Abstract: A method and apparatus for optimizing positional data for use in connection with a hard disk type magnetic memory storage device. The apparatus includes a pattern encoded on a dedicated track of the hard disk including first and second set of signals repetitively encoded in a series of cells. The method includes the steps of periodically accessing the dedicated track with the read/write head and calculating amplitude and phase information for a trigonometric instantaneous correction function. Amplitude and phase information are subsequently stored and the positional signal for the read/write head is continually modified by a most recent determination of the correction function. The apparatus of the present invention includes circuitry for distinguishing between sub-elements of the repetitive pattern on the hard disk.