Damaged Hard Disk

Source

Bad sectors are the most common form of harddisk physical damage. They are early signs of disk crash as it deteriorates over time. A bad sector is a sector on the disk which data cannot be written or read due to a physical damage or inconsistencies of parity checking bits on disk (CRC or Cyclic Redundancy error). To recover your data, the best method is to copy its data to another hard disk before attempting to recover its data.
The new disk must be at least exactly the same size (check the number of LBA sectors) or larger; when larger, it's usually not a problem because the number of heads per cylinder and sectors per head will be the same if both disks use LBA mode. Windows may have some problems in dealing with bad sectors on a damaged hard disk, so the best solution is to use a Linux OS to copy data to another hard disk.
You can also use TestDisk to help analyze the sectors copied from a hard drive with physical problems onto a good drive.

• 1 Booting from Knoppix, a Linux LiveCD
• 2 Identifying an HDD's device
  • 2.1 Identifying an HDD's Linux device
  • 2.2 Identifying an HDD's Mac OS X device
• 3 Disk Duplication
  • 3.1 The classic method using 'dd'
  • 3.2 Kurt Garloff's 'dd_rescue'
  • 3.3 The best method: Antonio Diaz's GNU 'ddrescue'
• 4 Early detection of bad sectors