Re: howto verify burn?
On Sat, 8 Mar 2003 06:55, Narins, Josh wrote:
> > From: bob parker, Sent: Friday, March 07, 2003 11:10 AM
> >
> > On Fri, 7 Mar 2003 03:16, Brad wrote:
> > > See this post for more detail on this subject:
> >
> > http://lists.debian.org/debian-devel/2002/debian-devel-200211/
> > msg03076.html
> >
> > > -Brad
> >
> > Checked it out. From the posts it is still inconclusive.
> > So far as jigdo is concerned I have the isos and the md5sums
> > all match the
> > source. This is about verifying the burnt cdr.
> >
> > So far, the only reliable technique I have been able to find
> > is to do it file
> > by file.
> >
> > That is easy if you have no subdirectories on the cdr, but
> > gets a little
> > messy if you do, the files have to be piped to md5sum from
> > find and xargs.
> >
> > Example:
> > find /cdrom1/ -type f -print | xargs md5sum | cut -d ' ' -f 1
> >
> > | sort > sumscdr
> >
> > mount whatever.iso -r -t iso9660 -o loop /mnt
> >
> > ind /mnt/ -type f -print | xargs md5sum | cut -d ' ' -f 1 |
> > sort > sumsiso
> >
> > diff sumsiso sumscdr
> >
> > Not sure if the sort step is really needed.
>
> I'm confused, Bob.
>
> If you copy the ISO from the CD-R to your hard drive, and do an md5sum on
> it, and it matches the original ISO's md5sum, you just can't have two files
> that are different, unless they are different in miraculously md5sum
> balancing ways.
My big problem is that I can't copy the iso from the cdr to the hard drive,
not with dd, cat, nor with readcd. They all crash with errors toward the end
of the copy. Naturally I can't pipe it into md5sum either.
In spite of that, I can recreate the iso from the cdr using mkisofs, and the
file by file md5 check against the original iso all check out ok.
The iso in question is knoppix 3.1 en.
Cdrs burnt from it boot into knoppix ok and I have tested it by running many
of the applications.
Morover, I've burnt the cdrs on 2 different burners, on 2 brands of media,
same computer and kernel.
I'm looking closer at my use of cdrecord for now.
Bob
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