[plug] Partitions on external hard disk gone awry

[Haydon Knight]

Hi,

I have messed up the partitions on an external hard drive and would
like to restore it without deleting my data, but don't know how to do
this.  I would appreciate any help from pluggers greatly...

I run computers with XP, vista, mac osx 10.5, and ubuntu linux hardy
8.04.  I own a 500GB external USB hard drive and wanted to store data
on it formatted so that all the above operating systems could read and
write to it.  The external HDD had 3 partitions on it:

+ a mac time machine partition (hfs+)

+ a linux partition (ext3) that I use for backups plus storing some other stuff

+ another junk ext3 partition

Windows wasn't seeing any of the partitions so I decided to reformat
the 3rd partition to a couple of NTFS partitions using gparted.  I set
this up from ubuntu but forgot to close the nautilus windows that pop
up showing the contents of the partitions.  gparted reported an error
something like cannot repartition as in use and suggested I wouldn't
be able to see the partitions until a reboot.  I rebooted but now the
disk seems to be in a funny state:

+ the first 2 partitions work fine in general use

+ the 3rd partition has disappeared

+ gparted terminal reports 'Invalid partition table on /dev/sdc --
wrong signature 0.'

+ gparted gui shows the whole disk as unallocated

I would like to just restore the disk but can't seem to use gparted to
do it.  I'm not keen on copying the hfs+ partition to another disk as
I don't know of a utility I can trust - as I understand it a time
machine file system has an extra property of directories being able to
have multiple hard links and I'm not sure whether backup programs
handle this properly or not.  Also I'm not sure how fussy osx is about
moving around of time machine volumes.

I'm very worried about taking a step that irreversibly affects my data.

So can anyone recommend a tool/method that can restore the partition
table?  Or if that is not possible, a tool that can definitely backup
my hfs+ and ext3 partitions safely and reversibly?

Thanks a lot!

-Haydon