Re: 2.9test9-mm1 and DAO ATAPI cd-burning corrupt

Prakash K. Cheemplavam
2003-11-05T09:58:45Z

Jens Axboe wrote:
> On Wed, Nov 05 2003, Prakash K. Cheemplavam wrote:
>
>>Jens Axboe wrote:
>>
>>>On Mon, Nov 03 2003, Prakash K. Cheemplavam wrote:
>>>
>>>
>>>>Hi,
>>>>
>>>>well I am using k3b0.10.1 and either choosing cdrdao or cdrecord in DAO
>>>>mode to burn the cd ends up in non-bit identical copies, wheres ion TAO
>>>>(atleast with my 10x CD-RW I tested) the copy succeded. I tried several
>>>>times, and always got this issue.
>>>>
>>>>bash-2.05b$ md5sum livecd-2.6_10-23-2003.iso
>>>>f73f3a74239dfe94b322b85fd14a306e livecd-2.6_10-23-2003.iso
>>>>
>>>>TAO:
>>>>bash-2.05b$ md5sum /dev/cdroms/cdrom1
>>>>f73f3a74239dfe94b322b85fd14a306e /dev/cdroms/cdrom1
>>>>
>>>>DAO:
>>>>bash-2.05b$ md5sum /dev/cdroms/cdrom1
>>>>09e7e2a51af4c64685831513fbac18c2 /dev/cdroms/cdrom1
>>>
>>>
>>>Could you please try and cmp the two images, finding out how big the
>>>corrupted chunks are and what kind of data they contain?
>>
>>After some further investigation I found out, that the data is NOT
>>corrupted, but in a way truncated in DAO mode: When I read out the image
>>from the CD-RW drive, about 5kbyte are missing at the end (and doing
>>several burn, it is always the same amount). Strange enough if I read
>>the DAO burnt disk out by my DVD-ROM, the image can be read out
>>completely! Can you understand this behaviour? I don't think it is a
>>problem of my burner, but rather of the atapi driver?
>
>
> This is not a problem per-se (you can read the files, right?), it's just
> an artifact of burning the images differently. When you say truncated,
> do you mean that actual data is missing?

I am not an expert of iso image structure, but I would say yes. The
original iso is about 5kb bigger than the image read after DAO burning.
So when you imagine this truncated image would be burn, read, burnt etc,
nothing of the original image would be left.

Prakash