Samsung Electronics Co., Ltd.

Keung Youn Cho

Sang Won Lee

Hae Jung Lee

Geng Wang

Peng Luo

Shuyu Sun

Zhaohui Li

Carl Xiaodong Che

Shuo-Hao Chen

Ki-Ook Park

Hao Ping Wen

Ken Bovatsek

Andrew S Kao

Soo-Youl Hong

A method for erasing a disk of a hard disk drive. The method includes moving the hard disk drive adjacent to an erasure head that emanates a magnetic field. The magnetic field and moving hard disk drive cause a disk of the hard disk drive to spin under a Lorentz force created by the magnetic field and moving disk. The magnetic field is applied by the erasure head for a duration that causes erasure of the entire disk. The spindle motor is not activated during the entire process. Not activating the spindle motor eliminates any Faraday coupling from the erasure head into the motor.

Self-spinning disk bulk erasure for hard disk assembly

A perpendicular recording head for a hard disk drive. The head includes a non-magnetic backside shield that minimizes or eliminates the flow of backside flux through the head. The head can be fabricated by forming a non-magnetic backside shield layer on a main pole. Portions of the backside shield and main pole can be removed to form a tapered pole portion. A non-magnetic write-gap layer and write shield are then formed onto the backside shield and main pole.

Dual write gap perpendicular recording head with a non-magnetic backside shield

A hard disk drive with a disk that has a servo field with an A servo burst and a B servo burst. The A servo burst has a trimmed erase band. The trimmed erase band can be created by offsetting the write head relative to a burst centerline to reduce the width of the erase band. For example, the write head can be moved toward a centerline of the A servo burst. The offset can be a function of write current and cylinder location of the disk. The offsets are selected so that the resultant burst profiles do not contain a flat minimum portion.

Erase band compensated offset servo trimming

The invention includes a testing method which may be applied to at least one writer in a disk drive during the self-test phase to generate write parameters, focused on the Over Shoot Control (OSC) of the write current parameter to improve the reliability of write operations by that writer. The Minimum OSC is used for write operations in normal temperatures. The Optimum OSC is used for a first lower temperature range, preferably between essentially 15 degrees Centigrade and essentially 5 degrees Centigrade. The Maximum OSC is preferred below essentially 5 degrees Centigrade. The Minimum OSC should preferably guarantee both an Adjacent Track Write (ATW) criteria, as well as guarantee a Write Induced Instability (WII) criteria. The invention includes the write parameter collection, as well as the disk drive containing the generated write parameter collection. The invention also includes the method of using that write parameter collection to control a writer while writing to tracks belonging to the radial zone collection and program systems implementing the invention's methods.

Methods and apparatus determining and/or using overshoot control of write current for optimized head write control in assembled disk drives

Thermal pole tip protrusion is caused by materials in and around head slider expanding during write operations till they protrude, leading to contact with the rotating disk surface, altering the flying height and often wearing down part of the disk surface. While well known that read-write heads expand during writing, the inventors who recognized this situation's significance, particularly as flying height decreases and data rates increase, both required for high areal density disk drives. The inventors realized that they could detect the problem at the spin stand level by testing head gimbal assemblies to reliably, and inexpensively, predict the tendency for thermal pole tip protrusion. This leads to selection of head gimbal assemblies, which do not have the thermal pole tip protrusion tendency. The selected head gimbal assemblies have better reliability, as do actuators and disk drives made with the selected head gimbal assemblies.

Method of estimating a thermal pole tip protrusion for a head gimbal assembly

The invention includes a testing method which may be applied to at least one writer in a disk drive during the self-test phase to generate write parameters, focused on the Over Shoot Control (OSC) of the write current parameter to improve the reliability of write operations by that writer. The Minimum OSC is used for write operations in normal temperatures. The Optimum OSC is used for a first lower temperature range, preferably between essentially 15&#xb0; Centigrade and essentially 5&#xb0; Centigrade. The Maximum OSC is preferred below essentially 5&#xb0; C. The Minimum OSC should preferably guarantee both an Adjacent Track Write (ATW) criteria, as well as guarantee a Write Induced Instability (WII) criteria. The invention includes the write parameter collection, as well as the disk drive containing the generated write parameter collection. The invention also includes the method of using that write parameter collection to control a writer while writing to tracks belonging to the radial zone collection and program systems implementing the invention's methods.

The present invention is a method and system to optimize a write channel in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, and selecting a target track from the plurality of tracks. Data is written at least once on a predetermined plurality of tracks adjacent to either side of the target track and on the target track. Data is also written a predetermined number of times on tracks immediately adjacent to the target track. Data written on the predetermined plurality of tracks adjacent to either side of the target track and on the target track is then read. The process then determines if a number of errors on the tracks is greater than a predetermined criteria, if so, a write current value of the write channel is decreased, otherwise the write current value is increased.

Method and apparatus for providing write current optimization

The present invention is a method and system to determine a quality of a head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, writing on a predetermined track on the plurality of tracks and reading a profile of the predetermined track to provide a first profile value. The head is then moved to an adjacent track where it writes on the adjacent track. A profile of the predetermined track is then read to provide a second profile value. A quality of the head can then be determined based on the first and second values.

Method and apparatus to distinguish effects of adjacent track encroachment from head thermal movement

A method and system for detecting electrostatic noise in a magneto-resistive head which may be caused by a plurality of conditions manifesting in the frequency domain as either an amplitude spike or an unstable baseline. In one embodiment, the signals generated by the head when reading a DC-erased track are compared. When viewed in the frequency domain the spectrum gap between the signals is used to determine if the head being tested suffers from defects causing an unstable baseline or from defects causing an amplitude spike.

Method for magneto-resistive head electrostatic popping detection

An air bearing slider that flies above a surface of a recording disk during relative rotation of the recording disk. A plurality of projections extend along the side of the slider body, and a plurality of negative pressure air cavities are formed between the projections. The projections act as pneumatic bearings, creating supporting positive forces for supporting the slider. The negative pressure air cavities create negative forces for pulling the slider down. The positive and negative forces on the center of mass of the slider are balanced to provide a more stable, static, and dynamic flying attitude for the slider. The resulting pressure profile of the slider has high pressure near the leading end, relatively low pressure in the middle, and relatively high pressure near the trailing end. This ensures minimum spacing between the slider and the disk that is very insensitive to roll parameters.

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San Jose, CA, United States of America

Keung Youn Cho