Western Digital Technologies, Inc.

Seagate Technology Incorporated

Other

Duc T Phan

Chuanwen Ji

Alexander Babinski

Min Chen

Yanan Huang

Alain Chahwan

Mark A Pajdowski

Aswartha Narayana

Robert P Ryan

Orhan Beker

Donald Joseph Brunnett

Jianghong Ding

Zhenyu Zhang

Yanning Liu

Hien T Chu

T Jay Cameron

Shan Tang

Hengchang Guo

Xin Ru Wang

Daniel Lee Helmick

Don Brunnett

Timothy A Ferris

Jifang Tian

Alexei Hiram Sacks

Young-Hoon Kim

Zhi Ning Wang

Dean V Dang

Ich V Pham

Jonathan V Nguyen

Erik Jesper Eklund

Nathan J Santee

John Yin Kwong Li

Li Yi

Ming Ying Wang

Eugene Chun-Tsing Wu

Yanbin Song

Tien Q Le

Qixing Zheng

Yakov M Lifschitz

Jun Huang

Alan M Fossen

Gary Gaoxiang Zhu

Tien Quang Le

Lingfei Zhou

Mark Lowell Elliot

Jong Hyun Lee

Shang-Chen Wu

Chui Lyn Cheong

A data storage device is disclosed comprising a plurality of disk surfaces including a first disk surface and a second disk surface. A first head is actuated over the first disk surface, and a second head is actuated over the second disk surface. A ramp is located proximate an outer diameter of the disk surfaces. A stroke difference between the first and second heads is measured by moving the first and second heads toward the ramp and detecting when the heads contact the ramp.

Disk drive measuring stroke difference between heads by detecting a difference between ramp contact

An apparatus includes: a media; a head over the media; a read channel, coupled to the head, configured to extract data from the media; control circuitry, coupled to the read channel, configured to execute a read command; and wherein the read channel is further configured to: generate, based on extracting the data from the media, a data condition indicator, and provide, for use by the control circuitry, the data and the data condition indicator.

Electronic system with media scan mechanism and method of operation thereof

A data storage device is disclosed comprising a head actuated over a disk surface comprising tracks defined by servo sectors, wherein each servo sector comprises at least one servo burst comprising a periodic pattern. The servo burst of one of the servo sectors is read to generate a read signal, and M intermediate integration points yare computed according to: where r(kT) represents a sample point of the read signal, Trepresents a sample interval between the sample points, and &#x3c9; represents a frequency of the periodic pattern in the servo burst.

Data storage device demodulating servo burst by computing slope of intermediate integration points

A disk drive is disclosed comprising a disk having a plurality of tracks, a head, and a voice coil motor (VCM) and a microactuator for actuating the head over the disk in response to a feed-forward compensation value. A sinusoidal disturbance is applied to the microactuator, and the resulting feed-forward compensation value is processed to characterize the microactuator.

Disk drive characterizing microactuator by injecting sinusoidal disturbance and evaluating feed-forward compensation values

An apparatus includes: a media; a head over the media; a primary-actuator coupled to the head; and control circuitry, coupled to the primary-actuator and a secondary-actuator, configured to limit a secondary-actuator slew rate.

Electronic system with actuator control mechanism and method of operation thereof

A data storage device is disclosed comprising a first disk surface, a first head, and a first microactuator configured to actuate the first head over the first disk surface. The first microactuator is configured into a first sensor, and a first load operation is executed to load the first head over the first disk surface. A fly height instability of the first head is detected during the first load operation based on a first sensor signal generated by the first microactuator.

Data storage device detecting fly height instability of head during load operation based on microactuator response

A disk drive is disclosed comprising a disk, and a voice coil motor (VCM) operable to rotate an actuator arm about a pivot to actuate a head radially over the disk. A voice coil voltage is measured across the voice coil, a velocity command of the VCM is set to substantially zero, an inductor compensation circuit is toggled at least once by enabling and disabling the inductor compensation circuit, the inductor compensation circuit is enabled, the velocity command of the VCM is adjusted, and a control signal is generated and applied to the voice coil in order to move the actuator arm, wherein the control signal is generated in response to the adjusted velocity command, the voice coil voltage, and the estimated inductance voltage.

Disk drive toggling VCM inductor compensation to reduce acoustic noise

A disk drive is disclosed comprising, a head, a disk surface, and a dual stage actuator (DSA) servo loop comprising a voice coil motor (VCM) servo loop comprising a VCM and a microactuator servo loop comprising a microactuator operable to actuate the head over the disk surface. A frequency component of a servo signal in the DSA servo loop is evaluated, wherein the frequency component is based on a peak frequency of an error rejection curve of the DSA servo loop. A degradation of the microactuator is detected based on the frequency component of the servo signal.

Disk drive detecting microactuator degradation by evaluating frequency component of servo signal

A disk drive is disclosed wherein N data wedges of write data are buffered in a buffer. After writing at least two of the data wedges to the disk including a first data wedge and a second data wedge, a first servo metric value is measured when reading a first servo sector, and a second servo metric value is predicted based on the first servo metric value, wherein the second servo metric value corresponds to a second servo sector following the first servo sector. When the first servo metric value indicates a safe write condition and the second servo metric value indicates an unsafe write condition, the first data wedge is released from the buffer, and when the first servo metric value indicates a safe write condition and the second servo metric value indicates a safe write condition, the first and second data wedges are released from the buffer.

Disk drive releasing variable amount of buffered write data based on sliding window of predicted servo quality

A disk drive comprises a track follow control system having a plurality of selectable frequency modes, the track follow control system configured to receive a position error signal and to output a control signal based on the position error signal, wherein the control signal is used by a head assembly to position a head over a disk. The disk drive also comprises a state estimator configured to receive the control signal and a position signal indicating a position of the head, to estimate a disturbance based on the control signal and the position signal, and to output an estimated disturbance signal based on the estimated disturbance. The disk drive further comprises a disturbance evaluator configured to receive the estimated disturbance signal, and to select one of the frequency modes of the track follow control system based on the estimated disturbance signal.

Adaptive track follow control

A disk drive is disclosed comprising a head actuated over a disk, and a spindle motor operable to rotate the disk. A baseline relationship is generated between a baseline current draw of the spindle motor over a temperature range. An operating current draw of the spindle motor is measured and a corresponding operating temperature is measured. Failure of the spindle motor is predicted based on the operating current draw, the operating temperature, and the baseline relationship.

Disk drive predicting spindle motor failure by evaluating current draw relative to temperature

Determining a polarity of a piezoelectric (PZT) actuator of a disk drive including a disk for storing data and a head for reading and writing data. A test signal is injected into the PZT actuator and a position signal is received which indicates a position of the head over the disk resulting from the test signal. A test compensation signal is generated based on the received position signal and the polarity of the PZT actuator is determined based on a phase of the generated test compensation signal.

Polarity detection of piezoelectric actuator in disk drive

A disk drive is disclosed comprising a disk comprising a plurality of data tracks, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk. When an access command is received to access a target data track, a seek operation is initiated to seek the head toward the target data track, wherein the seek operation includes integrating a first state of the servo control system and limiting an output range of the integrating. The output range of the integrating is increased during the seek operation, for example, if an error occurs during the seek operation.

Disk drive increasing integrator output range to complete seek operation

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of non-circular servo tracks for defining a plurality of substantially circular tracks. Each non-circular servo track comprises a plurality of servo sectors defining a plurality of servo wedges. The head is positioned at a first offset relative to a first circular track and a relationship of servo bursts for each servo wedge is first generated. The head is positioned at a second offset relative to the first circular track and the relationship of the servo bursts for each servo wedge is second generated. For each servo wedge, a selection is made between the first generated relationship at the first offset and the second generated relationship at the second offset, and the servo bursts at the selected offset are evaluated to generate a track squeeze indicator.

Disk drive detecting track squeeze when circular tracks are defined from non-circular servo tracks

A disk drive is disclosed comprising a head actuated over a disk, and control circuitry including a shock detector. A shock threshold of the shock detector is initialized, and a first number of shock events is detected in response to the shock detector operating at the initial shock threshold. When the first number of shock events exceeds an upper event threshold, a control signal is adjusted in order to adjust a frequency spectrum of noise affecting the shock detector. After adjusting the control signal, a second number of shock events is detected in response to the shock detector operating at the initial shock threshold. When the second number of shock events exceeds the upper event threshold, the shock threshold is increased.

Disk drive adjusting noise spectrum to reduce resonance excitation of shock detector

Growing community of inventors

Saratoga, CA, United States of America

Duc T Phan