Patents by Inventor Michael E. Hammersley

Michael E. Hammersley 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).

  • Disc drive error mapping using threshold comparison methods
    Patent number: 4949036
    Abstract: An apparatus and method for testing a variety of hard disk drives is disclosed. The apparatus includes a computer connected to a control board and an interface board. The interface board is connected to a testing board. The hard disk drive is connected to the control board and testing board. The hard disk is tested by first erasing a track of data bits at full write current in one direction or polarity and second erasing the track at minimal write current in the opposite direction. The track is read and compared to a predetermined threshold and any level exceeding the threshold is considered defective.
    Type: Grant
    Filed: July 7, 1988
    Date of Patent: August 14, 1990
    Assignee: Seagate Technology, Inc.
    Inventors: David J. Bezinque, Mark R. McCornack, Michael E. Hammersley