Abstract: A method of operating a data storage device is disclosed comprising an enclosure comprising a first head actuated over a first disk surface and a second head actuated over a second disk surface. A manufacture printed circuit board (PCB) is coupled to the enclosure, wherein the manufacture PCB comprises at least one dual channel configured to execute concurrent access operations. While the manufacture PCB is coupled to the enclosure, the data storage device is operated as a dual channel device. The manufacture PCB is decoupled from the enclosure and a product PCB is coupled to the enclosure, wherein the product PCB comprises a single channel configured to execute a single access operation.

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.