Dual booting problems

Jerry McAllister jerrymc at msu.edu
Fri Mar 2 17:52:05 UTC 2007

On Fri, Mar 02, 2007 at 05:39:05PM +0000, Alex Zbyslaw wrote:

> Jerry McAllister wrote:
> >If you select F5 (maybe F6 or more,  I should try that some time) it
> >will instead cause the MBR from that second (maybe third, etc) disk to 
> >be loaded and passes control to it.
> >
> F5 moves to the next disk.  From that next disk F5 moves on to the next 
> disk again and so forth until there are no more disks and then it moves 
> you back to the first disk.  No F6 or greater.

OK.  That makes sense.  I have not had enough disk on hand to try
beyond two.

> F5 will only successfully move on if there is a FreeBSD MBR (*) on the 
> next disk.  If there is not such an MBR, the F5 option is displayed but 
> will not work (maybe beep?) and after a while you will timeout and boot 
> whatever default you have.

Hmmm.   I thought it would still do a 'dedicated' FreeBSD disk as the
second one without an MBR.   It will do the first disk, but that is
a different situation, of course.

> Bad idea to lose the MBR from a disk in the middle of a chain, but easy 
> to put back booting from CD1.

Yup.  If you lose the MBR, it can be put back using the Fixit from
the installation CD  (CD-1).

> So as the OP had:
> F1: FreeBSD
> F5: Disk 2 (Windows)
> but had not put FreeBSD MBR on that second disk, F5 did nothing and then 
> the F1 default kicked in and booted FreeBSD.  Had the MBR been on that 
> second disk it would have started to boot windows and then likely 
> rebooted because the disk was no longer in the same position in the 
> chain as it had been when Windows was installed.

Makes sense.  I don't keep up with the Windows stuff much, but I knew
it would not be happy in that position and the lack of an MBR on the
second disk was where the boot process was stopping.

> I don't believe it is necessary for Windows to always be the first disk, 
> just that the disk has to stay in the same position as it was in when 
> Windows was installed, which is usually the first disk!  (Never tested 
> that though).

Hmmm.   Might be interesting to experiment, though that time spent on
MS could probably be better spend elsewhere.

> --Alex
> (*) Actually I have no idea what would happen if you stuck some other 
> booter like grub or gag on a later disk.  But blank (new) disk or 
> Windows MBR will not move on.

Don't know this one.


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