Restoration can be done in full or in part of the data stored in deleted or damaged data files. In case of file deletion, if the space originally occupied by the deleted file is not overwritten (or the disk is not reformatted after deletion) the file may be recoverable through common ‘undelete’ programs. In case of damaged files (or files stored on damaged media), custom-written software and sophisticated equipment is required for any extent of recovery. Also called data restoration.
In the hard drive data recovery category, a few different types of techniques are applied to specific scenarios. Hardware data recovery techniques work on situations where a system failure prevents easy access to a hard drive. With more sophisticated hardware, this problem is easily solved. Another type of data recovery technique applies to disk level failure, where more elaborate approaches may be required. Other types of data recovery pertain to data that has been deleted and possibly overwritten, where data recovery involves specific manipulation of the bits recorded on a drive.
Certain key data recovery services that apply to disk failures and other scenarios are sometimes called in-place to repair and read-only data recovery. The first type of approach uses utilities and other resources to try to fix disk errors. A read-only approach creates a copy of a drive, where data can be extracted. In another approach, professionals may try to physically repair a failed disk with replacement parts.
A key to understanding data recovery is to look at the difference between older magnetic drive mediums and new solid-state drives, which record data in different ways.
The most common data recovery scenario involves an operating system failure, malfunction of a storage device, accidental damage or deletion, etc. (typically, on a single-drive, single-partition, single-OS system), in which case the goal is simply to copy all wanted files to another drive. This can be easily accomplished using a Live CD, many of which provide a means to mount the system drive and recover data, and to move the files from the system drive to the backup media with a file manager or optical disc authoring software. Such cases can often be mitigated by disk partitioning and consistently storing valuable data files (or copies of them) on a different partition from the replaceable OS system files.
Another scenario involves a drive-level failure, such as a compromised file system or drive partition, or a hard disk drive failure. In any of these cases, the data cannot be easily read. Depending on the situation, solutions involve repairing the file system, partition table or master boot record, or drive recovery techniques ranging from hdd recovery of corrupted data, hardware- and software-based recovery of damaged service areas (also known as the hard disk drives”firmware”).
The term “data recovery” is also used in the context of forensic applications or espionage, where data which have been encrypted or hidden, rather than damaged, are recovered soon.