Subject: Re: Two NetBSDs on one (i386) drive
To: None <tech-kern@netbsd.org>
From: David Laight <David.Laight@btinternet.com>
List: tech-kern
Date: 12/21/2001 00:53:58
> > If we recognize more than one NetBSD partition on a disk, that means
> > more than one disklabel.  Wouldn't that cause a bunch of problems?  For
> > example, how do I write the second disklabel when I've booted from the
> > first partition?  I would find it confusing because now there are two
> > different NetBSD views of the disk (i.e. the meaning of "wd0a" depends on
> > which partition you booted from - what if you boot from a floppy?)
> 
> Isn't the disklabel inside the NetBSD partition on i386?  e.g. at offset
> xyz from the start of the partition, not the start of the disk?

The stew is thick - partially due to there being 3 cooks.

fdisk writes the mbr (sector 0 of the disk)

installboot will write the netbsd bootstrap to sectors 0,2+ of any raw
bsd disc partition (provided it can mount it)

disklabel does nasty things to your disk!  In particlar it writes the
bsd label to sector 1 of the specified bsd partition, tells the kernel
that is the ruleset for that physical disk and sometimes deletes the
bootstrap code!

    David