Abstract: The A burst and B burst for tracking are recorded with the width of track pitch, the address signal is recorded as the same signal with the interval equal to two track pitches (2×Tp) and B1 bit is also recorded with deviation of one track pitch from the address signal with the interval equal to two track pitches (2×Tp). Therefore, the servo pattern of one track can be written as much as one track pitch and thereby the recording time can be shortened. Moreover, accurate track address can be calculated by the correcting process using the B1 bit.

Abstract: A magnetic recording and reproducing apparatus arranged to use a magnetic tape. The apparatus operates to derive the current taken-up position of the magnetic tape from the signals that are proportional to the rotation frequencies of a capstan motor, a supply reel and a take-up reel. Only when the taken-up position is near the tape end, the apparatus activates LEDs (light emitting elements) for sensing the tape end and photo-transistors (light receiving elements), for sensing the tape end.

Abstract: A method and apparatus for compensating for written-in repeatable runout in a disc drive is provided. Compensation values are determined through an iterative learning process in which parameters of the learning process such as learning gain, servo loop gain, etc. are functions of the iteration number. The learning process also employs a nominal double integrator model of an actuator of the disc storage system. The learning process is also a function of a zero-phase low-pass filter.