Dual Frequency Servo Positioning System Employing Saturated Recording
Original Publication Date: 1978-Mar-01
Included in the Prior Art Database: 2005-Feb-20
A system for positioning heads over selected concentric data tracks in a magnetic disk file employs a servo pattern on the surface of one of the disks having alternate tracks recorded with transitions at different frequencies f(1) and f(2) between opposite states of magnetic saturation. The servo tracks are contiguous and the boundary between alternate tracks is followed by a servo head. The servo head is ganged for motion with one or more data heads which are located over data tracks when the servo head is located at a servo track boundary. The servo and data heads are positioned by a common actuator, typically a voice coil motor. A convenient ratio for the servo track frequencies is f(1):f(2) = 3:4.