The first concept to understand is the difference between degaussing a hard drive and degaussing a tape. Hard drive degaussing is a process designed to reduce the coercivity of the material, usually by applying a magnetic field so as to eliminate any residual magnetism left from previous recordings. LTO tape degaussing is a process that aims to remove any surface contaminants, such as dust or fingerprints that might adhere to the data storage media.
Pirate techs have been degaussing hard drives and LTO tapes in the same machine for years. The basic principle of degaussing is that it removes all data from a device by emitting, through an alternating magnetic field, magnetic fluxes strong enough to cause domain walls to flip. For this reason, it’s not possible to degauss a hard drive without also degaussing the tape that it’s stored with.
Hard disk drives (HDDs) typically contain magnetic media that is sensitive to outside interference. One way to protect these devices against the influence of electro-magnetic fields, such as those generated by power cables, running trains or microwaves is degaussing. A degausser consists of a coil that emits strong magnetic fields, which erase what’s stored on the hard drive. However, the process isn’t perfect and it may not be enough to protect your data.
