Re: installation problem

[steve%prd.co.uk@localhost (Steve Blinkhorn)]

I solved this one by using gpt -f to create a new GUID partition
table, all attempts at destroying or fixing the existing one having
failed.   After that the installation went smoothly, but the same
offset of 1 shows up in the disk label - I wonder whether the units
for the offset are misleading, since all the layout is sysinst
default?

Meanwhile I have another box which doesn't go to BIOS setup, and won't
boot since I installed NetBSD - before that it ran Windows 7 and Linux
without problems.   NetBSD installed itself into the "unused" portion
of the disk, apparently sanely, from a disk image on a nootable USB disk,
but now I can't even boot from the USB disk.   Suggestions welcome.

--
Steve Blinkhorn <steve%prd.co.uk@localhost>

You wrote:
> 
> On Fri, Jul 03, 2015 at 06:26:09PM -0400, Greg Troxel wrote:
> > 
> > Robert Elz <kre%munnari.OZ.AU@localhost> writes:
> > 
> > >     Date:        Fri, 3 Jul 2015 17:09:15 +0100 (BST)
> > >     From:        steve%prd.co.uk@localhost (Steve Blinkhorn)
> > >     Message-ID:  <20150703160916.5D2031E488%body.prd.co.uk@localhost>
> > >
> > > What's this supposed to be?
> > >
> > >   | 16 partitions:
> > >   | #        size    offset     fstype [fsize bsize cpg/sgs]
> > >   |  a: 976773167         1     4.2BSD   4096 32768     0  # (Cyl.      0*- 1033622*)
> > >   |  c: 976773167         1     unused      0     0        # (Cyl.      0*- 1033622*)
> > >   |  d: 976773168         0     unused      0     0        # (Cyl.      0 - 1033622*)
> > >
> > > I am fairly sure that you need to allow more than 1 block for the 2nd stage
> > > boot loader to fit.   Your other disc used the common, but meaningless, 63
> > > as the start offset for a & c partitions.   Better (though it might not matter
> > > on those drives) would be a power of 2 (or at least, a multiple of 8).  32
> > > should work fine.   
> > 
> > You do need more, nominally 14, but the 2nd stage loader goes in blocks
> > 2-15 of the root filesystem partition.  Still, the use of offset 1 is
> > irregular and risks testing unused code paths, which is recommended only
> > if you want to encounter and fix new obscure bugs for the greater good.
> 
> Some 1st stage bootloaders assume they can use more than 1 sector,
> and I think some boot sector virus protection 'stuff' can use other
> sectors in the first track.
> 
> > In all seriousness, on x86, use 64 for a filesystem or raid at a these
> > days, in order to avoid misalignment of 4K native sectors.
> 
> Some modern partitioning tools reserve 1MB.
> I've used that space to add a boot partition to a USB stick.
> Finding an mbr editor that would let me do that wasn't trivial.
> I think I was the one that stopped the netbsd one letting me do it!
> 
> 	David
> 
> -- 
> David Laight: david%l8s.co.uk@localhost
>