An alternating current (AC) bulk eraser (degausser) is used for complete erasure of data and other signals on magnetic media. Degaussing is a process where magnetic media is exposed to a powerful, alternating magnetic field. Degaussing removes any previously written data, leaving the media in a magnetically randomized (blank) state.

The degausser must subject the media to an alternating magnetic field of sufficient intensity to saturate the media and then by slowly withdrawing or reducing the field, the magnetic media is left in a magnetically neutral state.

To erase recorded data, it is necessary for the strength of the degaussing field to be greater in value than the coercivity of the magnetic media. Simply stated, coercivity is the magnetic field strength, rated in oersteds (Oe), required to change the magnetic orientation of the magnetic material. Check with knowledgeable dealers or degausser manufacturers to identify degausser models that meet your requirements.

Data is typically not lost until its level has been decreased 65% to 75% (or more) below its original saturation recording signal level, dependent upon the drive system.

 

For more information on video tape erasers, erasing hard drives, degaussing equipment, and degaussing services, see also: how to erase an cd data warehouse security social security death data base how to wipe a hard drive and load new os computer data network security hard drive wipeout how to clean a hard drive degauss jewelry box disk erasers hard disk clean data security organization erase cd access data wipe drive 3.0 free disk eraser cassette tape eraser cdrw erase erase cd-rw cleaning the hard drive erase entire network hard drive data security organization how do i erase my harddrive computer data network security secure erase security and data technology v91m hd hard disk drive degausser hard disk cleaner data cleaning shareware how to wipe a hard drive and load new os erase cd-rw data security in healthcare how do i erase data off a cd-rw secure erase hard drive data distribution security degausser handheld magnetic media breathe easy media air cleaner v91m hd hard disk drive degausser eraser disk securities data corp. hard drive erase how do i erase my harddrive

A complete erasure level, for most users, is considered to be 60 dB below the original signal level – this of course depends on user requirements. A 60 dB signal decrease equates to reducing the signal to one tenth of one percent of its original value.

Magnetic media products that have factory prerecorded magnetic servo patterns should not be degaussed. Degaussing would erase the factory written magnetic servo signals and leave the media unusable. For all other magnetic media (without magnetic servo signals), after proper degaussing, the quality of subsequent data recording should be unchanged or even improved.

It is very important to understand and follow the degausser’s operating instructions. This is especially important for manual units where the operator controls the media’s movement through the degaussing field. For higher coercivity media, four passes are often recommended – two passes, with a 90 degree rotation for the second pass, and then repeat the process with the media turned upside-down. Of course, these and other important operating considerations will vary with the type, power and construction of the individual degausser models.

For more information on video tape erasers, degaussers, erasing hard drives, cleaning hard drives, degaussing, and erasing harddrives, see also: