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remastering peculiarities



Hi,

I am remastering the KNOPPIX V5 CD to free up some space for some different 
software.

I am following the quantian_howto_build guide (written for a 3.X series of 
KNOPPIX) with some suitable modifications for the latest version of KNOPPIX.

Specifically, I have copied the contents of the cd to my hard drive and used 
the cloop module to copy the compressed file system to a "source" directory.  
I then chroot to the "source" directory and make modifications, namely, 
remove some unneeded packages.  

I then exit the chroot'ed "source" and make a compressed file system using the 
following writing things to my "release" directory:

mkisofs -R -l -V "KNOPPIX iso9660 filesystem" -hide-rr-moved -v  \
        source/ | create_compressed_fs - 65536 > release/KNOPPIX/KNOPPIX

I then copy a bunch of files from the original cd to my "release", 
specifically, I do the following:

cp -vax orig-cdrom/[abci]* release/
cp -vax orig-cdrom/KNOPPIX/[biklLmMR]* release/KNOPPIX/
cp -vax orig-cdrom/KNOPPIX/KNOPPIX-* release/KNOPPIX/

After creating md5sums, I then make the iso using the following:

mkisofs -pad -l -r -J -v -V "KNOPPIX" -no-emul-boot -boot-load-size 4 \
   -boot-info-table -b boot/isolinux/isolinux.bin -c boot/isolinux/boot.cat \
      -hide-rr-moved -o ../knoppix.iso ../release

I then use qemu to boot this iso via:

qemu -m 512 -cdrom knoppix.iso -boot d

When I started this, I first tested that I could recreate the knoppix.iso 
without doing any package deletion.  That worked, so I then went to work 
pruning packages.  I did a big prune, and then made my iso going through the 
above steps.  When booting with qemu, I got the error:

	"Couldn't find KNOPPIX filesystem . . "

I then started the whole process of pruning over again, thinking that I may 
have deleted a crucial package.  I then started to prune a few packages at a 
time, creating an iso and testing with qemu.  I could create bootable 
modified knoppix.iso that worked.  

However, I would occasionally, find that after deleting some packages and 
recreating the iso, I would get the "Couldn't find KNOPPIX filesystem . . ." 
error.  When I got this error, I would try and do the above two mkisofs 
commands and test with qemu to see if the KNOPPIX filesystem error was 
non-deterministic.  

I then tried to prune a few more packages from my "source" and recreate the 
iso, and I was surprised to find that I created a bootable knoppix iso with 
this new (slightly smaller package set) filesystem.  

When I got the "Couldn't find KNOPPIX filesystem . . " error, I never tried to 
actually burn my iso and reboot with my new computer.  All testing 
of "bootability" was through qemu.

Why would the KNOPPIX filesystem errors present themself with a certain set of 
packages removed, the large ones, such as openoffice, firefox, scribus, 
thunderbird, etc, and then go away when a few more larger packages were 
removed from the chrooted "source"?

Am I getting some false errors by using qemu instead of actually burning them 
to a cd and rebooting my computer?  Using qemu was really a fast and 
convenient way to test the iso.  I would hate to have to actually burn the 
iso when I go about remastering KNOPPIX.

Thanks for any insights,

John Schmidt
jaschmidt@uofu.net



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