System and method for detecting head-to-disk contact in-situ a direct access storage device using a position error signal

Abstract

An apparatus and method for detecting low flying read/write heads provides for the detection of contact between an air bearing slider/transducer assembly and a surface feature developed on a surface of a data storage disk. The apparatus includes a transducer disposed on an air bearing slider. An actuator is coupled to the slider/transducer assembly typically by employment of a head suspension assembly. The processor, in response to position error signals developed from servo information provided on the disk surface, moves the actuator and slider/transducer assembly to prescribed disk surface locations. The processor further processes non-repeatable position error signal values developed at a plurality of disk surface locations to detect an occurrence of contact between the slider/transducer assembly and a surface feature arising from the disk surface. Detecting the occurrence of a head-to-disk contact event generally involves acquiring position error signals from a first disk location and a second disk location using a particular transducer. The processor computes a power ratio value using a first power value and a second power value respectively derived from non-repeatable position error signals acquired from the first and second disk locations. The processor then compares the power ratio value with a power ratio threshold value, such that a power ratio value exceeding the power ratio threshold value indicates an occurrence of contact between the air bearing slider and a surface feature of the disk. The head-to-disk contact detection methodology of the present invention may be field upgradable in-situ a data storage system.

Dependencies are inferred from the claim text.