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 degauss magnet, erasing hard drives, degaussing equipment, and degaussing services, see also: cds1500 tape eraser clean hard drive free trial cleaning data in a data warehouse td1b tape degausser hd-1 audio tape degausser hd-1 eraser v-890 video tape degausser mac blank cd erase strip erase ntfs hard drive free hd-1 eraser mds-4 audio tape eraser cannot delete data folders from outlook 2002 freeware erase internet files cds1500 disk eraser v-880 eraser hard drive dod wipe magnetic degausers how do i wipe a hard drive hd-1 audio tape eraser v92 hard drive eraser windows xp delete unnecessary files second hard drive magnetic degausers visual basic mshflexgrid erases row data recordset cleaning data in a data warehouse delete hard drive compaq pressario v-94 tape degausser honeywell f150 media air cleaner media cleaner 6 v-860 video tape degausser manually cleaning hard drive erase hard drive computer v-880 tape eraser erase your harddrive western digital disk eraser freeware delete all data windows me v-880 degausser erase page files degauss camcorder clean up hard drive file erase rewritable cd utility

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 degauss magnet, degaussers, erasing hard drives, cleaning hard drives, degaussing, and erasing harddrives, see also: