In some cases useful info is found in syslog - try
        dmesg | tail  or so

...Taking its advice,
% dmesg | tail
attempt to access beyond end of device
hda: rw=0, want=8, limit=4
EXT2-fs: Couldn't read superblock on 2nd try.


I'm really pulling my hair out here.  Yes, I've tried different drives 
in different machines.  The messages in dmesg are the same both places. 
  It's this "attempt to access beyond end of device" business that has 
me really wondering...  something about the burned disc is causing the 
drive to not report its size correctly.

Is there something special I need to tell the cdrecord command to make a 
dual-layer DVD+R burn correctly?

CD-RWs work perfectly in the drive, burning and mounting.

~Brian