Rotary Carrier Patents (Class 360/77.02)
  • Patent number: 10389283
    Abstract: A motor drive apparatus includes a drive unit to supply motor coils with sinusoidal drive signals, a signal output unit outputs signals that change with rotation of a rotor, and a control unit. The control unit acquires first information relating to the sinusoidal drive signals at a timing of change of a corresponding one of the output signals in a case where there is no follow-up delay of the rotor relative to the drive signals. When the corresponding one of the output signals is changed, the control unit acquires second information relating to the sinusoidal drive signals at a timing of change of the corresponding one of the output signals in a case where there is a follow-up delay of the rotor relative to the drive signals. The control unit corrects the follow-up delay of the rotor based on a determined difference between the first and second information.
    Type: Grant
    Filed: March 6, 2014
    Date of Patent: August 20, 2019
    Assignee: Canon Kabushiki Kaisha
    Inventor: Yoshihiro Mizuo
  • Patent number: 10381030
    Abstract: A data storage device is disclosed comprising a voice coil motor (VCM) and a secondary actuator configured to actuate a head over a disk. A position error signal (PES) is generated based on servo data recorded on the disk, and a first control signal is generated based on the PES. The PES is adjusted based on the first control signal to generate a first adjusted PES, and a second control signal is generated based on the first adjusted PES. A secondary actuator control signal is generated based on the first control signal and the second control signal, wherein the secondary actuator control signal is applied to the secondary actuator. The first adjusted PES is adjusted based on the second control signal to generate a second adjusted PES, and a VCM control signal is generated based on the second adjusted PES, wherein the VCM control signal is applied to the VCM.
    Type: Grant
    Filed: July 13, 2018
    Date of Patent: August 13, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventor: Yanning Liu
  • Patent number: 10381031
    Abstract: Apparatus and method for disturbance rejection in a control system. In some embodiments, a controller is adapted to position a control object. A disturbance observer generates a disturbance compensation value which is applied to reduce position error resulting from application of mechanical disturbance to the control object. The disturbance observer includes an adaptive filter with at least one dead zone providing a pass-through response with a scalar gain of less than one.
    Type: Grant
    Filed: March 31, 2015
    Date of Patent: August 13, 2019
    Assignees: Seagate Technology LLC, Industry-Academic Cooperation Foundation, Yonsei University
    Inventors: Sung-Won Park, Sung-Yong Lim, Jae-Seong Lee, Hyunseok Yang
  • Patent number: 10276198
    Abstract: This disclosure describes apparatuses and techniques for multi-channel servo demodulation. Multiple servo demodulation channels enable additional information to be obtained during the self-servo writing process, such as relative positions of multiple read heads and tracking of multiple servo patterns. This additional information enhances accuracy for self-servo writing and can lead to higher recording densities in media drives, and thus more storage with little or no additional cost.
    Type: Grant
    Filed: December 20, 2017
    Date of Patent: April 30, 2019
    Assignee: Marvell International Ltd.
    Inventors: Supaket Katchmart, David Sue-Hong Liaw, Li Zhang
  • Patent number: 10096771
    Abstract: According to one embodiment, a magnetic element includes a first stacked unit and a third ferromagnetic layer. The first stacked unit includes first and second ferromagnetic layers, and a first non-magnetic layer. The first ferromagnetic layer has a first magnetization. The second ferromagnetic layer is separated from the first ferromagnetic layer in a first direction, and has a second magnetization. The first non-magnetic layer is provided between the first and second ferromagnetic layers. The third ferromagnetic layer is stacked with the first stacked unit in the first direction, and has a third magnetization. 2?NzMs is not less than 0.9 times of a magnetic resonance frequency (Hz) of the third ferromagnetic layer, when the second magnetization is Ms (emu/cc), a demagnetizing coefficient of the second ferromagnetic layer is Nz, and a gyro magnetic constant is ? (Hz/Oe).
    Type: Grant
    Filed: September 12, 2016
    Date of Patent: October 9, 2018
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Daisuke Saida
  • Patent number: 9882523
    Abstract: To suppress a decline in the control accuracy of an applied voltage associated with an increase in quantum noise, and to increase the control accuracy of a motor speed. When generating a driving voltage signal supplied to a motor from a driving command signal, a motor-driving voltage control device reduces the gradation level and performs noise-shaping modulation before performing PWM modulation. Reducing the gradation level allows the degree of gradation of the driving voltage signal to be within the resolution range of the PWM modulation, and thus PWM modulation can be performed even when the driving voltage signal has a high frequency. Noise-shaping modulation reduces the level of quantum noise near the low frequency range by causing the quantum noise due to digitization, included in the driving voltage signal, to be biased toward the high frequency range side.
    Type: Grant
    Filed: October 14, 2016
    Date of Patent: January 30, 2018
    Assignee: Schaft Inc.
    Inventors: Junichi Urata, Masayuki Inaba
  • Patent number: 9812164
    Abstract: Implementations disclosed herein provide a method comprising applying voltage to a read head during an unload state, detecting characteristic read head data, and storing the detected characteristic read head data in a buffer. In another implementation, the method further comprises performing a read retry operation in response to a read failure, reading the detected characteristic read head data from the buffer, determining if the detected characteristic read head data meets a threshold for a first predetermined criterion, performing a correction operation if the threshold for the first the first predetermined criterion is met, determining whether a media sector is read successfully, and ending the read retry operation if the media sector is read successfully.
    Type: Grant
    Filed: January 25, 2017
    Date of Patent: November 7, 2017
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Mingyeong Son, Seungyoul Jeong, Man Sik Shim, Woo Chan Kim
  • Patent number: 9691420
    Abstract: According to one embodiment, a disc device outputs a first signal for canceling out a first disturbance at a predetermined frequency of a position error, outputs a second signal which gain or phase of the first signal are changed, and corrects an operation amount or the position error by using the second signal.
    Type: Grant
    Filed: March 30, 2015
    Date of Patent: June 27, 2017
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Takuji Matsuzawa
  • Patent number: 9495982
    Abstract: One example includes an amplifier system. The system includes a gain stage configured to conduct a gain current in response to an input voltage. The system also includes a current limit stage coupled to the gain stage and being configured to one of source and sink the gain current and to define a limit amplitude of the gain current during a current limit condition. The system further includes an output stage coupled to the gain stage and configured to conduct an output current through an output node in response to the gain current, the output current having a maximum amplitude during the current limit condition that is proportional to the limit amplitude.
    Type: Grant
    Filed: May 1, 2014
    Date of Patent: November 15, 2016
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Daijiro Otani, Keita Ikai
  • Patent number: 9460743
    Abstract: According to one embodiment, a servo writing method for a magnetic disk apparatus that includes a magnetic disk and a head is provided. The method rotates the magnetic disk, derives a path obtained by adding a second specifying value to a first specifying value, the first specifying value corresponding to a separation distance from a rotation center of the magnetic disk, the second specifying value periodically displacing the separation distance in a radial direction synchronously with a rotation angle of the magnetic disk, the second specifying value being a value in which the separation distances at a start point and an end point of one rotation of the magnetic disk coincide, and, while causing the head to follow the path, writes servo information onto the magnetic disk with the head.
    Type: Grant
    Filed: September 3, 2015
    Date of Patent: October 4, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Daisuke Sudo
  • Patent number: 9401168
    Abstract: A disk apparatus control device including an A/D converting section that samples an analog current amount signal indicating a current amount for a drive current of a motor that moves a head for accessing a storage disk of a disk apparatus, and converts the analog current amount signal into a digital current amount signal indicating the current amount. The device can further include a control signal generating section that, according to digital control, generates a digital control signal corresponding to a manipulation amount of the drive current, based on a difference between the current amount indicated by the digital current amount signal and a target value for the current amount of the drive current. Additionally, the device can include a D/A converting section that converts the digital control signal into an analog control signal, and outputs the analog control signal to a drive current generating section that generates the drive current.
    Type: Grant
    Filed: January 9, 2015
    Date of Patent: July 26, 2016
    Assignee: Marvell International Ltd.
    Inventor: Kiyotada Ito
  • Patent number: 9354974
    Abstract: A method includes issuing write commands to DS storage units regarding encoded data slices. A write command causes a storage unit to store an encoded data slice, but not allow access to the stored encoded data slices. The method includes receiving write acknowledgements from at least some of DS storage units to produce received write acknowledgements. The method includes, when a write threshold number of the received write acknowledgements have been received within a given time frame, issuing commit commands to the DS storage units. A commit command causes the storage unit to allow access to the stored encoded data slice. The method includes, when the write threshold number of the received write acknowledgements have not been received within the given time frame, issuing rollback commands to the DS units. A rollback command causes the storage unit to continue to not allow access to the stored encoded data slice.
    Type: Grant
    Filed: July 6, 2015
    Date of Patent: May 31, 2016
    Assignee: International Business Machines Corporation
    Inventors: Bart Clifone, Andrew Baptist, Greg Dhuse, Ilya Volvovski, Jason K. Resch
  • Patent number: 9336073
    Abstract: Systems and methods are disclosed for write fault modulation. In an embodiment, an apparatus may comprise a circuit configured to adjust a write fault value for a data storing system based on a circumferential point of a target data storage location, and write data based on the write fault value. The write fault value may represent an amount of off-track deviation of a data writing system within which data writing operations may be performed. In another embodiment, a memory device may store instructions that cause a processor to perform a method including receiving a write command including write data, determining a write fault threshold for a circumferential point of a target location of the write data, performing, using a transducer, a write operation at the circumferential point based on the write fault threshold, and suspending the write operation when a positional deviation of the transducer exceeds the write fault threshold.
    Type: Grant
    Filed: February 27, 2014
    Date of Patent: May 10, 2016
    Assignee: Seagate Technology LLC
    Inventors: Kurt Charles Wiesen, Randall Clement Bauck
  • Patent number: 9269386
    Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising tracks defined by servo sectors. A location of the head is generated based on the servo sectors, and a position error signal (PES) representing a difference between a target location for the head and the measured location for the head is generated. An actuator control signal (ACS) is generated in response to the PES, a disturbance compensation signal (DCS) is generated based on the PES and the ACS, and the DCS is filtered with a disturbance observer filter. The DCS is filtered with a plurality of band-pass filters, and an output of one of the band-pass filters is filtered with a peak detection filter configured to detect a peak frequency corresponding to a peak in a frequency response of the band-pass filter, wherein the disturbance observer filter is adjusted based on the peak frequency.
    Type: Grant
    Filed: December 8, 2014
    Date of Patent: February 23, 2016
    Assignee: Western Digital Technologies, Inc.
    Inventors: Wei Xi, Young-Hoon Kim, Kuang-Yang Tu
  • Patent number: 9230583
    Abstract: According to an embodiment, there is provided a disc device that execute a filtering process to remove one or more resonances from the first signal by the sum of transfer functions, the one or more resonances being included in first transfer characteristics from the first signal transmitted via the first control line to response of the first head, the transfer functions being indicative of resonances included in second transfer characteristics from the first signal transmitted via the second control line to response of the first head.
    Type: Grant
    Filed: April 10, 2015
    Date of Patent: January 5, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yusuke Nojima
  • Patent number: 9142234
    Abstract: A method of operating a disk drive is disclosed, the disk drive comprising a disk comprising a plurality of tracks, and a closed loop servo system comprising a seek servo loop and a settle servo loop for actuating the head over the disk, the settle servo loop comprising a feed-forward compensator. The seek servo loop seeks the head toward a target track, and when the head approaches the target track a state trajectory of the feed-forward compensator is initialized with an initial value in response to a measured state of the servo system. The settle servo loop then settles the head on the target track in response to a feed-forward compensation generated by the feed-forward compensator.
    Type: Grant
    Filed: June 8, 2012
    Date of Patent: September 22, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Mingji Lou, Orhan Beker, Kexiu Liu
  • Patent number: 9135205
    Abstract: A data storage assembly for cold storage. The data storage assembly includes a circuit board and a plurality of hard disk assemblies (HDA). Each HDA includes a platter and a head assembly to read and write data on the platter. The circuit board includes a processor and a read channel. The processor acts as a hard disk controller for the plurality of HDAs and controls the platters. The processor further manages which HDAs are active at a time and the read channel is shared by the plurality of HDAs.
    Type: Grant
    Filed: January 29, 2015
    Date of Patent: September 15, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Robert P. Ryan, Dean M. Jenkins
  • Patent number: 9099133
    Abstract: A disk drive is disclosed comprising a disk comprising a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors, and an actuator for actuating a head over the disk in response to an actuator control signal. The servo sectors are read to generate a first sequence of control samples x[k] at a sample frequency corresponding to a frequency of the servo sectors. A hybrid upsample filter is used to upsample by a factor of N the first sequence of control samples x[k] to generate a second sequence of control samples y[ki], wherein the hybrid upsample filter provides a higher phase gain than a zero-order type upsample filter at frequencies less than one kilohertz, and approximately the same attenuation as a first-order type upsample filter around the sample frequency. The actuator control signal is generated in response to the second sequence of control samples y[ki].
    Type: Grant
    Filed: January 29, 2013
    Date of Patent: August 4, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Shan Tang, Lu Feng, Yanan Huang, Alexander Babinski, Min Chen, Orhan Beker
  • Patent number: 9093122
    Abstract: Systems and methods for improving the accuracy of test measurements involving aggressor tracks written to the disks are provided. One such method involves erasing a circumferential band of a disk, writing a central track on the circumferential band, measuring and storing a first track profile of the central track, writing an aggressor track on each side of the central track at a preselected aggressor track offset from the central track, measuring and storing a track profile of the aggressor tracks at the preselected aggressor track offset, measuring and storing a second track profile of the central track, performing the prior actions exactly n times where n is greater than or equal to 1, determining an estimated distance between the aggressor tracks based on the respective track profiles, determining a selected measurement using the estimated distance between the aggressor tracks, and the first and second track profiles of the central track.
    Type: Grant
    Filed: June 24, 2013
    Date of Patent: July 28, 2015
    Assignee: WD Media, LLC
    Inventors: Dragos I. Mircea, Steven E. Lambert, Andreas Moser, Harold H. Gee, Douglas N. Bartholomew
  • Patent number: 9087540
    Abstract: Systems and methods are disclosed that implement asymmetrical write fault thresholds. A data storage device may apply a different write fault threshold to each side of a target track, allowing a write head to deviate from a track center more in one direction than in the other direction. In some embodiments, the asymmetrical write fault thresholds may be applied to shingled tracks, allowing a lower write fault threshold to be applied in the direction of previously written shingled tracks, and a higher write fault threshold to be applied in the direction of tracks which are not yet written.
    Type: Grant
    Filed: July 18, 2014
    Date of Patent: July 21, 2015
    Assignee: Seagate Technology LLC
    Inventors: Jungho Lee, Jae Myung Chung, Jung Min Yoon, Hwa Jun Kim
  • Patent number: 9047900
    Abstract: A media drive includes a head, a servo signal processing circuit, an actuator and a processor. The head is positioned near a data storage medium, and includes a servo element. The servo signal processing circuit is coupled to the servo element to output a position error signal. The actuator controls a position of the head relative to the data storage medium. The processor communicates with the actuator and the servo signal processing circuit. The processor provides a filtered position error signal to the actuator to compensate for a position displacement between the head and the data storage medium. The filtered position error signal includes a sum of outputs from a first compensation filter and a second compensation filter that is each applied to the position error signal output. The compensation filters attenuate disturbance frequencies that contribute to the position displacement. Each of the compensation filters has a sampling rate relating to the respective disturbance frequency.
    Type: Grant
    Filed: June 20, 2014
    Date of Patent: June 2, 2015
    Assignee: Quantum Corporation
    Inventors: Turguy Goker, Ming-Chih Weng, Umang Mehta, Ryan Taylor
  • Patent number: 9036284
    Abstract: Systems and methods are disclosed for isolated bands of fractional tracks in data storage devices, particularly devices employing shingled magnetic recording. In one embodiment, a device may comprise a data storage medium including a first data storage area including tracks overlapped in a shingled manner and having a first circumferential portion of a track to store data, a second data storage area, and a guard area disposed between the first data storage area and the second data storage area, the guard area including a second circumferential portion of the track as a partial guard track. In some embodiments, the guard area may include at least one sector in the first circumferential portion of the track, such that at least one sector of the guard area is interposed between data storage sectors of the first data storage area.
    Type: Grant
    Filed: September 16, 2013
    Date of Patent: May 19, 2015
    Assignee: Seagate Technology LLC
    Inventor: Timothy R. Feldman
  • Patent number: 9036291
    Abstract: Systems and methods are provided that may be implemented to provide a mechanical indicator to correlate magnetic disk drive IOP performance with features of mechanical and/or acoustic vibrational frequencies that are generated and captured or sensed outside of the disk drive itself. In one example, disk drive PES data may be collected concurrently with the capture of mechanical and/or acoustic vibrational data at different and progressive locations of vibration source, vibration path and vibration receiver in a disk drive operating environment, e.g., such as for disk drives installed within a server and/or storage chassis enclosure. In such case, PES threshold may be utilized to correlate performance of Drive IOP or drive servo-mechanical performance as a function of measured characteristics of vibration source/s that impart vibration to a disk drive.
    Type: Grant
    Filed: August 22, 2014
    Date of Patent: May 19, 2015
    Assignee: Dell Products, LP
    Inventors: Jose A. Nava, Haesung Kwon
  • Patent number: 9025264
    Abstract: Methods for measuring media performance associated with adjacent track interference are provided. One such method includes iteratively writing data to a target track for each of a plurality of n frequencies, measuring a first signal amplitude and a first noise for each of the n sectors on the target track, writing an aggressor track pattern proximate the target track, measuring a second signal amplitude and a second noise for each of the n sectors on the target track, calculating a weighted sum for each of the signal amplitude measurements for each of the plurality of n frequencies, and calculating a weighted sum for each of the noise measurements for each of the plurality of n frequencies, and repeating the writing the aggressor track pattern, the measuring the second signal amplitude and the second noise, and calculating the weighted sums for preselected numbers of times.
    Type: Grant
    Filed: March 28, 2014
    Date of Patent: May 5, 2015
    Assignee: WD Media, LLC
    Inventors: Mrugesh Desai, Harold H. Gee, Mark A. Nichols
  • Publication number: 20150116862
    Abstract: A data storage device may be configured at least with an actuating assembly that has a head-gimbal suspension assembly (HGSA), first pivot point, and second pivot point. The head-gimbal assembly can be constructed and operated with at least first and second transducers aligned along a longitudinal axis of the head-gimbal suspension assembly. A controller may be adopted to manipulate the head-gimbal suspension assembly about at least one of the pivot points in response to a head-gimbal suspension assembly offset misalignment to compensate for such an offset.
    Type: Application
    Filed: October 29, 2013
    Publication date: April 30, 2015
    Applicant: Seagate Technology LLC
    Inventors: Tzung-Sz Shen, Chih-Wu Jen
  • Publication number: 20150109700
    Abstract: Techniques for writing data to a buffer region of a magnetic disk are described. In one example, a hard disk drive comprises a magnetic disk comprising a data buffer region including a first zone and a second zone. Data may be written to the magnetic disk using shingled magnetic recording (SMR) and the buffer region may be an exception region (E-region). A hard disk drive may be configured to calculate a position accuracy value associated with a data writing head. The hard disk drive may select one of the zones based on the position accuracy value. Further, a selected zone may have a determined zone format. The hard disk drive may be configured to write data to the selected zone using the determined zone format.
    Type: Application
    Filed: October 18, 2013
    Publication date: April 23, 2015
    Applicant: HGST Netherlands B.V.
    Inventors: Hidekazu KASHIWASE, Hiroyasu TANABE, Hideki ZAITSU
  • Patent number: 9013818
    Abstract: A disk drive is disclosed comprising a disk, and a head actuated radially over the disk, wherein the head comprises a read element separated from a write element by a reader/writer gap. A disk-locked clock is synchronized to a rotation of the disk, wherein the disk-locked clock comprises a plurality of clock cycles, and the reader/writer gap spans a first number of the clock cycles comprising an integer of the clock cycles plus a fraction of one of the clock cycles. The fraction of one of the clock cycles is measured when the head is positioned at a first plurality of radial locations across the disk, and a second plurality of radial locations is estimated where the fraction substantially equals a full one of the clock cycles.
    Type: Grant
    Filed: December 20, 2013
    Date of Patent: April 21, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Zhenyu Sun, Teik Ee Yeo
  • Patent number: 9001452
    Abstract: In one implementation, a method and apparatus is provided for determining an active fly height setting for a transducer head from samples collected from a proximity sensor during less than a single revolution of a disc. Implementations of the method and system use adaptive discrete wavelet transform parameters generated from the collected samples to determine an active fly height setting for a transducer head.
    Type: Grant
    Filed: October 25, 2013
    Date of Patent: April 7, 2015
    Assignee: Seagate Technology LLC
    Inventors: Antanas Daugela, Jon D. Trantham, Srinivas Tadepalli
  • Patent number: 8994298
    Abstract: A movement control apparatus includes: an actuator that causes a driven body connected to a driving coil to perform reciprocating movement; a signal generation unit that generates a velocity command signal which indicates a target velocity of the driven body; a driving unit that supplies electric current corresponding to a driving signal to the driving coil; a voltage detection unit that detects induced voltage generated in the driving coil, and outputs a voltage signal corresponding to the induced voltage; a signal correction unit that corrects, based on the driving signal and the voltage signal, the voltage signal to adjust a shift of a resistance value from a reference resistance value of the driving coil, thereby generating a velocity signal; and a control unit that generates the driving signal based on the velocity command signal and the velocity signal, and outputs the driving signal to the driving unit.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: March 31, 2015
    Assignee: Panasonic Intellectual Property Management Co., Ltd.
    Inventors: Toshio Inaji, Takeshi Shimamoto, Kozo Ezawa
  • Publication number: 20150049399
    Abstract: A storage device has a device body and a read/write head for reading and writing data in a data track of a storage medium. An actuator system is mounted on the device body for effecting movement of the read/write head relative to the data track to align the head with the data track. The actuator system has a plurality of degrees of freedom, and a controller controls the actuator system to effect the movement. A body vibration sensor provided on the device body generates a signal indicative of vibration of the body. An actuator vibration sensor generates a signal indicative of vibration of the actuator system. The controller is adapted to process the signals from the sensors to derive a coupling signal indicative of vibration coupling between the degrees of freedom, and to control the actuator system dependent on the coupling signal and the signal from the body vibration sensor.
    Type: Application
    Filed: March 5, 2013
    Publication date: February 19, 2015
    Inventors: Mark A. Lantz, Angeliki Pantazi
  • Patent number: 8947811
    Abstract: A disk drive is disclosed comprising a head actuated over a disk, wherein data is written to the disk comprising a first periodic pattern, a payload, and a second periodic pattern. The data is first read from the disk to generate a first read signal, and the first read signal is sampled asynchronously to generate first asynchronous signal samples. The first asynchronous signal samples representing the first periodic pattern are processed to measure a first phase, and the first asynchronous signal samples representing the second periodic pattern are processed to measure a second phase. A first phase error is generated based on a difference between the first phase and the second phase. The first asynchronous signal samples representing the payload are adjusted in response to the first phase error to generate first adjusted asynchronous signal samples.
    Type: Grant
    Filed: March 12, 2013
    Date of Patent: February 3, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventor: James P. R. McFadyen
  • Patent number: 8941942
    Abstract: According to one embodiment, there is provided a method, implemented in a magnetic disk drive, for adjusting a linear recording density. The method obtains a first flying-dependent error sensitivity for each of two or more heads. The first flying-dependent error sensitivity represents a change in read error rate corresponding to a change in flying height of the head during write. In addition, the method reduces the linear recording density of a first recording surface associated with a first head of the two or more heads if the first flying-dependent error sensitivity is a second flying-dependent error sensitivity higher than a threshold and corresponds to the first head.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: January 27, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroaki Sato, Hiroyuki Tanaka
  • Patent number: 8902534
    Abstract: A method, apparatus and a data storage device are provided for implementing track following and data recovery with readback of shingled data written in overlapping shingled data tracks on a recordable surface of a storage device. Positional information is identified with data readback of shingled data written in overlapping shingled data tracks. The identified positional information is used to selectively modify at least one predefined channel parameter, for example, to provide enhanced track following and enhanced data recovery.
    Type: Grant
    Filed: August 3, 2012
    Date of Patent: December 2, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Richard Michael Brockie, Richard Leo Galbraith, Petrus Antonius Van Der Heijden, Roger William Wood
  • Patent number: 8896961
    Abstract: Systems and methods are disclosed for positioning of a reader element in a data storage device employing shingled recording. In an embodiment, a system may comprise a data storage medium configured to store data in a shingled manner where at least one track is partially overlapped by an adjacent track, a read element to read data from the data storage medium, and a processor. The processor may be configured to receive a read command to retrieve data from the data storage medium, and when the data is stored to a shingled portion of the data storage medium, adjust a position of the read element according to a squeeze offset value based on an amount of overwrite of a shingled data track by an adjacent data track.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: November 25, 2014
    Assignee: Seagate Technology LLC
    Inventor: Peter S Harllee, III
  • Patent number: 8891194
    Abstract: A disk drive is disclosed comprising a head actuated over a disk. A position y of the head is measured based on servo sectors, and the measured position y of the head is adjusted based on: z1=y+c1(y) where z1 represents a first adjusted position and c1(y) represents first correction values. The first adjusted position z1 is adjusted based on: z2=z1+c2(z1) where z2 represents a second adjusted position and c2(z1) represents second correction values. The first and second correction values are combined based on: c3(y)=c1(y)+c2(y+c1(y)). The measured position y of the head is adjusted based on: z3=y+c3(y) where z3 represents a third adjusted position comprising the adjustment based on c1(y) and the adjustment based on c2(y), and c3(y) represents third correction values.
    Type: Grant
    Filed: June 20, 2013
    Date of Patent: November 18, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Sanghoon Chu, Richard K. Wong, Min Chen
  • Patent number: 8885283
    Abstract: A disk drive is disclosed comprising a head actuated over a disk having a plurality of data tracks. A vibration is detected, and a write operation is configured to write a first plurality of blocks and a second plurality of blocks to a target data track based on the detected vibration. The first plurality of blocks are written to the target data track during a first revolution of the disk, and the second plurality of blocks are written to the target data track during a second revolution of the disk.
    Type: Grant
    Filed: November 3, 2011
    Date of Patent: November 11, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Jianguo Zhou, Wei Xi
  • Patent number: 8879185
    Abstract: Systems, methods, apparatus, and techniques are provided for controlling synchronization of a write clock. A frequency offset is estimated based, at least partially, on a location of the servo synchronization marker to produce the frequency offset estimate. A phase correction value and a frequency correction value associated with the write clock are obtained, and a data clock timing control signal is produced based on the frequency offset estimate, the phase correction value, and the frequency correction value. The data clock timing control signal is applied to a phase interpolator to modify a phase of the write clock.
    Type: Grant
    Filed: November 3, 2011
    Date of Patent: November 4, 2014
    Assignee: Marvell International Ltd.
    Inventors: Qiyue Zou, Gregory Burd, Michael Madden
  • Patent number: 8873179
    Abstract: A bit-patterned media (BPM) magnetic recording disk has two sizes of dots of magnetic material. The large and small dots are formed together in a hexagonal-close-packed (HCP) pattern. In the data regions none of the larger sized dots are adjacent one another; however in the servo regions some of the larger sized dots are adjacent one another. The adjacent larger sized dots form blocks that provide large amplitude “bursts” as the readback signal, as required for servo burst fields. The disk is made by imprint lithography using an imprint template, which can be made by directed self-assembly (DSA) of a block copolymer (BCP). The imprint template has two sizes of recesses, resulting in BPM disks with two sizes of dots. After the disks are imprinted they are exposed to a DC magnetic field, which magnetizes all the dots in the same direction.
    Type: Grant
    Filed: September 12, 2013
    Date of Patent: October 28, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Yoshiyuki Hirayama, Taku Iwase
  • Patent number: 8867162
    Abstract: According to one embodiment, a magnetic head, a magnetic disk and a magnetic recording controller are provided. The magnetic disk has a burst pattern recorded thereon for determining a position of the magnetic head on a track based on a reading result by the magnetic head. The magnetic recording controller corrects a demodulation position of the magnetic head based on an offset correction value subject to fluctuation of the burst pattern.
    Type: Grant
    Filed: February 4, 2013
    Date of Patent: October 21, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Daisuke Sudo
  • Patent number: 8854758
    Abstract: A method and apparatus for storing a disk drive media defect table or list. Defect table entries for a subject disk track are stored on the subject track and retrieved for determining defective sectors only when the subject track is accessed for a data read or write operation.
    Type: Grant
    Filed: May 19, 2006
    Date of Patent: October 7, 2014
    Assignee: AGERE Systems Inc.
    Inventors: Walter Allen, Robert Alan Reid
  • Patent number: 8824093
    Abstract: According to one embodiment, a head position detecting method and a magnetic disk device includes measuring a burst output by reading a burst pattern, which is recorded on a magnetic disk, with a magnetic head and calculating a demodulation position of the magnetic head on the basis of the result of the correction of the phase shift of the burst output corresponding to magnetization transition curvature of the burst pattern.
    Type: Grant
    Filed: September 10, 2013
    Date of Patent: September 2, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Daisuke Sudo
  • Publication number: 20140233362
    Abstract: An information device includes a slider (100) including a first metal antenna (103a), a second metal antenna (103b), and a heater (107) configured to vary the distance between the first metal antenna (103a) and the second metal antenna (103b) in a direction orthogonal to a track direction on the surface of a disk (104), and an arm motor (120) configured to move the slider (100) in parallel to the surface of the disk (104). The arm motor (120) and the heater (107) cause the first metal antenna (103a) and the second metal antenna (103b) to respectively follow corresponding target tracks.
    Type: Application
    Filed: October 16, 2012
    Publication date: August 21, 2014
    Inventors: Kenji Kondo, Kenji Fujiune, Takeharu Yamamoto
  • Patent number: 8797673
    Abstract: An implementation of a circuit disclose herein comprises a vibration sensor circuit that generates a sensor signal from a disturbance signal, a lattice filter circuit that decorrelates the sensor signal to generate orthogonal backward prediction errors, and a multiple regression filter that estimates a disturbance correction signal using the orthogonal backward prediction errors.
    Type: Grant
    Filed: June 16, 2011
    Date of Patent: August 5, 2014
    Assignee: Seagate Technology LLC
    Inventor: Lou Supino
  • Publication number: 20140211339
    Abstract: Misalignment of a transducer head over a bit-patterned media (BPM) may cause a bit to experience conflicting magnetization forces from the writer, resulting in improperly written data and stored data corruption. The likelihood of data corruption is reduced when a write transition is performed when the write sync margin is increased or maximized. Therefore, a write precompensation system may calculate time shift information for adjusting the timing of an individual write current transition at the transducer that compensates for write sync margin degradation due to any or all of skew angle of the transducer, track misregistration, and write field curvature.
    Type: Application
    Filed: January 29, 2013
    Publication date: July 31, 2014
    Applicant: Seagate Technology LLC
    Inventor: Harry S. Edelman
  • Patent number: 8792193
    Abstract: A magnetic media tester comprising a Laser Doppler Vibrometer (LDV) head; and a magnetic read head; the LDV head and the magnetic read head being configured for obtaining correlatable data of a region on a magnetic disk.
    Type: Grant
    Filed: March 26, 2010
    Date of Patent: July 29, 2014
    Assignee: Agency for Science, Technology and Research
    Inventors: Siang Huei Leong, Budi Santoso, Chun Lian Ong, Joo Boon Marcus Travis Lim, Zhimin Yuan, Kaidong Ye
  • Patent number: 8780476
    Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, some embodiments of the present invention provide clock generation systems that include: a first clock multiplier circuit, a second clock multiplier circuit, a modulus accumulator circuit, and a data clock phase control circuit. The first clock multiplier circuit is operable to multiply a reference clock by a first multiplier to yield a first domain clock, and the second clock multiplier circuit is operable to multiply the reference clock by a second multiplier to yield a second domain clock. The modulus accumulator circuit is operable to yield a value indicating a fractional amount of the second domain clock that an edge of the second domain clock is offset from a trigger signal. The data clock phase control circuit is operable to phase shift the second domain clock by a phase amount corresponding to the fractional amount.
    Type: Grant
    Filed: September 23, 2011
    Date of Patent: July 15, 2014
    Assignee: LSI Corporation
    Inventor: Jeffrey P. Grundvig
  • Patent number: 8773808
    Abstract: A magnetic disk device includes a magnetic disk on which servo information is recorded, a head to read the servo information of the magnetic disk, and a position control module. When carrying out positioning control of the head, the position control module estimates frequency components of noise in a head positioning control process, using a high-order digital filter that includes first and second variable coefficients that are each based on position error information generated from the servo information read by the head.
    Type: Grant
    Filed: September 7, 2012
    Date of Patent: July 8, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masafumi Iwashiro, Takao Abe, Hiroshi Kubota, Kazuhiko Takaishi
  • Patent number: 8773809
    Abstract: A contact event between a sensing device and a storage medium is detected by receiving a signal indicating a physical proximity between the sensing device and the storage medium; generating a plurality of frequency bin outputs; comparing one or more frequency bin outputs to a corresponding first level threshold to yield a corresponding comparator output; summing the comparator output with at least one prior instance of the comparator output to yield an aggregated value; comparing the aggregated value to an aggregate threshold to yield an aggregate output; and generating a contact event output if one or more of a first group of the plurality of frequency bin outputs has an associated aggregate output set to a predefined binary value and a predefined minimum number of a second group of the plurality of frequency bin outputs has an associated aggregate output set to a predefined binary value.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: July 8, 2014
    Assignee: LSI Corporation
    Inventors: Ming Jin, Erich F. Haratsch, Jason S. Goldberg, Kurt J. Worrell, Scott M. Dziak, Jeffrey P. Grundvig
  • Patent number: 8773807
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of normal servo tracks each comprising a plurality of normal servo sectors storing head position information, and a fly height calibration servo track comprising fly height calibration servo sectors, each fly height calibration servo sector comprising head position information and a spacing pattern. After positioning the head over the fly height calibration servo track, the head is servoed over the fly height calibration servo track in response to the fly height calibration servo sectors. A dynamic fly height (DFH) setting is calibrated for the DFH actuator in response to the spacing pattern in the fly height calibration servo sectors. After calibrating the DFH setting, the control circuitry seeks the head to a data track defined by at least one of the normal servo tracks, and startup data is read from the data track.
    Type: Grant
    Filed: July 24, 2012
    Date of Patent: July 8, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Galvin T. Chia, Huanxiang Ruan
  • Patent number: 8767332
    Abstract: A disk drive is disclosed comprising a disk, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk. A vibration signal VS(k) is measured representing a disturbance in the servo control system. A first future value of the vibration signal VS(k) is predicted based on: VS1(k+1)=?1[VS(k)?VS(k?1)]+VS(k) where ?1 is a first scalar corresponding to a first frequency range. A second future value of the vibration signal VS(k) is predicted based on: VS2(k+1)=?2[VS(k)?VS(k?1)]+VS(k) where ?2 is a second scalar corresponding to a second frequency range different from the first frequency range.
    Type: Grant
    Filed: April 3, 2013
    Date of Patent: July 1, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Jianguo Zhou