[Pkg-libburnia-devel] Large size penalty from -isohybrid-mbr and -partition_offset 16?

[Colin Watson]

Hi,

I'm working on converting Ubuntu's CD images over to xorriso in order to
make use of -isohybrid-mbr.  (Thanks for adding the jigdo facilities!)

I'm a bit perplexed at the size increase that -partition_offset 16
causes, though, and was wondering if it was a bug or if I need to fiddle
about with command-line options.  Here's a table of sizes with my
current test image contents:

  genisoimage                                                689254400
  xorriso                                                    689281024
  xorriso -isohybrid-mbr isohdpfx.bin                        690270208
  xorriso -isohybrid-mbr isohdpfx.bin -partition_offset 16   693415936

The 1MB penalty for -isohybrid-mbr is larger than I expected, but the
last size is particularly weird.  Why is there a 3MB size penalty for
having a 32KB partition offset?

My full command line is:

  xorriso -as mkisofs -r -checksum_algorithm_iso md5,sha1 --hardlinks -V Ubuntu-Server\ 11.10\ i386 -o /srv/cdimage.ubuntu.com/scratch/ubuntu-server/daily/debian-cd/i386/oneiric-server-i386.raw -jigdo-jigdo /srv/cdimage.ubuntu.com/scratch/ubuntu-server/daily/debian-cd/i386/oneiric-server-i386.jigdo -jigdo-template /srv/cdimage.ubuntu.com/scratch/ubuntu-server/daily/debian-cd/i386/oneiric-server-i386.template -jigdo-map Debian=/srv/cdimage.ubuntu.com/ftp/ -jigdo-exclude boot1 -md5-list /srv/cdimage.ubuntu.com/scratch/ubuntu-server/daily/tmp/oneiric-i386/md5-check -jigdo-min-file-size 1024 -jigdo-exclude README\* -jigdo-exclude /doc/ -jigdo-exclude /md5sum.txt -jigdo-exclude /.disk/ -jigdo-exclude /pics/ -jigdo-exclude Release\* -jigdo-exclude Packages\* -jigdo-exclude Sources\* -jigdo-exclude Contents\* -jigdo-force-md5 /pool/ -isohybrid-mbr syslinux/usr/lib/syslinux/isohdpfx.bin -partition_offset 16 -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table boot1 CD1

This is with xorriso 1.0.8.

Thanks,

-- 
Colin Watson                                       [cjwatson at ubuntu.com]