9.0 beta2 & the new bsdinstaller

Matthew D. Fuller fullermd at over-yonder.net
Tue Sep 20 21:34:07 UTC 2011

On Tue, Sep 20, 2011 at 04:23:49PM +1000 I heard the voice of
Peter Jeremy, and lo! it spake thus:
> On 2011-Sep-19 13:25:27 +0100, Bruce Cran <bruce at cran.org.uk> wrote:
> >Will 64 kB be enough for 9.x?
> At least for x86 architectures, it seems adequate.  [...]
> As for size, I'd suggest that if the default freebsd-boot size is
> going to be changed, it should be adjusted so that the following
> partition is aligned to a reasonably sized power of 2 - 128KB or
> 256KB.

I've been meaning to mention this, but we really should document
somewhere that it has a _MAXIMUM_ size.

I setup a system a few weeks back with GPT, and figured I'd just make
the first 'real' partition start at the 1 meg mark.  And make
everything before that (1 meg - the however many sectors for the pmbr)
the freebsd-boot partition.

It worked fine, up 'till the point that I tried to boot, and it
completely failed to, complaining that the boot code was too big.  I
had to track around in pmbr to find

.   .   cmp $0x9000,%ax..   .   # Don't load past 0x90000,
.   .   jae err_big..   .   #  545k should be enough for
.   .   mov %ax,%es..   .   #  any boot code. :)

and redo the partition to 512k (leaving a few hundred k unused before
the next partition started) before it would boot.  That's a little
nerve-wracking to hit on a critical system...

Matthew Fuller     (MF4839)   |  fullermd at over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/
           On the Internet, nobody can hear you scream.

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