Re: Are BSD partitions not supported?

[Grégoire Sutre]

On 06/01/2010 01:21 PM, Vladimir 'φ-coder/phcoder' Serbinenko wrote:

> For FreeBSD we have to investigate 'c' partition to determine delta.

Right.

> > In short, the normal interpretation of BSD label offsets would be the
> > relative one (b), and we would make an exception to handle NetBSD and
> > OpenBSD (a).
> The bottom line is: bsdlabel is broken concept. Unless support of
> $config is required I would omit it to disencourage further propagation
> of broken concepts.

I am not sure I understand what you mean here.

Regarding bsdlabel: it is not broken by itself.  The problem comes from
the fact that several OSes use it as (native) disklabel, but do not
interpret the fields in the same way.

I guess it's easier to maintain coherence when the disklabel is used
(natively) by a single OS.

> > Now, when BSD label offsets are detected absolute (a), should we
> > consider them as absolute:
> > - w.r.t. to the start of the disk (as is done in the code right now),
> >    or
> > - w.r.t to the location of the msdos partmap?
> > I prefer the second option since it is compatible with dd-ing an entire
> > disk into an msdos partition.  Maybe the loopback feature also requires
> > the second option (I don't know the internals).
> Second one is cleaner. But perhaps it's pointless to support such config
> since no BSD will be able to bootstrap from such a config

You could at least boot the kernel from such a config. And, for NetBSD,
I believe that the use of wedges should allow the kernel to mount the
root file system (but I'm not an expert on wedges), provided that grub
gives the wedge information in the bootinfo structure.

Grégoire