Patent ID: 7719788

Claim:
A servo controlling method, which is used in a disk storage device, for controlling a head to be positioned on a target track by reading servo information and a post code, which indicates an eccentricity of the servo information, from each servo frame recorded on each track of a disk recording medium via the head provided in an actuator, by correcting a demodulation position demodulated from the servo information with the post code, and by driving the actuator on the basis of the corrected demodulation position, comprising: storing the post code, which is read from each servo frame on the target track of the disk recording medium, in a memory if an on-track condition for determining that the head is controlled to be positioned on the target track is satisfied; and using the post code stored in the memory in order for a correction of the demodulation position if the post code corresponding to each servo frame is stored in the memory and the on-track condition is satisfied, in the correction of the demodulation position in each servo frame.