Patent ID: 7619848

Claim:
A method of searching to find a servo pattern corresponding to a servo pattern copy operation, the method comprising: unparking a magnetic head and moving the magnetic head onto an intermediate area of a rotating disk; moving the magnetic head to a servo pattern copy start area by applying an initial search current to a voice coil of a voice coil motor (VCM); periodically measuring the speed of the magnetic head; controlling the speed of the magnetic head by adjusting a search current to the voice coil according to the measured speed and the speed corresponding to the initial search current so that the measured speed of the magnetic head converges to a pre-set speed; and confirming the servo pattern recorded in the servo pattern copy start area using the magnetic head, wherein the speed of the magnetic head is measured using a back electromotive force of the VCM, and the back electromotive force of the VCM is measured by measuring a voltage across the voice coil when the search current applied to the voice coil and a differential value of the current converge to 0.