Patents by Inventor Kezhao Zhang

Kezhao Zhang 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: 8395857
    Abstract: Approaches for a testing device for selecting a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). The testing device comprises a continuous magnetic-recording disk, rotatably mounted on a spindle, which stores data using a continuous media format. The testing device also comprises a testing module configured to simulate reading data, stored using a discrete track media (DTM) format, from the continuous magnetic-recording medium. Advantageously, testing time and cost is reduced as both discrete track media (DTM) disks and expensive discrete track media (DTM) recording testing hardware are not required to select the optimal a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). In addition, embodiments may be used to optimize features of the tracks of the DTM disk, such as the land to groove ratio.
    Type: Grant
    Filed: November 8, 2010
    Date of Patent: March 12, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Kezhao Zhang, Jizhong He, Shanlin Duan, Jane Jie Zhang, Zhupei Shi
  • Publication number: 20120113538
    Abstract: Approaches for a testing device for selecting a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). The testing device comprises a continuous magnetic-recording disk, rotatably mounted on a spindle, which stores data using a continuous media format. The testing device also comprises a testing module configured to simulate reading data, stored using a discrete track media (DTM) format, from the continuous magnetic-recording medium. Advantageously, testing time and cost is reduced as both discrete track media (DTM) disks and expensive discrete track media (DTM) recording testing hardware are not required to select the optimal a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). In addition, embodiments may be used to optimize features of the tracks of the DTM disk, such as the land to groove ratio.
    Type: Application
    Filed: November 8, 2010
    Publication date: May 10, 2012
    Inventors: Kezhao Zhang, Jizhong He, Shanlin Duan, Jane Jie Zhang, Zhupei Shi
  • Patent number: 8174783
    Abstract: Magnetic disk drive systems and associated methods are described for testing magnetic disk performance for certification with a plurality of magnetic disk drive systems prior to installation. The test system may position a slider at a first spacing between the magnetic disk in the slider and simulate the recording performance of a disk drive system with the magnetic disk at the first spacing. The disk drive test system may then transfer a control signal to a heating element in the slider to move the slider to a different spacing between the magnetic disk and the slider to simulate the recording performance of another disk drive system. The test system may, thus, use a single slider to certify a magnetic disk with a plurality of disk drive systems.
    Type: Grant
    Filed: July 23, 2009
    Date of Patent: May 8, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Shanlin Duan, Zhen Jin, Jane Jie Zhang, Kezhao Zhang
  • Patent number: 8102613
    Abstract: Track pitch in a hard disk drive is selected to satisfy the requirements of both off-track capacity (OTC) and adjacent track interference (ATI). The invention separately measures the track pitch requirements for OTC and ATI. The track pitch for the drive is set with the larger of the OTC and ATI track pitches. The OTC track pitch is measured with a 747 curve, and the ATI track pitch is measured by the positions of adjacent tracks at which the on-track error rate is not worse than a given value after the targeted number of adjacent track writes in the ATI requirement.
    Type: Grant
    Filed: September 25, 2009
    Date of Patent: January 24, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Shanlin Duan, Zhen Jin, Jane Jie Zhang, Kezhao Zhang
  • Patent number: 7969675
    Abstract: Methods and test systems are disclosed for determining the quality of an erase process for perpendicular magnetic recording (PMR) disks. After performing an erase process on a PMR disk and before the PMR disk is assembled into a hard disk drive, a first test pattern of magnetization pulses is written to a region of the PMR disk. A second test pattern is subsequently read from the region of the PMR disk. The second pattern of magnetization pulses is analyzed in relation to the first test pattern and measured to determine the quality of the erase process.
    Type: Grant
    Filed: November 7, 2008
    Date of Patent: June 28, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Shanlin Duan, Zhupei Shi, Jane Jie Zhang, Kezhao Zhang
  • Publication number: 20110075286
    Abstract: Track pitch in a hard disk drive is selected to satisfy the requirements of both off-track capacity (OTC) and adjacent track interference (ATI). The invention separately measures the track pitch requirements for OTC and ATI. The track pitch for the drive is set with the larger of the OTC and ATI track pitches. The OTC track pitch is measured with a 747 curve, and the ATI track pitch is measured by the positions of adjacent tracks at which the on-track error rate is not worse than a given value after the targeted number of adjacent track writes in the ATI requirement.
    Type: Application
    Filed: September 25, 2009
    Publication date: March 31, 2011
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Shanlin Duan, Zhen Jin, Jane Jie Zhang, Kezhao Zhang
  • Publication number: 20100134911
    Abstract: A method for optimizing design parameters of a magnetic write head. The method involves compiling a table of data points for a plurality of design parameters. An experimentally derived optimal design point is determined a first set of tests are performed at this experimentally determined design point. A three dimensional response surface is generated based on the testing. Then, a projected optimal design point is determined from the three dimensional response surface. Another test is performed using this projected optimal design point, and a convergence is determined by comparing the results of the first and second tests. If the convergence is within a predetermined value, then the process is complete. If the convergence is not within the predetermined value, then the process is repeated using the most recent projected optimal design point.
    Type: Application
    Filed: December 2, 2008
    Publication date: June 3, 2010
    Inventors: Zhen Jin, Kezhao Zhang
  • Publication number: 20100118423
    Abstract: Methods and test systems are disclosed for determining the quality of an erase process for perpendicular magnetic recording (PMR) disks. After performing an erase process on a PMR disk and before the PMR disk is assembled into a hard disk drive, a first test pattern of magnetization pulses is written to a region of the PMR disk. A second test pattern is subsequently read from the region of the PMR disk. The second pattern of magnetization pulses is analyzed in relation to the first test pattern and measured to determine the quality of the erase process.
    Type: Application
    Filed: November 7, 2008
    Publication date: May 13, 2010
    Inventors: Shanlin Duan, Zhupei Shi, Jane Jie Zhang, Kezhao Zhang
  • Patent number: 7170700
    Abstract: A method of determining side track erasure in a disk drive having a disk and a transducer. A target track and one or more side tracks proximate to the target track on the disk are selected, and recording parameters for recording signals on the target track and each side track with the transducer are selected. Thereafter, signals are recorded on each side track and then signals are recorded on the target track multiple times. A reduction in the integrity of the recorded signals on each side track due to recording signals on the target track multiple times is detected, and the detected reduction in the integrity of the recorded signals on each side track represents the amount of the erasure of the recorded signals on the side track. Recording parameters are changed based on the signal integrity reduction to minimize side track erasure.
    Type: Grant
    Filed: April 18, 2002
    Date of Patent: January 30, 2007
    Assignee: Maxtor Corporation
    Inventors: Gang H. Lin, Erhard Schreck, Kezhao Zhang, Don Brunnett, Duc Banh, Kurt Rusnak, Jingbo Yu, Suet Teo, Nick Warner, John Vicars