Package ddrescue

Data recovery tool trying hard to rescue data in case of read errors

http://www.gnu.org/software/ddrescue/ddrescue.html

GNU ddrescue is a data recovery tool. It copies data from one file or block
device (hard disc, cd-rom, etc) to another, trying hard to rescue data in
case of read errors. GNU ddrescue does not truncate the output file if not
asked to. So, every time you run it on the same output file, it tries to
fill in the gaps.

General Commands (Section 1)
ddrescue
GNU ddrescue - Data recovery tool. Copies data from one file or block device to another, trying to rescue the good parts first in case of read errors. Always...
ddrescuelog
GNU ddrescuelog - Tool for ddrescue mapfiles. Manipulates ddrescue mapfiles, shows their contents, converts them to/from other formats, compares them, and tests...