Subject: Disklabel Locations
To: None <tech-kern@netbsd.org>
From: Matt Thomas <matt@3am-software.com>
List: tech-kern
Date: 03/07/2002 21:26:28
Eariler today I thinking about the cross build problem regarding
disklabel and that got me to investigate where each port keeps it's
disklabel.  Here's what I found:

sector/offset:  port(s)

0/0:    mvme68k next68k
0/64:   algor alpha amiga amigappc luna68k mac68k macppc news68k
         newsmips pc532 pmax sun3 sun68k vax walnut x68k
0/128:  sparc sparc64
0/516:  atari
1/0:    arc arm bebox cobalt hpcarm hpcmips i386 mipsco mvmeppc
         ofppc playstation2 sandpoint sbmips sgimips sh3 x86_64
1/64:   prep
2/0     cesfic hp300

Almost all ports that use MBRs use 1/0 except prep which uses 1/64.
It seems that prep should be using 1/0 as well if there is no techincal
reason why it can't.

atari seems to believe in > 512 byte blocks.  Not sure about the 0/0
usage by mvme68k and next68k but it seems that at least for mvme68k
it should be relatively simple to support either 0/64 or 1/0.

But the point is that there only a few places disklabels show up and
it shouldn't be hard to modify both the user and kernel disklabel code
to search the disk for a disklabel.  This would make the ability to
cross built full snapshots much easier.


-- 
Matt Thomas               Internet:   matt@3am-software.com
3am Software Foundry      WWW URL:    http://www.3am-software.com/bio/matt/
Cupertino, CA             Disclaimer: I avow all knowledge of this message