Subject: Re: Garbled message from bootblocks [ Re: bootxx_ffsv1 or bootxx_ffsv2? ]
To: <>
From: David Laight <>
List: current-users
Date: 08/12/2003 09:27:55
On Tue, Aug 12, 2003 at 07:21:00AM +0100, Neil Booth wrote:
> David Laight wrote:-
> > > 3) Why does it try to boot hd0f:netbsd and not hd0a:netbsd?
> > 
> > It has remembered the disk block of the start of the partition, and it
> > assuming the kernel (etc) is in the same place).
> > 
> This is odd, because all the examples on the net seem to assume
> this works, at least they don't mention interrupting the boot sequence
> to tell it to use hd0a.

None of them got changed after I modified the boot code :-)

If you setup multiple netbsd mbr partitions, you can boot with the
root filesystem at the start of any on the partitions by using the mbr
bootsel code.  Since there is only a single disklabel (anything else is
far too fraught) the boot code scans the disklabel to locate the name
of the partition that was booted.

The raid1 boot is a hack!  Consider what you would have to do to
boot a striped raid volume.  The kernel would need to be in the non-raid
boot filesystem and be told where it's root filesystem was (since it
wouldn't be where the kernel came from).

The boot sequence doesn't (at the moment) support loading a kernel from
other than the root partition (or rather it always tells the kernel that
the root filesystem is where the kernel came from - which the kernel can

Raid1 can be made bootable, it isn't actually hard.


David Laight: