Re: switching root fs '/' to boot from RAID1 with grub

["H. Peter Anvin" <hpa@zytor.com>]

Doug Ledford wrote:
> 
> Correct, and that's what you want.  The alternative is that if the BIOS
> can see the first disk but it's broken and can't be used, and if you
> have the boot sector on the second disk set to read from BIOS disk 0x81
> because you ASSuMEd the first disk would be broken but still present in
> the BIOS tables, then your machine won't boot unless that first dead but
> preset disk is present.  If you remove the disk entirely, thereby
> bumping disk 0x81 to 0x80, then you are screwed.  If you have any drive
> failure that prevents the first disk from being recognized (blown fuse,
> blown electronics, etc), you are screwed until you get a new disk to
> replace it.
> 

What you want is for it to use the drive number that BIOS passes into it 
(register DL), not a hard-coded number.  That was my (only) point -- 
you're obviously right that hard-coding a number to 0x81 would be worse 
than useless.

	-hpa