Re: How to prepare an ISO 9660 CD for booting via GRUB ?

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

> GRUB2 iso generated with grub-mkrescue is a bit special: it can be boot
> as either CD, HDD or floppy. For CD boot it follows El Torito no
> emulation boot.

Ahum ... grub-1.98/util/grub-mkrescue.in :

  iso_uuid=$(date +%Y-%m-%d-%H-%M-%S-00)
  grub_mkisofs_arguments="${grub_mkisofs_arguments} --modification-date=$(echo ${iso_uuid} | sed -e s/-//g)"
  [...]
  grub_mkisofs_arguments="${grub_mkisofs_arguments} -b boot/grub/i386-pc/eltorito.img -boot-info-table \
                --embedded-boot ${embed_img}"
  [...]
  grub-mkisofs ${grub_mkisofs_arguments} --protective-msdos-label -o ${output_image} -r ${iso9660_dir} ${source}


Do i get it right that there are two
boot files:
- eltorito.img for CD
- ${embed_img} for MBR style booting

I don't see the -no-emul-boot option, though.
Are you sure it is effectively used ?
man mkisofs says -b is by default floppy
emulation.

For comparison, this is the official ISOLINUX
production gesture which already works 
with xorriso:
  mkisofs -o output.iso \
      -b isolinux/isolinux.bin -c isolinux/boot.cat \
      -no-emul-boot -boot-load-size 4 -boot-info-table \
      root-of-iso-tree

So if there is indeed a -no-emul-boot option in
grub-mkrescue then it seems to be mainly about
implementing option --embedded-boot combinable
with the El Torito option -b.


These seem to be Robert's novelties:

  --modification-date         Override modification date
     Probably ECMA-119, 8.4.27,
     Volume Modification Date and Time
     (BP 831 to 847 of Primary Volume Descriptor)

  --protective-msdos-label    Patch a protective DOS-style label in the image
     What is this ?
     How does it look and at what address
     to write it ?


> I'll happily discuss GRUB and
> xorriso collaboration. Would you mind joining our IRC channel?

I would prefer e-mail. Public or private.
It's so nicely asynchronous.


Have a nice day :)

Thomas