Subject: Re: Some help with disklabel please?
To: None <current-users@NetBSD.ORG>
From: Leo Weppelman <email@example.com>
Date: 08/10/1995 13:31:00
> > > Another point to make here, I suppose, is that not all ports that use
> > > NetBSD-format disklabels keep them in the same place (for various
> > > reasons). Just something else to think about :-)
> > Can they be told apart?
> Huh? I assume you mean ``Is it easy to tell the difference between them?''
> Umm .. the _is_ no difference between them, except for the size of the
> partition map in them. For example, the MAXPARTITIONS value on the hp300
> is 8, but on the Amiga it's 16. This means that sizeof(struct disklabel)
> is different on these platforms. So, the disklabel checksums will be
> wrong if an hp300 reads an amiga's disklabel, since it won't read the
> whole disklabel ... The biggest problem is _finding_ the disklabels...
This problem is far from trivial. Mostly the exact location depends on
the contents of the systems native partition table, because disks tend to
be shared between more than on OS. This means that if you want to read
the NetBSD-disklabel from an atari disk on some other platform, you first
have to interpret the native AHDI partitioning to find out what partitions
are not used by GEM (the native OS). The remaining partitions _may_
contain an NetBSD label or a Linux label or .... .
An extra problem is that some ports 'fake' a disklabel from the 'native'
disklabel when there is no real NetBSD label. These disks look perfectly
labeled from NetBSD.... This is true for the atari and ,if i am correct,
also for the amiga.