(no subject) [GRUB boot problems]

[Phil Schaffner]

On Tue, 2004-01-13 at 03:42, Paolo wrote:
> Scott Talbot said:
> > On Mon, 2004-01-12 at 13:07, Krikket wrote:
> >> On Mon, 12 Jan 2004, Paolo wrote:
> >
> >>Snip<
> >
> >> > now the real issue,
> >> > I installed fc1 but when I boot the machine I can only boot windowsXp,
> >> > there is no sign of grub ( I installed it the MBR)
> >
> > The only thing I can figure is that you either installed GRUB to the MBR
> > of the second hard drive, or to the boot sector of a partition or it
> > wasn't actually installed anywhere.
> >
> > Assuming you booted into linux using a disk, get onto a terminal as root
> > and issue the command:  grub-install /dev/hda
> >
> > That should get you going.
> 
> It doesn't work. I already tried it...
> 
> Thanks.

Have seen a number of cases where the BIOS disk mapping does not match
what the running system sees.  This seem to happen particularly with
RAID controllers and/or SCSI controllers mixed with IDE.  Try making a
grub boot floppy on a working system and doing a "find /grub/stage1" (or
"find /boot/grub/stage1" if you do not have a /boot partition) and find
out what grub sees as (hdM) and (hdM,N) where M=[disk 0, 1, etc.] and
N=[partition 0, 1, ...].  You should be able to boot the system from the
floppy once you figure it out.

You may find that the floppy boot sees different mappings than the
installation saw, or that the running system will see if/when you get it
to boot.  Use /boot/grub/device.map to get consistent results after you
figure out the mapping.  When running grub from the command line when
the system is up, use "grub --device-map=/boot/grub/device.map" and do
finds similar to above to verify the mapping.  Once you have it right,
you should be able to do something like:
	# grub --device-map=/boot/grub/device.map
	grub> root(hd0,1)
	grub> setup (hd0)
	grub> quit

Good luck - this is a trial-and-error process in my experience on
systems where the grub disk ordering changes between boot-time and
running system.

Phil