Patents Examined by Alan T. Faber
  • Patent number: 7215494
    Abstract: A system and method for performing read retry operations with respect to an erroneously read data sector is disclosed. The system and method use estimates of bit error rates determined during previous attempts to read data from the sector to determine an optimal distance and direction to move a read transducer for a subsequent read retry of the erroneously data sector.
    Type: Grant
    Filed: October 1, 2002
    Date of Patent: May 8, 2007
    Assignee: Seagate Technology LLC
    Inventors: Jun Wang, Challa Anantha Lakshmi, Xueyi Miao, Kan Liang Gan, Myint Ngwe
  • Patent number: 7038873
    Abstract: A perpendicular magnetic recording medium has a substrate, a magnetic functional layer provided on the substrate, and a magnetic recording layer stacked in contact with the magnetic functional layer and having perpendicular magnetic anisotropy. ?4×2?Ms2?Ku?6×2?Ms2 is satisfied, wherein Ku represents a perpendicular magnetic anisotropy constant of the magnetic functional layer and Ms represents a saturation magnetization. The magnetic moment of the magnetic functional layer is rotated in a direction of an applied magnetic field during the recording, and the magnetic moment acts on the magnetization of the recording layer in such a manner that the applied magnetic field is assisted thereby. Minute magnetic domains can be stably retained and excellent thermal disturbance resistance can be obtained.
    Type: Grant
    Filed: December 30, 2003
    Date of Patent: May 2, 2006
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Katsusuke Shimazaki, Satoshi Matsunuma, Teruaki Takeuchi, Norio Ota
  • Patent number: 7027239
    Abstract: A data acquisition apparatus acquires an analog input signal from an analog sensor, and generates digital data based on the analog input signal for processing by a personal computing apparatus. The analog input signal generated by the analog sensor has a voltage component which varies according to a condition sensed by the analog sensor. The data acquisition apparatus includes a first conversion circuit, such as a voltage-to-frequency converter, coupled to the analog sensor which receives the analog input signal and generates an analog information transfer signal having a signal component which varies in relation to the voltage component of the analog input signal. A signal transfer device, such as a portable audio record/playback device, records the analog information transfer signal and transfers it to a first audio input of the personal computing apparatus.
    Type: Grant
    Filed: March 13, 2002
    Date of Patent: April 11, 2006
    Inventors: William B. Priester, Joseph H. Butler, Jr., Michael J. Twigg
  • Patent number: 7019923
    Abstract: A pre-amplifier, a Thevenin writer and a disk drive employing transistors having a breakdown voltage below a circuitry operating voltage. In one embodiment, the pre-amplifier includes an emitter-follower transistor pair couplable to a power supply and a differential transistor pair, having a collector-emitter breakdown voltage below a voltage of the power supply, that receives current from, and controlled by, the emitter-follower transistor pair.
    Type: Grant
    Filed: April 22, 2003
    Date of Patent: March 28, 2006
    Assignee: Agere Systems Inc.
    Inventors: John D. Leighton, Hao Fang, Michael J. O'Brien, Scott O'Brien, Cameron C. Rabe
  • Patent number: 7019926
    Abstract: A system and method for self-servo-writing of multi-slot timing patterns is described. Individual timing marks are replaced with groups of timing mark slots. At each timing mark location, a time measurement is made by detecting a timing mark in one of the slots. Also, extensions to the existing timing marks are written in other slots. The combination of timing measurements at every timing mark and extensions to those timing marks written at every opportunity improves the overall precision of the timing propagation. The improved accuracy of timing mark placement produces a commensurate improvement in the placement of the concomitantly written servo-data. In addition, the alignment accuracy of the written pattern is less sensitive to variations in rotation speed and variations in the shape of written transitions. Moreover, only a single disk revolution is required at each servo radius to write servo data and propagate the timing marks.
    Type: Grant
    Filed: June 27, 2002
    Date of Patent: March 28, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Timothy J. Chainer, Mark D. Schultz, Bucknell C. Webb
  • Patent number: 7006314
    Abstract: A driver circuit drives a write element for magnetic recording, and permits high speed recording while preventing noise from entering an adjacent read element. An H bridge circuit, which causes a write current to flow, in accordance with a write drive signal, in a write coil of the write element, is provided with an overshoot circuit, in which positive and negative power sources are of the same potential. It makes a flyback voltage vertically symmetrical. Further, a feedback circuit is provided which monitors the voltages at both ends of the write coil, and prevents a variation in the common potential of the write coil. Terminal resistors are further provided to prevent the effects of reflection in a transmission line, and to prevent a change in the write waveform.
    Type: Grant
    Filed: November 6, 2002
    Date of Patent: February 28, 2006
    Assignee: Fujitsu Limited
    Inventor: Yasuhiko Takahashi
  • Patent number: 7002764
    Abstract: A method and apparatus providing generalized write pre-compensation is disclosed. The present invention provides multiple phase signals to choose from for provide a shift to received write data to achieve a desired pre-compensation.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: February 21, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Firmin M. Musungu, Joey M. Poss, Brent A. Sadowy
  • Patent number: 6999255
    Abstract: A magnetic recording and reproducing system, including recording a signal on a magnetic recording medium by an inductive head and reproducing the signal by a magneto resistance head. The gap length of the inductive head is 0.3 ?m or less. The maximum particle diameter of ferromagnetic powder is from 1/10 to ½ of the gap length, the minimum particle diameter of the powder is from 1/100 to ? of the gap length, and the thickness of a magnetic layer is from 1/10 to ½ of the gap length. The average particle size of the powder is from 10 to 35 nm, the tabular ratio is from 2 to 6, the squareness ratio of in-plane of the magnetic layer is from 0.5 to 0.9 in the longitudinal direction, and from 0.2 to 0.6 in the thickness direction, and the thickness of the magnetic layer is from 0.01 to 0.2 ?m.
    Type: Grant
    Filed: November 8, 2002
    Date of Patent: February 14, 2006
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Kiyomi Ejiri, Takeshi Harasawa
  • Patent number: 6999279
    Abstract: The invention is directed to patterned magnetic media for use in magnetic recording and data storage, and various conditioning techniques that can be used to magnetically condition the patterns. For example, a medium can be formed to exhibit a pattern of surface variations defined by patterned areas and non-patterned areas. Techniques are described for magnetically conditioning the patterned areas. The techniques may be useful for perpendicular patterned media, i.e., media having patterns formed on the media surface and having a magnetic anisotropy that is perpendicular to the plane of the medium. In particular, perpendicular magnetic anisotropy has been found to be an important factor that allows effective conditioning of patterned features having relatively small widths.
    Type: Grant
    Filed: October 29, 2002
    Date of Patent: February 14, 2006
    Assignee: Imation Corp.
    Inventor: Garry R. Lundstrom
  • Patent number: 6996033
    Abstract: An optical path or waveguide for a laser-assisted transducing head is disclosed. The optical path extends between the poles of the transducing head to near the write gap. A solid-state laser is attached to or incorporated into the slider or head and is positioned to direct thermal energy through a waveguide and onto a track of a read/write surface to lower the coercivity of the recording medium to facilitate the write process.
    Type: Grant
    Filed: June 19, 2003
    Date of Patent: February 7, 2006
    Assignee: Advanced Research Corporation
    Inventors: Matthew P. Dugas, Jeffrey A. Wallhoff
  • Patent number: 6995932
    Abstract: A detection circuit or a perpendicular recording system includes a channel circuit to amplify the read data signal. A transient detector generates a transient detect signal. A first path and a second path are coupled to an output of the channel circuit. The first path includes a first data detector that generates a first detected data signal in response to detecting data in the read data signal. A second path includes a series connected combination of a data filter and a second data detector. The filter generates a filtered data signal in which low frequency components of the read data signal are attenuated. The second data detector generates a second detected data signal in response to detecting data in the filtered data signal. Either the first detected data signal or the second detected data signal is coupled to a data processor based on whether a transient is detected.
    Type: Grant
    Filed: July 2, 2003
    Date of Patent: February 7, 2006
    Assignee: Marvell International Ltd.
    Inventor: Runsheng He
  • Patent number: 6989952
    Abstract: A magnetic recording disk drive has an inductive write head and a heater to record data in laminated media on the recording disk. The laminated media, with at least two ferromagnetic layers separated by a nonmagnetic spacer layer, improves SNR. Each of the ferromagnetic layers can be formed of a material having an intrinsic coercivity capable of being written by a conventional inductive write head, but because of the desired lamination to increase SNR, the ferromagnetic layer farthest from the write head is exposed to a magnetic field less than its intrinsic coercivity and thus can not be written. To write to the laminated media, heat is directed to the lower ferromagnetic layer to reduce its intrinsic coercivity below the magnetic field to which it is exposed.
    Type: Grant
    Filed: July 15, 2003
    Date of Patent: January 24, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: David T. Margulies, Andreas Moser, Hal J. Rosen, Jan-Ulrich Thiele
  • Patent number: 6987629
    Abstract: A method for placing a predetermined number of notch filters in a disc drive servo control system to attenuate noise frequencies, in order of decreasing resonance magnitudes, is disclosed. The method involves calculating an open loop response for a response spectrum of the drive, calculating a notch filter for any noise frequency that exceeds a threshold, mathematically applying the notch filter into the servo control system, recalculating the open loop response and applying another filter for a noise frequency that exceeds the threshold and repeating until no noise frequencies exceed the gain threshold; selecting another frequency range and repeating the same process until a predetermined number of notch filters has been placed in the servo control system.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: January 17, 2006
    Assignee: Seagate Technology LLC
    Inventors: Christopher Ryan Fulkerson, Jeffrey Don Andress, Charles Randall Berry
  • Patent number: 6982842
    Abstract: A method of performing predictive failure analysis (PFA) for a disc drive includes maintaining at least two primary error counts during operation of the disc drive. The primary error counts each correspond to disc drive errors associated with different attributes of the disc drive and are potentially indicative of disc drive failure. Imminent disc drive failure is predicted based upon a combination of the primary error counts.
    Type: Grant
    Filed: January 30, 2003
    Date of Patent: January 3, 2006
    Assignee: Seagate Technology LLC
    Inventors: Gary Gang Jing, Scott Douglas Ulrich, Timothy Edward Langlais, Yi Q. Lin
  • Patent number: 6980382
    Abstract: The magnetic disk drive system has a read head and a write head, writes data on the track of the disk, and reads data on the track of the disk. In the present invention, the distance between the heads in the circumferential direction of the disk is computed. The distance between the heads is computed based on the distance between the position of the write head where said data is written and the position of the read head where said data is read. The timing when data is written by the write head is determined by adding said distance to the position where the data is written. Thus, the efficiency of the format of the disk is improved.
    Type: Grant
    Filed: March 5, 2002
    Date of Patent: December 27, 2005
    Assignee: Fujitsu Limited
    Inventors: Masakazu Hirano, Nobuyuki Suzuki
  • Patent number: 6977785
    Abstract: A magnetic-pattern transferring method is a method for transferring a magnetic pattern to a magnetic recording medium. The method comprises steps as follows. In a master transferring step, a magnetic field is applied to a master placed close to the magnetic recording medium. The magnetic field excites a magnetic layer having a pattern patterned on the master according to the magnetic pattern. Thereby, the pattern of the magnetic layer is transferred to the magnetic recording medium. In a pattern-difference measuring step, a magnetic condition of the magnetic recording medium is measured so as to measure a magnetically different part between the pattern transferred to the magnetic recording medium and the magnetic pattern. In a magnetic transferring step, a pattern transfer is performed to the magnetic recording medium by using the master while applying the magnetic field so as to correct a magnetic condition of the magnetically different part.
    Type: Grant
    Filed: March 27, 2002
    Date of Patent: December 20, 2005
    Assignee: Fujitsu Limited
    Inventors: Yutaka Nakamura, Hitoshi Komoriya, Hiroyuki Suzuki, Takao Hirahara
  • Patent number: 6970310
    Abstract: A disk system that conducts diagnoses of magnetic heads at regular or irregular interval to detect occurrence of unwritable failure. The history of regions on magnetic recording media where write operations took place is managed and a region where an unwritable failure occurred is specified. Data that corresponds to the unwritable failure is recovered by taking advantage of the redundancy of a RAID system. The disk system includes a unit that, upon reading data, checks whether the data to be read was written on the magnetic recording media through a normal write function. Through this, old data is prevented from being sent to host devices as a result of unwritable failure, and unwritable failures can be dealt with without increasing the processing time to detect unwritable failures.
    Type: Grant
    Filed: March 6, 2003
    Date of Patent: November 29, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kawaguchi, Kenichi Kageura, Takao Sato
  • Patent number: 6967798
    Abstract: A method and apparatus is described for gradually transitioning a slider from operation over a patterned data zone to landing on a patterned CSS zone. The ratio of raised area width to recessed area width of a pattern in a transition zone and/or CSS zone may be varied across the radial dimension of the disk. By changing the ratio of raised area width to recessed area width of the pattern in the transition from slider operation over the data zone to landing in the CSS zone, it is possible to gradually change the height of the slider from flying to non-flying conditions.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: November 22, 2005
    Assignee: Komag, Inc.
    Inventors: Andrew M. Homola, Judy Lin
  • Patent number: 6963460
    Abstract: A voltage regulator includes an output node and first and second regulator circuits. The first regulator circuit generates a first regulated voltage on the output node when a supply voltage equals or exceeds a predetermined threshold, and the second regulator circuit generates a second regulated voltage on the output node when the supply voltage is less than the predetermined threshold.
    Type: Grant
    Filed: November 14, 2002
    Date of Patent: November 8, 2005
    Assignee: STMicroelectronics, Inc.
    Inventors: Manish Jain, Roberto Alini
  • Patent number: RE38885
    Abstract: The invention comprises a magnetic disk storage system and comprises method for configuring the magnetic disk storage system. The magnetic disk storage system facilitates write and read operations that compensate for variances that are experienced with magnetic disk storage systems. When writing data to a data sector, the magnetic disk storage system utilizes a phase lock oscillator field that has a length that is specified for that data sector. When reading from a data sector, the magnetic disk storage system utilizes an incremental read delay that has a duration that is specified for that data sector. Data sectors with shorter data sector delay periods can have shorter phase lock oscillator fields than data sectors with larger data sector delay periods. This frees-up memory space and increases the capacity and performance of the magnetic disk storage system.
    Type: Grant
    Filed: September 19, 2002
    Date of Patent: November 22, 2005
    Assignee: STMicroelectronics N.V.
    Inventor: Aaron Wade Wilson