Subject: Re: A new partition handling scheme: wedges
To: Chris G. Demetriou <>
From: Charles M. Hannum <>
List: tech-kern
Date: 01/26/1998 06:54:44
BTW, something I didn't mention before is that, regardless of anything
else we do, I believe we should, on systems that have MBRs, do
essentially the same thing Linux does (and that the Amiga port does in
RDB) -- have special MBR partition types for `NetBSD root', `NetBSD
swap', and `other NetBSD file system' -- and provide the old
partitioning system only as a fallback for compatibility.

The parsing rules on the i386 port would be:

* If there is no MBR, look for a label.

* If there is a MBR with a type 0xa5 partition, read the label from
that (for compatibility).

* If there is a MBR with no type 0xa5 partition, look for type 0xa7
(NetBSD root), 0xa8 (NetBSD swap), and 0xa9 (other NetBSD file
system), and generate an internal `label' based on that.

Again, this avoids users having to know about multiple partitioning
schemes.  It also avoids incoherency problems between the MBR and the
NetBSD `label'.  Since AFAIK these are the only ports that actually
try to use two partitioning systems at the same time, it also obviates
the need for anything like `slices'.

It does not, however, deal with being able to use disks partitioned
for other platforms.