Patent ID: 7089649
Filing Date: 2006-08-15
Classification: G11B,Y10T

Abstract:
1. A method estimating a thermal pole tip protrusion tendency for a head gimbal assembly containing a read-write head, said method comprising, for each member of a track collection, the step of: determining said thermal pole tip protrusion tendency for said head gimbal assembly on said track collection member; and said method, further comprising the step of: predicting said thermal pole tip protrusion for said head gimbal assembly based upon, for each of said track collection members, said thermal pole tip protrusion tendency on said track collection member; wherein said track collection is comprised of an inside diameter track of a disk surface and an outside diameter track of said disk surface; wherein said read-write head provides a magneto-resistance from a disk surface while performing a write operation to said track collection member on said disk surface and provides a voltage while reading said track collection member at a bias current, for each of said track collection members; wherein said disk surface rotates at a rotational frequency; wherein the step determining said thermal pole tip protrusion tendency is comprised of at least one member of the collection comprising the steps of: monitoring a change of said magneto-resistance while said read-write head performs said write operation of said track collection member to determine said thermal pole tip protrusion tendency; wherein the step monitoring said change is further comprised of: observing said magneto-resistance while said read-write head performs said write operation on said track collection member to create a sudden MRR change event collection and to create a MRR value; determining a number of said sudden MRR change event collection members; determining a change characteristic based upon an amount MRR change divided by said MRR value, for each of said sudden MRR change event collection members; and determining said thermal pole tip protrusion tendency based upon said number of said sudden MRR change event collection members and based upon said change characteristic for said sudden MRR change event collection members.