[ale] replacing disk sda

[Michael H. Warfield]

On Wed, 2014-04-23 at 14:57 -0400, Derek Atkins wrote:
> "Michael H. Warfield" <mhw at WittsEnd.com> writes:
> 
> > On Wed, 2014-04-23 at 13:31 -0400, Paul Cartwright wrote:
> >> On 04/23/2014 01:15 PM, Michael H. Warfield wrote:
> >> > The partition table starts at +01BEh in the first sector.  Everything
> >> > before that is boot code and grub / grub2 installs part of itself in
> >> > there.
> >> >
> >> > http://en.wikipedia.org/wiki/Master_boot_record
> >> I started reading that and my eyes glazed over...
> >> 
> >>  so, sfdisk just backs up the partition table, not the bootloader code?
> >
> > Correct.
> >
> >> if your MBR got wiped out and you restored from an sfdisk file, would it
> >> boot ( assuming your OS partitions were still there)..
> >
> > Possibly, but not the way to bet.  Most drives have a default MBR on
> > them that may or way not work and would most certainly NOT contain grub.
> > OTOH, if you restored the entire drive from sector 0 onward, you would
> > restore the grub code to the MBR.  But...  If you restore a logical
> > backup of /boot, it probably won't boot until you rerun grub[2]-install
> > from a rescue CD.

> Really?  I think most drives have nothing in the MBR at all.  At least
> the last few drives I ordered certainly came empty.  I would never trust
> a drive to boot up without actually installing an MBR myself.

Most of the drives I've received, even very recently, have a VFAT
partition (gag) and a bootable MBR.

True, I wouldn't trust them.  But all my drives get reformatted and
reinstalled anyways so it's never a problem.  It was just a comment
about "would it boot" and my response was "Possibly, but not the way to
bet".

> -derek

Regards,
Mike
-- 
Michael H. Warfield (AI4NB) | (770) 978-7061 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
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