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 cds1500 disk eraser, erasing hard drives, degaussing equipment, and degaussing services, see also: td1b tape degausser hard drive dod wipe sv91m disk degausser erase free disk space mac per-1100 disk degausser cds1500 disk eraser permanantly delete data instructions to erase rewritable cd erase harddrive software cds1500 disk eraser pf252 tape eraser how to erase my hard drive hd-1 video tape eraser sv91m hard drive eraser cleaning out a full hard drive clean gb of memory from hard drive degauser make sv91m hard drive eraser erase rw cd disks pc hard drive cleaning v-860 degausser per-1100 disk eraser v-860 gsa schedule cleaning out a full hard drive degauss camcorder how to delete my hard drive per-1100 diskette eraser freeware erase internet files mac blank cd erase strip how to erase the hard drive cds 2500a feed hopper degausser visual basic msflexgrid erases row data recordset total erase hard drive v92 degausser erase free disk space mac 4000 fs video tape eraser erase hard drive with floppy disc dlt cleaning hard disk data wipe tools dod standard per-4516 degausser

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 cds1500 disk eraser, degaussers, erasing hard drives, cleaning hard drives, degaussing, and erasing harddrives, see also: