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Disklabel format



I am trying to see if I can read some netbsd partitions on my system
from freebsd.  With freebsd's geom system, all I have to do is make a
new geom and I can load it while the system is running.  I am basing it
off of the existing freebsd disklabel geom since netbsd's version is
very similar.  In fact, the struct for disklabel is almost identical.
The only differences I can see is that netbsd's version made some of the
fields into unions.  The unions are the same size and one element is the
same as the field used in freebsd which is the only element I need to
worry about.  The other difference may be that netbsd has more
partitions at the end of the disklabel, but that's a trivial matter.  This
means that all I have to worry about is how the existing fields are
interpreted correct?

I think one difference is that all offsets are from the beginning of the
disk, not slice.  This allows netbsd to make the d partition access the
whole drive including parts outside the disklabel.  Is there any good
documents thoughly describing the different disklabel formats (and
hopefully comparing the differences between freebsd and netbsd).  I know
there's the source code, but it may be harder to spot where the two
differ, especially since they came from the same code base.

-- 
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NT leads to Bluescreen.
Bluescreen leads to downtime.
Downtime leads to suffering.
NT is the path to the darkside.
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