Patent ID: 8896947
Filing Date: 2014-11-25
Classification: G11B

Abstract:
1. A disk storage apparatus comprising: a magnetic head comprising a high-frequency oscillation element disposed close to a main magnetic pole that generates a recording magnetic field for perpendicular magnetic recording, the high-frequency oscillation element applying a high-frequency magnetic field onto a magnetic disk during data recording; a detector configured to detect an electrical resistance of the high-frequency oscillation element, and to detect a plurality of minimum points near reversal of polarity of a recording current for generating the recording magnetic field, which are obtained after the reversal of polarity, and a maximum point between the plurality of minimum points; a calculator configured to calculate time axis data indicative of a variation, on a time axis, in the electrical resistance value detected by the detector; and a decision module configured to determine whether the high-frequency oscillation element is malfunctioning based on a variation amount obtainable by comparing the prior time axis data calculated by the calculator with the latest time axis data.