Bug report

[Rick Stevens]

On Thu, 2007-10-25 at 14:55 -0600, Karl Larsen wrote:
> Ian Burrell wrote:
> > Les Mikesell <lesmikesell <at> gmail.com> writes:
> >   
> >> Karl Larsen wrote:
> >>     
> >>>    I put the root and setup on the same thing, (hd5,3) which is disk 2. 
> >>> Disk 1 has root at (hd0,4) and setup at (hd0) and in the grub.conf it 
> >>> has a chainloader to disk 2.
> >>>
> >>>    This all works fine. But when disk 1 is booted it is at /dev/sdax. 
> >>> When disk 2 is booted IT is /dev/sdax.
> >>>
> >>> That is the problem.
> >>>       
> >> That's not a problem - it would be a problem if it didn't do that. 
> >> Windows (and probably some other things) have to boot from the first 
> >> bios drive and chainloader has no way to know what it is about to boot, 
> >> so it has to make the drive first in the bios table as part of the 
> >> chainloading operation.  So when linux is booted, it sees it as the 
> >> first drive too.  The only problem is that you told it to do that, then 
> >> filed the result as a bug...
> >>
> >> If you don't want it to do that, copy the kernel and initrd you want to 
> >> use into the linux boot partition on what you think is the primary drive 
> >> and use the menu selection to pick those and set the kernel root on the 
> >> other drive.
> >>
> >>     
> >
> > I am pretty sure that the grub chainloader command does not change the ampping
> > of drives.  There is a command, map, for remapping the drives.  As you said,
> > this is needed for booting DOS and early Windows that can only booting from the
> > first drive.  It should not be needed for chainloading other operating systems.
> >   Since Karl hasn't included his grub.conf, nobody can figure out where the
> > problem is coming from. 
> >
> >  - Ian
> >
> > timeout=5
> > splashimage=(hd0,5)/grub/splash.xpm.gz
> > hiddenmenu
> > title Fedora (2.6.22.9-91.fc7)
> >         root (hd0,5)
> >         kernel /vmlinuz-2.6.22.9-91.fc7 ro root=/dev/sda5  quiet
> >         initrd /initrd-2.6.22.9-91.fc7.img
> > title Fedora (2.6.22.7-85.fc7)
> >         root (hd0,5)
> >         kernel /vmlinuz-2.6.22.7-85.fc7 ro root=/dev/sda5  quiet
> >         initrd /initrd-2.6.22.7-85.fc7.img
> > title Fedora (2.6.22.5-76.fc7)
> >         root (hd0,5)
> >         kernel /vmlinuz-2.6.22.5-76.fc7 ro root=/dev/sda5  quiet
> >         initrd /initrd-2.6.22.5-76.fc7.img
> > title Fedora f7-64
> >         rootnoverify (hd1,2)
> >         makeactive
> >         chainloader +1

Ah, the makeactive thingie may have something to do with it.  That sets
the "active" flag in the partition table on the disk so the OS marks
that as /dev/sda.  There can only be one "active" partition in the
system.  DOS and early Windows systems use that flag to know where they
were booted from.  It shouldn't be necessary for a Linux kernel, grub
or lilo.

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- Rick Stevens, Principal Engineer             rstevens at internap.com -
- CDN Systems, Internap, Inc.                http://www.internap.com -
-                                                                    -
-                   To err is human, to moo bovine.                  -
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