On Sun, Feb 27, 2005 at 04:22:19AM +0100, Vegard Lundby Rekaa wrote:
> > 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 agree on the burnspeed, if you run at the maximum, anyway. Set it a
bit lower.
>
> 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.
>
>
From where you downloaded Knoppix, there should also be a file with the
md5sum of the ISOs, compare them _before_ burning...:)
I think you could try to burn on the command line, this way you have
more control over what's going on...
So to start, you should find your devices in cdrecord-speak:
cdrecord -scanbus
As you are running a 2.4 kernel, I assume that you get the correct
output of your devices (with SCSI emulation) right here. If you have
problems, do 'cdrecord -scanbus dev=help'. Then you can master a CD from
a set of files simply by doing
mkisofs -J -R -- directory_to_burn | cdrecord -v fs=6m speed=8 \
driveropts=burnfree dev=ATA:1,1,0 -
all on one line. The device is from the scanbus command. From here on it
only gets easier, as burning an ISO image doesn't require a pipe:
cdrecord -v fs=6m speed=8 driveropts=burnfree dev=ATA:1,1,0 file.iso
I have wrapped these two essential lines around a somewhat longer shell
script to be able to add options conveniently. And don't forget the
-dummy option if you already have enough coasters...:). I find burning
CDs/DVDs on the command line much less intrusive than using
k3b/xcdroast, <devilish_smile> plus think of all the poor Windows users
who have to wait before continuing to work 'because they don't want to
mess up their CD' </devilish_smile>.
Good luck,
--
Andreas Rippl -- GPG messages preferred
Key-ID: 0x81073379
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