Patent ID: 6798608
Filing Date: 2004-09-28
Classification: G11B

Abstract:
A servo system for detecting and acquiring a track following servo pattern of a magnetic tape, wherein said magnetic tape is subject to lateral motion, said magnetic tape having a track following servo pattern of at least one set of parallel linear servo edges, each said servo edge comprising an interface between two dissimilar recorded servo signals, each said set of servo edges comprising one of said servo edges on each of opposite lateral sides of a middle said recorded servo signal, said servo system comprising:at least one servo sensor of a tape head, said tape head movable laterally of said magnetic tape, said at least one servo sensor sensing said recorded servo signals of said magnetic tape and providing sensed servo signals; a servo loop for positioning said tape head laterally with respect to said magnetic tape; and servo loop logic coupled to said at least one servo sensor and to said servo loop, said servo loop logic: initially, from an off-track position of said at least one tape head servo sensor at a known side of, and displaced from, said track following servo pattern, operates said servo loop to slew said at least one tape head servo sensor laterally toward said track following servo pattern at a rate greater than the maximum rate of said lateral movement of said magnetic tape; monitors said signals of said at least one servo sensor as said tape head servo sensor is slewed, to detect said servo signals; upon detecting said sensed servo signals, decelerates said slewing rate; upon detecting that said sensed servo signals are within a lock window tolerance, locks said servo loop to a position error signal representing the current lateral position of said at least one tape head servo sensor, thereby acquiring said track following servo pattern; and upon acquiring said track following servo pattern, operates said servo loop to track follow said sensed servo signals at specific position error signals representing displacements from said at least one linear servo edge.