Method for controlling servo information detection timing, method for controlling rotational speed of disk, and disk drive

摘要

A method to enable servo information to be detected surely and stably even when a time interval between servo sectors is changed due to disk shifting is provided. A time interval TS(i) is calculated according to an internal variable value, which is in proportion to a displacement DELTAr(i) of a servo area SF(i) in a radial direction of a subject disk (step S6). The displacement DELTAr(i) is calculated from already detected servo information, thereby a time interval for detecting servo information is adjusted according to the above-described time interval TS(i) (steps S7 and S4). The time interval TS(i) is the time interval between passing of a servo sector in the servo area SF(i) under the head H and passing of a servo sector in the servo area SF(i+1) under the head H.