GRUB with IDE and SCSI disk

[Les Mikesell]

On Wed, 2006-03-22 at 22:29, Matthew Saltzman wrote:
> One of my systems has an IDE disk and a SCSI disk.  I upgraded the IDE 
> disk and I need to reinstall grub.  /boot is in /dev/sda1, but the system 
> boots off of /dev/hda.
> 
> I've tried various things to install GRUB on the new /dev/hda, but 
> everything results in a complaint during boot that
> 
> Error 21: Selected disk does not exist.
> 
> For example, in GRUB shell, I installed using:
> 
>  	> root (hd1,0)
>  	> setup (hd0)
> 
> The installation seems to work fine, but boot fails as above. I had this 
> working before, but for my life I can't recall how I did it differently 
> from this.
> 
> What am I missing?

You have to install on the drive bios will boot from and
the numbers are from the bios perspective.  If bios is
set to boot from the ide, then 'root (hd0,0)' would
mean the master boot block of the ide.  /boot/grub/device.map
should show how the drives are interpreted during install.

-- 
  Les Mikesell
   lesmikesell at gmail.com