Data Recovery Glossary

DAS to Dymanic Disk

Data Recovery Glossary home

List of pages

A - Access Rights to ASCII

B - Backup to BTRFS

C - CANON_DC to Cross-linked Files

D - DAS to Dynamic Disk

E - ECC to External Hard Drive

F - Failed Disk to fsck

G - Gigabyte to GUID

H - Hard Drive to Hybrid Disk

I - IDE to Internal Drive

J - JBOD to Jumper

L - LBA to LVM

M - Megabyte to Motherboard

N - NAS to Nuke & Pave

O - Operator Error to Overwritten Data

P - Parallel ATA to PSU

Q - QNAP to Quota

R - RAID to Resident File

S - SAS to Synology Hybrid RAID

T - Tailpacking to TrueCrypt

U - UDMA to USB Thumbdrive

W - WD to Write-Through Cache




DAS (Direct Attached Storage) - a device of external memory connected to a main computer directly and used only by this computer. The simplest example of DAS is an internal hard drive.

Data recovery

Data recovery - an activity to recover accidently deleted files or to recover data from the damaged device. There are data recovery services that work with physically damaged disks and companies which create software to work with logically damaged disks as well.

Data recovery service

Data recovery service - a company which extracts data from the damaged storage devices. Data recovery service has a special laboratory (called "clean room") in which it is possible to manually repair the hard disk without further damaging it.

Data recovery software

Data recovery software - software to recover accidently deleted files or to recover data from the damaged device. There are paid and free tools.


Deduplication - A technology that decreases the disk space usage by eliminating data redundancy. If there are two identical data blocks on a drive, only one copy is physically stored. If then it is needed to write new data in one of the blocks, therefore making the blocks different, a filesystem copies the data and modifies the copy. This technology is called copy-on-write. Deduplication is used in ZFS and BTRFS filesystems.


Defragmentation - a process of relocating the files so that they are placed contiguously. The defragmentation increases read and write speed.

Delayed parity

Delayed parity - a variety of parity blocks placement in RAID 5. With delayed parity the data block size does not equal to parity block size.


Destriping - the process when data blocks which were striped across different disks are written to a single storage device sequentially. Typically performed as a part of RAID recovery.

Disk image file

Disk image file - a file containing a copy of data from the storage device.

Disk pool

Disk pool - a set of physical disks from which Storage Spaces allocates its virtual storage.


DIY - short for Do It Yourself.


Drobo – the company, which produces NAS and DAS devices. Disks are combined into a single storage using the proprietary storage technique called BeyondRAID.

Dynamic disk

Dynamic disk - a technology built in Windows which allows to create software RAIDs and to partition disks using LDM.

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