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GNU ddrescue

gnu.org

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Spec score 8.4 #19 of 128 in Data recovery software

What it is

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.

Spec sheet

Purpose
GNU ddrescue copies data from a file or block device to another, trying to rescue readable parts first when read errors occur.Read 12 Oct 2026 · gnu.org
Free plan
YesRead 23 Sep 2026 · gnu.org
Integrations
The GNU project links to ddrescueview for viewing mapfiles and ddrutility and Partclone for related recovery workflows.Read 12 Oct 2026 · gnu.org
Support
The project directs bug reports and discussion to the bug-ddrescue mailing list.Read 12 Oct 2026 · gnu.org
License
GNU ddrescue is free software licensed under the GNU General Public License, version 2 or any later version.Read 12 Oct 2026 · gnu.org
Additional modes
It includes fill mode for selectively writing output areas and generate mode for creating an approximate mapfile from an input and partial copy.Read 12 Oct 2026 · gnu.org
Automatic recovery
Its basic recovery operation is fully automatic and does not require stopping and restarting at each read error.Read 12 Oct 2026 · gnu.org
Companion utility
The package includes ddrescuelog, which manipulates mapfiles, converts formats, compares mapfiles and checks rescue status.Read 12 Oct 2026 · lists.gnu.org
Compression limit
Because ddrescue needs random access, it cannot create a compressed image directly; the manual advises creating an uncompressed image first and compressing it afterward.Read 12 Oct 2026 · gnu.org
Data-loss risk
Using a device or partition as the destination overwrites data stored there.Read 12 Oct 2026 · gnu.org
Device compatibility
The tool works with device types supported by the kernel, including ATA, SATA, SCSI, floppy disks and flash media cards.Read 12 Oct 2026 · gnu.org
Direct access
Where supported, ddrescue can use direct disc access to bypass the kernel cache.Read 12 Oct 2026 · gnu.org
Memory card recovery
YesRead 23 Sep 2026 · gnu.org
Operating systems
POSIX systems recommended; Cygwin support is discussed in the manualRead 23 Sep 2026 · gnu.org
Recovery algorithm
The algorithm prioritizes good areas and schedules reads in bad or slow areas for later to reduce unnecessary drive movement.Read 12 Oct 2026 · gnu.org
Recovery sources
Files,devices,partitions,optical media (CD-ROMs/DVDs),kernel-supported devices including ATA,SATA,SCSI,floppy disks,and flash media cards such as SDRead 23 Sep 2026 · gnu.org
Resumable jobs
A mapfile tracks rescue progress so an interrupted recovery can resume later and reread only needed blocks.Read 12 Oct 2026 · gnu.org
Windows caveat
The manual recommends a POSIX system and warns that Cygwin use may produce misleading permission errors.Read 12 Oct 2026 · gnu.org

Plans and prices

GNU ddrescue Free Free software under GNU GPL version 2 or later · no paid plans stated Read 12 Oct 2026 · gnu.org

Every GNU ddrescue plan and price →

Strong points and limits

Strong points

  • Automatically prioritizes readable data during recovery.
  • Mapfiles let interrupted jobs resume on remaining blocks.
  • Supports kernel-supported devices, including flash media cards.
  • Includes ddrescuelog for mapfile and rescue-status tasks.
  • Free under GNU GPL version 2 or later.

Limits

  • Using a device or partition as destination overwrites its data.
  • Cygwin may produce misleading permission errors.
  • Compressed images cannot be created directly.

Who it suits

It suits users recovering data from files or supported devices who need a resumable copy process. POSIX systems are recommended; Windows users considering Cygwin should note the manual's warning about misleading permission errors.

Verdict

GNU ddrescue is built around automatic, resumable recovery that records progress in a mapfile. Choose the destination carefully, and use an uncompressed image first if you need compression afterward.

Where Specifiction places it

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