Rescue data

See also

Fixing iPods

Backups

The first line of defense in any situation is to back up drives. dd is a unix tool for when you want to make an exact copy of any drive. See the great primer at: http://www.linuxquestions.org/questions/linux-newbie-8/learn-the-dd-command-362506/

dd can also be used to improve the longevity of a drive, by reading the data from it and copying it back, thus preventing the magnetic information from fading away by rewriting it to original strength, bit by bit. You must start the computer from some drive besides the one you want to refresh, with a *nix system like Mac OS X or linux, then in a shell enter:

dd if=/dev/your-drive-name of=/dev/your-drive-name

Beware, DD is a very powerful command, and can destroy the data any drive without asking, if you give it the wrong parameters.

Tools

Foremost

http://foremost.sourceforge.net/

Foremost retrieves files from a disk or image based on header and footer data, so it can retrieve deleted files, as long as there wasn't a new file written over the same place on the disk. Follow the instructions, except use "sudo make install" instead of just "make install" if making it on mac. Use it on an image of the bad disk, not the bad disk itself, and certainly don't ever try writing the rescued files onto the disk/image you're rescuing, since that might overwrite the files you're trying to rescue.

dd_rescue

GNU ddrescue

Photorec

http://www.cgsecurity.org/wiki/PhotoRec

Finds files from raw disk data. Can find all sorts of media files.