Methods of overwriting
When the optional hard disk is installed, you can select a method of overwriting from the following:
NSA
Temporary data is overwritten twice with random numbers and once with zeros.
DoD
Each item of data is overwritten by a random number, then by its complement, then by another random number, and is then verified.
Random Numbers
Temporary data is overwritten multiple times with random numbers. The number of overwrites can be selected from 1 to 9.
The default method for overwriting is "Random Numbers", and the default number of overwrites is 3.
NSA stands for "National Security Agency", U.S.A.
DoD stands for "Department of Defense", U.S.A.