Anyone understand GRUB?

[Kurt Wall]

On Wed, Nov 29, 2006 at 09:52:54AM -0600, Michael Hipp wrote:
> My system boots off a RAID1 SCSI but has a potload of IDE disks after that. 
> I'm trying to figure out what to put in /boot/grub/menu.lst so it will boot 
> faithfully from either SCSI disk.
> 
> Here's what I currently have (somewhat leftover from when I had only IDE disks):
> 
> title           Ubuntu, kernel 2.6.15-27-server SCSI Disk1
> root            (hd0,0)
> kernel          /vmlinuz-2.6.15-27-server  md=0,/dev/sda1,/dev/sdb1
>                  md=1,/dev/sda2,/dev/sdb2 md=2,/dev/sda3,/dev/sdb3
>                  md=3,/dev/hda1,/dev/hdc1
>                  root=/dev/md1 ro quiet splash
> initrd          /initrd.img-2.6.15-27-server
> savedefault
> boot
> 
> That 'kernel' line is all one line but I wrapped it here for readability sake. 
> Here's what the md devices mean:
> 
>    md0  /boot
>    md1  /(root)
>    md2  swap
>    md3  bulk data storage (not need for booting)
> 
> The 'root' line is what bugs me. I think hd0 properly refers to sda since I 
> have BIOS set to boot SCSI first. (How to verify that?) But why does it boot 
> properly using the '0' partition (that's /boot). And what do I put in to allow 

hd0 refers to the first disk. It boots properly because (hd0,0) is where 
/boot lives, and /boot contains grub/ (/boot/grub).

Kurt
-- 
The farther you go, the less you know.
	-- Lao Tsu, "Tao Te Ching"