[ale] replacing disk sda

[Derek Atkins]

"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.

-derek
-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
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