CD/DVD Verify

[alan]

On Wed, 13 Sep 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
>
> 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.

You can try generating MD5 or SHA1 checksums for the files and see if they 
match.

There is a tool for detecting weak sectors on a burned cd-r, but I cannot 
remember the name.

k3b has a number of verification features. I usually use that for burning 
cds/dvds.

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