The easiest way to recover data is to restore it from a backup.
Failing that, data recovery generally refers to attempts to salvage data from a faulty or damaged storage media, e.g. a harddisk or memory stick. Where no backup exists, the approach to the problem will depend on several things:
- the value of the data
- the cause of the problem (software vs hardware)
- the severity of the problem (part of harddisk damaged vs catastrophic damage)
Extremely Valuable Data
There are dedicated, professional services for data recovery. These are prohibitively expensive
If the drive is still spinning, the inability to access the harddisk may be due to a software problem. In this situation, the computer can still be booted from an alternative source, e.g. a live Linux or Windows CD. In this situation, once the operating system is running from the live CD, data should be accessible as normal.
Using Linux Tools
The Knoppix Live CD or DVD is particularly good for data recovery and situations where there are data on your hard disk but for whatever reason, the operating system that is installed on it does not give you access - either because the OS has died or won't play nice.
Other interesting sources of info are:
- http://www.garloff.de/kurt/linux/ddrescue/ and *http://www.unixwiz.net/techtips/recovering-ext2.html
More a matter of computer forensics.