CD/DVD Verify

[Jonathan Allen]

Paul Howarth wrote:
> 
> You could read back the data from the CD device using dd and then 
> compare what you get back with the original ISO.

Thank you for the suggestion.  I just tried:

   # dd if=/dev/cdrom of=file

and got a clutch of errors like:

   hdc: command error: status=0x51 { DriveReady SeekComplete Error }
   hdc: command error: error=0x50 { LastFailedSense=0x05 }
   ide: failed opcode was: unknown
   end_request: I/O error, dec hdc, sector 1904, 1912, 1920, etc in turn

What does that mean ?  The result produces a file 901120 bytes long, when
the original ISO file is 987136 bytes long, but at least at the front they
look pretty identical to 'od -c'

When the drive is mounted, all the files on the CD seem OK and don't
generate any media errors.

Jonathan