Checking Record Characteristics Or Modifying Recording Signal For Characteristic Compensation Patents (Class 360/25)
  • Patent number: 10438619
    Abstract: A tape drive-implemented method, according to one embodiment, includes: determining formatting information which corresponds to a magnetic tape loaded in the tape drive, and using the formatting information to identify wraps on the magnetic tape. Identifying wraps on the magnetic tape includes: identifying an outermost wrap on the magnetic tape on a first side of the magnetic tape, and identifying an outermost wrap on the magnetic tape on a second side of the magnetic tape. A procedure is also performed for each of the wraps identified using the formatting information. Performing the procedure for a given one of the wraps includes: sending one or more instructions to position a magnetic head of the tape drive over the given wrap, sending one or more instructions to move the magnetic tape over the magnetic head, and collecting PES information which corresponds to the given wrap.
    Type: Grant
    Filed: October 23, 2018
    Date of Patent: October 8, 2019
    Assignee: International Business Machines Corporation
    Inventors: Michael E. Kilbey, Guillermo F. Paniagua
  • Patent number: 10410661
    Abstract: A hard disc drive includes a slider including a first reader and a second reader. The hard disc drive also includes a magnetic recording medium and a controller. The controller is configured to determine a distance between the slider and the magnetic recording medium based at least in part on amplitudes of read signals from both the first reader and the second reader.
    Type: Grant
    Filed: October 26, 2018
    Date of Patent: September 10, 2019
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Riyan Alex Mendonsa, Walter R Eppler, Puskal P Pokharel, Gary Ernest Hillukka, Stephanie Hernandez
  • Patent number: 10395673
    Abstract: A temperature compensation equation is generated during manufacture of a heat-assisted magnetic recording (HAMR) disk drive using initial total currents supplied to a laser diode of the disk drive at different initial operating temperatures. The total currents represent currents for recording data to or erasing data from the medium. The temperature compensation equation is stored in the disk drive, and updated, during field operation, using a subsequent total current associated with an operating temperature differing from the initial operating temperatures. The total current supplied to the laser diode for a subsequent write operation is adjusted using the updated temperature compensation equation in response to the operating temperature at the time of the subsequent write operation.
    Type: Grant
    Filed: October 25, 2018
    Date of Patent: August 27, 2019
    Assignee: Seagate Technology LLC
    Inventors: Alfredo Sam Chu, Franklin P. Martens, Drew Michael Mader, Steven J. Kimble, James E. Angelo
  • Patent number: 10388304
    Abstract: Mounting a data storage medium having information recorded thereon, where: the information is formatted according to a data storage format standard that includes first write and read functions, the information includes first and second datasets, the first dataset includes a first file mark, an index, and an empty space between the second dataset and a combination of the first file mark and the index; receiving, from a first application, a data block and a write command for writing the data block onto the data storage medium; and in response to receiving the write command: determining that the empty space is present in the first dataset, writing, by a second write function, the data block into the empty space, and writing a second file mark in the second dataset; wherein the empty space of the data storage medium is inaccessible to the first write function of the data storage format standard.
    Type: Grant
    Filed: September 25, 2018
    Date of Patent: August 20, 2019
    Assignee: International Business Machines Corporation
    Inventors: Tohru Hasegawa, Atsushi Abe
  • Patent number: 10290319
    Abstract: A method for performing a flaw scan test on a hard disk drive is disclosed. The hard disk drive includes a magnetic recording medium and spindle motor associated with a predetermined rated speed. The method includes writing a test pattern to the magnetic recording medium while operating the spindle motor at a speed greater than the predetermined rated speed. The method also includes reading the test pattern at the greater speed and detecting flaws in response to reading the test pattern.
    Type: Grant
    Filed: August 8, 2018
    Date of Patent: May 14, 2019
    Assignee: Seagate Technology LLC
    Inventors: Antonia Tsoukatos, Tim Rausch, Mehmet Fatih Erden, Benjamin W Parish, Prasanna Manja Ramakrishna, Morovat Bryan Tayefeh, Sai Sian Hon, ChengYi Guo, Teck Khoon Lim, Song Wee Teo
  • Patent number: 10270627
    Abstract: A receiver for data recovery from a channel signal of a communications channel. The receiver includes a quantization circuit to generate a quantized code corresponding to the channel signal. A first decision circuit recovers, in a first signal processing mode, digital data for the channel signal based on the quantized representation of the channel signal. A second decision circuit recovers, in a second signal processing mode, the digital data for the channel signal based on the quantized representation of the channel signal. A controller selects between the first signal processing mode and the second signal processing mode based on a parameter indicative of a signal quality of the channel signal.
    Type: Grant
    Filed: March 14, 2016
    Date of Patent: April 23, 2019
    Assignee: eTopus Technology Inc.
    Inventors: Kai Keung Chan, Danfeng Xu, Yu Kou
  • Patent number: 10255931
    Abstract: An apparatus may include a circuit configured to generate a set of first ADC samples based on a first signal associated with a first read head position and a failed segment and to generate a set of second ADC samples based on a second signal associated with a second read head position and the failed segment. The circuit may then generate, by a MISO equalizer, a set of equalized ADC samples based on the set of first ADC samples and the set of second ADC samples.
    Type: Grant
    Filed: March 5, 2018
    Date of Patent: April 9, 2019
    Assignee: Seagate Technology LLC
    Inventors: Jason Charles Jury, Marcus Marrow, Michael J Link, Jason Bellorado
  • Patent number: 10217481
    Abstract: A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a fly height actuator (FHA). An FHA control signal is applied to the FHA, wherein the FHA control signal comprises a rectangular wave having a duty cycle in the range of ten percent to thirty percent. While applying the FHA control signal to the FHA, the head touching down onto the disk is detected.
    Type: Grant
    Filed: March 19, 2018
    Date of Patent: February 26, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Shaomin Xiong, Na Wang, Robert Smith, Sripathi V. Canchi
  • Patent number: 10209458
    Abstract: An optical module for connecting a ferrule for connecting an optical fiber and a photoelectric transducer mounted on a substrate includes first lenses, second lenses, and a dummy lens. The first lenses are provided on a first side of the optical module to which the ferrule is to be connected. The second lenses and the dummy lens are provided on a second side of the optical module facing a surface of the substrate. The second lenses and the dummy lens are aligned on the same line. An image of the dummy lens is reflected from a mirror to be projected onto a plane on the first side of the optical module.
    Type: Grant
    Filed: April 13, 2018
    Date of Patent: February 19, 2019
    Assignee: FUJITSU COMPONENT LIMITED
    Inventors: Shigemi Kurashima, Hongfei Zhang, Shinichiro Akieda, Osamu Daikuhara
  • Patent number: 10199055
    Abstract: According to one embodiment, a magnetic disk device including a disk, a head that writes data in the disk, and reads data from the disk, and a controller that generates second data of when first data is written in the disk based on the first data read from the disk, generates third data indicating change in an amplitude of the first data due to thermal fluctuation based on the second data, and adjusts the first data based on the third data.
    Type: Grant
    Filed: February 20, 2018
    Date of Patent: February 5, 2019
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
    Inventor: Nobuhiro Maeto
  • Patent number: 10147458
    Abstract: Various embodiments for data error recovery in a tape storage system, by a processor device, are provided. In one embodiment, a method comprises, in a tape storage system using an iterative hardware and microcode decoder, initializing at least one iterative decode cycle on the buffered dataset when an uncorrectable read error occurs; and for a next iterative decode cycle, building upon data corrections obtained in a previous iterative decode cycle.
    Type: Grant
    Filed: January 25, 2017
    Date of Patent: December 4, 2018
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Steven R. Bentley, Pamela R. Nylander-Hill, Keisuke Tanaka
  • Patent number: 10147455
    Abstract: A memory system, sensor circuit, and method of operating a memory system are provided. The disclosed memory system includes a first transducer configured to output a first electrical signal indicative of a first operating parameter of the memory system. The memory system is further disclosed to include a second transducer configured to output a second electrical signal indicative of a second operating parameter of the memory system where the second transducer shares a node with the first transducer. The memory system is further disclosed to include a sense amplifier that receives the first electrical signal and the second electrical signal and provide an output responsive to both the first electrical signal and the second electrical signal to a preamplifier Integrated Circuit (IC).
    Type: Grant
    Filed: October 31, 2017
    Date of Patent: December 4, 2018
    Assignee: AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE. LIMITED
    Inventors: Scott M. O'Brien, Michael Straub
  • Patent number: 10134427
    Abstract: Mounting a data storage medium having information recorded thereon, where: the information is formatted according to a self-describing format standard that includes first write and first read functions, the information includes first and second datasets, the first dataset includes a first file mark, an index, and an empty space between the second dataset and a combination of the first file mark and the index; receiving, from a first application, a data block and a corresponding write command for writing the data block onto the data storage medium; and in response to receiving the write command: determining that the empty space is present in the first dataset, writing, by a second write function, the data block into the empty space, and writing a second file mark in the second dataset; wherein the empty space of the data storage medium is inaccessible to the first write function of the self-describing format standard.
    Type: Grant
    Filed: March 7, 2018
    Date of Patent: November 20, 2018
    Assignee: International Business Machines Corporation
    Inventors: Tohru Hasegawa, Atsushi Abe
  • Patent number: 10127950
    Abstract: A data storage device may be configured with a transducing head separated from a data storage medium by an air bearing. The transducing head and data storage medium are each contained within a housing. The transducing head can consist of a variable resistance sensor that is connected to a temperature module positioned within the housing. One or more operational variables can be measured by the variable resistance sensor to allow an ambient temperature within the housing to be calculated based on a measured operational variable.
    Type: Grant
    Filed: May 9, 2017
    Date of Patent: November 13, 2018
    Assignee: Seagate Technology LLC
    Inventors: Lihong Zhang, Samuel Gan, Xiong Liu, Tanghe Guo, Takashi Fujita
  • Patent number: 10121511
    Abstract: Systems and methods for forward corrupted track detection and by-pass are described. In one embodiment, a storage system comprising a storage controller performs a read operation for a target track of a shingled magnetic recording (SMR) disk drive and detects a read operation failure of the read operation for the target track. The storage controller also performs a boundary track read operation on one or more tracks including or adjacent to the target track and detect a forward corruption area based on the boundary track read operation. In another embodiment, a method is provided that includes detecting a read operation failure of a read operation for a track of a disk drive and performing a boundary track read operation on one or more tracks including or adjacent to the target track. The method also includes detecting a forward corruption area based on the boundary track read operation.
    Type: Grant
    Filed: February 2, 2018
    Date of Patent: November 6, 2018
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Junghwan Shin, Jae Ik Song, Dong Hyuck Shin, Eun Yeong Hong
  • Patent number: 10031793
    Abstract: An apparatus-implemented method according to one embodiment includes detecting an error while writing data to a tape volume on a tape and repositioning the tape in response to detecting the error. A determination whether a rewrite of data associated with the error to the tape volume is allowed is made based on a current position of the tape after the repositioning. The data is rewritten to the tape volume in response to determining that the rewrite of data associated with the error to the tape volume is allowed. A computer program product for protecting overwrite of a tape volume according to another embodiment includes a computer readable storage medium having program instructions embodied therewith, the program instructions readable and/or executable by a controller to cause the controller to perform the foregoing method.
    Type: Grant
    Filed: November 2, 2017
    Date of Patent: July 24, 2018
    Assignee: International Business Machines Corporation
    Inventors: Erika M. Dawson, David C. Reed, Max D. Smith, Joseph M. Swingler
  • Patent number: 9997176
    Abstract: A recording medium is written to using an energy source that heats the medium during the writing. A read error in a sector is determined when reading via a read transducer. While traversing a part of the recording medium that includes data, a write coil is activated before attempting to re-read the sector. The energy source does not heat the recording medium sufficiently to change a state of the data during the activation of the write coil. The activation of the write coil removes a magnetic instability of the read transducer.
    Type: Grant
    Filed: October 24, 2017
    Date of Patent: June 12, 2018
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Wenzhong Zhu, Jason C. Jury, Alfredo Sam Chu
  • Patent number: 9978421
    Abstract: The optical disk device performs recording/reproducing of data by a predetermined recording block on the track of an optical disk. The device has a recording unit, an optical-head, and a failure detection unit. The recording unit generates a recording signal by modulating the data. The optical-head records data on the track by optical beam emission to the track according to the recording signal, and detects light reflected off the track and then generates a detection signal based on the reflected light. The failure detection unit detects an abnormal condition based on the detection signal changed from a normal condition. If the sum of duration of an abnormal condition in the recording block is equal to or greater than a first time-length, the failure detection unit determines that the recording block has a flaw.
    Type: Grant
    Filed: October 15, 2017
    Date of Patent: May 22, 2018
    Assignee: Panasonic Intellectual Property Management Co., Ltd.
    Inventors: Kohei Nakata, Yoshihisa Takahashi, Junichi Minamino
  • Patent number: 9959892
    Abstract: Some embodiments of the present invention logically eliminate an end region of a user-data area of a magnetic storage tape during formatting (or re-formatting) of the tape, if the position error signal (PES) variance corresponding to the end region exceeds a threshold. An adjacent region, having a PES variance less than the threshold is designated as a new end region, thereby shortening the user-data area of the tape and extending its usable life.
    Type: Grant
    Filed: May 12, 2017
    Date of Patent: May 1, 2018
    Assignee: International Business Machines Corporation
    Inventors: Tsuyoshi Miyamura, Kazuhiro Tsuruta, Eiji Ogura, Tomoko Taketomi
  • Patent number: 9928854
    Abstract: An apparatus may include a circuit configured to generate a set of first ADC samples based on a first signal associated with a first read head position and a failed segment and to generate a set of second ADC samples based on a second signal associated with a second read head position and the failed segment. The circuit may then generate, by a MISO equalizer, a set of equalized ADC samples based on the set of first ADC samples and the set of second ADC samples.
    Type: Grant
    Filed: May 3, 2017
    Date of Patent: March 27, 2018
    Assignee: Seagate Technology LLC
    Inventors: Jason Charles Jury, Marcus Marrow, Michael J Link, Jason Bellorado
  • Patent number: 9916859
    Abstract: Systems and methods for forward corrupted track detection and by-pass are described. In one embodiment, a storage system comprising a storage controller performs a read operation for a target track of a shingled magnetic recording (SMR) disk drive and detects a read operation failure of the read operation for the target track. The storage controller also performs a boundary track read operation on one or more tracks including or adjacent to the target track and detect a forward corruption area based on the boundary track read operation. In another embodiment, a method is provided that includes detecting a read operation failure of a read operation for a track of a disk drive and performing a boundary track read operation on one or more tracks including or adjacent to the target track. The method also includes detecting a forward corruption area based on the boundary track read operation.
    Type: Grant
    Filed: June 6, 2017
    Date of Patent: March 13, 2018
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Junghwan Shin, Jae Ik Song, Dong Hyuck Shin, Eun Yeong Hong
  • Patent number: 9857852
    Abstract: Provided is a management control system for controlling the number of fan revolutions to avoid the number of fan revolutions likely to cause a high frequency of errors in a drive. The management control system includes: an error frequency calculating section for calculating a frequency of errors by acquiring the number of errors occurring in a drive and the number of fan revolutions, and then calculating the number of fan revolutions to avoid based on the frequency of errors; a storage section for storing the number of revolutions to avoid; and a fan revolution number controlling section for acquiring the number of fan revolutions and current ambient temperature in a housing, and controlling the number of fan revolutions within a revolution number range not including the number of revolutions to avoid stored in the storage section, depending on the ambient temperature.
    Type: Grant
    Filed: September 12, 2014
    Date of Patent: January 2, 2018
    Assignee: NEC CORPORATION
    Inventor: Takayuki Shirokaze
  • Patent number: 9830942
    Abstract: First and second different write precompensation values are associated with different first and second non-return-to-zero, inverted (NRZI) data patterns. The first and second different write precompensation values cause a predetermined phase shift to be written into test data that comprises the first and second NRZI data patterns. The test data is mitten to a recording medium of a storage device using the first and second write precompensation value. The test data is used to determine a response of the storage device to the predetermined phase shift.
    Type: Grant
    Filed: August 10, 2016
    Date of Patent: November 28, 2017
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Drew Michael Mader, Jason Charles Jury, Tim Rausch, Raman Venkataramani
  • Patent number: 9818447
    Abstract: A method comprises writing a waveform on a magnetic recording medium using a heat-assisted magnetic recording apparatus which includes a laser. The method also comprises reading back the waveform from the medium, and detecting one or more transition shifts in the readback waveform indicative of a mode hop of the laser. The method further comprises measuring a metric of the one or more transition shifts.
    Type: Grant
    Filed: March 21, 2017
    Date of Patent: November 14, 2017
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Xuan Zheng, Walter R. Eppler, Julius K. Hohlfeld, Heidi M. Olson
  • Patent number: 9812159
    Abstract: A slider of a magnetic recording head includes a plurality of electrical bond pads and a plurality of readers comprising at least a first reader and a second reader. Each of the readers is coupled to a different pair of electrical bond pads. A temporary contact sensor is provided on the slider and coupled between a bond pad of the first reader and a bond pad of the second reader. The temporary contact sensor is configured for operation during a certification process of the apparatus and to become inoperable after completion of the certification process.
    Type: Grant
    Filed: February 27, 2017
    Date of Patent: November 7, 2017
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventor: Declan Macken
  • Patent number: 9767842
    Abstract: In one embodiment, a system for processing data includes a processor and logic integrated with and/or executable by the processor. The logic is configured to detect and track positive peak amplitudes and negative peak amplitudes of a readback waveform during data reading using a tracking threshold module, and to detect and track positive peak amplitudes and negative peak amplitudes of the readback waveform during the data reading at an input to an equalizer using a second tracking threshold module in response to reading a data set separator (DSS). Moreover, the logic is configured to perform asymmetry compensation on the data using an asymmetry compensator in an asymmetry compensation loop based on input from the tracking threshold module when not reading a DSS and based on input from the second tracking threshold module when reading a DSS, an output of the asymmetry compensator being provided to the equalizer.
    Type: Grant
    Filed: September 8, 2015
    Date of Patent: September 19, 2017
    Assignee: International Business Machines Corporation
    Inventor: Robert A. Hutchins
  • Patent number: 9761279
    Abstract: Various embodiments of a magnetic stack are disclosed. In one or more embodiments, the magnetic stack includes first and second shield layers, and a magnetically responsive lamination disposed between the first and second shield layers. The magnetically responsive lamination can be configured to receive a sense current IS therethrough. The magnetic stack also includes a cooling element disposed between the first and second shield layers and thermally coupled to the magnetically responsive lamination. The cooling element can be configured to receive a bias current IB therethrough. And the cooling element can be configured to cool the magnetically responsive lamination during a read function.
    Type: Grant
    Filed: March 24, 2017
    Date of Patent: September 12, 2017
    Assignee: Seagate Technology LLC
    Inventors: David Deen, Eric Singleton, Vasudevan Ramaswamy, Mohammed Patwari, Taras Pokhil, Jae-Young Yi
  • Patent number: 9741378
    Abstract: A method includes moving a heat-assisted magnetic recording head relative to a magnetic recording medium comprising a plurality of tracks, the head comprising a reader and a writer including a near-field transducer (NFT) optically coupled to a laser diode, the writer comprising a center which is laterally offset relative to a center of the reader to define a writer-reader offset (WRO) therebetween. Patterns are written to a particular track at a plurality of laser diode current levels. The patterns are read and a WRO value is calculated at a peak amplitude position for each of the laser diode current levels. A slope of the WRO values is determined with the laser current diode levels. A health condition of the NFT is determined by determining if the slope is greater than a predetermined threshold indicative of non-uniform activation across the NFT.
    Type: Grant
    Filed: August 23, 2016
    Date of Patent: August 22, 2017
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventor: Won Choul Yang
  • Patent number: 9741386
    Abstract: Before writing to a heat-assisted magnetic recording medium, a current of a laser is modulated about a default threshold current level. A modulation level of an optical power sensor is measured, the optical power sensor being coupled to detect optical output of the laser in response to the modulated current. A bias current for subsequent activation of the laser is adjusted based on the modulation level of the optical power sensor.
    Type: Grant
    Filed: October 25, 2016
    Date of Patent: August 22, 2017
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Tim Rausch, Edward Charles Gage, Joshua Ward Christensen, Todd Michael Lammers
  • Patent number: 9720876
    Abstract: A serial communication circuit includes a receiving unit configured to serially receive input data including a command and a synchronization identification code that is different from the command and a determining unit configured to receive the synchronization identification code from the receiving unit and when the synchronization identification code coincides with a slave selection value, to instruct a start of response processing based on the command.
    Type: Grant
    Filed: October 22, 2013
    Date of Patent: August 1, 2017
    Assignee: Seiko Epson Corporation
    Inventors: Masataka Kazuno, Katsuhito Nakajima, Takashi Aoyama
  • Patent number: 9626998
    Abstract: A hard disk drive device and a method and apparatus for control of the hard disk drive is provided. The hard disk drive includes disk media, a slider head, a head gimbal assembly and a control means. The disk media includes at least two layers for data storage. The slider head flies above the disk media and includes a writer and a reader, and a head gimbal assembly supports the slider head above the disk media. The control means is physically coupled to the head gimbal assembly and electrically coupled to the writer and the reader for reducing write interference from the writer when the writer is writing to the disk media while the reader is reading from the disk media, wherein write interference is reduced in one or more of a time domain and a frequency domain.
    Type: Grant
    Filed: July 30, 2014
    Date of Patent: April 18, 2017
    Assignee: Marvell International Ltd.
    Inventors: Jingliang Zhang, Zhimin Yuan, Siang Huei Leong, Budi Santoso, Pantelis Sophoclis Alexopoulos
  • Patent number: 9620163
    Abstract: A method comprises writing a waveform on a magnetic recording medium using a heat-assisted magnetic recording apparatus which includes a laser. The method also comprises reading back the waveform from the medium, and detecting one or more transition shifts in the readback waveform indicative of a mode hop of the laser. The method further comprises measuring a metric of the one or more transition shifts.
    Type: Grant
    Filed: May 16, 2016
    Date of Patent: April 11, 2017
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Xuan Zheng, Walter R. Eppler, Julius K. Hohlfeld, Heidi M. Olson
  • Patent number: 9495987
    Abstract: The disclosed technology provides techniques for mitigating write-to-write bit error rate fluctuations that decrease accuracy of write precompensation (WPC) tuning. According to one implementation, such write-to-write bit error rate fluctuations are mitigated if a predetermined pattern is written at a particular radial offset from a target data track prior to testing a WPC register in association with the target data track. Selection of the particular radial offset can be performed according to an iterative offset track clean-up disclosed herein.
    Type: Grant
    Filed: May 1, 2015
    Date of Patent: November 15, 2016
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Ben Niu, Lan Xia, Fong Kheon Chong, Quek Leong Choo, Song Wee Teo
  • Patent number: 9472224
    Abstract: An apparatus comprising a writer, a reader, and a sensor configured to at least sense thermal asperities of a magnetic storage medium. The apparatus includes a writer heater configured to thermally actuate the writer, a reader heater configured to thermally actuate the reader, and a sensor heater configured to thermally actuate the sensor. The thermally actuated sensor is configured to detect thermal asperities arising from the magnetic storage medium during a topographical survey of the medium. The sensor heater is configured to be rendered inoperable subsequent to the survey in response to receiving a predetermined signal while the writer and the reader heaters remain operable.
    Type: Grant
    Filed: December 5, 2013
    Date of Patent: October 18, 2016
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Declan Macken, Erik Hutchinson, Brian William Karr
  • Patent number: 9443543
    Abstract: According to one embodiment, a head flying height control method includes detecting a contact of a head with a disk while floating the head from the disk and moving the head in a radial direction of the disk, increasing a flying height of the head after detecting the contact of the head with the disk, and decreasing the flying height of the head after a state where the contact of the head with the disk is not detected continues.
    Type: Grant
    Filed: June 22, 2015
    Date of Patent: September 13, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Shinsuke Akiya
  • Patent number: 9361939
    Abstract: A data storage device is disclosed comprising a head and a disk comprising servo information and a reference pattern comprising a plurality of magnetic transitions. The servo information on the disk is processed to actuate the head over the disk, and a read signal is sampled from the head as the head moves across a width of the reference pattern at a substantially constant velocity to generate signal samples. The signal samples are processed to characterize a geometry of the magnetic transitions.
    Type: Grant
    Filed: March 31, 2014
    Date of Patent: June 7, 2016
    Assignee: Western Digital Technologies, Inc.
    Inventor: Robert E. Eaton
  • Patent number: 9245550
    Abstract: A write head is tested by measuring the effect that magnetic fields have on the inductance of the write head. For example, a perpendicular write head may be placed in a magnetic field with a first angle, e.g., non-parallel and non-perpendicular, to the air bearing surface and the inductance is measured. After altering the angle of the magnetic field the inductance is again tested. In another embodiment, the angles may be parallel and perpendicular to the air bearing surface. The difference in the inductance value can be used to determine a characteristic of the write head, such as the presence of a recording pole. In some embodiments, the inductance may be measured while applying a bias current to the write head while the write head is in an external magnetic field.
    Type: Grant
    Filed: November 15, 2011
    Date of Patent: January 26, 2016
    Assignee: Infinitum Solutions, Inc.
    Inventor: Alexander M. Taratorin
  • Patent number: 9213968
    Abstract: Systems and methods for conducting financial transactions using non-standard magstripe payment cards are provided. One such system includes a magnetic stripe card storing information including a serial number on a magnetic medium of the magnetic stripe card, where the stored information does not include a Primary Account Number, a card reader configured to extract information from the magnetic medium, the extracted information including the stored serial number and a magnetic fingerprint including an intrinsic magnetic characteristic of the magnetic medium, and a computer coupled to the card reader and to a server, where the computer and the server are configured to execute a requested financial transaction using the extracted information.
    Type: Grant
    Filed: December 13, 2011
    Date of Patent: December 15, 2015
    Assignee: MAGTEK, INC.
    Inventor: Annmarie D. Hart
  • Patent number: 9196302
    Abstract: An apparatus includes: a media; a head over the media; a read channel, coupled to the head, configured to extract data from the media; control circuitry, coupled to the read channel, configured to execute a read command; and wherein the read channel is further configured to: generate, based on extracting the data from the media, a data condition indicator, and provide, for use by the control circuitry, the data and the data condition indicator.
    Type: Grant
    Filed: March 18, 2015
    Date of Patent: November 24, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Chin Phan Kuan, Nikki Poh Ling Khew, Wai Shin Chin
  • Patent number: 9135934
    Abstract: A write head is tested by measuring the effect that magnetic fields have on the inductance of the write head. For example, a perpendicular write head may be placed in a magnetic field with a first angle, e.g., non-parallel and non-perpendicular, to the air bearing surface and the inductance is measured. After altering the angle of the magnetic field the inductance is again tested. In another embodiment, the angles may be parallel and perpendicular to the air bearing surface. The difference in the inductance value can be used to determine a characteristic of the write head, such as the presence of a recording pole. In some embodiments, the inductance may be measured while applying a bias current to the write head while the write head is in an external magnetic field.
    Type: Grant
    Filed: November 16, 2011
    Date of Patent: September 15, 2015
    Assignee: Infinitum Solutions, Inc.
    Inventor: Alexander M. Taratorin
  • Patent number: 9118348
    Abstract: According to at least one embodiment, a decoding apparatus includes an error correcting module and a change module. The error correcting module decodes for correcting error of encoded data using a low-density party check code and likelihood information. The change module changes a value of the likelihood information if the value of the likelihood information is continuously smaller than a predetermined value.
    Type: Grant
    Filed: January 10, 2013
    Date of Patent: August 25, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventor: Nobuhiro Maeto
  • Patent number: 9025264
    Abstract: Methods for measuring media performance associated with adjacent track interference are provided. One such method includes iteratively writing data to a target track for each of a plurality of n frequencies, measuring a first signal amplitude and a first noise for each of the n sectors on the target track, writing an aggressor track pattern proximate the target track, measuring a second signal amplitude and a second noise for each of the n sectors on the target track, calculating a weighted sum for each of the signal amplitude measurements for each of the plurality of n frequencies, and calculating a weighted sum for each of the noise measurements for each of the plurality of n frequencies, and repeating the writing the aggressor track pattern, the measuring the second signal amplitude and the second noise, and calculating the weighted sums for preselected numbers of times.
    Type: Grant
    Filed: March 28, 2014
    Date of Patent: May 5, 2015
    Assignee: WD Media, LLC
    Inventors: Mrugesh Desai, Harold H. Gee, Mark A. Nichols
  • Patent number: 9019642
    Abstract: A method for detecting an information pattern includes obtaining a first sample stream and a second sample stream. The first sample stream and the second sample stream are obtained by sensing recorded information at a target location of a storage medium using a first sensor and a second sensor, respectively. A first metric is computed by comparing the first sample stream to a reference pattern representative of a target information pattern to be detected. A second metric is computed by comparing the second sample stream to the reference pattern. A combined metric is computed by combining the first metric and second metric using a weighting function. The target information pattern is detected using the combined metric.
    Type: Grant
    Filed: April 2, 2014
    Date of Patent: April 28, 2015
    Assignee: LSI Corporation
    Inventors: Haitao Xia, Rui Cao, Lingyan Sun, Lu Pan
  • Patent number: 9013815
    Abstract: A cluster size measurement method includes writing a first pattern of a first size of a first number of magnetic clusters. A second pattern of a second size of a second number of magnetic clusters is written, wherein the second plurality of clusters includes clusters of the first number of clusters and a switched cluster. A cluster size of the switched cluster is automatically determined by contrasting the first size and the second size.
    Type: Grant
    Filed: December 19, 2013
    Date of Patent: April 21, 2015
    Assignee: Seagate Technology LLC
    Inventors: Jason Charles Jury, Xiaowei Wu, Pierre Asselin
  • Patent number: 9013817
    Abstract: Inter-track interference cancelation is disclosed, including: receiving an input sequence of samples associated with a track on magnetic storage; using a processor to generate inter-track interference (ITI) data associated with a first side track including by performing a correlation between the input sequence of samples and a sequence of data associated with the first side track.
    Type: Grant
    Filed: January 17, 2014
    Date of Patent: April 21, 2015
    Assignee: SK hynix memory solutions inc.
    Inventors: Jason Bellorado, Marcus Marrow
  • Patent number: 9001442
    Abstract: Technologies are described herein for detecting adjacent track interference in a storage device using a size-adjustable sliding window. A value for an inter-track interference factor associated with at least one adjacent track is determined for a first area of a data track of the storage device. The first area may encompass a plurality of sectors of the data track. Next, it is determined whether the value of the calculated inter-track interference factor is greater than a threshold value, and if so, an indication of inter-track interference corresponding to the first area is stored in the storage device.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: April 7, 2015
    Assignee: Seagate Technology LLC
    Inventors: Donghyuk Park, Seungyoul Jeong, Joowon Cho
  • Patent number: 8988807
    Abstract: A hard disk drive has disks with data sector preambles that allow for inter-track interference. The same data sector preamble is used for all data sectors in a track but the preamble in each track is different from the preamble in radially adjacent tracks. In a first embodiment each preamble includes a synchronization field (SF) and synchronization mark (SM) that are the same in each track but different from the SF and SM in radially adjacent tracks. Only two unique SFs and two unique SMs are required, with the two SFs and two SMs alternating in radially adjacent tracks. In a second embodiment the preambles are “integrated”, meaning that the preamble is a sequence of bits that does not include separate dedicated fields, like SF and SM. The preamble bit sequences are decoded using matched filters to provide bit synchronization and start-of-data information.
    Type: Grant
    Filed: September 19, 2013
    Date of Patent: March 24, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Jonathan Darrel Coker, Richard Leo Galbraith, Weldon Mark Hanson, Travis Roger Oenning, Srinivasan Surendran
  • Patent number: 8964320
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of data tracks. A plurality of consecutive data tracks are written, and after writing to the plurality of consecutive data tracks, a first number of the consecutive data tracks are read and a second number of the consecutive data tracks are skipped, wherein the second number of data tracks are interleaved with the first number of data tracks. Defects in the data tracks are detected in response to reading the first number of data tracks.
    Type: Grant
    Filed: December 9, 2010
    Date of Patent: February 24, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Petrus Hu, Hasni Zaidy Abdul Hamid, Gunawathi Gunasekaran
  • Patent number: 8964323
    Abstract: A system including a first filter module configured to receive an input signal including (i) a first shift in a DC level of the input signal and (ii) a second shift in the DC level of the input signal. The first shift has (i) a first magnitude and (ii) a first duration. The second shift has (i) a second magnitude and (ii) a second duration. The second magnitude is different than the first magnitude. The second duration is greater than the first duration. The first filter module is configured to pass the first shift. The second filter module is configured to detect one or more of (i) the first shift and (ii) the second shift, and in response to detecting one or more of (i) the first shift and (ii) the second shift, filter one or more of (i) the first shift and (ii) the second shift.
    Type: Grant
    Filed: May 19, 2014
    Date of Patent: February 24, 2015
    Assignee: Marvell International Ltd.
    Inventors: Heng Tang, Yu-Yao Chang, Panu Chaichanavong, Michael Madden, Gregory Burd
  • Patent number: 8947801
    Abstract: Various aspects of the present disclosure are directed toward an apparatus, such as a disc drive, including a disc having multiple tracks, a magneto-resistive transducer assembly, and multiple-track signal correction circuitry. The multiple-track signal correction circuitry compensates for asymmetry in a readback signal of read data stored in at least one of multiple tracks based on different correction coefficients for respective ones of the multiple tracks.
    Type: Grant
    Filed: October 8, 2013
    Date of Patent: February 3, 2015
    Assignee: Seagate Technology LLC
    Inventor: Jason Charles Jury