An electrical or permanent magnet device which creates a magnetic field for the purpose of erasing data from storage devices (Hard Drives, Tapes, etc)

Unit of measurement of a magnetic field. 10,000 Gauss = 1 Tesla

Data is recorded magnetically on hard drives and tapes. Degaussing is accomplished by applying a strong enough magnetic field to “demagnetize” the media (hard drives, tapes, etc). During degaussing the magnetic media is passed through a powerful magnetic field to rearrange the pattern of the magnetic particles, completely removing any resemblance to the previously recorded signal.

No, some degaussers do not produce a strong enough magnetic field to sanitize newer media that has a higher coercivity.

Coercivity is the amount of field strength required to ensure Magnetic Media is erased (brought back to a blank/ zero state). Coercivity is measured in units known as “oersteds”.

Oersted is a unit of measurement. It describes the coercivity of the magnetic media (hard drives, storage tapes, etc).

No, data is not recorded magnetically on these devices. Degaussers are only effective on magnetic media (hard drives, DLT tapes, LTO tapes, floppy disks, etc.), not on solid state or flash media.

Certain tape formats can be reused after degaussing. However, hard drives, LTO and DLT tapes have certain components (servo track, timing track, control track, etc.), which are destroyed by degaussing, rendering it unusable. It is possible to reformat them if you send them back to the manufacturer…but given the relatively low cost of new hard drives it doesn’t really make sense to do that. The main thing to understand is that even though degaussing renders the hard drive / tape unusable, it is the safest way to protect your data by making sure it is forensically unrecoverable.

The National Security Agency (NSA), in the U.S., is the only organization that receives federal funding to test devices for properly sanitizing data from electronic media. If the devices pass all NSA testing they are placed on an Evaluated Products List. Devices on this list are approved to permanently erase data from media, including Classified and/or Top Secret data.