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

Prakash K. Cheemplavam
2003-11-05T10:29:55Z

Jens Axboe wrote:
> On Wed, Nov 05 2003, Prakash K. Cheemplavam wrote:
>
>>Jens Axboe wrote:
>>
>>>On Wed, Nov 05 2003, Prakash K. Cheemplavam wrote:
>>>
>>>
>>>>Jens Axboe wrote:
>>>>
>>>>
>>>>>On Wed, Nov 05 2003, Prakash K. Cheemplavam wrote:
>>>>>
>>>>>
>>>>>
>>>>>>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?
>>>>>>>
>>>>>>>
>>>>>>>Is actual data missing at the end? If yes, I'd say this looks a lot
>>>>>>>more
>>>>>>>like a cdrecord problem.
>>>>>>
>>>>>>Sorry, I wasn't precise: The data is on the disc, as my DVD-ROM
>>>>>>restores the full image (md5sum matches), but the CD-RW does not.
>>>>>
>>>>>
>>>>>You need to use the pad option to record.
>>>>
>>>>Uhm, could you be more specific? I just use the k3b frontend to burn,
>>>>and in the cdrdao manual I couldn't find something useful to it.
>>>
>>>
>>>it's a cdrecord option, I've never used k3b so cannot comment on how to
>>>make it enable that.
>>
>>Hmm, I'll take a look, but I don't really think it is a problem of the
>>recording programme, otherwise how could my reader read it out completely?
>
>
> It isn't a problem of the recorder program. But some drives wont read
> the very end of a disc unless there are some pad blocks at the end.
> Thus, you should always use the cdrecord pad option.

Uhm, ok, I just took a look at the source image and the last (missing)
4096 bytes are just 00, so nothing critical missing anyway...so your pad
parameter sounds sensible. :) Should drop a note to the k3b devs then,
as well...

> SG_IO or CDROM_SEND_PACKET? The latter should never have been merged in
> cdrecord, and you should never use it. If it is using SG_IO, I'm very
> interested in knowing more. vmstat 1 while doing the burn would be
> interesting, just for 10 seconds where you see the problem.

Uhh, I'll try to find out. I must go now, but I'll report back later.

>>probably is a new issue. Furthermore my hd reading (I once contacted you
>>because of that) didn't improve with the new kernel, though some
>>bugfixes in this directions are mentioned by Andrew Morton.
>
>
> Don't remember, sorry :)

I probably will make a new topic regarding issues (I think) I found with
the new mm kernel.

cya,

Prakash