GNU ddrescue vs PhotoRec

GNU ddrescue copies data from a file or block device to another location, prioritizing readable areas when read errors arise. Its basic recovery process is automatic, so it does not require stopping and restarting at every error. A mapfile records progress; an interrupted job can resume and reread only blocks that still need attention. The algorithm handles good areas first and defers bad or slow ones to reduce unnecessary drive movement. It works with kernel-supported devices, including ATA, SATA, SCSI, floppy disks, and flash media cards, and can use direct disc access where supported. Fill and generate modes provide additional ways to write selected output areas or create an approximate mapfile from an input and partial copy. The package includes ddrescuelog for manipulating and comparing mapfiles and checking rescue status. GNU ddrescue is free software under the GNU General Public License, version 2 or later, with no paid plans stated. POSIX systems are recommended; the manual discusses Cygwin but warns of potentially misleading permission errors. A device or partition used as the destination will have its data overwritten. Because ddrescue needs random access, create an uncompressed image before compressing it.

PhotoRec is a free file recovery program for retrieving lost videos, documents, archives, and pictures from storage media and disk images. It searches the underlying data instead of relying on the file system, which can help after file-system damage or reformatting. It recognizes more than 480 file extensions across about 300 file families, and listed file systems include FAT, NTFS, exFAT, ext2/ext3/ext4, and HFS+.

Supported sources include hard disks, CD-ROMs, memory cards, USB drives, raw disk images, and EnCase E01 images. PhotoRec runs on Windows, Linux, macOS, DOS, several BSD systems, Solaris, and other Unix systems. It accesses the recovery drive or card in read-only mode; recovered files should go to a different partition. The portable download runs after extracting its archive, without an installer. QPhotoRec provides a graphical interface, while PhotoRec can also run from scripts or batch files with command-line options. The maker says it usually cannot recover original filenames and does not work well with ReiserFS.