Western Digital Technologies, Inc.

Broadcom Corporation

Ess Technology, Inc.

Matsushita Electric Industrial Co., Ltd.

International Business Machines Corporation

Sony Corporation

Sony Electronics Inc

Michael A Chang

Guoxiao Guo

Wei Guo

Jie Yu

Russ A Quisenberry

Fernando Anibal Zayas

Richard Koonwai Wong

Michael A Sokol

Kou-Hu Tzou

Allan Yeh

Terence Patrick Purcell

Yuan Chen

Jack M Chue

Brian P Rigney

Carl E Barlow

Abhishek Dhanda

Sanghoon Chu

Jianyu Roy Zheng

Shuanglin Guo

Huanxiang Ruan

Brian L Baggett

Tai Jing

Yun Hong

Ou Jin

Honge Wang

James Lin

Hsin-jung Huang

Ying-Ming Wang

Provided are techniques for a Data-Partitioned Secondary Index (DPSI) partition level join. While using a Data-Partitioned Secondary Index (DPSI) to perform a join of an outer table and an inner table, a different task from multiple tasks is assigned to each partition of the inner table. With each task, a join is performed of the outer table and the assigned partition of the inner table using the DPSI to generate results. The results from each different task are merged.

Data-partitioned secondary index (DPSI) partition level join

A disk drive is disclosed comprising a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones, where a servo data rate of servo sectors in a first servo zone is different than a servo data rate of servo sectors in a second servo zone. A servo control system servos a head over the disk. An estimated servo state of a servo control system is generated, and when the head crosses from a first servo zone to a second servo zone, the estimated servo state is adjusted to compensate for a transient in a circumferential distance between a servo sector in the first servo zone and a servo sector in the second servo zone.

Disk drive adjusting estimated servo state to compensate for transient when crossing a servo zone boundary

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks defined by servo sectors forming a plurality of full wedges and a plurality of mini wedges. The wedge ID field of a servo sector forming one of the full wedges is offset from a beginning of a sync mark by a first offset, and the wedge ID field of a servo sector forming one of the mini wedges is offset from the beginning of the sync mark by a second offset equal to the first offset. A first servo sector is read from the disk to generate a read signal, the read signal is demodulated to detect the wedge ID of the first servo sector, and the detected wedge ID is evaluated to determine whether the first servo sector forms one of the mini wedges.

Disk drive detecting mini wedge by evaluating wedge ID of servo sector

A data storage device is disclosed comprising a first head actuated over a first disk surface comprising servo tracks defined by full servo sectors, and a second head actuated over a second disk surface comprising servo tracks defined by mini servo sectors. At least part of a track address is read from one of the full servo sectors to generate at least one high order bit of a full track address, and at least part of a track address is read from one of the mini servo sectors to generate at least one low order bit of the full track address. The high order bit and the low order bit are combined to generate at least part of the full track address, and during an access of the second disk surface, the second head is servoed over the second disk surface based on the full track address.

Data storage device employing full servo sectors on first disk surface and mini servo sectors on second disk surface

A data storage device is disclosed comprising a disk surface comprising a plurality of tracks, wherein each track comprises a plurality of data sectors and a plurality of servo sectors. The data storage device further comprises a head actuated over the disk surface, the head comprising at least one read element and at least one write element. Control circuitry is configured to use the head to write to a first data sector on the disk surface while simultaneously reading from a first servo sector on the disk surface.

Data storage device reading servo sector while writing data sector

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo tracks defined by full sectors and intervening short servo sectors, where each full servo sector comprises a preamble, a sync mark, and servo bursts, and each short servo sector comprises a reference pattern and servo bursts. A first phase error is generated based on the sync mark in a first full servo sector, and a disk locked clock is adjusted in response to the first phase error. A second phase error is generated based on the reference pattern in a first short servo sector, and the second phase error is processed to determine whether the disk locked clock slipped a cycle before the head reaching the first short servo sector.

Disk drive compensating for cycle slip of disk locked clock when reading mini-wedge

A disk drive is disclosed comprising a disk comprising tracks defined by servo sectors, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk in response to the servo sectors. After seeking the head to a first track, a position error signal (PES) is generated representing a difference between a target location for the head and a measured location for the head. A sinusoidal control signal is generated in response to the servo sectors, and a third point of the sinusoidal control signal is generated based on a first point and second point of the sinusoidal control signal and independent of the PES, wherein the first, second and third points correspond to respective servo sectors. A feed-forward compensation value is generated based on the third point of the sinusoidal control signal using a feed-forward compensator.

Disk drive generating feed-forward compensation value based on two points of a sinusoidal control signal

A data storage device is disclosed comprising a first disk surface comprising servo tracks defined by servo sectors and recorded at a first radial density, and a first head actuated over the first disk surface. A servo sector on the first disk surface is read to generate a first physical position measurement that is converted into a first virtual position measurement corresponding to a nominal radial density of servo tracks different from the first radial density. The first head is servoed over the first disk surface based on the first virtual position measurement.

Data storage device servoing heads based on virtual servo tracks

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones, and at least one servo sector of a servo track comprises a partial track address. A read signal generated by the head is processed to detect a current servo zone for the head, and the read signal is processed to detect the partial track address in one of the servo sectors of the current servo zone. A full track address is generated based on the detected servo zone and the detected partial track address.

Data storage device estimating servo zone to reduce size of track address

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks, wherein the servo tracks form a plurality of servo zones, and a servo data rate of servo sectors in a first servo zone is different than a servo data rate of servo sectors in a second servo zone. A disk locked clock is synchronized to the data rate of the servo sectors in the first servo zone, wherein the disk locked clock for generating a timing window relative to the servo sectors. When the head crosses from the first servo zone to the second servo zone, at least one of the disk locked clock and the timing window is adjusted to compensate for a timing transient.

Disk drive adjusting servo timing to compensate for transient when crossing a servo zone boundary

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones. A disk locked clock is synchronized relative to a servo data rate of the servo zone the head is over. A first reader/writer gap is measured in cycles of the disk locked clock at a first servo track in the first servo zone. A second reader/writer gap is measured in cycles of the disk locked clock at a second servo track in the second servo zone. The first and second reader/writer gaps are normalized to generate a normalized first and second reader/writer gaps. A third reader/writer gap is estimated in cycles of the disk locked clock at a third servo track in the second servo zone based on the normalized first and second reader/writer gaps.

Disk drive estimating reader/writer gap across servo zones

A system for reducing clock speed and power consumption in a network chip is provided. The system can have a core that transmits and receives signals at a first clock speed. A receive buffer can be in communication with the core and be configured to transmit the signals to the core at the first clock speed. A transmit buffer can be in communication with the core and configured to receive signals from the core at the first clock speed. A sync can be configured to receive signals in the receive buffer at a second clock speed and to transmit the signals from the transmit buffer at the second clock speed. The sync can be in communication with the transmit buffer and the receive buffer.

Method and apparatus for reducing clock speed and power consumption

A controller includes a combining module that generates a total control signal for the drive device of a disk drive by combining a feedback control signal and a feedforward control signal. A feedback control module generates the feedback control signal in response to at least one state of the drive device. A feedforward control module generates the feedforward control signal based on a smoothing function and a feedforward control function.

Feedforward controller and methods for use therewith

A controller is disclosed that can be used in controlling a drive device of a disk drive, or other systems, in the presence of sinusoidal disturbances. The controller includes a calibration module that generates a plurality of reference states for a reference region of a disk of the disk drive. An initialization state generation module generates a plurality of initialization states for at least one other region of the disk as a function of the plurality of reference states, a displacement between the other regions of the disk and the reference region of the disk, and a reference state transition matrix. A control module generates a control signal for the drive device based on the plurality of initialization states.

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San Jose, CA, United States of America

Michael A Chang