Abstract: An improved system and process is provided in a disc drive for determining and for compensating head/track offsets when a data (target) head is moved to a new data (target) track position. Such disc drives typically include an armstack with transducer heads thereon, either pivotally or linearly mounted to move the transducer heads radially across a plurality of memory discs in a disc stack. A dedicated reference head is provided for scanning dedicated servo tracks on a dedicated memory disc, and a data head is provided on each data disc.Head/track position offset is determined by generating an initial position offset signal indicative of the position offset between the dedicated head and an adjacent dedicated track while a selected data head, called the present head, is centered on its data track.

Abstract: Improvements are realized in magnetic disc drives in minimizing servo gain variations from one head to another and in differing track offset positions by providing servo code patterns and methods of fabricating such patterns in which magnetic heads of differing widths overlap the same amount of servo code and in which servo gain variations in track offset positions are minimized by maintaining servo code overlap by the magnetic heads relatively constant up to substantially one-half track offsets of magnetic head.

Abstract: This method and apparatus for eliminating apparent offset in the servo code adjacent to a guard band on a magnetic memory disc utilizes at least two phases of servo code per magnetic cell for seeking and track centering, or track following, operations and two phases or guard band code per magnetic cell. The two phases or guard band code are each either in phase or similarly out of phase with the respective phases of the servo code in individual magnetic cells.Phase locking on a selected phase of guard band code is achieved by providing a synchronizing code in the guard band using an irregular pattern of guard band code, providing a timing signal count representing a cell count, for example, decoding the synchronizing code to provide an end of code signal and utilizing the end of code signal and a predetermined cell count signal to achieve phase locking on the correct phase of the guard band code.

Abstract: A multiple dumping integrator having several periodic dumping integrators, ll sharing the same analog-to-digital converter. A selector dumps each periodic dumping integrator in a regular sequence, choosing the longest running such integrator for the next dump.