dual boot two disk
jerrymc at clunix.cl.msu.edu
Thu Mar 17 06:12:26 PST 2005
> I have a problem booting the second disk with fbsd's boot manager. I
> installed a new disk as pri/master (ad0) and moved my old disk to
> sec/master (ad2). Then devided ad0 (40GB) with fbsd's fdisk in 10G (ufs)
> and 30G (fat) and installed FreeBSD 5.3 with a boot manager on the first
> 10G. When I boot the system I get:
> F1 FreeBSD (the fbsd on ad0s1)
> F2 DOS (the 30G fat, ad0s2)
> F5 Other (again the fbsd)
> So there is no option to boot from the second disk!?
> Allso when I unlplug ad0 or change the BIOS to boot from ad2 (hd1 as he
> sees it), WinXP boots just fine, meaning, there is no problem with the
> mbr on ad2.
Hmmm. I am not exactly clear from your description, but...
I would expect that when you hit F5, you would be presented with
a new menu that included the ad2 disk. Maybe that disk does not
really have an MBR, but only a boot block (the second part of
the disk boot process [or third if you count BIOS]). I believe
each disk that has bootable slices (which have boot blocks/sectors)
also needs to have an MBR for it to work right. If you are brave,
try using fdisk to write the MBR to ad2 as well. I don't think
that would mess up anything and might be what is missing.
Something like: fdisk -BI -b /boot/boot0 ad2
I don't know if FreeBSD 5.3 still keeps its MBR in /boot/boot0.
You may have to check that.
> I read the man for boot0cfg, but I can't make heads or tails of ti!!!
> how do I configure/install the boo0 to show the second disk ni the boot
I generally use fdisk and not boot0cfg, but I think it is basically
the same for what you are trying to do here.
Something like: boot0cfg -B -b /boot/boot0 -o packet ad2
You might want to add -f some_file_name if you want it to save whatever
was in the sector0 before the command. You can put it back if you need.
You may also need -m 0x1 or -m 0x3 or -m 0x7 or -m 0xf depending
on if you have 1, 2, 3 or 4 slices actively bootable. I think it
is supposed to figure it out, but if it doesn't, then try those.
You migh also want to include the -v flag to make it print out more
stuff when it runs.
You might also want to do the exactly the same or the same fdisk to ad0
By the way, what happened to ad1? (I don't muck with IDE - I have SCSI
so, I am not up on its device naming schemes)
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