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From: sthaug@nethelp.no
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To: avalon@coombs.anu.edu.au
Cc: terry@lambert.org, randy@zyzzyva.com, freebsd-current@freebsd.org,
        freebsd-hackers@freebsd.org
Subject: Re: NetBSD filesystem compatibility
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Date: Thu, 02 May 1996 10:54:23 +0200
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> > > Is it safe to assume that a NetBSD filesystem is ufs mountable from
> > > a FreeBSD system. I'm about to find this out within the hour, but
> > > would appreciate a "heads-up" if anyone has anything to share.
> > 
> > Yes.
> > 
> > Going the other way, you would have to explicitly change the
> > label on the FreeBSD swap partition to "swap" for NetBSD to
> > recognize it.  The on disk structures are the same as for
> > 4.4BSD-Lite in both trees.
> 
> Unless something has changed since 2.1R in this area, fsck will not
> like the partition information used by NetBSD.
> 
> To stay on the safe side, I try to only mount the NetBSD partitions
> read-only and never read-write, if at all possible.

I can report on a small experiment I did last weekend.

I had an IDE disk which was only partially used (one DOS partition).

Running FreeBSD 2.2-960323-SNAP (from a SCSI disk on the same box), I
set up a new (0xa5) partition, disklabeled it (/, swap, /usr, /var),
and newfs'ed it. I then installed NetBSD-1.1 on the new partition by
unpacking the tar files, manually fixing up a few things, manually
installing boot blocks - while running FreeBSD.

The machine now boots NetBSD-1.1 from the IDE disk just fine. Things
seem to work just normal, but I haven't done any extensive testing.
The only problem I've noticed is that the NetBSD disklabel program
complains about partitions extending past the end of the disk - but
it still boots and runs. I can fsck the NetBSD file systems from
FreeBSD.

Steinar Haug, Nethelp consulting, sthaug@nethelp.no