DISK DEVICE, HEAD CONTROL DEVICE, HEAD CONTROL METHOD, COMPUTER-READABLE STORAGE MEDIUM, AND PROGRAM THEREFOR

摘要

A disk device or a head control device having a function of protecting data stored in a medium (2) against a magnetic field from the outside. The device comprises a magnetic sensor (5) disposed near a head (3) for measuring the external magnetic field, a sensor signal processing unit (6) for processing a sensor signal from the magnetic sensor (5) and judging from the sensor signal whether or not the intensity of the external magnetic field exceeds a predetermined intensity, and a head control unit for so controlling the head (3) as to move it from the data-written region of the medium (2) when it is judged by the sensor signal processing unit (6) that the intensity of the external magnetic field exceeds the predetermined intensity.