[lug] speaking of drive reordering...

D. Stimits stimits at comcast.net
Tue Oct 31 19:31:11 MST 2006

Looking at the drive reordering, I came up with what seems like a 
curiosity to me. If we load grub, it for example can point at a boot 
partition with the actual secondary part of the boot process, e.g., the 
selection list of what to boot with which arguments. This particular 
selection list can use labels or actual devices. But what about the MBR 
itself? It seems when running grub-install, or lilo, that the MBR has 
the boot sector it'll use hard coded. I know this is true for example 
for lilo, because there are two bytes that can be altered to point the 
MBR of a lilo boot loader at a new boot sector.

But how about bootable cd's? Sometimes the cdrom drive might be 
/dev/hda, or hdc, or even a scsi device on some systems. Not really 
important if you want to point at an existing install, but it's a bit of 
a catch-22 for a live cd distro or a rescue system. Can the MBR itself, 
using grub, point at a label which has some generic meaning like "the 
drive the boot sector originates from", so that a cd can always point at 
itself? How does a live cd know where to find itself? So far as I know, 
the ability to use a label is *normally* from the secondary loader. How 
would one custom program a grub MBR to point to an ISO9660 system of 
itself for the secondary loader?

D. Stimits, stimits AT comcast DOT net

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