Help w/ GRUB, dual boot

Help w/ GRUB, dual boot

Post by Douglas Ma » Sat, 22 Oct 2005 23:20:55



<snip>
You're all set then ;-)
root (hd2,0) <- wrong
rootnoverify (hd2,0) <- right
Notice: Part of response inline.

It sounds like you've been through a wringer. I am not sure my first
choice would have been to go back to an older version, just because it
had been working before. I think you were very close with the later
version (Suse 10).

Another thing that can throw of Grubs count of the devices is BIOS
settings. That is, if you have changed your BIOS to boot SCSI
devices before IDE devices, then the count will be off. You can know for
sure by entering the geometry command when grub boots (get to command
mode first with a "c").

Anyway, maybe the first little fix in the configuration file will be
enough to get you back on track.
 
 
 

Help w/ GRUB, dual boot

Post by Douglas Ma » Sun, 23 Oct 2005 00:48:04


The geometry command is something you can use as a simple identification
test. It will tell you what grub is seeing at that moment for a given
drive. For example, I can obviously idenetify which is the 80G drive and
which is the 160G drive in my system by entering these commands:

grub> geometry (hd0)
drive 0x80: C/H/S = 13526/16/63, The number of sectors = 79694496,
/dev/hda

grub> geometry (hd1)
drive 0x81: C/H/S = 9729/255/63, The number of sectors = 156301488,
/dev/hdb

(It's harder if your drives are exactly the same. This a simple case.)

You should be able to do the same thing with your setup to identify your
drives. The point I am trying to make is that if you have set your system
_BIOS_ to boot from SCSI first (for Windows), then sda may actually be hd0.

Because grub appears to be correctly installed, (menu display, linux
starts, etc.), you can check that your assumptions are correct by entering
grub's command mode at system boot (using "c" after the menu is
displayed). From there, you can enter the geometry commands to check your
assumptions are the same as what grub is using at that moment. You can
also enter any commands which appear in your menu.lst file in that command
environment.