[NBLUG/talk] Recovery Partition ( Empty Partition

[Andrew]

h.schnirman at pacbell.net wrote on Tue, 14 Dec 2010 15:04:50 -0800
(PST):

> I've got an HP Pavilion Laptop that had it's OS corrupted
> to the point that it doesn't boot. The recovery partition type
> says Empty.
> 
> So the Question is, Is it really empty or that HP has some
> proprietary file system that I can't see.

Well, it *could* be empty, or it could be a normal FAT16/32
partition for which the partition type has been set to 00-EMPTY.
Computer manufacturers will often do tricks like that to hide
their recovery/diagnostic partitions.

214 MB sounds kind of small-ish for a recovery partition. It
might just be diagnostic tools in there.

To see if there really is something in that partition, you could
use a hex dumper or editor on it. Boot the laptop using a
full-featured Linux LiveCD (I'd suggest Knoppix 5.1.1). Then
open up a terminal and issue this command:
sudo fdisk -l
(that's a lower-case "L"). This will show you the partitions and
how Linux refers to them (for example, /dev/sda3). Then run
hexdump on the partition in question:
hexdump -C /dev/sda3

If you get a line of all zeros, followed by a single splat
(asterisk) on the next line, the partition really is empty. See
http://en.wikipedia.org/wiki/Hex_dump#Compression_of_duplicate_lines
for an example.

If, however, you get lots of stuff scrolling by, the partition
is NOT empty, and the recovery features (if they exist) may still
be there and useable.

For either outcome, you can either let hexdump run until it ends
and the command prompt returns (may take 1/2 hour or more), or
you can stop it with CTRL-C.

If the partition is not empty, Google for
"laptop_model_number recovery" (without quotes). Maybe someone
out there can tell you the proper way to access the recovery
features.

One other thing you could do if the partition is not empty is
to try to mount it, letting Linux attempt to auto-detect the
partition type:
sudo mount -o ro /dev/sda3 /mnt
The "-o ro" will mount the partition in read-only mode so you
can't possibly mess anything up.

If you get no errors, then browse around in /mnt, using either
the terminal or graphical file browser. Maybe you can get an
idea of what is actually in the partition.

Then Google as above.

Good luck!

A.