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I'm trying to copy a SUSE 9 DVD using basic linux commands. The ultimate goal is to modify the DVD content before creating the new image. It works after a fashion except the new .iso is a bit larger than the original, and won't fit back on a DVD.

Where does the bloat come from, and how can I get rid of it?

Here's what I did;

isoinfo -d -i /dev/sr0    # note blocksize and volumesize
dd if=/dev/sr0 bs=blocksize count=volumesize of=foo.iso 
mkdir foo
mount -t iso9660 -o loop foo.iso foo
cp -av foo bar
mkisofs -b boot/loader/isolinux.bin -c -boot-info-table -no-emul-boot -r -J -o bar.iso bar

Note that I didn't change anything in bar, yet the bar.iso is bigger than foo.iso, enough so that it won't fit back on a DVD. 'du' shows bar is bigger than foo, but 'diff' shows no differences

du -sk foo bar
4699143 foo
4710654 bar

du -sk foo.iso bar.iso 
3888145 foo.iso
4708322 bar.iso

isoinfo -d -i foo.iso
Volume size is: 1942170

isoinfo -d -i bar.iso
Volume size is: 2351864
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up vote 0 down vote accepted

Be sure to use mkisofs from cdrtools, and not from dvdrtools or cdrkit, the latter contain ancient versions of mkisofs which are slow and produce large ISOs.


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checked using --version as linked article described, and I do have the wrong one. Where do I get the right one? Will it be on the Suse 9.3 install disks? – CAB Sep 12 '12 at 17:31
That's very much dependent on the linux distribution, I don't know about Suse, though you can always download the sources and compile yourself. – wich Sep 13 '12 at 0:35
We were pressed by lack of time to settle for using a dual layer DVD, which for now, seems to work for us. – CAB Sep 14 '12 at 12:43

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