Patents Represented by Attorney, Agent or Law Firm Milad G. Shara
  • Patent number: 7099099
    Abstract: The invention may be embodied in a disk drive for use in a mobile device. The mobile device may be a hand held computing device such as a personal digital assistant (PDA) or a mobile terminal such as a cellular telephone. The mobile device includes a host processor for accessing data on the disk drive. The disk drive has a rotating disk media and a moveable read/write head disposed over the disk media. The disk media is divided into a first data storage zone and a second data storage zone. The data storage zones are radially disposed in discrete areas of the disk media and each zone has a plurality of tracks for storing data. The mobile device may read data from the first data storage zone when the mobile device is in a mobile environment. The mobile device may read data from the second data storage zone only when the mobile device is in a non-mobile environment and may not read data from the second data storage zone when the mobile device is in a mobile environment.
    Type: Grant
    Filed: April 30, 2001
    Date of Patent: August 29, 2006
    Assignee: Western Digital Technologies, Inc.
    Inventors: Raffi Codilian, Anil Sareen, Thomas D. Hanan
  • Patent number: 7050252
    Abstract: A disk drive is disclosed wherein if multiple retries beyond a threshold are required to recover a data sector during a normal read operation, the data sector is added to a marginal sector list. During an off-line scan, the data sectors in the marginal sector list are verified. If the verification of a data sector fails, the data sector is relocated.
    Type: Grant
    Filed: June 1, 2002
    Date of Patent: May 23, 2006
    Assignee: Western Digital Technologies, Inc.
    Inventor: Mark F. Vallis
  • Patent number: 7006320
    Abstract: A disk drive is disclosed comprising an interface for receiving a primary supply voltage and a secondary supply voltage from a host computer. The primary supply voltage is applied to the windings of a multi-phase spindle motor in a commutation sequence, and the secondary supply voltage is connectable to a center tap of the windings.
    Type: Grant
    Filed: July 31, 2002
    Date of Patent: February 28, 2006
    Assignee: Western Digital Technologies, Inc.
    Inventors: George J. Bennett, Charles R. Patton, III
  • Patent number: 6996501
    Abstract: A disk drive is disclosed for executing a drive operating program and a manufacturing program during a manufacturing process. An external test system executes a test program comprising platform independent executable code segments and host interface executable code segments. The external test system for executing the host interface executable code segments to send disk commands to a development drive. The manufacturing program comprises the platform independent executable code segments of the test program and disk access executable code segments. The drive operating program comprises a disk access procedure for processing disk commands and a disk access vector for calling the disk access procedure. The disk access executable code segments of the manufacturing program execute disk commands by calling the disk access procedure of the drive operating program through the disk access vector.
    Type: Grant
    Filed: December 24, 2002
    Date of Patent: February 7, 2006
    Assignee: Western Digital Technologies, Inc.
    Inventor: Michael S. Rothberg
  • Patent number: 6996669
    Abstract: The present invention relates to a disk drive including a cache memory having a plurality of sequentially-ordered memory clusters for caching disk data stored in sectors (not shown) on disks of a disk assembly. The disk sectors are identified by logical block addresses (LBAs). A cache control system of the disk drive comprises a cluster control block memory, having a plurality of cluster control blocks (CCB), and a tag memory 22, having a plurality of tag records, that are embedded within the cache control system. Each CCB includes a cluster segment record with an entry for associating the CCB with a particular memory cluster and for forming variable length segments of the memory clusters without regard to the sequential order of the memory clusters. Each tag record assigns a segment to a continuous range of LBAs and defines the CCBs forming the segment. Each segment of the memory clusters is for caching data from a contiguous range of the logical block addresses.
    Type: Grant
    Filed: July 28, 2003
    Date of Patent: February 7, 2006
    Assignee: Western Digital Technologies, Inc.
    Inventors: Quoc N. Dang, Tsun Y. Ng, Ralph H. Castro, Virgil V. Wilkins
  • Patent number: 6992848
    Abstract: A method of writing product servo bursts to a disk in a disk drive is disclosed. An external spiral servo writer comprising a head positioning pin and head positioning mechanics periodically writes a plurality of reference servo bursts in a plurality of spiral reference patterns to the disk. The reference servo bursts in the spiral reference patterns are processed to write product servo bursts to the disk. In one embodiment control circuitry within the disk drive processes the reference servo bursts to self-servo write the disk drive, and in another embodiment an external product servo writer processes the reference servo bursts to write the product servo bursts to the disk. In one embodiment, a slope of each spiral reference pattern is selected so that each spiral reference pattern is written over at least twenty revolutions of the disk to increase the accuracy of the head position error generated from the reference servo bursts.
    Type: Grant
    Filed: March 29, 2002
    Date of Patent: January 31, 2006
    Assignee: Western Digital Technologies, Inc.
    Inventors: Vinay K. Agarwal, Robert L. Cloke
  • Patent number: 6965489
    Abstract: A method of writing product servo sectors to a disk of a disk drive is disclosed. An external spiral servo writer writes a plurality of reference servo sectors at an outer diameter of the disk and a plurality of spiral tracks that spiral from an outer diameter to an inner diameter of the disk. At the beginning of the product servo writing process, the reference servo sectors are demodulated to initially synchronize a servo write clock. The spiral tracks are then demodulated to maintain synchronization of the servo write clock as well as maintain the head along a target circumferential path while writing product servo sectors to the disk.
    Type: Grant
    Filed: January 31, 2004
    Date of Patent: November 15, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Tehri S. Lee, Robert L. Cloke, Siri S. Weerasooriya
  • Patent number: 6965966
    Abstract: A disk drive is disclosed which pre-computes first seek parameters to seek to a continuation track storing read-ahead data, and second seek parameters to seek to a target track of a next command. An abort window is also computed for aborting a read-ahead operation early in order to seek to the target track of the next command. If the head enters the abort window, the disk drive is programmed with the second seek parameters to seek to the target track of the next command. If the read-ahead operation requires a seek to the continuation track prior to the head entering the abort window, the disk drive is programmed with the first seek parameters to seek to the continuation track.
    Type: Grant
    Filed: October 31, 2002
    Date of Patent: November 15, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Michael S. Rothberg, Jonathan V. Nguyen, Gregory B. Thelin
  • Patent number: 6947251
    Abstract: A disk drive includes a disk, a voltage supply, a head stack assembly and a switching circuit. The head stack may include a coil portion that includes a coil assembly having first and second wound coils. The switching circuit is electrically coupled to the voltage supply and to the coil assembly, and is configured to selectively switch the first and second wound coils between a first configuration and a second different configuration in which the first wound coil is electrically in parallel with the second wound coil.
    Type: Grant
    Filed: November 26, 2003
    Date of Patent: September 20, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kamran Oveyssi, Raffi Codilian
  • Patent number: 6948165
    Abstract: The present invention may be embodied in a method, performed in a computer system having a disk drive, for installing an application program for execution under a user's preferred operating system without requiring user intervention. A command is received by the disk drive for reading a first data block to initiate a bootload of the user's preferred operating system. The disk drive detects the command and transfers a second data block which bootloads an installer program for installing the application program. The installer program is executed in the computer system to transfer the application program from a protected area of the disk drive to a user area of the disk drive, to modify a parameter of the user's preferred operating system to cause the application program to be loaded during a bootload of the user's preferred operating system, and to reboot the system to bootload the user's preferred operating system.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: September 20, 2005
    Assignee: Western Digital Ventures, Inc.
    Inventors: Vu V. Luu, Mark F. Vallis
  • Patent number: 6943978
    Abstract: A method of writing product servo sectors to a disk of a disk drive is disclosed. A plurality of spiral tracks are written to the disk, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. During the product servo writing process, the sync marks in the spiral tracks are read to generate a coarse timing recovery measurement, and the high frequency signal in the spiral tracks is read to generate a fine timing recovery measurement. The coarse and fine timing recovery measurements are processed to synchronize a servo write clock used to write the product servo sectors to the disk. In one embodiment the control circuitry within the disk drive synchronizes the servo write clock by reading the spiral tracks, and in an alternative embodiment an external product servo writer synchronizes the servo write clock by reading the spiral tracks.
    Type: Grant
    Filed: January 31, 2004
    Date of Patent: September 13, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventor: Tehri S. Lee
  • Patent number: 6934126
    Abstract: A disk drive comprises a housing including a base; a disk rotatably attached to the base; a printed circuit board coupled to the base and including a plurality of circuit board pads; a head stack assembly pivotally coupled to the base about a pivot axis and a flex-to-board connector. The head stack assembly includes a head for reading and writing to the disk and a flex cable assembly that includes a flexible film including a plurality of conductive traces that are electrically coupled to the head. The flexible film includes a connecting portion in which each of the plurality of conductive traces defines a trace pad. Each trace pad is disposed on a surface of the flexible film that is generally parallel to the pivot axis. The flex-to-board connector is attached to the base and is configured to couple to the connecting portion of the flexible film and to maintain the surface of the flexible film on which the trace pads are disposed in an orientation that is generally parallel to the pivot axis.
    Type: Grant
    Filed: December 23, 2002
    Date of Patent: August 23, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Keith R. Berding, Shawn E. Casey
  • Patent number: 6934135
    Abstract: A disk drive is disclosed comprising a spindle motor for rotating a disk and a voice coil motor (VCM) for actuating a head over the disk. The spindle motor comprises a plurality of windings, and the VCM comprises a voice coil. If the current flowing from a supply voltage exceeds a threshold, the windings are disconnected from the supply voltage, the voice coil is disconnected from the supply voltage, and the first and second ends of the voice coil are connected to ground.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: August 23, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventor: Robert P. Ryan
  • Patent number: 6931439
    Abstract: A method of operating a mobile terminal comprising a local memory and a screen is disclosed. Web pages are received by the mobile terminal and stored in the local memory. A cache status of each web page identified by each link is determined, wherein the cache status is evaluated to control the display of the links of a web page on the screen of the mobile terminal.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: August 16, 2005
    Assignee: Western Digital Ventures, Inc.
    Inventors: Jonathan Lee Hanmann, Anil Sareen, Kenneth J. Smith
  • Patent number: 6928470
    Abstract: A network switch is disclosed for resolving requests from a plurality of host initiators by scheduling access to a plurality of disk storage devices. The network switch comprises a switched fabric comprising a plurality of switching elements. Each switching element comprises a plurality of bi-directional switched fabric ports, and a control input connected to receive switch control data for selectively configuring the switching element in order to interconnect the bi-directional switched fabric ports. The network switch further comprises a memory for storing a routing and scheduling program, and a microprocessor, responsive to the requests, for executing the steps of the routing and scheduling program to generate the switch control data to transmit scheduled requests through the bi-directional switched fabric ports. At least one of the plurality of switching elements comprises a disk storage interface for connecting to a selected one of the disk storage devices.
    Type: Grant
    Filed: July 31, 2000
    Date of Patent: August 9, 2005
    Assignee: Western Digital Ventures, Inc.
    Inventor: Christopher L. Hamlin
  • Patent number: 6924961
    Abstract: A method is disclosed for writing servo patterns for tracks on a rotating magnetic disk medium of a disk drive. Servo patterns are written on a reference track of the disk medium. Track following of the written servo patterns on the reference track is performed using a servo loop having a closed-loop response. A position error signal is generated for the reference track based on the track following. A correction signal is generated based on the track following using an observer of a one-dimensional state model that is equivalent to a two-dimensional state model of the servo loop. Servo patterns are written on a target track during track following of the reference track. The position error signal of the servo loop is adjusted based on the correction signal to reduce radial error propagation from the reference track to the target track.
    Type: Grant
    Filed: August 30, 2002
    Date of Patent: August 2, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Hemant Melkote, Robert L. Cloke, Vinay K. Agarwal
  • Patent number: 6920004
    Abstract: The present invention may be embodied in a method for adjusting a servo sector detection delay time between detection windows in a disk drive. The disk drive includes a magnetic disk with a spiral track having contiguous storage segments. Each storage segment has a servo sector and a predetermined number of uniformly-sized data sectors. The storage segments are written at a relatively constant linear density along the spiral track. In the method, the magnetic disk is rotated at a constant angular velocity. A servo sector is detected. An adjustable delay time is provided for opening a window to detect a next servo sector. The window is opened after the adjustable delay time expires. A next servo sector is detected in the window. A time between the servo sector detections is measured and the adjustable delay time is adjusted based on the measured time.
    Type: Grant
    Filed: March 29, 2002
    Date of Patent: July 19, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Raffi Codilian, Charles W. Frank, Jr.
  • Patent number: 6914743
    Abstract: Disclosed is a disk drive using an accelerometer to sense linear vibration and cancel its effects with an adaptive algorithm during track following. The accelerometer is oriented to detect acceleration associated with torque that tends to cause the actuator to move off-track notwithstanding the efforts of the servo control system. The accelerometer's filtered output is used to modify the control effort. The disk drive uses the position error signal to adaptively filter the accelerometer's output in an effort to mathematically converge on a set of optimal filter coefficients and thereby reduce the effect of vibration that may otherwise impose a torque on the actuator.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: July 5, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Aswartha Narayana, Raffi Codilian, Lan V. Ngo
  • Patent number: 6914740
    Abstract: A disk drive is disclosed employing either back electromotive force (BEMF) spindle speed control or wedge spindle speed control. The BEMF spindle speed control is used to calibrate a reference time period representing an accumulation of a predetermined number of wedge-to-wedge times. During wedge spindle speed control, a wedge time period representing an accumulation of a predetermined number of wedge-to-wedge times is measured, and a wedge speed error is computed as the difference between the reference time period and the wedge time period.
    Type: Grant
    Filed: November 26, 2003
    Date of Patent: July 5, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kuang-Yang Tu, Chuanwen Ji
  • Patent number: 6910099
    Abstract: A disk drive is disclosed which receives a read command from a host computer, the read command comprising a command size representing a number of blocks of read data to read from the disk. A number M of cache segments are allocated from a cache buffer, wherein each cache segment comprises N blocks. The number M of allocated cache segments is computed by summing the command size with a predetermined default number of read-ahead blocks to generate a summation, and integer dividing the summation by N leaving a residue number of default read-ahead blocks. In one embodiment, the residue number of default read-ahead blocks are not read, in another embodiment the residue number of default read-ahead blocks are read if the residue number exceeds a predetermined threshold, and in yet another embodiment the number of read-ahead blocks is extended so that the summation divides evenly by N.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: June 21, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Ming Y. Wang, Gregory B. Thelin