Subject: Re: netbsd 2.0 no operating system
To: None <>
From: Nenad Crnko <>
List: netbsd-users
Date: 04/09/2005 16:59:08
On Saturday 09 April 2005 05:54, David Laight wrote:
> On Sat, Apr 09, 2005 at 05:34:26AM -0700, Nenad Crnko wrote:
> > 
> > We have missed the opportunity to get the content from wd1 mbr when
> > your system still failed to boot. It would have been useful to get it
> > like so:
> >   # dd if=/dev/wd1d of=/tmp/funny_mbr count=1
> > or
> >   # dd if=/dev/wd0d count=1 | hexdump -C
> > 
> > It seems that for some reason the sector lost its MBR_MAGIC during
> > or after installation. If there is a bug in sysinst and you would
> > like to help tracking it down, you would probably have to repeat your
> > ordeal a few times to find out and document how to reliably reproduce
> > the problem.
> There is a known bug in installboot that causes it to copy the first
> 8k of the disk to the start of the partition.
> This might be the cause.
>  David

I have not encountered this problem largely because since 1.6 I for
various reasons usually manually install and set up the new version on
a secondary disk.

It is not completly clear what exactly happens with Olivers's installation
since he does not report precisely enough what happens. But he apparently
can not get past mbr into boot1.

But given the fact tha he saw the "No operating system" string, it must have
come from the mbr without bootselector code. This error message can be triggered,
as far as I can tell, only by mbr boot code not seing MBR_MAGIC in the same
sector. So something must be stepping on the offending sector, or
perhaps sysinst does not put MBR_MAGIC into the mbr in the first place.

Thank you for your "rototilling" of this code. It is now greatly improved
since 1.3 and now provides full and unambiguous control during disk maintenance.

Best regards