Patent ID: 7330324
Filing Date: 2008-02-12
Classification: G11B

Abstract:
1. A magnetic disk drive, comprising: a memory or magnetic disk that stores thermal protrusion (TPR) amount information about each magnetic head used within said magnetic disk drive, the TPR amount information including information of an amount of protrusion of a flying surface of the magnetic head protruding toward the magnetic disk as a result of thermal expansion of the magnetic head; and a management module configured to perform magnetic head flying height management to manage a flying height of each magnetic head with respect to the magnetic disk in actual use based on the stored TPR amount information; wherein the TPR amount information stored in said memory or magnetic disk is previously measured during a test process for actual use for said magnetic disk drive, wherein the previously measured TPR amount information is obtained by capturing replay output changes of a first single frequency signal used to write a single pattern signal on a specific track or cylinder on the magnetic disk, and a second single frequency signal, wherein the second frequency signal is written on a portion of the specific track or cylinder written by the first single frequency signal.