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 thurough hard drive cleaning, erasing hard drives, degaussing equipment, and degaussing services, see also: homeland security data bases how to erase a video tape destroy data and hard drive and emergency clean a hard drive cd rw and erase erase files software how to erase a video tape campus data and security hard drive wipeout homemade degausing coil delete from data adapter erase hard drive computer free windows 2000 hard disk clean old compressed files slow hard disk clean up software free wipe out a hard drive how to clean a hard drive clean and re format hard drive ships degaussing principle how do i erase a hard drive how to erase hard drive in dos clean and re format hard drive r.s. andrews high efficiency media retrofit air cleaner software to clean up hard drive how to clean a hard drive instant hard disk eraser grid data security how to delete unwanted files from hard drive how do i completely erase a hard drive erase free space on hard drive degaussing color monitors rsa data security inc. selling computer erase disk clean hard drives securely erase hard disk degauser coil erase free space on hard drive media cleaner profiles download v91m hd hard disk drive degausser windows 2000 hard disk clean old compressed files slow clean hard drive completely

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 thurough hard drive cleaning, degaussers, erasing hard drives, cleaning hard drives, degaussing, and erasing harddrives, see also: