On Wed, Sep 13, 2006 at 05:17:01PM +0100, Peter Hardman wrote:
> 
> NetBSD appears to install OK, but when I try to boot (pointing the BIOS
> to the correct drive with the BIOS boot menu) I get:
>  
> NetBSD MBR boot
> Error no operating system

That error message is output after the mbr code (ie the code in sector
0 of the disk) has read the first sector of the partition (sector 63),
and discovered that either:
- the first byte read is a zero
or
- the last two bytes aren't 0x55,0xaa
which usually mean that there isn't any code there.

Geometry issues are unlikely to be an issue (the BIOS can't be THAT broken!).
However if 'hexdump -C -n512 -s63b /dev/rwd1d' reports valid code, maybe
the BIOS is broken!

You might find that the mbr_ext bootcode (which always does LBA reads)
avoids any issued with the bios reading the wrong sector with CHS reads.
OTOH the mbr code you are using verifies that the geometry reported by
the bios converts the CHS value to in the mbr entry to the LBA value.

	David

-- 
David Laight: david@l8s.co.uk