Patent ID: 7209313

Claim:
A method for re-magnetizing a servo region of a perpendicular magnetic recording medium in a discrete track disk type in a magnetic storage device which is provided with a magnetic head, in order to prevent reduction in a reproduced output of a servo signal recorded in the servo region, wherein the magnetic head has a write head portion to record a data signal and a read head portion to read the data signal, the method comprising: a first step of measuring a first amount which is indicative of a magnitude of magnetization in the servo region, by the read head portion; and a second step of re-magnetizing at least one of the servo regions as a target servo region by the write head portion, when a degraded servo region is detected in which a ratio of the first amount measured at the first step to an initial value of the first amount is smaller than a predetermined ratio, wherein the target servo region is detected by counting a number of clocks corresponding to a time required for the magnetic head to move across a data region preceding the target servo region.