Degaussing, in computing terms, is the term used to describe a process that permanently removes data from a computer, drive or disk. Unlike standard deletion processes which may leave data behind on a medium even though they remove front end pointers to it, degaussing will permanently remove data once and for all. Degaussing is carried out by using a specially designed degausser.

The process of degaussing involves making changes to the magnetic media on which data is stored. Types of media here include drives, disks and tapes. During the degaussing process the magnetic fields on these kinds of devices that store data are altered so that the data that they hold cannot be recovered and used again. This involves actually changing the magnetic fields themselves so that they cannot orientate themselves in an organised manner but are changed to a random function. This method can make data recovery virtually impossible if implemented in the correct way.

The disadvantage to degaussing is that it can destroy the basic functions of a computer so that it cannot be used again. For this reason degaussing may only be used if data needs to be completely erased from a computer and if the computer does not need to be used in the future. If it does need to be used again then an alternative data erasure methodology may be deployed instead. This isn’t so much of an issue which other magnetic media devices such as floppy disks which can usually be viable for re-use if they are reformatted.