Data Recovery Glossary
The complete A-Z reference for data recovery terminology. 96 terms covering hard drives, SSDs, RAID, file systems, backup, encryption, and recovery techniques, reviewed by data recovery engineers.
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Backup vs Archive
Backup and archive are two distinct data management concepts that are frequently conflated but serve different purposes.
Bad Sectors
Bad sectors compound.
BitLocker
Microsoft's full-disk encryption built into Windows since Vista.
Boot Sector
The boot sector is the disk's entry point.
BSOD-Related Data Loss
The Blue Screen of Death is a symptom, not a cause. The real question is what triggered it.
Btrfs
Linux's native answer to ZFS.
Chip-Off Recovery
When the controller on an SSD or USB drive is destroyed, chip-off recovery skips it entirely: desolder the NAND chips from the dea...
chkdsk
Microsoft's built-in file system check and repair utility for FAT, exFAT, and NTFS volumes.
Cleanroom Data Recovery
Hard drive read/write heads fly only a few nanometers above the platter surface. A single dust particle is far larger than that ga...
Click of Death
The click of death is loud, rhythmic clicking from a failing hard drive whose heads can't find their position on the platters.
Cloud Backup
Backup copies of your data stored on remote cloud infrastructure rather than local disks or tape.
Cluster (Allocation Unit)
A cluster is the smallest unit of disk space a file system can allocate.
CRC Error (Cyclic Redundancy Check)
A CRC error means data on disk doesn't match the checksum stored alongside it.
Data Corruption
Data corruption is the unintended alteration of stored or transmitted data.
Data Recovery
Data recovery is the process of retrieving inaccessible, deleted, or damaged data from storage media.
dd Command (Linux/Mac)
The Unix command-line utility for low-level byte-by-byte data copying between block devices and files.
Deep Scan vs Quick Scan
Quick Scan reads file system metadata; Deep Scan does file carving.
Deleted File
When you delete a file, the file's data isn't erased. Only the directory entry that points to it changes.
Differential Backup
A backup type that captures all data changed since the last full backup, regardless of any intermediate differential backups.
Disk Image
A disk image is a sector-by-sector copy of a storage device stored as a single file.
Disk Mirroring
Real-time replication of logical disk volumes onto separate physical drives to ensure continuous availability when one drive fails...
diskpart
Microsoft's command-line disk partitioning utility for Windows.
Donor Drive
A donor drive is a healthy hard drive that gives up its parts to repair a failed one.
Drive Not Initialized
Drive Not Initialized in Windows Disk Management means the operating system can see your drive but can't read its partition table.
Drive Not Recognized
"Drive Not Recognized" describes several distinct scenarios users tend to lump together.
Dynamic Disk vs Basic Disk
Two distinct Windows storage architectures.
exFAT (Extensible File Allocation Table)
exFAT is the file system every SDXC card ships with from the factory and the right answer for cross-platform external drives in 20...
ext4 (Fourth Extended File System)
ext4 is everywhere except where you'd expect to see it.
External Hard Drive
An external hard drive is a regular drive in a USB enclosure with a small bridge chip in between.
FAT32 (File Allocation Table 32)
FAT32 is the most universally compatible file system in existence and the easiest to recover deleted files from.
File Carving
File carving extracts files by recognizing them, not by reading metadata.
File Corruption
File corruption is when a file's contents are partially scrambled or truncated such that the application opening it can't make sen...
File Fragmentation
A file's data clusters can sit anywhere on the disk. The file system tracks the order, but the storage itself doesn't enforce it.
File Signature / Magic Number
A specific sequence of bytes at the beginning of a file that uniquely identifies its format.
FileVault
Apple's full-disk encryption built into macOS.
Firmware Corruption
Firmware corruption is when the software embedded inside your storage drive becomes damaged.
Forensic Recovery
Forensic recovery is data recovery with one critical addition: the recovered data must hold up in court.
fsck
The Linux/Unix file system check and repair utility.
Hard Disk Drive (HDD)
The hard disk drive is the most recoverable storage device ever made
Hard Drive Platter
The platter is the actual data storage medium of a hard drive.
Hardware Encryption
Cryptography performed by dedicated silicon, not CPU software.
Hash Verification (MD5/SHA)
The process of confirming data integrity by comparing cryptographic hash values calculated from a file or disk image at different...
Head Crash
A head crash is when a hard drive's read/write heads make contact with the spinning platter surface.
Hex Editor
Software that displays and edits file or disk contents as hexadecimal byte values rather than as the formatted content the file re...
HFS+ (Mac OS Extended)
HFS+ ran the Mac for 19 years and is still the right answer for HDD-based external drives in 2026.
HPA & DCO (Hidden Drive Areas)
Two ATA specification features that hide portions of a hard drive from the operating system.
M.2 Drive
An M.2 drive is a connector specification, not a speed promise.
Mac Kernel Panic
Mac kernel panic is the macOS equivalent of Windows BSOD: a fatal OS error that forces an immediate restart.
MBR (Master Boot Record)
MBR is the 1983-vintage partition table standard that ran the PC world for 30 years.
NAND Flash
NAND flash is the silicon that holds your data on every SSD, USB drive, SD card, and modern smartphone.
NAS (Network Attached Storage)
A NAS is a small file server that lives on your network with multiple drives in RAID.
NTFS (New Technology File System)
NTFS is the only consumer file system designed with recoverability as a built-in goal.
NVMe SSD
An NVMe SSD is the fastest mainstream storage device, and the one with the shortest recovery window.
RAID (Redundant Array of Independent Disks)
RAID is fault tolerance, not a backup.
RAID 0 (Disk Striping)
The simplest RAID configuration: pure speed, zero redundancy.
RAID 1
The simplest redundant RAID configuration: mirroring without striping.
RAID 10
The canonical performance-with-redundancy combination.
RAID 5
The most commonly deployed parity-based RAID configuration historically.
RAID 6
The modern parity-based default for multi-TB arrays.
RAID Rebuild vs RAID Recovery
Two distinct operational responses to RAID failure.
RAW Partition / RAW Drive
RAW is Windows' label for a partition where the file system can't be identified.
Read/Write Head
The read/write head is the business end of a hard drive.
ReFS (Resilient File System)
Microsoft's modern file system for Windows Server.
S.M.A.R.T. Attributes
S.M.A.R.T. is the system that lets a hard drive or SSD warn you before it dies.
SD Card
An SD card is a thumbnail-sized flash chip with one of the worst recovery profiles in modern storage.
Sector (Disk Sector)
The sector is the foundation everything else stands on.
Sector-by-Sector Clone
A sector-by-sector clone copies every byte of a drive, including bad-sector regions, deleted file remnants.
Secure Erase / ATA Secure Erase
Firmware-level data destruction commands that sanitize storage media completely.
Signature-Based Recovery
Signature-based recovery finds files by what's inside them rather than where the file system says they live.
Slack Space
File systems allocate storage in fixed-size clusters. A 500-byte file in a 4KB cluster occupies the entire 4KB cluster.
Solid-State Drive (SSD)
An SSD is the fastest mainstream storage device, and the hardest to recover from.
SSD Controller Chip
The controller chip is the brain of every SSD.
SSD Garbage Collection
Garbage collection is the background housekeeping that keeps SSDs working.
SSD Over-Provisioning
Over-provisioning is the SSD capacity that the host can't see but the controller relies on for everything.
SSD Wear Leveling
Wear leveling is the firmware technique that makes SSDs last as long as they do.
Storage Snapshot
A point-in-time logical view of a file system, volume, or virtual machine state, typically implemented as metadata pointers to dat...