Patents Represented by Attorney Howard H. Sheerin, Esq.
  • Patent number: 7804657
    Abstract: A method is disclosed for setting an operating bias current for a magnetoresistive (MR) element. A bias current is applied to the MR element, and a voltage across the MR element is measured corresponding to the bias current. The bias current is then adjusted in response to the bias current multiplied by a ratio of a target voltage and the measured voltage. The adjusted bias current is then applied to the MR element. In one embodiment, the bias current is adjusted until the measured voltage substantially equals the target voltage.
    Type: Grant
    Filed: June 11, 2007
    Date of Patent: September 28, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: Dennis W. Hogg, Jonas A. Goode, Tuyen V. Trinh
  • Patent number: 7675707
    Abstract: A disk drive is disclosed comprising a disk, a head actuated over the disk, and control circuitry operable to generate a fly height control signal. A fly height of the head is measured, and the measured fly height is combined with a target fly height and a feedforward signal, wherein the feedforward signal is generated according to: a1┬Ěcos(2?n1k/N)+b1┬Ěsin(2?n1k/N) where a1 and b1 are coefficients and 2?n1k/N represents a frequency of a repeatable disturbance in the fly height of the head.
    Type: Grant
    Filed: November 21, 2008
    Date of Patent: March 9, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: Hain-Ling Liu, Min Chen, Soo-Choon Kang
  • Patent number: 7672072
    Abstract: A disk drive is disclosed including a disk, and a head actuated over the disk. A refresh monitor is maintained for data stored on the disk, wherein the refresh monitor comprises an update function responsive to an operating parameter of the disk drive. A duration monitor is maintained, and the update function of the refresh monitor is modified in response to the duration monitor. The data stored on the disk is refreshed in response to the refresh monitor.
    Type: Grant
    Filed: June 27, 2007
    Date of Patent: March 2, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: William B. Boyle, Michael S. Rothberg
  • Patent number: 7671599
    Abstract: A static electricity monitor is disclosed operable to test a garment worn by a person, the garment comprising a first piece of footwear worn on a first foot of the person. The static electricity monitor comprises a first footpad electrode having a length of at least one meter, and a first handrail electrode running generally parallel to the first footpad electrode. The static electricity monitor further comprises control circuitry coupled to the first footpad electrode and the first handrail electrode, and operable to determine if the garment worn by the person passes a soundness test by taking a measurement as the person walks the first piece of footwear along the first footpad electrode while contacting a first hand to the first handrail electrode.
    Type: Grant
    Filed: January 31, 2007
    Date of Patent: March 2, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: Huynh P. Tan, Julius A. Turangan, Muralidhar R. Dugyala
  • Patent number: 7669711
    Abstract: A disk pack balancing station is disclosed for balancing a disk pack assembly, the disk pack assembly comprising a plurality of components including a plurality of disks coupled to a hub of a spindle motor with at least one disk spacer between the disks. The disk pack balancing station comprises a first biasing arm rotated about a pivot to apply a first biasing force to a first component of the disk pack assembly, and a second biasing arm moved linearly to apply a second biasing force to a second component of the disk pack assembly. This configuration enables the disk pack balancing station to balance a number of different disk pack assemblies, including a disk pack comprising an even number of disks and a disk pack including an odd number of disks.
    Type: Grant
    Filed: October 19, 2005
    Date of Patent: March 2, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventor: Barnaby Brian Westwood
  • Patent number: 7660067
    Abstract: A disk drive is disclosed including a disk, a head coupled to a distal end of an actuator arm, and a voice coil motor (VCM) operable to rotate the actuator arm about a pivot to actuate the head radially over the disk, wherein the VCM comprises a coil. Control circuitry within the disk drive measures a load resistance of the coil prior to executing a load operation, wherein the load operation moves the actuator arm off a ramp to load the head onto the disk. The load resistance of the coil is then converted into an initial coil temperature estimate.
    Type: Grant
    Filed: September 19, 2007
    Date of Patent: February 9, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: Chuanwen Ji, Jianghong Ding, Duc T. Phan
  • Patent number: 7656763
    Abstract: A method is disclosed for performing a defect scan for a disk drive. Data is recorded on a first data area of a disk substantially free from defects and on a second data area of the disk substantially affected by at least one defect. A defect scan parameter is initialized with an initial setting. The first data area is read to determine a first defect threshold, and the second data area is read to determine a second defect threshold. A margin is saved representing a difference between the first and second defect thresholds. The setting for the defect scan parameter is adjusted, and the elements of reading the first and second data areas and saving a corresponding margin are repeated at least once. A setting is then selected for the defect scan parameter in response to the saved margins.
    Type: Grant
    Filed: June 4, 2007
    Date of Patent: February 2, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: Ming Jin, Teik Ee Yeo
  • Patent number: 7656607
    Abstract: A disk drive is disclosed operable to generate an actuator control signal for actuating a head over a disk. A memory address is used to read a first state k variable from a first state variable memory SVM1. The first state k variable is stored in a second state variable memory (SVM2) while processing the first state k variable to generate a first state k+1 variable. The first state k+1 variable is stored in the SVM2, and the memory address is assigned to the SVM2 so that the first state k+1 variable becomes a second state k variable and the first state k variable becomes a first state k?1 variable.
    Type: Grant
    Filed: October 21, 2008
    Date of Patent: February 2, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7656604
    Abstract: A disk drive is disclosed comprising a disk including a plurality of spiral tracks, wherein each spiral track comprises a high frequency signal interrupted by a sync mark at a sync mark interval, and a head actuated over the disk. The spiral tracks are demodulated by reading a spiral track to generate a spiral track crossing signal g(xn), where xn is a time in a demodulation window, and determining a position error signal (PES) by determining a time-shift L that maximizes a correlation between g(xn) and a function that estimates a nominal spiral track crossing signal having the time-shift of L.
    Type: Grant
    Filed: December 10, 2007
    Date of Patent: February 2, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jiangang Liang, Siri S. Weerasooriya, Charles A. Park
  • Patent number: 7653983
    Abstract: A manufacturing assembly is disclosed for manufacturing a disk drive. The manufacturing assembly comprises a pre-merge arm having a contact surface for contacting an actuator arm of the disk drive, and an actuator operable to actuate the pre-merge arm. When installing the actuator arm into the base of the disk drive, the actuator is operable to actuate the pre-merge arm in a first direction so that the contact surface biases the actuator arm rotationally about a pivot to bias the lift tab away from the ramp. After installing the actuator arm into the base of the disk drive, the actuator is operable to actuate the pre-merge arm in a second direction opposite the first direction so that the lift tab moves towards and contacts a ramp near an outer periphery of a disk.
    Type: Grant
    Filed: June 26, 2007
    Date of Patent: February 2, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventor: Andrew S. Klassen
  • Patent number: 7653927
    Abstract: The present invention may be regarded as personal video recorder and a method of selecting a pay per view program to be transmitted to a personal video recorder having a program receiver. A schedule of pay per view programs is obtained. Each of the pay per view programs has a title and at least one transmission time and an associated transmission channel for each transmission time. A title list comprising the titles of at least one pay per view program is generated based on the schedule. The title list is provided to a display device for display to a user. A selection by title of the pay per view program to be received by the program receiver is received from the user. A potential transmission time of the pay per view program to be received by the program receiver is determined based on the at least one transmission time. Alternatively, selection of the pay per view program to be received by the program receiver may be based on user's preferences or a pre-selected list of titles.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: January 26, 2010
    Assignee: Keen Personal Media, Inc.
    Inventors: L. Jeffrey Kapner, III, Timothy J. Elliott, Peter J. Schwartz
  • Patent number: 7649704
    Abstract: A disk drive is disclosed including a disk having a plurality of tracks, and a head actuated over the disk. A refresh monitor is maintained for refreshing data stored on the disk. A need for a refresh operation is detected when the refresh monitor exceeds a first threshold, wherein the refresh operation is deferred based on an environmental condition.
    Type: Grant
    Filed: June 27, 2007
    Date of Patent: January 19, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: Marc A. Bombet, William B. Boyle
  • Patent number: 7647544
    Abstract: A disk drive is disclosed comprising a disk, a buffer memory, and control circuitry operable to receive a write command from a host, wherein the write command comprises write data and a write data address. Write EDC data is generated in response to the write data and the write data address, wherein the write data and the write EDC data are stored in the buffer memory. The write data is read from the buffer memory, and write check data is generated in response to the write data and the write data address. The write EDC data is read from the buffer memory and compared to the write check data to detect a write error. If the write error is not detected, the write data is written to the disk without writing the write EDC data to the disk.
    Type: Grant
    Filed: November 22, 2005
    Date of Patent: January 12, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventor: John C. Masiewicz
  • Patent number: 7630162
    Abstract: A method is disclosed for selecting a dynamic fly height (DFH) control setting for a head in a disk drive, the disk drive comprising a plurality of disk surfaces and plurality of respective heads. The method comprises servoing a first head over a first disk surface in response to servo data recorded on the first disk surface, adjusting a DFH control setting for a second head, and while servoing the first head over the first disk surface, detecting whether the second head has contacted a second disk surface.
    Type: Grant
    Filed: February 4, 2008
    Date of Patent: December 8, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventors: Hongchao Tim Zhao, Jiangang Liang
  • Patent number: 7626782
    Abstract: A disk drive is disclosed operable to seek a head from a first radial location over a disk to a second radial location over the disk. A reference signal is initialized, a feed-forward control signal is initialized, and a seek is initiated. During the seek operation, a position error signal (PES) is generated and saved, wherein the PES represents a position error of the head relative to the reference signal. The PES is filtered with a compensation filter to generate a feed-back control signal. The feed-back control signal is combined with the feed-forward control signal to generate a VCM control signal. When the seek is done, the saved PES is processed using an iterative learning control (ILC) algorithm to adjust at least one of the reference signal and the feed-forward control signal.
    Type: Grant
    Filed: July 23, 2008
    Date of Patent: December 1, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jie Yu, Kuang-Yang Tu, Young-Hoon Kim, Wei Xi
  • Patent number: 7619844
    Abstract: A disk drive is disclosed including a disk having a plurality of servo sectors that define a plurality of servo tracks, an actuator arm, a head attached to a distal end of the actuator arm, a mechanical position sensor operable to detect an estimated position of the actuator arm, and a voice coil motor for rotating the actuator arm about a pivot. The disk drive further comprises control circuitry operable to process the servo sectors to generate a control signal applied to the voice coil motor, detect an estimated velocity of the actuator arm, detect a runaway condition in response to the estimated position of the actuator arm and the estimated velocity of the actuator arm, and adjust the control signal applied to the voice coil motor if the runaway condition is detected.
    Type: Grant
    Filed: December 30, 2005
    Date of Patent: November 17, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7619841
    Abstract: A disk drive is disclosed including a disk having a plurality of data tracks, wherein each data track comprises a plurality of data sectors and a plurality of servo sectors, and each servo sector comprises a plurality of servo bursts. A data path comprising a data decoder decodes a data read signal generated as a head passes over the data sectors, and a servo path demodulates a servo read signal generated as the head passes over the servo bursts. The servo path comprises a low pass filter operable to extract a low frequency component from the servo read signal, wherein the low pass filter does not operate on the data read signal. The servo path further comprises a subtractor operable to subtract the low frequency component from the servo read signal to generate a servo burst signal, and a servo demodulator operable to demodulate the servo burst signal.
    Type: Grant
    Filed: November 23, 2005
    Date of Patent: November 17, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventor: Hanan Kupferman
  • Patent number: 7602575
    Abstract: A disk drive is disclosed comprising control circuitry for self servo writing a disk. An estimated reader/writer offset is initialized, servo bursts in a first servo track are read, the head is moved radially using the estimated reader/writer offset, and propagated servo bursts are written to a target servo track. The propagated servo bursts are read from the target servo track to generate a read signal, the read signal is processed to generate a burst crossing signal (BCS), and the estimated reader/writer offset is adjusted in response to the BCS.
    Type: Grant
    Filed: May 14, 2008
    Date of Patent: October 13, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventors: Yakov M. Lifchits, Lawrence M. Bryant, Siri S. Weerasooriya, Wing Ying
  • Patent number: 7599139
    Abstract: A disk drive is disclosed including a disk having a plurality of tracks, and a head actuated over the disk. A write frequency of write data received from a host is monitored. When the write frequency falls below a threshold, the disk drive is configured to operate in a low frequency access mode when accessing the disk, wherein a parameter of the disk drive is configured to increase the reliability of the disk drive. When the write frequency rises above a threshold, the disk drive is configured to operate in a high frequency access mode when accessing the disk, wherein the parameter of the disk drive is configured to increase the performance of the disk drive.
    Type: Grant
    Filed: June 22, 2007
    Date of Patent: October 6, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventors: Marc A. Bombet, William B. Boyle
  • Patent number: 7583470
    Abstract: A disk drive is disclosed including a disk having a plurality of tracks, wherein each track comprises a plurality of servo sectors. The disk drive further comprises a head having a read element offset from a write element by a reader/writer offset. The read element is positioned over a first track and the write element is positioned over a second track. A first servo control signal is generated for servoing the head in response to the servo sectors in the first track, and first wedge repeatable runout (RRO) data is written to the second track along a substantially sinusoidal path corresponding to the reader/writer offset, wherein the first wedge RRO data are for writing data to a third track.
    Type: Grant
    Filed: August 29, 2007
    Date of Patent: September 1, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventors: Teddy T.C. Chen, Guoxiao Guo, Kuang-Yang Tu