Patent ID: 7768733

Claim:
A method for erasing data, that must be erased for ensuring security, from a magnetic tape storage medium, housed in a cartridge, containing a memory in which are stored the last written track position of the last written, most recent data and the last track position of past data written in the past and remaining unerased, said method comprising: reading out of said memory, before overwriting data onto said magnetic tape storage medium, the last written track position of said most recent data and the last track position of said past data; selecting, based on an instruction from a user, a final position, up to which said magnetic tape storage medium should be erased, from either one of the last written track position of said most recent data and the last track position of said past data; and erasing, by overwriting meaningless data, said data on said magnetic tape storage medium from the beginning of the magnetic tape storage medium up to said selected final position.