absolute vs. relative offsets in disklabel

[Dmitry Marakasov]

* Dan Nelson (dnelson at allantgroup.com) wrote:
> > Recent `disklabel differences FreeBSD, DragonFly' thread gave me a
> > thought - why do we have absolute offsets in disklabel? AFAIK, on
> > NetBSD and OpenBSD, label is not necessarily located `near'
> > filesystems stored in it's partitions - and even disklabel utility
> > shows absolute offsets (with 'c' covering entire device). FreeBSD,
> > however, seem to step far away from that standart - 8 partitions
> > instead of 16, label located in the beginning of a partition,
> > bsdlabel shows relative offsets. Now I wonder if there are any
> > reasons for offsets to be actually absolute? There are many weighty
> > arguments for relative offsets:
> I asked this question a few years ago after having problems dd'ing a
> FreeBSD installation from one disk to another, and the answer was "it's
> always been that way" :) It shouldn't be too hard to have the code
> autodetect whether the offsets are relative or absolute by looking at
> what the 'c' partition's offset is.
The only problem seem to be that older FreeBSD versions won't be able to
use modified labels.

-- 
Best regards,
 Dmitry                          mailto:amdmi3 at mail.ru