Re: cdrecord problems
> On Fri, Feb 25, 2005 at 10:58:11PM +0100, Vegard Lundby Rekaa wrote:
>> > Hi Vegard,
>> >
>> > what exactly are you comparing with md5sum? I ran into similar
>> problems
>> > when having an Iso image. When comparing the original Iso with the
>> burnt
>> > CD, I got read/write errors, IIRC. The way around was to mount the CD,
>> > do a
>> >
>> > mount -o loop image.iso /mnt/loop
>> >
>> > and then do something like:
>> >
>> > cd /mnt/loop/
>> > find ./ -type f | sort | xargs -n 1 md5sum > ~/iso.md5sum
>> > cd /cdrom/
>> > find ./ -type f | sort | xargs -n 1 md5sum > ~/cdrom.md5sum
>> > diff ~/iso.md5sum ~/cdrom.md5sum
>> >
>> > Hth,
>> > --
>> > Andreas Rippl -- GPG messages preferred
>> > Key-ID: 0x81073379
>> >
>> Thanks for the reply Andreas.
>>
>> I'm using the command 'md5sum /dev/cdrw' & 'md5sum image.iso', to
>> visually
>> compare the outputs. This have worked once before, do not know how.
>>
>> The method you mentioned gave no errormessages, and the final result
>> was:
>>
>> hjem:/mnt/loop# diff ~/iso.md5sum ~/cdrom.md5sum
>> hjem:/mnt/loop#
>>
>> Assuming this means the md5sum's are equal. Does this mean that the CD
>> burned is burned correctly, and the command 'md5sum /dev/cdrw' is not
>> working well?
>>
>> But still, the CD's I burn differ from the original. If I burn a
>> divx-movie, parts of the burned movie has big errors wich the original
>> does not have.
>>
>> Where is a good place to start looking for reasons for the error?
>>
>> Best regards Vegard
>>
> Hi Vegard,
>
> it's been a bit since I had these problems, but I remember that they
> mainly occurred because of lead-in/-out. From somewhere on the web I
> pulled the one-liner
>
> 'dd if=/dev/cdrom | head -c `stat --format=%s ISO_image` | md5sum'
>
> though I never really used it. My reasoning with the initial procedure
> is however: if it mounts and each single file has the same md5 sum as
> the original in the ISO, the CD is good. You have read each readable bit
> on the CD for the verification. I consider this a pragmatic approach
> which has worked for me so far.
>
> Regarding the errors in the movie, what command did you use to burn the
> CD? And does a verification between the loop-mounted ISO and the mounted
> CD show the metnioned errors? Otherwise I have no clues for that
> problem...
>
> Regards,
> --
> Andreas Rippl -- GPG messages preferred
> Key-ID: 0x81073379
>
I will investigate on this matter, and it may be a while I will be posting
again. I need to understand more of my computer. I will try these methods
you mention. I asked my uncle (advanced linuxuser) who said these errors
could be solved by lowering the burnspeed. What is your oppinion on this?
I will check md5sum's on the movies to see if they differ. Havn't thought
of doing that before. Used xcdroast to burn the movies.
Mainly my problem concerns using k3b or xcdroast in a satisfactory way.
The problems gives serious errors in these programs, and is not easy to
use as it is today.
Is it a possibility that the knoppix-iso-image contains errors?
Thanks for your help!!
Best regards Vegard.
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