Abstract: A track address pattern suitable for being applied to a magnetic disk apparatus which positions a head to a track with a desired address by a sector servo system, for example, wherein a gray code of a plurality of bits corresponding to a track address of the magnetic disk apparatus is divided per 2 bits thereof into groups, the respective groups of 2 bits are converted into codes of 3 bits (001), (010), (100) and (111) depending on the values thereof, respectively, whereby the converted codes are recorded on the magnetic disk as the track address pattern.

Abstract: The present invention provides a disc drive apparatus having an improved tracking control and seek time adjustment. The head tracking error distribution along the disc radius is determined with reference to the phases of a plurality of position sensors and is calculated based on the tracking error of a reference track in first and second reference regions with respect to the signal from one of the position sensors. This information is used to determine the tracking error distribution along the disc radius with respect to that one of the position sensors. The tracking error distribution is used to determine the tracking error of a reference track in a third reference region with respect to the signal from the same position sensor. This tracking error is used to determine the tracking error of other reference tracks in the third reference region with respect to the signals from other of the position sensors.