When degaussing a traditional hard drive, the magnetically coated platters that store data are completely erased. Degaussing involves subjecting a hard drive to a magnetic field, which essentially demagnetizes the platters. The drive is rendered completely inoperable because there are no longer tracks and sectors on the platter which are used to organize and locate data.
Degaussing provides permanent removal of data and is recommended as a step in the data sanitization of traditional hard drives, tape, and other magnetic media. After degaussing, devices can be physically destroyed using a special shredder—the process guards against the possibility of any potential for possible data recovery.