Abstract: A method for controlling a ball auto-balancing system of an optical disk drive is provided. A rotational member is fixed on a rotating axis of an optical disk drive and rotates synchronously therewith. A spindle motor drives the rotational member to accelerate and decelerate within the rotating speed range at least twice. When the spindle motor accelerates and decelerates for many times, if the measured central error value is greater than the last measured one, the accelerating and decelerating range is adjusted.

Abstract: A method for controlling a ball auto-balancing system of an optical disk drive is provided. A rotational member is fixed on a rotating axis of an optical disk drive and rotates synchronously therewith. A spindle motor drives the rotational member to accelerate and decelerate within the rotating speed range at least twice. When the spindle motor accelerates and decelerates for many times, if the measured central error value is greater than the last measured one, the accelerating and decelerating range is adjusted.

Abstract: A method and optical disc drive for accessing data on optical storage medium are provided. The optical disc drive includes a sled motor and an optical pickup head. When the sled motor performs a track positioning, the optical pickup head uses a differential astigmatic detection (DAD) method to generate a focus error signal. When the track positioning is finished, the optical pickup head is switched to an astigmatic detection (AD) method to generate the focus error signal to assist to access data on an optical storage medium. Therefore, it can greatly reduce reading and writing errors of the optical disc drive.