GNU ddrescue is a tool for recovering data from failing digital media. Often, when a device is dying but not quite dead, data can be successfully read simply by retrying several times. GNU ddrescue uses this fact to copy data from a dead or dying drive to either a new drive or a disk image file. Because the speed of a data transfer from a disk depends in part on the size of the block being copied, ddrescue performs multiple passes over the failing disk using first a large, then medium, and finally a small block size. This technique allows ddrescue to work quickly on healthy sections of a drive while still working carefully with failing portions. It also keeps track of which portions of the disk have been read, allowing users to pause and resume a recovery effort (e.g. to more thoroughly clean a scratched optical disc). GNU ddrescue is free software, licensed under the GNU General Public License and distributed as source code via the project website. Linux and BSD users can install ddrescue via their operating system's package manager, macOS users can use MacPorts or Homebrew, and Windows users can use Cygwin. The website can be read in English, Spanish, French, and Italian.
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