Patent ID: 7660059

Claim:
A method of controlling write strength of a hard disk drive (HDD), the method comprising: calculating a flying height of a head before starting a recording operation; and controlling the write strength according to the calculated flying height, wherein the calculation of the flying height of the head comprises: setting a reference value of an initial reproducing signal by measuring the magnitude of the initial reproducing signal read from a measuring area of a disk while rotating the disk at a regular rotation speed using constantly-maintained operating conditions of the HDD and measuring a reference flying height of the head corresponding to the reference value of the initial reproducing signal; measuring the magnitude of a subsequent reproducing signal read from the measuring area of the disk while rotating the disk at the regular rotation speed; and calculating the flying height of the head by using the measured magnitude of the subsequent reproducing signal, the reference value of the initial reproducing signal, and the reference flying height corresponding to the reference value of the initial reproducing signal.