Patents by Inventor Jai N. Subrahmanyam

Jai N. Subrahmanyam has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6972922
    Abstract: A disk drive includes a sampled servo controller for periodically adjusting a control effort signal during a track-following operation based on embedded distributed position information and repeatable runout (RRO) cancellation values for reducing effects of RRO in the distributed position information during track following. A magnetic disk in the disk drive stores RRO information relating to predetermined RRO cancellation values for a data storage track. The RRO information for the data storage track includes at least one first data structure having a first predetermined number of data bits for representing an initial RRO cancellation value, and includes at least one second data structure having a second predetermined number of data bits associated with a respective subsequent RRO cancellation value. The first predetermined number of data bits is greater than the second predetermined number of data bits.
    Type: Grant
    Filed: February 7, 2003
    Date of Patent: December 6, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jai N. Subrahmanyam, Jack M. Chue, Robert J. McNab
  • Patent number: 6972930
    Abstract: A Head Gimbal Assembly (HGA) for use in a disk drive and comprising an ESD-protected slider comprising a head formed on a slider substrate. The slider may comprise an electrical-isolation circuit; an electrically-resistive path between head input connections and the slider; or both isolation circuits and resistive paths for reducing electrostatic charge on the slider while remaining connected during disk drive operations.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: December 6, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kathy X. Tang, Jai N. Subrahmanyam, Rahmat Karimi
  • Patent number: 6941642
    Abstract: Disclosed is a head stack load comb used in the controlled loading of a head of a head stack assembly (HSA) onto a disk during the assembly of a disk drive. The HSA includes an actuator arm, a head, and a loading surface. The load comb includes a base structure and at least one ramp finger projecting approximately perpendicularly from the base structure. In order to load the head in a controlled manner onto the disk, the loading surface of the HSA is rotated along the ramp finger until the head is in a load position and then the base structure is actuated in a vertical direction such that the ramp finger is correspondingly actuated in the vertical direction towards the disk until the head is loaded onto the disk.
    Type: Grant
    Filed: December 24, 2002
    Date of Patent: September 13, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jai N. Subrahmanyam, Serge Hauert
  • Patent number: 6862154
    Abstract: Disclosed is a ramp used for the controlled loading of a head of a head stack assembly (HSA) onto a disk of a disk drive. The HSA includes an actuator arm, a head, and a loading surface. The ramp comprises a base structure and at least one ramp finger projecting approximately perpendicularly from the base structure. In order to load the head in a controlled manner onto the disk, the loading surface of the HSA is rotated along the ramp finger until the head is in a load position. The base structure is then actuated in a vertical direction such that the ramp finger is correspondingly actuated in the vertical direction towards the disk until the head is loaded onto the disk.
    Type: Grant
    Filed: December 24, 2002
    Date of Patent: March 1, 2005
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jai N. Subrahmanyam, Serge Hauert
  • Patent number: 6826003
    Abstract: A disk drive is disclosed comprising a disk and a head actuated radially over the disk. A pattern detector detects a predetermined pattern in write data to be written to the disk, and in response, adjusts a write current overshoot in a write current applied to the head.
    Type: Grant
    Filed: January 31, 2002
    Date of Patent: November 30, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventor: Jai N. Subrahmanyam
  • Patent number: 6801402
    Abstract: A Head Gimbal Assembly (HGA) for use in a disk drive and further includes a head having a read element and a write element; and a Trace Gimbal Assembly (TGA) attached to the head. The TGA includes a conductor array having a first end connected to the read element and the write element and a distal end for connecting the read element and the write element to a signal processing circuit, a conductive substrate supporting the head and the conductor array and a dielectric layer disposed between the conductor array and the conductive substrate. The TGA further includes a shunt connected at the distal end for shunting the read element; and an anti-static coating, covering a substantial portion of the conductor array for neutralizing electrostatic charge accumulation on the conductor array.
    Type: Grant
    Filed: October 31, 2002
    Date of Patent: October 5, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jai N. Subrahmanyam, Darrell D. Palmer, Jack M. Chue