How to recover an integer ext3 partition from a disk with a damaged partition table ? [SOLVED] !!!

[Andrea Mastellone]

Todd Denniston wrote:
> Andrea Mastellone wrote, On 09/24/2008 11:12 AM:
>> Hi,
>>
>> I have a broken solid state disk, in facts badblocks has found about a 
>> hundred of damaged blocks. The most shortcoming is that I have lost 
>> the partition table too, and I suspect that some bad blocks are in 
>> relation with the partition table data since testdisk can not write 
>> the recovered partition table to the disk. Now, I need to rescue a 10 
>> GB ext3 partition (that is the last one on device).
>>
>> So, I would like to use dd (or dd_rescue) to physically transfer the 
>> partition in a file on an ext3 USB disk, and then mount the file as an 
>> ext3 partition (like an iso file by means of loopback device, is it 
>> possible ? how ?).
>>
>> Since I am poor experienced with the CHS and LBA notations, someone 
>> can me confirm this: testdisk signals that the partition begins at 
>> 6403, 1 ,1 and ends at 7798, 254, 63 in CHS notation. Since the disk 
>> has 255 heads and 63 sectors, the corrispective LBA addresses would be 
>> 102864258 and 125290810, isn't it ?
>>
>
> if I had less space (and no time to buy an extra USB hard drive) and 
> could translate the CHS to bytes/blocks of disk space, I would do 
> something like:
> assume 512 blocks, and HeadSector size of 7697074bytes
> bc of 7697074*6402/512 yields 96243491 which is probably completely wrong.
> (is this roughly a 55GB device?)
> 
> dd if=/dev/whole_solid_state_disk \
>    of=/path/to/spare11GB/SSD.image \
>    seek=96243491 conv=noerror bs=512
> 
> 
> And remember, the device is already failing... you MIGHT only get one 
> more read, so take that into consideration when choosing the method for 
> getting the image.
> 

Successful ! I just issued

dd if=/dev/hda of=/mnt/usb/partition skip=102864258 count=22426552

and then

mount -o loop /mnt/usb/partition targetdir/

and all important data have been fully recovered !!

Andrea