Head positioning control method and apparatus

摘要

A head positioning control system has a speed control mode in which a head is moved by controlling a speed of said head and a position control mode in which the head is positioned onto a target track in accordance with position data of the head attained from servo data. The head positioning control system controls the movement of the head in the speed control mode until the head reaches within a first predetermined distance from the target track, and switches the control mode to the position control mode when the head reaches within the first predetermined distance from the target track, whereby the head is controlled to track the target track. When the head shifts from the target track by a second predetermined distance or more in the position control mode, this control system switches the mode to the speed control mode and immediately executes a control sequence from the speed control mode to the position control mode, starting at the head's current position.