What is DOD purging?

STB Suite | The Industry Standard in Peripheral Testing.

DOD Purging means erasing all data on a drive to a standard defined by the Department of Defense (DOD), or by other government agencies. The basic DOD purge specification states that all blocks on a drive will be written with a data pattern, then all blocks will be written with the inverse of that data pattern, then all blocks will be written with another, usually random, data pattern, then the overwrite is verified.