Patents by Inventor David M. Oldham

David M. Oldham 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: 5018126
    Abstract: A magnetooptic recorder player provides for residual data checking and media defect checking. Media defect checking is effected by comparing the reflected light intensity of a modulated optical beam with the input data characteristics. A difference between the input data and the detected light intensities represents asperities in the record media. Residual data is checked by selectively gating MO detected signals during recording, which are intermediate the high intensity light beam pulses used for recording signals. Both the detected residual data and detected media asperities are counted for each addressable record storage area on the medium.
    Type: Grant
    Filed: April 4, 1990
    Date of Patent: May 21, 1991
    Assignee: International Business Machines Corporation
    Inventors: John E. Kulakowski, Rodney J. Means, David M. Oldham, Morovat Tayefeh
  • Patent number: 4941139
    Abstract: A magnetooptic recorder player provides for residual data checking and media defect checking. Media defect checking is effected by comparing the reflected light intensity of a modulated optical beam with the input data characteristics. A difference between the input data and the detected light intensities represents asperities in the record media. Residual data is checked by selectively gating MO detected signals during recording, which are intermediate the high intensity light beam pulses used for recording signals. Both the detected residual data and detected media asperities are counted for each addressable record storage area on the medium.
    Type: Grant
    Filed: September 2, 1988
    Date of Patent: July 10, 1990
    Assignee: International Business Machines Corporation
    Inventors: John E. Kulakowski, Rodney J. Means, David M. Oldham, Morovat Tayefeh
  • Patent number: 4937800
    Abstract: In method of operating a magnetic recorder, magnetooptic, for example, the erasure direction for successive recording areas (sectors) are determined by the direction of magnetization of prior recording. When the erasure direction is reversed, the direction of remanent magnetiaztion indicating a "non-erasure", record or information representing direction is also reversed. A mark is placed in each sector for identifying its erasure direction.
    Type: Grant
    Filed: August 10, 1988
    Date of Patent: June 26, 1990
    Assignee: International Business Machines Corporation
    Inventor: David M. Oldham
  • Patent number: 4916680
    Abstract: In a magnetooptic record member the erasure direction for successive recording areas (sectors) are determined by the direction of magnetization of prior recording. A mark is placed in each sector for identifying its erasure direction. The mark is preferably a sequence of longer ones, of one-half wavelengths appearing in the recorded information-bearing signals. The erasure and recording directions are reversed such that in the recording direction in a successive recording area equal to the erasure direction of a proceeding area. This selection is based upon the current direction of a magnetic steering field.
    Type: Grant
    Filed: August 10, 1988
    Date of Patent: April 10, 1990
    Assignee: International Business Machines Corporation
    Inventor: David M. Oldham
  • Patent number: 4789972
    Abstract: In a magnetic recorder, magnetooptic, for example, the erasure dircetion for successive recording areas (sectors) are determined by the direction of magnetization of prior recording. A mark is placed in each sector for identifying its erasure direction.
    Type: Grant
    Filed: December 22, 1986
    Date of Patent: December 6, 1988
    Assignee: International Business Machines Corporation
    Inventor: David M. Oldham