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 delete hard drive compaq pressario, erasing hard drives, degaussing equipment, and degaussing services, see also: cleaning up a hard drive hard drive dod wipe automatically erase file after reading basic instructions on how to delete a hard drive partition pf252 video tape degausser visual basic recordset mshflexgrid erases row data data security holdings disk eraser free pf252 tape eraser pf252 tape degausser total erase hard drive v-94 tape degausser per-1100 hard drive eraser per-1100 drive eraser how do i wipe a hard drive degaus zenith tv v-860 gsa schedule remove data from harddrive data security holdings sv91m disk eraser adt security services data center nashville tennessee v-880 tape eraser v-94 gsa schedule software to erase hard disk what files are safe to delete from my hard drive degausing television screen clean gb of memory from hard drive degauss magnet when i reinstall windows 98 does it erase all my files v92 video tape eraser when i reinstall windows 98 does it erase all my files erase reload dell hard drives mds5 video tape degausser sv91m diskette eraser how to delete all data from hard drive sv91m tape eraser cleaning up a hard drive delete hard drive compaq pressario per-1100 hard drive eraser make clean room hard disk

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 delete hard drive compaq pressario, degaussers, erasing hard drives, cleaning hard drives, degaussing, and erasing harddrives, see also: