Western Digital (fremont), Inc.

Jagdeep S Buttar

David D Terrill

Kenneth R Davies

Trung Vinh

Tahir A Ali

Eugene Shapiro

Tao Pan

Xiaodong Che

Herman Ferrier

Victor Rudman

Yogesh P Kharady

Systems and methods for improving loading and unloading of a read or write head onto and off of a disk medium. Particular embodiments may assist in loading a read or write head to, or unloading a read or write head from, a load location over a surface of a disk medium in such a manner that damage to the surface of the disk medium (e.g., load location) is either prevented or minimized. The prevention or reduction of damage may be achieved by ensuring that a read or write head has sufficient clearance over the surface of a disk medium as the read or write head moves over the surface (e.g., as the head moves parallel to the surface) during a head loading or unloading process.

Apparatuses and methods for loading a head onto a disk medium

A method monitors operation of a disk drive. The method includes providing a disk drive which includes a rotating disk and a head having a read transducer in proximity to a surface of the disk and an adjustment mechanism which controllably adjusts an average relative spacing between the read transducer and the surface. The method further includes generating a read-back signal by reading from the surface using the read transducer. The read-back signal includes a high frequency carrier signal having an envelope that is modulated by a lower frequency signal. The method further includes varying the average relative spacing between the read transducer and the surface using the adjustment mechanism. The method further includes analyzing the envelope in the frequency domain and detecting an emergence of at least one frequency component of the envelope within an air bearing resonance range of frequencies.

Method of monitoring operation of a disk drive by analyzing the envelope of a read-back signal in the frequency domain

Head stack fixtures for securing head stack assemblies to spin stand testing systems, and spin stand testing systems incorporating such fixtures, are disclosed. Exemplary head stack fixtures comprise a base supporting a piezoelectric actuator. The base includes an attachment mechanism for securing the HSA in such a way that the HSA will pivot relative to the base. When the HSA is secured to the base, the piezoelectric actuator engages the HSA. The piezoelectric actuator is therefore able to pivot the HSA relative to the base for fine positioning of a head of the HSA.

Spin stand testing system with fine positioner for head stack assembly

A spin stand testing system is used to determine a positioning range of a microactuator disposed on a head gimbal assembly. The microactuator is configured to laterally translate a read sensor of a head of the head gimbal assembly through the positioning range. The spin stand testing system includes a disk having a track, and a secondary mover configured to laterally translate the head gimbal assembly. During testing, a feedback loop keeps the read sensor locked to the track. While the read sensor remains locked, the head gimbal assembly is translated laterally. The microactuator translates the read sensor in an opposite direction until the microactuator reaches an end of its range, which is determined by monitoring a signal. The amount of translation of the head gimbal assembly by the secondary mover when the signal indicates the end of the range is the measured positioning range in one direction.

Method for determining a microactuator range of movement

Methods of measuring position error due to pole tip protrusion are provided. In exemplary embodiments, a head having a write element is aligned to a track, and then pole tip protrusion is induced in the write element by writing to the track. The position error is measured after the pole tip protrusion has been induced. The position error can be measured just after the write element stops writing so that the position error is measured before the position error degrades or relaxes. Alignment of the head to the track, and measurement of the position error are accomplished while the head is over a servo segment of the track. The servo segment can be provided with separate alignment and evaluation portions for aligning the head and for measuring the position error, respectively. The alignment and evaluation portions can each encode two parallel sub-tracks, each with a different frequency.

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Fremont, CA, United States of America

Jagdeep S Buttar