Abstract: In a disk apparatus, a movable-base position sensing switch (169) is provided such that the sensing switch is turned from ON state into OFF state at a time a turntable (20) of a movable base (13) is separated from a clamper (16) during movement of the movable base (13) to an unclamped position. A motor (91) is controlled (190, 191, S12-S20) so that a driving force of the motor is used to move a tray and/or to move the movable base through a drive device. The motor is actuated in a first direction to move the movable base to the unclamped position for a first period from the time the position sensing switch is turned into OFF state. The motor is actuated in a reverse direction for a second period from an end of the first period. The driving of the motor is stopped for a third period from an end of the second period. The motor is actuated in the first direction from an end of the third period such that the tray is moved to the disk-change position.

Abstract: The present invention provides an information storage apparatus generating a tracking error signal in which apparatus and method the differential push-pull method is applied to a three spot method using a main beam and two sub-beams, the main beam for writing data on a recording medium and reading data from the recording medium, the information storage apparatus including the following parts. A beam moving part moves the main beam from a blank track to a recorded track. A center value calculating part calculates a center value of the tracking error signal when said main beam is moved from the blank track to the recorded track so that a reference value of the tracking error signal is corrected in accordance with the center value when said main beam writes data on the recording medium.