On Wed, Sep 05, 2007 at 06:43:32PM +0200, Job Hanssen wrote:
> Problem solved...
> 
> Suddenly it hit me: I shouldn't have reinstalled the bootblocks on 
> /dev/rdw0a, but on /dev/rdw0d, as this is wat the disklabel looks like:
> 
> testbak# disklabel /dev/rwd0
> # /dev/rwd0d:
...
> 
> 13 partitions:
> #        size    offset     fstype [fsize bsize cpg/sgs]
>  a:   2097152        63     4.2BSD   2048 16384 21848  # (Cyl.      0*-   
>  2080*)
>  b:   8388608   2097215       swap                     # (Cyl.   2080*-  
>  10402*)
>  c: 488397105        63     unused      0     0        # (Cyl.      0*- 
>  484520)
>  d: 488397168         0     unused      0     0        # (Cyl.      0 - 
>  484520)
...
> testbak# hexdump -x -s0x418 -n4 /dev/rwd0a
> 0000418    c200    0001
> testbak# hexdump -x -s0x418 -n4 /dev/rwd0d
> 0000418    9600    0000

Hmmm...  I suspect things have got themselves very confused!
The disklabel looks like a 'standard' i386 pc config with a single
type 169 mbr partition covering all but the first track.
In that case sector zero of the disk would usually contain one of
/usr/mdec/mbr* files, and sector 63 (ie the first of the mbr partition)
/usr/mdec/bootxx_xxxfs.
For various reasons the pbr code does have space for the mbr table,
so it does all work - but is somewhat confusing - as you found out.

	David

-- 
David Laight: david@l8s.co.uk