Looking for a GPT-aware boot manager

[Peter Wemm]

On Thu, Jul 10, 2008 at 8:09 PM, Carlos A. M. dos Santos
<unixmania at gmail.com> wrote:
> Hello,
>
> I'm attempting quad-boot my notebook with STABLE and CURRENT, both
> i386 and AMD64. I installed them manually by booting from a thumb
> drive, partitioning the hard disk and extracting the distributions
> from ISO images that I had stored on an external hard drive. My disk
> layout is as follows:
>
> ad0p1  boot
> ad0p2  freebsd, partitioned with disklabel for 7.0/AMD64
> ad0p2a 7.0 AMD64 root
> ad0p2d 7.0 AMD64 /var
> ad0p2f 7.0 AMD64 /usr
> ad0p3  freebsd, partitioned with disklabel for 7.0/i386
> ad0p3a 7.0 i386 root
> ad0p3d 7.0 i386 /var
> ad0p3f 7.0 i386 /usr
> ad0p4  freebsd, partitioned with disklabel for 7.0/AMD64
> ad0p4a 8.0 AMD64 root
> ad0p4d 8.0 AMD64 /var
> ad0p4f 8.0 AMD64 /usr
> ad0p5  freebsd, partitioned with disklabel for 7.0/AMD64
> ad0p5a 8.0 i386 root
> ad0p5d 8.0 i386 /var
> ad0p5f 8.0 i386 /usr
> ad0p6  freebsd, partitioned with disklabel for all
> ad0p6b swap
> ad0p6d /temp
> ad0p6e /local
>
> The problem now is that I don't have a boot manager capable of
> selecting a partition to boot from. The FreeBSD boot manager (boot0)
> does not recognize GPT. I atempted to pass "0:ad(0p3)/boot/loader" to
> gptboot but had no success.
>
> I did a lot of googling and even attempted to read the source code of
> gptboot but could not figure out how to solve the problem, so any help
> will be appreciated.

I think your biggest mistake was putting a disklabel inside a gpt
partition.  You've kind of missed the point of gpt.  There are 16,000
partitions so that we don't have to deal with nested partition tables.

Even loader doesn't handle this scenario.  It understands the
mbr/disklabel style disk0s1a, disk0s1, as well as gpt style disk0p1,
but not gpt+disklabel disk0p1a.

If it wasn't for that, you could do a simple menu in the loader
scripts that did something like:
  set currdev=disk0p3:
  boot kernel
.. to select the root partition that you wanted.
-- 
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com; KI6FJV
"All of this is for nothing if we don't go to the stars" - JMS/B5
"If Java had true garbage collection, most programs would delete
themselves upon execution." -- Robert Sewell