Patents by Inventor Hidetsugu Tanka

Hidetsugu Tanka 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).

  • Method and apparatus for detecting abnormal magnetic head fly height
    Patent number: 6671110
    Abstract: A method and apparatus for detecting an abnormal fly height of a magnetic head. The method includes reproducing a servo signal recorded on a magnetic disk in advance by the magnetic head when a write operation for writing data on the magnetic disk by the magnetic head is initiated. Next, the gain of the servo signal based on the head part of the servo signal reproduced by the magnetic head is determined. The gain of the servo signal is then compared with a reference value to detect an abnormal fly height of the magnetic head. In an advantageous embodiment, the reference value is the gain of a servo signal determined when the fly height of the magnetic head is normal. Alternatively, in other advantageous embodiments, the reference value is based on the gain of a previous servo signal.
    Type: Grant
    Filed: February 2, 2001
    Date of Patent: December 30, 2003
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Sachiyo Baba, Yukio Fukushima, Hidetsugu Tanka, Tetsuo Ueda
  • Method and apparatus for detecting abnormal magnetic head fly height
    Publication number: 20010013985
    Abstract: A method and apparatus for detecting an abnormal fly height of a magnetic head. The method includes reproducing a servo signal recorded on a magnetic disk in advance by the magnetic head when a write operation for writing data on the magnetic disk by the magnetic head is initiated. Next, the gain of the servo signal based on the head part of the servo signal reproduced by the magnetic head is determined. The gain of the servo signal is then compared with a reference value to detect an abnormal fly height of the magnetic head. In an advantageous embodiment, the reference value is the gain of a servo signal determined when the fly height of the magnetic head is normal. Alternatively, in other advantageous embodiments, the reference value is based on the gain of a previous servo signal.
    Type: Application
    Filed: February 2, 2001
    Publication date: August 16, 2001
    Applicant: International Business Machines Corporation
    Inventors: Sachiyo Baba, Yukio Fukushima, Hidetsugu Tanka, Tetsuo Ueda