Maxtor Corporation

Intel Corporation

Sigma Designs, Inc.

Boly Media Communications, Inc.

Nec Corporation

Seagate Technology Incorporated

Western Digital Technologies, Inc.

Hitachi Global Storage Technologies Netherlands B.v.

Chips and Technologies, Llc.

Xiaoping Hu

Lin Guo

Yu Sun

Wei Guo

Yan Fei Liu

Kuei-Chung Tu

Hungviet Nguyen

Erhard Theodor Schreck

Michael L Mallary

David Marcus Tung

Don Brunnett

Jifang Tian

Donald Joseph Brunnett

Francis P Crimi

Bruce C Schardt

Stan Shepherd

Yunfeng Li

Scott A Hughes

Hongqi Li

Kazuhiro Saito

Jason Adler

Jong-Ming Lin

Mark Heimbaugh

Jingbo Yu

Mark S Seymour

Andrew LeFebvre

William Flynn

Douglas J Krajnovich

Chris Hawks

Hungviet H Nguyen

Joerg Ferber

Roger Wencheng Hsu

Francisco Obregon

Duc Bahn

William M Marvin, Jr

Jeff Franks

Donald Brunett

Jack Ouyang

David Sokmin Kang

Mark Hall

Jun Takamura

Thomas Calihan

A vibration testing apparatus comprises a first mooring bar coupled to the base; a second mooring bar coupled to the base such that the second mooring bar is disposed away from and faces the first mooring bar to define a space between the first and second mooring bars; a first strap comprising a first end secured to the first mooring bar, and a second strap comprising a first end secured to the first mooring bar. A second end of each of the first and second straps may be secured to the second mooring bar such that the first and second straps span the space between the first and second mooring bars and such that a tension on at least one of the first and second strap is controllable.

Devices and methods for system-level disk drive vibration and shock testing

A method and system for minimizing bus traffic in a video decoder is disclosed. A method and system for processing a portion of a reference picture includes designating the reference picture, selecting a display picture within the reference picture, transmitting a display picture size, and sending a display picture offset. A method and system for compressing IDCT coefficients corresponding to a macroblock, the macroblock having a plurality of blocks, includes locating each non-zero IDCT coefficient corresponding to one of the plurality of blocks, assigning an index to the non-zero IDCT coefficient, the index designating a location within the one of the plurality of blocks, packing the non-zero IDCT coefficient in little endian format, and specifying a terminator bit corresponding to the non-zero coefficient, the terminator bit indicating the end of all non-zero IDCT coefficients for the one of the plurality of blocks. A method and system for selectively controlling each hardware device within a video decoder includes obtaining a video stream, performing VLC decoding, encoding a plurality of instructions to control each hardware device within the video decoder, decoding each one of the plurality of instructions, and optionally performing an IDCT in response to each one of the plurality of instructions.

Method and system for data management in a video decoder

Embodiments of the present invention reduce the written-in run-out in servo data written to a storage medium. A set of servo controllers are evaluated and the controller having the best expected performance among the set is selected and employed. One embodiment of the present invention is a servo controller configured to select and employ a controller having a least amount of expected written-in run-out among a set of controllers. Another embodiment of the present invention is a method comprising a step for applying a set of controllers; and selecting a controller from the set of controllers with a least expected amount of written-in run out. Another embodiment of the present invention is a system comprising a servo controller for employing and selecting a disk controller that has a least expected amount of written-in run-out among a set of controllers.

Controller selection to reduce written-in run-out

A microactuator reference limit used to prevent over-accumulation of internal states may be set based on the microactuator's mechanical properties and is applied at the reference point to the microactuator servo subsystem. A microactuator variable input limit to prevent over-accumulation of internal states may be dynamically determined based on the difference between a signal corresponding to the maximum physical stroke of the microactuator and an estimated motion of the microactuator. Either configuration of servo system automatically ensures that all the internal states of the microactuator controller will not over-react and cause excessive overshoot, sluggish response, and/or saturation.

Microactuator reference input limit to prevent internal states over-accumulation

Embodiments of the present invention allow for controlling a microactuator based at least in part on an output of a temperature sensor. Also, embodiments of the present invention allow for adjusting a control of a microactuator so as to compensate for changes in a gain of the microactuator due to changes in temperature.

Microactuator control adjustment using temperature sensor measurements

A servo system for a hard disk drive comprising a first actuator, a second actuator, a head, and a disk on which is formed a plurality of tracks containing servo data. The servo system comprises a first stimulus, a second stimulus, and a calibration system. The first stimulus causes the first actuator to move the head to at least two calibration tracks on the disk. The second stimulus causes the second actuator to move the head relative to the at least two calibration tracks. The calibration system generates a calibration factor based on the second calibration signal and the movement of the second actuator relative to each of the at least two calibration tracks.

Micro actuator DC gain calibration scheme for HDD dual-stage actuator systems

Methods of controlling reading/writing by a read/write head of a disk drive include generating a position error signal indicative of a displacement of the read/write head from a desired radial location on a surface of a data storage disk. A control signal for moving the read/write head to the desired location is calculated responsive to the position error signal. Writing by the read/write head is inhibited responsive to the control signal exceeding a control signal threshold value. A disk drive includes a controller configured to generate a position error signal indicative of a displacement of a read/write head from a desired location on a surface of a disk, and to generate a control signal for moving the read/write head to the desired location. The controller is further configured to inhibit writing by the read/write head responsive to a predictive metric that is predictive of the position error signal exceeding a threshold.

Methods and apparatus for managing write inhibit in response to a predictive metric

A disk drive includes a rotatable storage disk, an actuator motor, a slider that magnetically interacts with the storage disk, and a drive circuitry. A portion of the slider moves between a first position wherein the slider does not contact the storage disk and a second position wherein the slider contacts the storage disk. The drive circuitry can detect when the position of the slider changes between these positions. In one embodiment, the drive circuitry monitors off-track movement of the slider to detect when the slider has moved between these positions. The drive circuitry can also current that is directed to the actuator motor that is used to compensate for off-track movement to detect when the slider moves between these positions. In yet another embodiment, the drive circuitry monitors a rotational velocity of the storage disk to detect approximately when the slider moves between these positions.

System for detecting a change in head-to-disk contact status in a disk drive

A technique is presented for compressing data which leverages the frequency of an escape symbol for better compression. The prefix of a data string is evaluated and the probability of all characters that might succeed it is predicted in tabular form. Symbols are designated 'Hit' or 'Miss' based upon whether they are in the table. A binary tree is generated by partitioning nodes into Zero and One groups based on a single bit value. A partition bit is chosen to maximize the difference of probability sums of Hit symbols in Zero and One groups, with exceptions for partitions having non Hit symbols in one of the groups. A probability value is assigned to each branch, based on the probabilities of Hit and Miss symbols. Encoding or decoding a symbol is facilitated by encoding or decoding the branch probabilities on the shortest path from the root to the leaf node containing the symbol using arithmetic encoding or decoding method.

Bitwise adaptive encoding using prefix prediction

A disk drive and method are provided for controlling seeking of a transducer that is adjacent to a rotatable data storage disk in a disk drive. The disk drive includes an actuator for positioning the transducer relative to the disk, the method comprising. The actuator is controlled to move the transducer toward a target track on the disk during an initial phase of a seek mode during which the transducer is primarily accelerated toward the target track. During a settle phase of the seek mode which follows the initial phase the actuator is controlled to settle the transducer onto the target track. An initial position, an initial velocity, and an initial acceleration of the transducer are determined at a phase switch time at about when control of the actuator switches from the initial phase to the settle phase of the seek mode. Feed-forward control information is generated based on the determined initial position, initial velocity, and initial acceleration of the transducer. The actuator is controlled responsive to the feed-forward control information to settle the transducer onto the target track during the settle phase of the seek mode.

Multi-stage actuator disk drive and methods for controlling a transducer with settle-switching state dependent feed-forward control

A disk drive detects head touchdown based on a magnitude of a position error signal at a discrete frequency. The discrete frequency is one-half the disk rotation frequency or an integral multiple of the disk rotation frequency. The head is heated by turning on a heater at the discrete frequency, thereby injecting bias into a servo system that increases the PES magnitude. In addition, the servo system has a first transfer function for tracking the head during read and write operations and a second transfer function for tracking the head during head touchdown detection. The second transfer function has smaller vibration rejection than the first transfer function so that the disk drive is less sensitive to vibration during read and write operations than during head touchdown detection.

Disk drive head touchdown detection with improved discrimination

Methods of compensating for repeatable runout in a disk drive are provided. The disk drive includes a data storage disk, a transducer adjacent to the disk, a primary actuator for positioning the transducer over a first range of movement, and a secondary actuator for positioning the transducer over a second range of movement that is less than the first range of movement. Estimates are made of the position of the secondary actuator in the second range of movement. Data is read from the disk via the transducer. A position error signal is determined based on the read data. Positioning of the transducer by the primary actuator is controlled based on the estimated position of the secondary actuator in the second range of movement and based on the position error signal to compensate for repeatable runout.

Multi-stage actuator disk drives, methods, and computer program products that compensate for repeatable runout based on estimated secondary actuator position

A disk drive includes a transducer and a rotatable disk, which includes a plurality of tracks. A vibration state of the transducer relative to the disk is determined. The transducer is positioned relative one of the tracks based on a compensation scheme that varies based on the determination of the vibration state. The compensation scheme may be varied by selecting among output of two or more compensators, based on the determined of the vibration state of the transducer, to control positioning of the transducer. The compensation scheme may alternatively, or additionally, be varied by varying a contribution from a vibration state actuator compensator to the control of positioning of the transducer. The vibration state actuator compensator is configured to improve transducer track following while the transducer is subjected to vibration.

Positioning transducers based on a compensation scheme that varies based on transducer vibrational state

A control system and method for a disk drive comprising first and second actuator arms. The control system comprises first and second stages and a reset system. The first stage displaces the first arm. The second stage displaces the second arm relative to the first arm. The second stage defines a displacement offset when the disk drive begins a seek operation. The reset system discharges at least a portion of the displacement offset over time.

Displacement resetting systems and methods for the second stage of a hard disk drive dual-stage actuator

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Milpitas, CA, United States of America

Xiaoping Hu