In computing, data recovery refers to recovering data that is inaccessible, lost, damaged, corrupted, or formatted from removable media or files, secondary storage, when the data stored in them cannot be accessed systematically.
Usually, the data is salvaged from storage media such as internal or external hard disk drives, solid-state drives, USB flash drives, compact disks, DVDs, magnetic tapes, electronic devices, and RAID subsystems. Physical damage to the storage system or logical damage to the file system can lead to the requirement of recovery.
Physical damage to a hard drive, even when there is an occurrence of a head crash, does not essentially mean the permanent loss of data as a professional data recovery company can salvage this loss of data if the complete data is not recovered, then too most of it gets salvaged.
Much like your bike, your hard disk is a mechanical device as well. Even though most of the parts of a computer are mostly electronic and can only be damaged by electronic stress (power surge) but the hard disk can be affected by both electronic and mechanical stress.
Hard disks fail mainly because of any of the following reasons:
- The computer is bumped or jostled while running
- Electric motor allowing the platter to spin fails due to bad bearings
- Filter on air intake gets clogged or stops working
- Electric circuit board fails due to excessive heat
- Sudden power failure while the disk is in write mode
There are two different types of hard drive failure – Physical and Logical.
There are four phases to successful data recovery, as mentioned below:
Phase 1 – Repair the hard drive
Phase 2 – Image the hard drive to a new drive or disk image file
Phase 3 – Logical recovery of files, MBR and file-system structure, partition
Phase 4 – Repair the retrieved but damaged files
Recovery experts do not require physical access to the damaged hardware. When the lost data can be salvaged by software means and techniques, remote access software over the internet, LAN, or other connection to the physical location of the damaged media can as well help in the recovery process. Though, it is essential to note that this process generally requires a stable internet connection with an adequate bandwidth.
Below are some renowned data recovery softwares:
- Consistency checker
CHKDSK: for DOS and Windows systems
Disk First Aid: for MAC OS 9
- File Recovery
CD Roller: recovers data from an optical disk
Data Recovery Wizard: A Windows file recovery utility by EaseUS
EnCase: a suite of forensic tools that are developed by Guidance Software
Foremost: open-source command-line file recovery program
- Imaging tools
Clonezilla: free disk cloning, imaging, data recovery, and deployment boot disk
ddrescue: an open-source tool
- Bootable –
On a live running system, data recovery cannot be made in some cases for which a boot disk, live CD or USB, or any other type of live distro can be used that at least has an OS.
BartPE: a variant of Microsoft Windows XP or Windows Server 32 bit OS
Finnix: Debian based live CD