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Definitions


Hard drive

A hard drive (often abbreviated as HD, or HDD) is a storage device that permanently stores and retrieves data on a computer. It consists of a spinning magnetic disk to which data is written using a read​​/write magnetic head on a mechanical arm called an actuator, all inside of an air-sealed casing.

Partition and (logical) disk

A partition is an area on a physical storage device separated from other device segments. For the operating system and computer users, although the separation is pure logical, it appears as an independent storage device with a separate file system. There are several reasons for such partitioning. For example, Windows 10 creates several service partitions, apart from the system partition (disk C:), like boot and recovery partitions that it uses to ensure system stability and recoverability. Another reason to separate the system and user data partitions is if the system has to be re-installed, the user data will remain untouched.

To be accessible for the computer user, a partition must have an assigned letter. In this case such a partition is called a logical disk and is referred to by its letter.

SSD and NVME storage devices

Click to expand/collaps SSD Device Icons

SSD_Disk

SSD storage devices.

NVME_Disk

NVME storage devices: SSD devices connected to the computer through a special interface.

A solid-state drive (SSD) is a storage device that stores data on nonvolatile solid-state flash memory and has no moving parts, unlike hard drives or optical disks. They are much faster than traditional hard drives and more shock-resistant, but their life span is shorter and storage space is more expensive. NVME devices are SSD devices connected to the computer through a special interface.

Click to expand/collapse Peculiarities of file recovery from SSD and NVME storage devices

All considerations below are applicable for files deleted from or without Recycle Bin. If you must recover files after a system crash, it will not differ much from file recovery from conventional hard drives.

SSD devices have some specific obstacles for file recovery, especially for files deleted from or without the Recycle Bin. Periodically, Windows issues a special command TRIM that informs the SSD device that some files have been deleted and their storage space is needed no more. Upon receiving this command, the device frees its internal space where the deleted files have resided. When the OS accesses that space, the device simply returns zeros even without reading the actual data. Moreover, Microsoft uses a so called DZAT procedure (deterministic zeroes after TRIM) that fully and permanently cleans that space by overwriting it with zeros. It is impossible to recover files after this procedure.

The main question is when that will happen. Depending on many circumstances, it may take from several seconds to several days. Within this time period, the file data will remain stored on the SSD device, and R‑Undelete can recover them.

Usually, Windows executes the TRIM command during shutdown and startup. That is why the main advice for the case of deleted files is to power your computer off by long-pressing the Power button of your computer. Do not shut down it. Then remove the SSD disk from the computer and connect it to another one. Use that second computer for file recovery.

Quick Scan

A disk operation in which R‑Undelete quickly analyzes information about files stored on the disk, including search for deleted files. Then it lists all found files in its Files panel.

Recovery chances

R-Undelete estimates chances for successful file recovery while listing the files. Those estimations may not be quite accurate immediately upon file listing, but Deep Scan greatly improves those estimations.

Click to expand/collapse Recovery chances

Rec_Undef

Undefined

Rec_Good

Good

Rec_Above

Above average

Rec_Average

Average

Rec_Below

Below average

Rec_Bad

Bad

File mask

A file mask is a pattern of characters and wildcards used to match folder and file names.

File signatures and raw file search

A file signature (sometimes is called as a file magic number) is a data pattern within the file that is unique to certain file types. It can be used to identify the format of the file and recover its content even when the disk file system contains no information about such a file. This method of file recovery is called "raw file search" or search for known file types and used to recover deleted files from damaged, deleted, or re- formatted disks, as well as from partitions with unrecognized file systems. R‑Undelete uses raw file search when performing Deep Scan .

Click to expand/collapse List of known file types

Document

AbiWord Document: .abw

Adobe PDF document: .pdf

Final Draft Document: .fdr

FrameMaker Document: .fm

Garmin MapSource data: .mps

GNU Info Document: .info

HTML Document: .html

Lotus AMI Pro Document: .sam

Lotus Organizer Report: .rep

Lotus Word Pro Document: .lwp

Microsoft Money Data: .mny

Microsoft Office Open XML Document *

Microsoft OneNote section file: .one

Microsoft Pocket Streets Map File: .mps

Microsoft PowerPoint 2007 XML Document*: .pptx

Microsoft PowerPoint Document*: .ppt

Microsoft Reader eBook: .lit

Microsoft Reader eBook annotations: .ebo

Microsoft Word 2007 XML Document*: .docx

Microsoft Word Document*: .doc

Microsoft Word2 Document: .doc

Microsoft WordPad Document: .wri

OLE Storage

OpenDocument Document

PostScript document:* .ps

QuickBooks Backup File: * .qbb

QuickBooks Primary Data File: * .qbw

Quicken Data: * .qdf

Rich Text Document: .rtf

TEX Document: .tex

Text Document: .txt

TurboTax return file: .tax

Unicode Document: .txt

Word for Macintosh Document: .mcw

WordPerfect Document: .doc

XML Document: .xml

Document: Spreadsheet

Lotus Spreadsheet: .wks

Lotus3 Spreadsheet: .wk3

Microsoft Excel 2007 XML Document*: .xlsx

Microsoft Excel Document*: . xls

Microsoft Excel2 Spreadsheet: .xls

Microsoft Excel3/4 Spreadsheet: .xls

Quattro Pro Spreadsheet: .wq1

 

 

Document: Database

Data Interchange Format file: .dif

dBase III Database: .dbf

Microsoft Access 2007 Database: .accdb

Microsoft Access 2007 XML Document: .accdt

Microsoft Access Database: .mdb

Microsoft Linker Database: .lk

Microsoft Program Database: .pdb

Microsoft SQL Database: .mdf

Microsoft SQL Log: .ldf

MySQL Database: .myi

Omnis Studio Database: .df1

Omnis Studio Library: .lbs

Internet-related files

Compiled HTML file: .chm

Internet shortcut: .url

Microsoft OutLook Personal Folder: .pst

Microsoft Outlook​​/Inbox offline folder: .ost

Mozilla Firefox browser extension: .xpi

Mozilla Mail Summary file: .msf

Outlook Express Messages: .dbx

The Bat! Address book: .abd

The Bat! Message Base: .tbb

The Bat! Message Index: .tbi

Windows Address Book: .wab

XML document (Unicode): .xml

Font

Adobe PostScript Font: .pfb

Adobe Printer Font: .pfm

BDF Unix font

BGI font: .chr

CPI DOS font: .cpi

MyTest Font: .mtf

TrueType Font: .ttf

Windows System Font: .fon

 

Graphics​​/Picture

3D XML file: .3dxml

3DStudio Mesh: .3ds

Adobe InDesign File: .indd

Adobe Photoshop Image: .psd

Agfa​​/Matrix Scodl Image: .scd

Alias Wavefront Raster Image: .rla

ArcView Shape: .shp

AutoCAD Binary Image: .dxf

AutoCAD Drawing: .dwg

AutoCAD Image: .dxf

Autodesc Animator Image: .pic

Autodesc Animator Pro color map: .col

Autodesc Animator Pro Image: .pic

Autologic Image: .gm

AVHRR Satellite Image: .sst

Bentley MicroStation CAD Drawing: .dgn

BMF Image: .bmf

Canon RAW graphics file: .crw

Canon RAW graphics file*: .cr2

Canon RAW graphics file: .crw

ColoRIX Image: .rix

CompuServe GIF Image: .gif

ComputerEyes Raw Image: .ce1

Continous Edge Graphic Image: .ceg

Corel Texture Image: .tex

CorelDraw CMX Image: .cmx

CorelDraw Image: .cdr

Cubicomp Picture Maker Image

Dr. Halo palette: .pal

Enhanced MetaFile Image: .emf

Epson Stylus Image: .prn

Erdas LAN​/GIS Image: .lan

Fractal Image Format: .fif

Freehand (MX) Database: .fh10

GEM Raster Image: .img

GEM VDI Image: .gdi

GOES Satellite Image: .goe

Graphics Workshop for Windows Thumbnail: .thn

Gridded Binary Image: .grb

Hitachi Raster Image: .hrf

Hotspot Image: .shg

HP Command Language Image: .pcl

HP Raster Image: .rtl

HSI JPEG Image: .hsi

IBM Picture Maker Image: * .pic

iPhoto Image: .attr

Jovian Logic Image: .vi

JPEG 2000: .jp2

JPEG Digital Camera*: .jpg

JPEG Image: .jpg

Kodak PhotoCD Image: .pcd

LBM/IFF Image: .lbm

Lightwave Object: .lwo

Lotus PIC Image: .pic

Macintosh Paint Image: .mac

Macintosh PICT Image: .pct

Microsoft Paint Image: .msp

Minolta RAW image: .mrw

Nikon RAW image*: .nef

Olympus RAW image: .orf

PaintShop Pro Image: .psp

PaperPort Image: .max

PBM Image: .pbm

PGM Image: .pgm

Pictor PC Paint Image: .pic

PIX Image: .pix

PM Image: .pm

PNG Image: .png

PPM Image: .ppm

Print Shop Image: .pds

QuarkXpress Database: .qxp

QuarkXPress file: .qxd

Quick Link II fax Image: . qfx

QuickDraw 3D Metafile: .3dmf

RenderMan Image: .rib

SGI Image: .sgi

Sigma RAW image: .x3f

Sketch Image: .sk

SmartDraw file: .sdr

SmartDraw template: .sdt

Sony RAW image: .arw

STAD Image: .pac

Sun Raster Image: .sun

SymbianOS Image: .mbm

Tagged Image Format File: .tif

TI Image: .92i

TrueVision Image: .tga

Utah Raster Toolkit Image: .rle

VITec Image: .vit

Windows Animated cursor: .ani

Windows Bitmap Image: .bmp

Windows cursor: .cur

Windows Fax Cover Image: .cpe

Windows icon: .ico

Windows MetaFile Image: .wmf

WordPerfect Graphics Image: .wpg

X PixMap Image: .xpm

X Window Dump Image: .xwd

Xara Drawing: .xar

ZSoft PCX Image: .pcx

 

 

Multimedia: Audio Files

Advanced Streaming Format file: .asf

AIFF Sound: .aif

Amusic tracker: .amd

aPac Audio: .apc

AudioCD file: .cda

AVR Sound: .avr

CMF Music: .cmf

Creative Voice File: .voc

DiamondWare Sound: .dwd

Digital Speech File: .dss

Digital Voice File: . dvf

EA ASF/MUS Audio: .asf

Extended M3U playlist: .m3u

FLAC Audio

La Lossless Audio: .la

Liquid Audio: .la1

MIDI Instrument definition: .idf

MIDI Music: .mid

MIDI stream: .mds

Monkeys Audio: .ape

MPEG Layer I Audio: .mpg

MPEG Layer II Audio*: .mp2

MPEG Layer III Audio*: .mp3

MUS Music: .mus

Musepack Audio: .mpc

Next​/Sun Sound: .au

Ogg Vorbis Audio: .ogg

OptimFROG Audio: .ofr

RIFF MIDI Music: .rmi

RK Audio Sound: .rka

Sierra AUD Sound: .aud

Sony OpenMG Audio: .oma

Super NES Audio: . spc

TTA Audio: .tta

VQF Sound: .vqf

WavPack Audio: .wv

Westwood AUD Sound: . aud

Windows Audio Compression Manager driver: .acm

Windows Media Audio: .wma

Windows WAVE Sound: .wav

X-MIDI Music: .xmi

ZyXEL Sound: .zyx

Multimedia: Video Files

3GPP multimedia audio​​/video: .3gp

3GPP2 multimedia audio​​/video: .3g2

4X Movie Video: .4xm

Adobe Filmstrip Animation: .fsf

AMV Video: .amv

ANIM Animation: .cel

Autodesk Animator: .fli

BCS Video: .bcs

BINK Video: .bik

DeluxePaint Animation: .anm

Director Video: .dcr

DriveCam Video: .dce

DVM Video: .dvm

Eyemail Video: .eye

Flash Video: .flv

Google Video: .gvi

Intel DVI Video: .dvi

Intel Indeo Video File: .ivf

Interplay MVE Video: .mve

Lotus ScreenCam Video: .scm

LZA Animation: .lza

MPEG Video: .mpg

Nancy Codec Video: .noa

NEOchrome Animation: .ani

Nullsoft Video: .nsv

NuppelVideo (MythTV) Video: .nuv

QuickTime Video: .mov

QV-10 Video: .cam

RPL Video: .rpl

Sega FILM​​/CPK Video: .cpk

SGI movie format: .mv

Shockwave Video: .swf

Smacker Video: .smk

SMJPEG Video: .mjpg

Sony Movie Player Video: .mqv

VideoCD MPEG: .dat

VideoCD Video: .vcd

Vivo streaming Video: .viv

VOB video files: .vob

VP6 encoded Video: .vp6

Windows AVI Video: .avi

Windows Media Video: .wmv

Multimedia Files

Material Exchange File: .mxf

MP4 file: .mp4

Real Networks audio​​/video: .rm

RIFF Multimedia File

 

 

Archive Files

7-Zip archive: .7z

ACE archive: .ace

AIN archive: .ain

ARJ archive: .arj

ARX archive: .arx

Aladdin Systems StuffIt archive: .sit

BAG archive: .bag

BIX archive: .bix

BOA archive: .b58

BZip2 archive: .bz2

BlackHole archive: .bh

Blink archive: .bli

CPIO archive: .cpio

CRUSH archive

ChArc archive: .chz

Compress archive: .z

FOXSQZ archive: .sqz

GZip archive: .gz

HA archive *: .ha

HAP archive: .hap

HPACK archive: .hpk

Hyper archive: .hyp

InstallShield Cabinet archive: .cab

InstallShield Data archive: .z

InstallShield archive

JAM archive: .jam

JAR archive: .jar

JRC archive: .jrc

LHA​​/LZARK archive: .lzh

LIMIT archive: .lim

LZA archive: *.lza

LZOParchive: .lzo

LZSH archive

LZX archive: .lzx

Microsoft Cabinet archive: .cab

Microsoft Compress 5 archive

Microsoft Compress 6 archive

PAKLEO archive: .pll

Pack archive

QFC archive: .qfc

Quantum archive *: .ark

Quark archive

RAR archive: .rar

RPM archive: .rpm

ReSOF archive: .sof

SAR archive: .sar

SBC archive: .sbc

SCO archive *

SQZ archive: .sqz

SZip archive

StuffIt archive: .sit

TAR archive: .tar

UFA archive: .ufa

UHArc archive: .uha

UltraCompressor 2 archive: .uc2

UltraCrypt 2 archive: .ue2

WIN-Freeze archive*: .ice

WRAptor archive: .wra

WinImp archive: .imp

YAC archive: .yc

YBS archive: .ybs

ZIP archive: .zip

ZOO archive: .zoo

ZZip archive: .zz

Apple Safari Web Archive: .webarchive

Microsoft Internet Explorer Web Archive: .mht

R-Drive Image Archive: .arc

R-Drive Image V1 Archive: .arc

WinImage Archive: .imz

Executable​/Library/DLL

DOS Style Executable: .exe

ELF Executable (UNIX)

ELF Library (UNIX)

ELF Module (UNIX)

Java Bytecode: .class

Novell NetWare executable: .nlm

RDOFF executable

Win32 DLL*: .dll

Win32 Executable*: .exe

Windows OCX File: .ocx

 

 

Development files

Borland Delphi 6 Library: .dcu

Borland Turbo Pascal compiled Unit: .tpu

COM Type Library: .tlb

Delphi 7 Compiled Unit: .dcu

Library: .lib

Microsoft .NET XML Resource template: .resx

Microsoft ClassWizard file: .clw

Microsoft Linker database

Microsoft Precompiled header: .pch

Microsoft Visual C++ Database: .mdp

Microsoft Visual Studio Database: .dsp

Microsoft Visual Studio Solution: .sln

Microsoft Program database

Microsoft Visual C++ project

Microsoft Visual Studio workspace: .dsw

OMF Object library: .lib

VisualBasic Database: .vbp

Windows Compiled resource (16bit)*: .res

Windows Compiled resource (32bit): .res

 

 

Other file types

ABBYY Lingvo dictionary: .lsd

File Crypt file: .rzx

Kaspersky Anti-virus data base: .avc

NOD32 Antivirus Update file: .nup

OziExplorer Map data: .map

RegEdit file: .reg

RegEdit file (UNICODE): .reg

Windows Backup File: .bkf

Windows Clipboard file: .clp

Windows Color Profile: .icm

Windows Minidump

Windows National locale: .nls

Windows Password file: .pwl

Windows Policy file: .pol

Windows Registry file: .dat

Windows Registry hive: .hiv

Windows shortcut: .lnk

WinHelp: .hlp

WinHelp Contents: .cnt

 

 

Note: Using scan for Known File Types, R‑Undelete can successfully recover only un-fragmented files.

Disk Image

An image is a file containing an exact, byte by byte, copy of a hard drive or a disk. When created, images can be connected to R‑Undelete and processed like their original objects.

Images are very useful if there is a risk of total data loss due to hardware malfunction. If bad blocks are constantly appearing on a hard drive or its S.M.A.R.T. state is poor, an image of this hard drive should be immediately created. All data search and recovery can be done from this image.

The Disk Images help page explains how to create and work with images.

Smart technology

S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) is a technology widely used in hard drives and solid-state devices that monitors their reliability conditions to predict possible hardware failures.

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