Grub and XP

[Jeff Vian]

On Thu, 2004-07-22 at 21:14, Buck Lemke wrote:
> Jeff Vian wrote:
> 
> >On Thu, 2004-07-22 at 19:24, Wesley (Buck) Lemke wrote:
> >  
> >
> >>I had linux installed.  I installed XP.  Then I re-installed Grub to the 
> >>MBR ->
> >>
> >>grub> root (hd0,0)
> >>grub> setup (hd0)
> >>
> >>I now have XP installed on the master drive of the first ide controller, 
> >>and FC2 on the slave.  How should my grub.conf look?  This is what I 
> >>have now:

<snipped>

> >
> >for me hd2 is my scsi drive and I have the bios set to boot from scsi.
> >
> >-----
> >
> >
> >default=0
> >timeout=10
> >splashimage=(hd1,0)/grub/splash.xpm.gz
> >title Fedora Core (2.6.6-1.435.2.3)
> >        root (hd2,0)
> >        kernel /vmlinuz-2.6.6-1.435.2.3 ro root=/dev/sda3 rhgb quiet
> >acpi=no
> >        initrd /initrd-2.6.6-1.435.2.3.img
> >title Fedora Core (2.6.5-1.358)
> >        root (hd2,0)
> >        kernel /vmlinuz-2.6.5-1.358 ro root=/dev/sda3 rhgb quiet
> >        initrd /initrd-2.6.5-1.358.img
> >title Win
> >        rootnoverify (hd0,0)
> >        chainloader +1
> >
> >
> >
> >  
> >
> Well, I'm replying to this in XP.  I got it to work with hd1 for XP and 
> hd0 for linux.  I also had to put the map (hd0) (hd1) and map (hd1) 
> (hd0) for XP to boot.
> 
> The wierd thing is that if I'm in Linux, and do a 'df' it shows root 
> mounted on /dev/hdb1.  So the way I understand it, that means that I 
> couldn't boot to linux if I have root (hd0, 0)....but that is the only 
> way it works.
> 
> 
> Basically I have no idea why it is working, but it is working now...
> 

What are the contents of /boot/grub/device.map ??

It sounds like your grub was installed mapping /dev/hdb as hd0 and
/dev/hda as hd1.

It certainly will work as you have it, but it seems you have to use the
map trick in the grub stanza to allow grub to actually see the master
disk as hd0.  Since the map command uses the devices mapping as
configured in device.map then swaps them I expect the difference can be
seen there.

Also, what device is BIOS set to boot from?  

Windows always sees the boot device from BIOS (or from grub) as C:\ .,
but Linux uses the position where it is physically attached to the
controller to set its name. Thus, under Linux, the slave drive on the
primary IDE controller is always /dev/hdb in Linux, and the master
device on the secondary controller is always /dev/hdc regardless of
which is used to boot or how many drives are physically attached.