Mac Disc does not mount - superblock bad

How to use TestDisk to recover lost partition
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TalaatHarb
Posts: 3
Joined: 30 Apr 2012, 08:18

Mac Disc does not mount - superblock bad

#1 Postby TalaatHarb » 30 Apr 2012, 09:12

Hi,

the disk is a WD external USB/Firewire/eSATA disk sized 1GB.
Formatted as HFS+ I use it on my PowerPC Mac, but sometimes connect it to a windows XP machine which reads HFs+ via MacDrive. Windows crashed with the disc attached and since then the WDs does not mount (Linx, PC, Mac).

I still hope that all the data is there, but somehow the partition map/superblock/driver (?) is gone.

After start on my Mac testdisks shows:

Code: Select all

Select a media (use Arrow keys, then press Enter):   
 Disk /dev/disk0 - 82 GB / 76 GiB
 Disk /dev/disk1 - 163 GB / 152 GiB (RO)
 Disk /dev/disk2 - 2000 GB / 1863 GiB (RO) 
>Disk /dev/disk3 - 1000 GB / 931 GiB
 Disk /dev/rdisk0 - 82 GB / 76 GiB           
 Disk /dev/rdisk1 - 163 GB / 152 GiB (RO)
 Disk /dev/rdisk2 - 2000 GB / 1863 GiB (RO)
 Disk /dev/rdisk3 - 1000 GB / 931 GiB           


the disk in question is the 1GB one. Do I have to choose /dev/disk3 or /dev/rdisk3? I choosed /dev/disk3.

pdisk shows for this disk:

Code: Select all

Partition map (with 512 byte blocks) on '/dev/rdisk3'
 #:                type name       length   base       ( size )
 1: Apple_partition_map Apple          63 @ 1         
 2:          Apple_Free Extra      262144 @ 64         (128.0M)
 3:           Apple_HFS p1     1073741824 @ 262208     (512.0G)
 4:          Apple_Free Extra   879521136 @ 1074004032 (419.4G)

Device block size=512, Number of Blocks=1953525168 (931.5G)
DeviceType=0x0, DeviceId=0x0


In testdisk when I select Analyze, it shows:

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Disk /dev/disk3 - 1000 GB / 931 GiB - CHS 1953525168 1 1                                                                           
Current partition structure:
     Partition                  Start        End    Size in sectors
                                                                                                                                   
 1 P partition_map                  1         63         63
 2 P Free                          64     262207     262144
 3 P HFS                       262208 1074004031 1073741824
 3 P HFS                       262208 1074004031 1073741824   
 4 P Free                  1074004032 1953525167  879521136


Question: Why is partition 3 listed two times?


testdisk from menu "Advanced" (Partition table gets recognized as Mac. Fine):

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Disk /dev/disk3 - 1000 GB / 931 GiB - CHS 1953525168 1 1       
                                                                                                                               
     Partition                  Start        End    Size in sectors
> 1 P partition_map                  1         63         63
  2 P Free                          64     262207     262144
  3 P HFS                       262208 1074004031 1073741824
  4 P Free                  1074004032 1953525167  879521136

Partition 4 is listed as free, but there is encrypted data. But I do have a backup of these, but not for partition three.


Selecting part#3, then superblock gives

Code: Select all

Disk /dev/disk3 - 1000 GB / 931 GiB - CHS 1953525168 1 1
     Partition                  Start        End    Size in sectors
 3 P HFS                       262208 1074004031 1073741824                                         
                                                                                                                                   
Volume header
Bad
                                                                                                                                   
Backup volume header
Bad
                                                                                                                                   
Sectors are not identical.               




I do not know how to proceed from here. Maybe someone can help me with this.

Question: Shouldn't there be a driver after partition1? On my built-in discs there is one and there is plenty of free space in part. #2.



Any help appreciated. Thank you in advance!

TH

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User avatar
Fiona
Posts: 2839
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: Mac Disc does not mount - superblock bad

#2 Postby Fiona » 03 May 2012, 10:35

TestDisk doesn't write on a PowerMac but it provides the result and let you write them to your partition map using pdisk!
Infos;
http://www.cgsecurity.org/wiki/OS_Notes ... PowerPC.29
If your disk appears as not initialized, don't use pdisk to initialize it but your disk utilities first.

Fiona

TalaatHarb
Posts: 3
Joined: 30 Apr 2012, 08:18

Re: Mac Disc does not mount - superblock bad

#3 Postby TalaatHarb » 03 May 2012, 11:02

Thank you very much for your reply and the link.

Fiona wrote:If your disk appears as not initialized, don't use pdisk to initialize it but your disk utilities first.


I am not sure what to do after having analyzed the disk with testdisk.

My disk does not mount - so i guess it is not initialized. The finder wants to do that when I connect the disk.

Should I initialize with DiskUtils using HFS+, Mac partition table etc as it was before? Should i then partition with DiskUtils ( I know how the disk was partitioned) or should I partition the disk with pdisk?

Anyway, after having done this, I'll guess my disk will mount the first 512MB partition and the second encrypted partition will probably be untouched and may be mountable. But the firsts partition directory will be erased?

How to proceed from here?

Any help appreciated and needed badly...




Please note: in my original post you can see pdisks output. I am absolutely happy with the layout, but the disk does not mount anyway. Maybe its just the driver missing in partition #2?

TalaatHarb
Posts: 3
Joined: 30 Apr 2012, 08:18

Re: Mac Disc does not mount - superblock bad

#4 Postby TalaatHarb » 07 May 2012, 15:45

any help please...?


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