Patents by Inventor Thomas Charles Christensen

Thomas Charles Christensen 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: 6040955
    Abstract: A self servo writing file and method for writing servo patterns in a direct access storage device are provided. First servo information is written on a data storage media at a first crash stop. The transducer heads are moved offset from the written servo information while reading the last written servo information until the detected servo signal equals a predetermined value. Then servo information is written on the data storage media responsive to the detected servo signal equal to the predetermined value. The moving and writing steps are sequentially repeating until a second crash stop is reached. A quad-burst servo amplitude pattern or phase pattern can be used for the servo information. The servo writing method is adapted easily for many different servo options. When the file uses a hybrid servo or sector servo, the other surfaces can be written by duplicating the servo bursts with a high bandwidth servo system of the file.
    Type: Grant
    Filed: August 8, 1994
    Date of Patent: March 21, 2000
    Assignee: International Business Machines Corporation
    Inventors: Dana Henry Brown, Thomas Charles Christensen, Earl A. Cunningham, Wayne A. Rogelstad
  • Patent number: 6014277
    Abstract: A multipath channel apparatus for a data storage device wherein data is stored on a storage medium and is read from the storage medium by a transducer or for a data communications system wherein data is transmitted to a receiver. A data channel having a plurality of data paths is operatively connected to the transducer to receive data read from the storage medium by the transducer, or operatively connected to receive data demodulated by the receiver or base band data received by the receiver. Preferably, each of the data paths has a differing parameter value. An error checking unit checks customer and redundancy data from each of the data paths. A selecting unit, which is responsive to the error checking unit, selects data from one of the data paths. In a preferred embodiment, the data stored on a storage medium includes a data field and an error correcting code field, and the customer and redundancy data from each of the data paths is checked using a calculated error correcting code sydrome.
    Type: Grant
    Filed: May 8, 1996
    Date of Patent: January 11, 2000
    Assignee: International Business Machines Corporation
    Inventors: Thomas Charles Christensen, Earl Albert Cunningham
  • Patent number: 5949603
    Abstract: A self servo writing file and method for writing servo patterns in a direct access storage device are provided. First servo information is written on a data storage media at a first crash stop. The transducer heads are moved offset from the written servo information while reading the last written servo information until the detected servo signal equals a predetermined value. Then servo information is written on the data storage media responsive to the detected servo signal equal to the predetermined value. The moving and writing steps are sequentially repeated until a second crash stop is reached. A quad-burst servo amplitude pattern or phase pattern can be used for the servo information. The servo writing method is adapted easily for many different servo options. When the file uses a hybrid servo or sector servo, the other surfaces can be written by duplicating the servo bursts with a high bandwidth servo system of the file.
    Type: Grant
    Filed: January 4, 1999
    Date of Patent: September 7, 1999
    Assignee: International Business Machines Corporation
    Inventors: Dana Henry Brown, Thomas Charles Christensen, Earl A. Cunningham, Wayne A. Rogelstad
  • Patent number: 5923502
    Abstract: A magnetic head including a shielded MR element which incorporates a low reluctance path between the shields to reduce interference picked up by inductive reading of the shields. The low reluctance path is provided outside a conductive loop of material which includes the MR element and its associated leads. The low reluctance path may include a magnetic short between the two shields.
    Type: Grant
    Filed: December 21, 1995
    Date of Patent: July 13, 1999
    Assignee: International Business Machines Corporation
    Inventors: Thomas Charles Christensen, Jodie Ann Christner, Earl Albert Cunningham, Jay Michael Mosbrucker