Patent ID: 8085491

Claim:
A method of determining a flying height of a magnetic head from a magnetic disk, the magnetic head being placed in a slider arranged at an interval with the magnetic disk, the method comprising: an initial setting process, including gradually increasing driving power to a heater from a state where the heater arranged at a position near the magnetic head in the slider is not driven, until the magnetic head makes contact with the magnetic disk; obtaining an electrical resistance value, which increases due to heat from the heater, of the sensor which is arranged at a position near the magnetic head in the slider and at least a portion of which is exposed on an air bearing surface of the slider, and either an approach distance of the magnetic head relative to the magnetic disk or the flying height of the magnetic head from the magnetic disk; and preparing basic data by obtaining a relationship between a variation of the electrical resistance value of the sensor and the flying height of the magnetic head from the magnetic disk, the flying height being either obtained by the obtaining step of the initial setting process or calculated based on the obtained approach distance in the obtaining step of the initial setting process, in a range including a state in which the change in the driving power of the heater and the change in the electrical resistance value of the sensor are nonlinear due to the cooling effect caused by rotation of the magnetic disk; and a flying height detecting process, including determining an electrical resistance value of the sensor; and obtaining the flying height of the magnetic head from the magnetic disk in the state where the electrical resistance value of the sensor has been determined, based on the basic data in the range which includes the state in which the change in the driving power of the heater and the change in the electrical resistance value of the sensor are nonlinear which is obtained in the initial setting process, using the variation of the electrical resistance value calculated from the determined value.