Patents Examined by James L Habermehl
  • Disk drive resetting fly height reference generated from a degrading calibration track
    Patent number: 8773802
    Abstract: A disk drive is disclosed comprising a head actuated over a disk and a fly height actuator operable to control a fly height of the head in response to a fly height control signal. A touchdown operation is executed to set an operating fly height control signal by adjusting the fly height control signal until the head contacts the disk. A fly height calibration track is then read to set a fly height reference. When calibrating the operating fly height control signal, the fly height calibration track is read and the operating fly height control signal is adjusted in response to the fly height reference. When the adjusted operating fly height control signal is invalid, the touchdown operation is re-executed to reset the operating fly height control signal and then the fly height calibration track is read to reset the fly height reference.
    Type: Grant
    Filed: June 10, 2011
    Date of Patent: July 8, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kent D. Anderson, Shafa Dahandeh, Galvin T. Chia, Alvin W. Tan, Noureddine Kermiche, Ming Jin
  • Tape cartridge auxiliary memory based library
    Patent number: 8767330
    Abstract: A data storage library is described including a plurality of tape cartridges wherein each of the tape cartridges possesses an auxiliary radio frequency memory device in which auxiliary digital data is stored. The library also includes at least one drive disposed substantially within the library capable of transferring user data to and from one of the tapes. The library further includes at least one auxiliary radio frequency memory device reader that capable of reading the auxiliary digital data and transmitting the auxiliary digital data to at least one designated location, the reader is independent of the at least one drive.
    Type: Grant
    Filed: September 29, 2011
    Date of Patent: July 1, 2014
    Assignee: Spectra Logic, Corp.
    Inventors: Ray D. Heineman, Samuel J. Guleff, Matthew Thomas Starr, Michael Jerard Goberis, Walter Wong
  • System and computer program product for fast recovery to a write state
    Patent number: 8760788
    Abstract: In one embodiment, a tape drive system includes a magnetic head having at least one servo sensor for track-following at least one defined servo track of a longitudinal tape, a tape motion controller configured to move the longitudinal tape past the magnetic head, a compound actuator configured to translate the magnetic head laterally with respect to the longitudinal tape, and a control configured to track-follow the at least one defined servo track by reducing a position error between the magnetic head and a desired position, transition from a write state to a monitor state when the position error is greater than a threshold, transition from the monitor state to a stop write state when the position error is greater than the threshold for a first period, and transition from the monitor state to the write state when the position error is less than the threshold for a second period.
    Type: Grant
    Filed: June 2, 2011
    Date of Patent: June 24, 2014
    Assignee: International Business Machines Corporation
    Inventors: Nhan X. Bui, Reed A. Hancock, Tomoko Taketomi
  • Disk drive detecting track squeeze when circular tracks are defined from non-circular servo tracks
    Patent number: 8743495
    Abstract: 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.
    Type: Grant
    Filed: June 3, 2011
    Date of Patent: June 3, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Min Chen, Duc T. Phan
  • System for fast center calibration of a tape drive for a flangeless tape path
    Patent number: 8724246
    Abstract: A servo system according to one embodiment includes a servo control configured to: determine position error between a magnetic head and a desired position related to at least one defined servo track on a longitudinal tape based on at least one servo signal; calculate a first average position of the magnetic head while the longitudinal tape is moved in a first direction; calculate a first offset of the magnetic head while the longitudinal tape is moved in the first direction based on a target position and an assumption that the first average position of the magnetic head occurred when the tape was at a top-most position or a bottom-most position of a supply reel; and operate an actuator to position the actuator substantially at the target position using the first offset and the first average position.
    Type: Grant
    Filed: June 4, 2013
    Date of Patent: May 13, 2014
    Assignee: International Business Machines Corporation
    Inventors: Nhan X. Bui, Reed A. Hancock, Randy C. Inch
  • Harmonic sensor
    Patent number: 8711510
    Abstract: A system including a weighting function module, a frequency sensor module, and a control module. The weighting function module is configured to receive a plurality of samples of data, the data having been obtained based on a head having read the data from a storage medium while the head was at a given height above the storage medium, and to apply a weighting function to the plurality of samples to generate weighted samples. The frequency sensor module is configured to estimate, based on the weighted samples, (i) a first magnitude of a first frequency component, and (ii) a second magnitude of a second frequency component. The control module is configured to estimate, based on the first magnitude and the second magnitude, the height of the head above the storage medium.
    Type: Grant
    Filed: April 16, 2013
    Date of Patent: April 29, 2014
    Assignee: Marvell International Ltd.
    Inventors: Michael Madden, Zining Wu
  • Contact detection between a disk and magnetic head
    Patent number: 8711508
    Abstract: A HDD including a magnetic disk, a magnetic head, an embedded contact sensor embedded in the magnetic head and configured to detect a contact between the magnetic disk and the magnetic head, and TFC embedded in the magnetic head and configured to facilitate in detecting the contact between the magnetic disk and said magnetic head.
    Type: Grant
    Filed: November 17, 2010
    Date of Patent: April 29, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Masayuki Kurita, Toshiya Shiramatsu, Yuki Shimizu
  • Magnetic head drive device with micro-actuators of end arms rotating in a direction opposite micro-actuators of intermediate arms
    Patent number: 8699166
    Abstract: A magnetic head drive device including a suspension for supporting a magnetic head, and a main actuator that produces rotary movement of the magnetic head by applying current to a coil. The main actuator includes end arms each comprising a single micro-actuator, and an intermediate arm comprising two micro-actuators. The micro-actuators of the end arms are driven in the same direction, and the micro-actuators of the intermediate arm are driven in the opposite direction to the drive direction of the micro-actuators of said the arms.
    Type: Grant
    Filed: December 8, 2010
    Date of Patent: April 15, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Kenji Suzuki, Shinsuke Nakagawa, Toshihiko Shimizu, Eiji Soga, Takaaki Deguchi, Mutsuro Ohta
  • Thermal read/write offset compensation
    Patent number: 8699165
    Abstract: A HDD comprising a temperature sensor disposed inside the HDD configured to periodically measure temperature inside of said hard disk drive; a magnetic disk; a read head; a write head; memory for storing RWO data. The RWO data is a function of a distance between the read head and the write head. The HDD also includes a RWO data adjustor configured to adjust the RWO data in response to a change in temperature of the HDD to compensate for a change in the distance between the read head and the write head based on the change in temperature.
    Type: Grant
    Filed: June 30, 2010
    Date of Patent: April 15, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Lidu Huang, Fu-Ying Huang, Tetsuo Semba
  • Actuator arm unlatching
    Patent number: 8693132
    Abstract: Apparatuses and methods are disclosed that relate to movement of actuator arms from a stopped position. In one example, a method may include attempting to unlatch an actuator arm from a stop and measuring an electrical parameter of a driver circuit of the actuator arm. The method may further include detecting an unsafe unlatch event using a controller when the electrical parameter does not exceed a first threshold within a predetermined period of time.
    Type: Grant
    Filed: October 23, 2012
    Date of Patent: April 8, 2014
    Assignee: Seagate Technology, LLC
    Inventors: KarWei Koay, LingZhi Yang, SangHoon Lee
  • Ultra fast disk access using arrays of fixed read/write transducers
    Patent number: 8693126
    Abstract: An apparatus comprising a magnetic media and a read/write unit. The magnetic media may be configured to store data. The magnetic media may also be rotated during access of the magnetic media. The read/write unit may comprise a plurality of transducers arranged in a linear array. Each of the transducers may be fabricated on a semiconductor substrate with fixed head positions with respect to the magnetic media. The read/write unit may also be positioned in close proximity to and across the surface of the magnetic media. Each transducer may be configured to read data from the magnetic media and write data to the magnetic media.
    Type: Grant
    Filed: July 21, 2010
    Date of Patent: April 8, 2014
    Assignee: LSI Corporation
    Inventors: Wayne L. Buckholdt, Robert W. Warren
  • Methods for fast center calibration of a tape drive for a flangeless tape path
    Patent number: 8687314
    Abstract: According to one embodiment, a method includes sensing a first servo sensor while a longitudinal tape is moved in a first direction; determining position error between the magnetic head and a desired position related to the at least one defined servo track; providing signals to operate a fine actuator to translate the magnetic head laterally in a manner to reduce the determined position error; calculating a first average position of the magnetic head for at least one first run-out cycle while the longitudinal tape is moved in the first direction; calculating a first offset of the magnetic head while the longitudinal tape is moved in the first direction; operating a coarse actuator to position the coarse actuator substantially at a target position using the first offset and the first average position.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: April 1, 2014
    Assignee: International Business Machines Corporation
    Inventors: Nhan X. Bui, Reed A. Hancock, Randy C. Inch
  • Disk drive detecting gas leaking from head disk assembly
    Patent number: 8687307
    Abstract: A disk drive is disclosed comprising a head disk assembly (HDA) filled with a gas, the HDA comprising a head actuated over a disk, and an electrical heating element. A pressure inside the HDA is measured, and the electrical heating element is heated for a first heating time. A rate of temperature change of the electrical heating element is measured, and the gas leaking from the HDA is detected in response to the pressure and the rate of temperature change.
    Type: Grant
    Filed: November 18, 2010
    Date of Patent: April 1, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventor: Charles R. Patton, III
  • Zone servo write with multi-frequency self-spiral write
    Patent number: 8687308
    Abstract: In one aspect, systems, apparatuses and techniques obtain, through read circuitry, timing information for a machine-readable medium to determine head position; and write, by write circuitry, a first set of spiral servo reference tracks at a first frequency on a first zone of the medium and a second set of spiral servo reference tracks at a second, different frequency on a second zone of the medium. The second zone may be different from the first zone. Further, at least one of the first and second sets of spiral servo reference tracks may be written to the medium based on at least the timing information.
    Type: Grant
    Filed: June 1, 2011
    Date of Patent: April 1, 2014
    Assignee: Marvell International Ltd.
    Inventor: Supaket Katchmart
  • Speed control systems and methods for decreasing power consumption in rotating storage devices
    Patent number: 8638519
    Abstract: A system including a monitoring module configured to monitor whether, during a first predetermined period, at least one of a read operation, a write operation, or a seek operation is performed on a platter of a storage device in response to the platter of the storage device rotating at a first speed. A speed control module is configured to rotate the platter of the storage device at a second speed in response to none of the read operation, the write operation, or the seek operation being performed on the platter of the storage device during the first predetermined period. The second speed is (i) less than the first speed, and (ii) greater than zero. None of the read operation, the write operation, or the seek operation is performed on the platter of the storage device in response to the platter of the storage device rotating at the second speed.
    Type: Grant
    Filed: September 4, 2012
    Date of Patent: January 28, 2014
    Assignee: Marvell International Ltd
    Inventors: Edy Susanto, Foo Leng Leong, Cheng Yong Teoh
  • Adjusting VGA analog gain for misaligned servo sectors in a disk drive
    Patent number: 8625231
    Abstract: Embodiments of the invention include data storage system with a servo system with a VGA feedback loop that corrects gain errors for servo bursts arising from track phase misalignment and difference in frequencies between AGC and servo bursts for seamed and seamless servo patterns. After the servo fields have been written as part of the manufacturing process, in one embodiment measurements of phase misalignment are made and recorded in nonvolatile memory for use during normal operation of the drive. One embodiment includes measuring misalignment using relative signal magnitudes from test bursts with various linear densities written in a data area during the self-servo writing process. In an alternative embodiment the measurements of phase misalignment can be made real-time during normal operation of the drive.
    Type: Grant
    Filed: November 8, 2012
    Date of Patent: January 7, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Abhishek Dhanda, Toshiki Hirano, Tetsuo Semba
  • System, method, and computer program product for servo compensator switching in high vibration environments
    Patent number: 8611038
    Abstract: A tape drive system according to one embodiment includes a magnetic head having at least one servo sensor; a tape motion controller; a fine actuator; a skew actuator; a coarse actuator; and a control. The control is configured to perform various operations that help account for vibrations that effect track-following a servo track when operating a tape drive. Additional systems, methods and computer program products are also described.
    Type: Grant
    Filed: June 2, 2011
    Date of Patent: December 17, 2013
    Assignee: International Business Machines Corporation
    Inventors: Nhan X. Bui, Reed A. Hancock, Tomoko Taketomi
  • Disk drive adjusting microactuator gain by injecting a sinusoid into a servo control system
    Patent number: 8611040
    Abstract: 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 and a microactuator servo loop operable to actuate the head over the disk surface. A microactuator compensator in the microactuator servo loop is disabled, a sinusoid is injected into a control signal applied to the microactuator, and coefficients of a corresponding sinusoidal response in a DSA error signal of the DSA servo loop is measured. The sinusoid is injected into a model of the microactuator to generate a compensation signal. A gain of the microactuator is adjusted based on a VCM error signal and the coefficients of the sinusoidal response in the DSA error signal.
    Type: Grant
    Filed: September 27, 2012
    Date of Patent: December 17, 2013
    Assignee: Western Digital Technologies, Inc.
    Inventors: Wei Xi, Young-Hoon Kim
  • Disk drive performing lifetime logging of microactuator sensitivity
    Patent number: 8605384
    Abstract: A disk drive is disclosed comprising a head, a disk surface, and a voice coil motor (VCM) and a microactuator operable to actuate the head over the disk surface. A sensitivity of the microactuator is periodically measured over a lifetime of the microactuator. Each measured sensitivity is stored in a timeline log, wherein the timeline log represents a degradation curve of the microactuator over the lifetime of the microactuator.
    Type: Grant
    Filed: November 6, 2012
    Date of Patent: December 10, 2013
    Assignee: Western Digital Technologies, Inc.
    Inventors: Yanning Liu, Chuanwen Ji, Duc T. Phan, Ming Ying Wang
  • Disk drive to load a head to a load/unload (LUL) zone of a disk
    Patent number: 8605382
    Abstract: A disk drive to load a head to a load/unload (LUL) zone of a disk is disclosed. The disk drive comprises an actuator including a head; a disk having a plurality of tracks; and a processor to control the movement of the actuator and the head relative to the disk. The processor may further: measure a back electromagnetic force (BEMF) of a spindle stator of a spindle motor after turning off the spindle motor; identify a modulation feature of the BEMF that indicates an identifiable circumferential position; command the storage the modulation feature of the BEMF; and control loading the head onto the LUL zone of the disk when the modulation feature is matched.
    Type: Grant
    Filed: June 8, 2011
    Date of Patent: December 10, 2013
    Assignee: Western Digital Technologies, Inc.
    Inventors: Michael L. Mallary, Donald Brunnett, Diep L. Nguyen, Gerardo A. Bertero