Re: Creating a bootable cdrom that includes Grub.

[Thierry Laronde]

Hello,

On Sat, Jul 20, 2002 at 10:08:20AM +0900, umidori kamome wrote:
> Hey Yo Hoh, Harry!
> 
> > While I have not had any problems [..] booting
> > an operating system off my hard drive
> 
> me neither
> 
> > when trying to actually boot Linux off the cdrom
> 
> that is propably my problem, too -
> but i was trying to boot an install-cd (win i am
> afraid) - so do i need the following, as well?
> 
> > using hard drive emulation.
> 
> And then
> 
> > Which device should I be calling to boot the cdrom?  >
> (hd0,0) along with /dev/hda1 or should I be calling
> > the loop device /dev/loop0p0 or loop1p1 instead?
> 
> hope that makes the problem a little clearer - and
> someone can help us

The problem is that the emulation doesn't survive for Linux, that is,
what was for GRUB under El Torito emulation (hd0) [the hard disk
emulation] is no more accessible to Linux, since Linux doesn't use
directly the BIOS for that. Hence, you need to give to Linux the name of
the CDROM device, which must be accessible i.e. which must be driven
with the correct driver inserted in Linux OR loaded as a module, but
then you need to put this module in an initrd residing in the hard disk
emulation and loaded by GRUB. To try to load something residing as a
part of the HD emulation will be tricky, and will imply to mount the HD
emulation file from the CDROM device on a loop device.

So the solution is IMHO, to load Linux with a initrd where the needed
modules for the possible CDROM drives reside, and to let Linux load the
correct module and then access the whole CDROM via the correct device
name to pivot_root.

Cheers,
-- 
Thierry Laronde (Alceste) <address@hidden>
Key fingerprint = 0FF7 E906 FBAF FE95 FD89  250D 52B1 AE95 6006 F40C