CD/DVD Verify
Paul Howarth
paul at city-fan.org
Thu Sep 14 10:24:11 UTC 2006
Jonathan Allen wrote:
> 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
Try:
# dd if=dev/cdrom of=file bs=2048
> 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.
Given that the length of the resulting file is *less* than that of the
original ISO, I suspect that there is a problem with the recording. If
you got a resulting file that was *bigger* than the original ISO then
that might not be an issue, as you could have read back some of the
lead-out data after the end of the filesystem; as long as the files are
identical up to the length of the original ISO, all should be OK but
that's not the case here.
Paul.
More information about the users
mailing list