extrait de
/usr/share/doc/mkisofs/README.eltorito.gz
ca explique comment faire à partir d'un disquette boot.
=======================================================
How To Make Bootable CDs
------------------------
For the x86 platform, many BIOS's have begun to support bootable CDs.
The standard my patches for mkisofs is based on is called "El Torito".
The "El Torito" standard works by making the CD drive appear, through BIOS
calls, to be a normal floppy drive. This way you simply put an floppy
size image (exactly 1440k for a 1.44 meg floppy) somewhere in the
iso fs. In the headers of the iso fs you place a pointer to this image.
The BIOS will then grab this image from the CD and for all purposes it
acts as if it were booting from the floppy drive. This allows a working
LILO boot disk, for example, to simply be used as is.
It is simple then to make a bootable CD. First create a file, say "boot.img"
which is an exact image of the boot floppu currently in use. There is
at least one HOWTO on making bootable floppies. If you have a bootable
floppy handy, you can make a boot image with the command
dd if=/dev/fd0 of=boot.img bs=10k count=144
assuming the floppy is in the A: drive.
Place this image somewhere in the hierarchy which will be the source
for the iso9660 filesystem. It is a good idea to put all boot related
files in their own directory ("boot/" under the root of the iso9660 fs,
for example), but this is not necessary.
One caveat - Your boot floppy MUST load any initial ramdisk via LILO,
not the kernel ramdisk driver! This is because once the linux kernel
starts up, the BIOS emulation of the CD as a floppy disk is circumvented
and will fail miserably. LILO will load the initial ramdisk using BIOS
disk calls, so the emulation works as designed.
The "El Torito" specification requires a "boot catalog" to be created as
ll.
This is a 2048 byte file which is of no interest except it is required.
My patches to mkisofs will cause it to automatically create the
boot catalog. You must specify where the boot catalog will go in the
iso9660 filesystem. Usually it is a good idea to put it the same place
as the boot image, and a name like "boot.catalog" seems appropriate.
So we have our boot image in the file "boot.image", and we are going to
put it in the directory "boot/" under the root of the iso9660 filesystem.
We will have the boot catalog go in the same directory with the name
"boot.catalog". The command to create the iso9660 fs in the file
bootcd.iso is then
mkisofs -b boot/boot.img -c boot/boot.catalog -o bootcd.iso .
The -b option specifies the boot image to be used (note the path is
relative to the root of the iso9660 disc), and the -c option is
for the boot catalog file.
Now burn the CD and its ready to boot!
===========================================================
bonne chance