Re: broken pmbr?

From: John Baldwin <jhb_at_freebsd.org>
Date: Tue, 21 Jul 2009 09:36:18 -0400
On Tuesday 21 July 2009 1:51:08 am Edho P Arief wrote:
> On Mon, Jul 20, 2009 at 9:57 PM, John Baldwin<jhb_at_freebsd.org> wrote:
> > On Friday 17 July 2009 10:42:07 pm Edho P Arief wrote:
> >> I just managed to, um, break my installation boot using these steps:
> >>
> >> 1. system with at least two disks (say ad0 and ad4)
> >> 2. create gpt partition on ad0
> >> 3. create at least one freebsd-ufs on ad0
> >> 4. install freebsd on ad4 using gpt (
> > http://m8d.de/news/freebsd-on-gpt.php )
> >> 5. reboot and boot to ad4
> >> 6. 'Missing boot loader'
> >>
> >> (Rearranging ad0 to adX where X>4 or removing ad0 solves the problem, btw)
> >>
> >> Does pmbr only search first drive with gpt it found?
> >
> > /boot/pmbr only looks on the current disk, yes.  You could put the boot
> > partition on ad0 and then put a /boot.config in the UFS partition on ad0 that
> > points to ad4 if you want it to find the boot loader from ad4 instead of ad0.
> 
> I looked to me pmbr only find *first* disk-containing-gpt, not the
> disk where it's booted from.

No, it uses the %dl register from the BIOS to do all it's disk I/O and that is
always the drive that contains the pmbr code itself.

-- 
John Baldwin
Received on Tue Jul 21 2009 - 11:44:00 UTC

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