Patents by Inventor John C. Purkett
John C. Purkett 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: 8891200Abstract: Apparatus and method for mitigating impedance changes in a microactuator conductive joint. In accordance with some embodiments, a microactuating element has a conductive input junction, the junction having dissimilar metals in contact with one another. The microactuating element is adapted to mechanically deform to displace a control object responsive to a micractuation control signal that is applied to the junction. A control circuit applies a bi-directional transition signal to the conductive input junction to reduce an increased impedance of the junction.Type: GrantFiled: June 24, 2013Date of Patent: November 18, 2014Assignee: Seagate Technology LLCInventors: John C. Purkett, David L. Schell, Robert A. Alt, KarWei Koay
-
Patent number: 7561370Abstract: Various embodiments of the present invention are generally directed to propagating repeated runout (RRO) correction values for radially concentric servo seams on a storage medium in relation to an RRO correction value for an adjacent seam and a radial separation between the seams.Type: GrantFiled: August 28, 2007Date of Patent: July 14, 2009Assignee: Seagate Technology LLCInventors: Thomas O. Melrose, Bruce Liikanen, John C. Purkett
-
Publication number: 20090059420Abstract: Various embodiments of the present invention are generally directed to propagating repeated runout (RRO) correction values for radially concentric servo seams on a storage medium in relation to an RRO correction value for an adjacent seam and a radial separation between the seams.Type: ApplicationFiled: August 28, 2007Publication date: March 5, 2009Applicant: Seagate Technology LLCInventors: THOMAS O. MELROSE, Bruce Liikanen, John C. Purkett
-
Patent number: 7193807Abstract: A disk drive provides increased read and write element widths and tolerances, and also provides reduced track widths. The head with the read and write elements has a large skew angle relative to the tracks on the disk. The skew angle reduces the effective width of the read and write elements. Based on this reduction in effective width, the physical width of the read and write elements may be increased. Furthermore, the width of the tracks may be reduced instead of, or in addition to, the increased read and write element width.Type: GrantFiled: September 17, 2001Date of Patent: March 20, 2007Assignee: Maxtor CorporationInventors: Bruce Liikanen, John C. Purkett, Terry Keefer
-
Patent number: 6606216Abstract: A magnetic storage system is disclosed which has one or more rotating disks. In one embodiment, the system includes a first transducer and a second transducer operatively associated with a respective first surface or second surface. Each of the first and second surfaces has a data track with a data region and an embedded servo sector. The first transducer has a data reader which includes a first MR strip and a servo reader which includes a second MR strip. The first MR strip is electrically isolated from the second MR strip. The first transducer performs a servo reading operation of the servo sector while the second a transducer performs either a data writing operation to the data region or a data reading operation from the data region. Also disclosed is a method for reading within a magnetic storage system. The storage system includes a first magnetic surface, a data reader and a servo reader. The first magnetic surface includes a first data region and a first servo sector.Type: GrantFiled: May 5, 1999Date of Patent: August 12, 2003Assignee: Maxtor CorporationInventors: Bruce A. Liikanen, Moris M. Dovek, John C. Purkett
-
Patent number: 6332207Abstract: An apparatus for correcting read errors in a disk drive is disclosed. In one embodiment, the apparatus includes circuitry for determining that an undesired distortion exists in a data signal read from a surface of a data storage disk; circuitry for finding an approximate starting location of said distortion within said data signal; and, circuitry for correcting errors in said data signal caused by said undesired distortion using said approximate starting location of said distortion. A method for correcting read errors in a disk drive is also disclosed.Type: GrantFiled: April 28, 2000Date of Patent: December 18, 2001Assignee: Maxtor CorporationInventors: Bobby Ray Southerland, Jin-Hong Hsueh, Lace J. Herman, John C. Purkett
-
Patent number: 6147827Abstract: An apparatus for correcting read errors in a disk drive is disclosed. In one embodiment, the apparatus includes circuitry for determining that an undesired distortion exists in a data signal read from a surface of a data storage disk; circuitry for finding an approximate starting location of said distortion within said data signal; and, circuitry for correcting errors in said data signal caused by said undesired distortion using said approximate starting location of said distortion. A method for correcting read errors in a disk drive is also disclosed.Type: GrantFiled: August 24, 1999Date of Patent: November 14, 2000Assignee: Maxtor CorporationInventors: Bobby Ray Southerland, Jin-Hong Hsueh, Lace J. Herman, John C. Purkett
-
Patent number: 6104558Abstract: A system and method for encoding a servo address in a disk drive system having at least one disk for storing data is disclosed. A servo address associated with a sector in a track, or cylinder, on a surface of a disk and comprised of a sector number, a track number, and in multiple disk systems, a head number is encoded into the encoded servo address. Encoding the servo address saves disk storage space because the encoded servo address uses fewer bits than a conventional servo address while still enabling the disk drive system to verify the location of any sector.Type: GrantFiled: March 20, 1998Date of Patent: August 15, 2000Assignee: International Business Machines CorporationInventors: Richard Greenberg, John C. Purkett
-
Patent number: 6084734Abstract: An apparatus for correcting read errors in a disk drive is disclosed. In one embodiment, the apparatus includes circuitry for determining that an undesired distortion exists in a data signal read from a surface of a data storage disk; circuitry for finding an approximate starting location of said distortion within said data signal; and, circuitry for correcting errors in said data signal caused by said undesired distortion using said approximate starting location of said distortion. A method for correcting read errors in a disk drive is also disclosed.Type: GrantFiled: December 8, 1997Date of Patent: July 4, 2000Assignee: Maxtor CorporationInventors: Bobby Ray Southerland, Jin-Hong Hsueh, Lace J. Herman, John C. Purkett
-
Patent number: 5757568Abstract: A servo address is encoded in a disk drive system having at least one disk for storing data. A servo address associated with a sector in a track, or cylinder, on a surface of a disk and comprised of a sector number, a track number, and in multiple disk systems, a head number is encoded into the encoded servo address. Encoding the servo address saves disk storage space because the encoded servo address uses fewer bits than a conventional servo address while still enabling the disk drive system to locate positions on the disk.Type: GrantFiled: July 12, 1996Date of Patent: May 26, 1998Assignee: International Business Machines CorporationInventors: Richard Greenberg, John C. Purkett
-
Patent number: 5615064Abstract: A digital storage system is disclosed in which a flying read/write head is loaded onto the surface of moving storage media with controlled velocity to avoid contact with the surface of the storage media. Head load velocity is detected by measuring the back EMF generated by the head arm actuator. Improved control and accuracy is obtained by breaking up the head arm actuator drive power into a series of pulses and measuring the back EMF induced into the low impedance voice coil of the head arm actuator in between pulses but only after the actuator current has been reduced to substantially zero in order to avoid interference by actuator current induced voltages.Type: GrantFiled: October 3, 1994Date of Patent: March 25, 1997Assignee: International Business Machines CorporationInventors: Timothy J. Blank, Kevin J. Erickson, Richard Greenberg, John C. Purkett
-
Patent number: 5596460Abstract: A servo address is encoded in a disk drive system having at least one disk for storing data. A servo address associated with a sector in a track, or cylinder, on a surface of a disk and comprised of a sector number, a track number, and in multiple disk systems, a head number is encoded into the encoded servo address. Encoding the servo address saves disk storage space because the encoded servo address uses fewer bits than a conventional servo address while still enabling the disk drive system to locate positions on the disk.Type: GrantFiled: December 27, 1994Date of Patent: January 21, 1997Assignee: International Business Machines CorporationInventors: Richard Greenberg, John C. Purkett