Distinct Servo Sector Patents (Class 360/77.08)
  • Patent number: 7982993
    Abstract: A disk drive is disclosed having a first disk surface, and a head actuated over the first disk surface. The first disk surface comprises a plurality of servo tracks and a plurality of data tracks. The data tracks of the first disk surface are banded together into a plurality of data zones, including a first data zone and a second data zone. A first servo tracks per inch (STPI) to data tracks per inch (DTPI) ratio of the first data zone is substantially different from a second STPI to DTPI ratio of the second data zone.
    Type: Grant
    Filed: December 19, 2008
    Date of Patent: July 19, 2011
    Assignee: Western Digital Technologies, Inc.
    Inventors: Chun Sei Tsai, William B. Boyle, Carl E. Barlow
  • Patent number: 7973297
    Abstract: When writing a hard disk pattern on a substrate applied with a resist by scanning an electron beam on the substrate while rotating a rotation stage, writing is started with respect to each radial direction position of each area based on a predetermined encoder pulse for each radial direction position among those generated according to the rotational angle of the rotation stage that occurs after a predefined encoder pulse that occurs ahead in a rotational direction of a radial direction position whose write start position in a circumferential direction in each area arrives first at the writing position as the rotation stage rotates and ahead of the write start position in the circumferential direction with respect to each radial direction position, and after a predetermined time from the predetermined encoder pulse.
    Type: Grant
    Filed: February 3, 2009
    Date of Patent: July 5, 2011
    Assignee: Fujifilm Corporation
    Inventors: Toshihiro Usa, Kazunori Komatsu
  • Patent number: 7969686
    Abstract: Methods of defining servo patterns and data patterns for forming patterned magnetic media are described. For one method, a lithographic process is performed to define a servo pattern in servo regions on a substrate. The lithographic process also defines a first data pattern in data regions of the substrate. The first data pattern is then transferred to (i.e., etched into) the data regions. Self-assembly structures are then formed on the data pattern in the data regions to define a second data pattern. The servo pattern is then transferred to the servo regions and the second data pattern is transferred to the data regions. Thus, the servo pattern is defined through lithographic processes while the data pattern is defined by a combination of lithographic processes and self-assembly.
    Type: Grant
    Filed: December 26, 2007
    Date of Patent: June 28, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Thomas R. Albrecht, Xiao Z. Wu, Henry Hung Yang
  • Publication number: 20110149433
    Abstract: An embodiment of the present invention implements some or all major servo subfunctions for a storage device in integrated servo fields comprising sequences of encoded bits having selected mathematical properties. The integrated servo field is composed of a number of encoded sequences, which are members of a selected sequence set that is constrained to preferably provide some or all of the following functions: the Servo Track Mark (STM), the Position Error Signal (PES) and positional information such as the track-ID. In one embodiment the plurality sequences encoding a location identifier such as a track-ID are distributed across a set of servo wedges. A method of encoding the location identifier using a Chinese Remainder Theorem is described.
    Type: Application
    Filed: December 18, 2009
    Publication date: June 23, 2011
    Inventors: Jonathan Darrel Coker, David Timothy Flynn, Yuval Cassuto
  • Publication number: 20110149434
    Abstract: An embodiment of the present invention implements some or all major servo subfunctions for a storage device in integrated servo fields comprising sequences of encoded bits having selected mathematical properties. The integrated servo field is composed of a number of encoded sequences, which are members of a selected sequence set that is constrained to preferably provide some or all of the following functions: the Servo Track Mark (STM), the Position Error Signal (PES) and positional information such as the track-ID. The integrated servo fields can provide a Position Error Signal (PES) in relation to the center of a data track through the amplitude of the signal read for adjacent sequences. The servo system detects the sequences in the signal from the read head using a set of digital filters for the set of encoded sequences.
    Type: Application
    Filed: December 18, 2009
    Publication date: June 23, 2011
    Inventors: Jonathan Darrel Coker, David Timothy Flynn
  • Publication number: 20110149432
    Abstract: An embodiment of the present invention implements some or all major servo subfunctions for a storage device in integrated servo fields comprising sequences of encoded bits having selected mathematical properties. The integrated servo field is composed of a number of encoded sequences, which are members of a selected sequence set that is constrained to preferably provide some or all of the following functions: the Servo Track Mark (STM), the Position Error Signal (PES) and location information such as the track-ID. The juxtaposition of sequences in the servo wedges is additionally constrained to increase the detectability of the contribution of adjacent sequences in the read signal. The integrated servo fields can provide a Position Error Signal (PES) in relation to the center of a data track through the amplitude of the signal read for adjacent sequences.
    Type: Application
    Filed: December 18, 2009
    Publication date: June 23, 2011
    Inventors: Jonathan Darrel Coker, David Timothy Flynn
  • Patent number: 7961416
    Abstract: Approaches for estimating the operating radius of a head in a hard-disk drive. These approaches may be used in a constant or approximately constant density servo scheme. Statistics, which describe the proportion of high frequency values to low frequency values in a readback signal read by the read/write head of a persistent storage medium, such as a hard-disk drive (HDD), are maintained. An estimated location for the read/write head using the statistics is determined. The estimated location may be expressed as an estimated operating radius, which is an estimated distance from the center of the magnetic-recording medium to a current position of the read/write head. Based on the estimated location of the read/write head, an estimated clock frequency for a readback channel to use in reading the servo data stored on the magnetic recording medium is determined. The readback channel reads the servo data using the estimated clock frequency.
    Type: Grant
    Filed: August 11, 2009
    Date of Patent: June 14, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Roger William Wood, Jonathan Darrel Coker
  • Patent number: 7961422
    Abstract: A disk drive is disclosed comprising a disk having a plurality of servo tracks that define a plurality of data tracks, and a head actuated over the disk by a voice coil motor (VCM), wherein the head comprises a read element offset radially from a write element. The read element is positioned over a first servo track and the write element is positioned over a second servo track, and a first repeatable runout (RRO) of the first servo track is measured. The read element is positioned over the second servo track, and a second RRO of the second servo track is measured. A data center off-track is computed in response to the first RRO and the second RRO.
    Type: Grant
    Filed: February 19, 2009
    Date of Patent: June 14, 2011
    Assignee: Western Digital Technologies, Inc.
    Inventors: Min Chen, Li Yi, Duc T. Phan
  • Patent number: 7948707
    Abstract: A magnetic recording medium includes a disk substrate and a magnetic recording layer formed on one surface or both surfaces of the disk substrate. The magnetic recording layer includes at least one pattern area forming a plurality of data tracks in which a position for magnetic recording is patterned with a magnetic body and at least one continuous area formed of a continuous magnetic body, and at least a part of a servo pattern for following the data track is recorded in the continuous area. A method of recording a servo pattern on a magnetic recording medium includes determining a center position of the data track and a start position of the continuous area and recording a servo pattern for following the data track in the continuous area with respect to center position of the data track and the start position of the continuous area.
    Type: Grant
    Filed: November 8, 2007
    Date of Patent: May 24, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Yong-su Kim
  • Patent number: 7948701
    Abstract: Servo patterns and associated methods of fabricating servo patterns are described. For patterned storage media, data sectors and servo sectors may be patterned using self-assembly. In one embodiment, self-assembly is used to form a first array of islands and a second array of islands in servo sectors that are track-wise offset. A servo writing process is then performed to write a desired servo pattern in the arrays, such as for burst fields, synchronization fields, etc.
    Type: Grant
    Filed: November 30, 2009
    Date of Patent: May 24, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Thomas R. Albrecht, Zvonimir Z. Bandic, Xiao Z. Wu
  • Patent number: 7948708
    Abstract: An apparatus, system, and method comprise a magnetoresistive head configured to respond to magnetization states of patterned cells formed on a patterned medium. The magnetoresistive head detects the magnetization states of at least two patterned cells formed on a patterned medium. The magnetoresistive head generates a readback signal based on the magnetization state of the at least two patterned cells. A detector circuit coupled to the head determines a bit pattern corresponding to the readback signal. A processor circuit coupled to the detector circuit determines positional information associated with the magnetoresistive head relative to the at least two patterned cells based on the bit pattern. The system further comprises a patterned medium.
    Type: Grant
    Filed: March 23, 2009
    Date of Patent: May 24, 2011
    Assignee: Carnegie Mellon University
    Inventors: William C. Messner, Hiroyuki Suzuki, James A. Bain, Vijayakumar Bhagavatula, Sheida Nabavi
  • Patent number: 7933088
    Abstract: According to one embodiment, a disk drive has a DTM type disk. The DTM type disk has a servo area on one recording surface. In the servo area, a servo pattern is recorded. The servo pattern is composed of a projection-depression pattern and an N- and P-pole magnetic pattern. The N- and P-pole magnetic pattern is recorded in an address-data region that contains a cylinder code.
    Type: Grant
    Filed: December 18, 2008
    Date of Patent: April 26, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideo Sado, Masatoshi Sakurai, Yuji Sakai
  • Patent number: 7920355
    Abstract: According to one embodiment, disclosed herein is a disk drive that has a disk of discrete-track media (DTM) type. The DTM disk has servo regions. Each servo region has dividing grooves and non-servo data parts. Each dividing grooves extends along the centerline of any projecting region having a width larger than a prescribed value. Each non-servo data part suppresses reproduction noise. The disk drive has a read/write channel that includes a reproduced-signal processing unit. This unit reproduces servo data from each servo region.
    Type: Grant
    Filed: March 4, 2009
    Date of Patent: April 5, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuji Sakai
  • Patent number: 7920354
    Abstract: A recordable medium according to some embodiments includes a servo control field having a bit patterned media (BPM) pattern. The pattern includes a plurality of isolated magnetic islands or dots arranged in a down-track orientation and in a cross-track orientation. A phase of dots arranged on the medium in the servo control field varies in a first cross-track direction. The dots arranged on the medium may include a first phase pattern that has a first phase gradient in the first cross-track direction and a second phase pattern that has a second phase gradient, different from the first phase gradient, in the first cross-track direction. The dots may include a plurality of dot composites including a plurality of dots.
    Type: Grant
    Filed: September 15, 2008
    Date of Patent: April 5, 2011
    Assignee: Seagate Technology LLC
    Inventors: Puskal Prasad Pokharel, Mustafa Can Ozturk
  • Patent number: 7916415
    Abstract: A disk drive is disclosed comprising a disk including a plurality of servo tracks defined by a plurality of servo sectors, wherein each servo sector comprises a plurality of servo bursts, and each servo burst comprises at least one of four phases. A first two of the phases are orthogonal, and a second two of the phases are orthogonal. As a head is actuated over the disk a servo sector is read to generate a read signal. The read signal is processed to demodulate the servo bursts into a position error signal (PES) representing an offset of the head from a target radial location on the disk, and the read signal is also processed to decode at least two of the phases of the servo bursts into a binary sequence.
    Type: Grant
    Filed: March 27, 2008
    Date of Patent: March 29, 2011
    Assignee: Western Digital Technologies, Inc.
    Inventor: Jack M. Chue
  • Patent number: 7916422
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo tracks defined by a plurality of servo sectors, wherein each servo sector comprises a plurality of servo bursts, and each servo burst comprises a predetermined phase. After positioning the head over one of the servo tracks, a servo burst in one of the servo sectors is read to generate a read signal, and a sine and cosine component are extracted from the read signal. At least one of the sine and cosine components is rotated by an angle based on a radial location of the head. A position error signal for the head is generated in response to the rotated component.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: March 29, 2011
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Abhishek Dhanda, Jie Yu
  • Patent number: 7916416
    Abstract: A disk drive is disclosed comprising a disk having servo data defining a plurality of servo tracks. The servo data comprises a preamble comprising a varying length across a radius of the disk, and a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble. The tilt angle varies across the radius of the disk commensurate with the varying length of the preamble. A position error signal (PES) is generated in response to a phase difference when reading the preamble and the slanted line servo bursts.
    Type: Grant
    Filed: September 29, 2008
    Date of Patent: March 29, 2011
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Jie Yu
  • Patent number: 7903364
    Abstract: Provided are a method of protecting a head and a disk in a HDD from shocks and an apparatus therefor by detecting the movement of the HDD using the amount of jitter in servo signals and unloading the head when the movement is great enough to damage the head and the disk. The method of protecting the HDD from shocks includes: reading the servo signals from the rotating disk using the head that follows tracks on the disk, detecting an amount of jitter in the servo signals, comparing the detected amount of jitter with a predetermined threshold amount of jitter corresponding to a movement great enough to damage the head and the disk, and unloading the head if the detected amount of jitter is greater than the predetermined threshold amount of jitter.
    Type: Grant
    Filed: July 15, 2005
    Date of Patent: March 8, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Woo-cheol Jeong
  • Patent number: 7898762
    Abstract: A disk drive is disclosed comprising a head actuated over a disk, the disk including a plurality of servo sectors wherein each servo sector comprises at least one servo burst. A read signal emanating from the head is sampled while reading a servo burst in a servo sector to generate a plurality of sample values. A quality metric is generated in response to a plurality of sample values of a servo sub-burst representing part of the servo burst. When the quality metric does not exceed a threshold, the servo sub-burst sample values are excluded when generating a position error signal (PES) representing a position of the head over the disk. When the quality metric exceeds the threshold, the servo sub-burst sample values are included when generating the PES. The head is then positioned over the disk in response to the PES.
    Type: Grant
    Filed: October 21, 2009
    Date of Patent: March 1, 2011
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Abhishek Dhanda, Jie Yu
  • Patent number: 7894156
    Abstract: In a disk drive, a wedge-based scheme is used to determine wedge offset correction values for a track of the disk drive. Correction values for the offset of each servo wedge are calculated wedge-by-wedge, based on the position error signal (PES) of the most recently measured servo wedge in combination with the measured PES of other servo wedges. To minimize transport delay of the servo, the majority of servo-control calculations may be pre-calculated prior to measuring the PES at the current wedge. Wedge offset correction values for a given servo wedge are corrected iteratively with each revolution of the storage disk.
    Type: Grant
    Filed: March 30, 2009
    Date of Patent: February 22, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Richard M. Ehrlich, Anton L. Gerasimov
  • Patent number: 7889450
    Abstract: A technique is described for reducing overhead in a magnetic medium utilizing interspersed timing synchronization fields. In particular, a reader reads timing synchronization fields interspersed within data fields of the medium to obtain timing measurements. The reader is separated from a writer by a distance greater than a distance of the reader to traverse a select timing synchronization field. As such, the writer may perform a direct current (DC) write to the medium to suspend transitional write operations while the reader is reading the select timing synchronization field, and/or while the writer is over a unipolar field (e.g., a timing synchronization field).
    Type: Grant
    Filed: November 7, 2008
    Date of Patent: February 15, 2011
    Assignee: Seagate Technology LLC
    Inventors: Barmeshwar Vikramaditya, Bruce Douglas Buch, Jon Karsten Klarqvist
  • Patent number: 7880992
    Abstract: In a servo control loop, phase detection between a clock signal and servo burst fields on a movable storage media is carried out with compensation for the effects of frequency variation in the timing of servo burst fields.
    Type: Grant
    Filed: October 30, 2008
    Date of Patent: February 1, 2011
    Assignee: Seagate Technology LLC
    Inventors: Mustafa Can Ozturk, Richard Lyle Keizer, Puskal Prasad Pokharel
  • Patent number: 7872829
    Abstract: According to one embodiment, there is provided a disk drive that can perform dynamic offset control (DOC). The disk drive has a magnetic head, a disk, and offset calculating modules. The magnetic head has read head. Offset-measuring position data is written in a non-servo area provided in the disk. The read head reads the offset-measuring position data from the disk. Based on the offset-measuring position data thus read, the offset calculating modules calculate an offset value that changes during a one-rotation period of the disk.
    Type: Grant
    Filed: October 2, 2008
    Date of Patent: January 18, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuji Sakai
  • Patent number: 7864485
    Abstract: A magnetic recording medium enhances the quality of a reproducing signal. The magnetic recording medium has a servo pattern formed in a servo pattern area on at least one surface of a disk-shaped substrate by a concave/convex pattern having convex portions (recording areas) and concave portions (non-recording areas), and a data track pattern formed by the concave/convex pattern in a data recording area on the at least one surface of the disk-shaped substrate. In a state where recording data is not recorded in the data recording area, the convex portions in the servo pattern area are DC-magnetized, and the convex portions in the data recording area are AC-magnetized.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: January 4, 2011
    Assignee: TDK Corporation
    Inventors: Tatsuhiro Kobayashi, Makoto Moriya
  • Patent number: 7864469
    Abstract: Data track patterns and servo patterns are formed on an information recording medium by concave/convex patterns divided into ring-shaped regions that are concentric with the data track patterns. In the servo patterns, a unit convex length and a unit concave length along the direction of rotation increase in each ring-shaped region from an inside to an outside of the ring-shaped region in proportion to the distance from the center of the data track patterns and a value produced by dividing an average unit convex (or concave) length inside each ring-shaped region by a distance from the center to the ring-shaped region decreases toward the outer periphery of the medium. The ring-shaped regions include plural first regions between an innermost region and an outermost region. Respective lengths along a radial direction of the first regions increase toward an outer periphery of the medium.
    Type: Grant
    Filed: December 23, 2008
    Date of Patent: January 4, 2011
    Assignee: TDK Corporation
    Inventors: Yoshikazu Soeno, Kazuya Shimakawa
  • Patent number: 7864486
    Abstract: According to one embodiment, a hard disc apparatus comprises a disc, wherein areas between neighboring servo areas are allocated to data areas including data sectors, a head module, and a storage module configured to store head alignment data, wherein the head alignment data are defined for the data areas, and includes information indicating an interval from the servo area to a first data sector, information indicating a data area in one track, a first data sector which is a start sector of the track, and information indicating the presence/absence of a defective sector including a primary defect, and the start sector of a track including the defective sector is a data sector next to the defective sector.
    Type: Grant
    Filed: January 29, 2009
    Date of Patent: January 4, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuma Aso, Yasuhiko Ichikawa
  • Patent number: 7859779
    Abstract: A magnetic disk apparatus includes a magnetic disk, a magnetic head, a servo reproduction signal generator and a magnetic head controller. The disk includes a data recording area and a servo-pattern area. The data recording area includes a non-magnetic area scattered with magnetic regions, and the servo-pattern area includes uniformly magnetized magnetic regions larger than the magnetic regions in the recording area. The magnetic head reciprocates radially of the disk, giving a magnetization direction to the magnetic regions in the data recording area and reading the magnetization direction of the magnetic regions in the data recording area and the servo-pattern area. The servo reproduction signal generator reads the servo-pattern area, using the magnetic head, via an absolute-value calculation circuit to generate a servo reproduction signal before the recording or reading with respect to the data recording area.
    Type: Grant
    Filed: June 5, 2009
    Date of Patent: December 28, 2010
    Assignee: Toshiba Storage Device Corporation
    Inventors: Mineo Moribe, Masakazu Taguchi, Kazuyuki Ozaki
  • Patent number: 7848050
    Abstract: There is provided with a positioning control system which includes: a head moving unit configured to move a head for recording or reproducing information with respect to a disk capable of recording information; a position detecting unit configured to detect a position of the head; an error detecting unit configured to detect a position error signal of a detected head position with respect to a predetermined target position; a compensation controller configured to generate control input by performing phase lead compensation and phase delay compensation for the position error signal and supply the control input to the head moving unit; and a gain controller configured to control at least one of gains the phase lead compensation and the phase delay compensation based on frequency components contained in the position error signal and an amplitude of the position error signal.
    Type: Grant
    Filed: February 26, 2009
    Date of Patent: December 7, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiyuki Ishihara, Shinji Takakura
  • Patent number: 7843661
    Abstract: One illustrative embodiment of the present invention pertains to a device. The device is configured to evaluate a Gray code value and to provide compensation for error in the Gray code value. Another illustrative embodiment of the present invention pertains to a method. The method includes comparing Gray code information with servo information. The method also includes evaluating error in the Gray code information based on the comparison between the Gray code information with servo information. Another illustrative embodiment of the present invention pertains to a data storage system. The data storage system includes a data storage medium, a head, and a controller. The head is controllably positionable relative to the data storage medium. The controller includes a means for sensing position information from the head. The controller also includes a means for compensating for error in the position information, to position the head relative to the data storage medium.
    Type: Grant
    Filed: August 24, 2005
    Date of Patent: November 30, 2010
    Assignee: Seagate Technology LLC
    Inventors: David Louis Schell, Chris T. Settje, Thomas Zirps
  • Patent number: 7839594
    Abstract: A data-storage disk includes a disk sector for storing data and a servo wedge located at the beginning of the sector. The servo wedge indentifies the sector in conjunction with both an initial positioning of a read-write head and a data read or write operation. By using a servo wedge to provide both an initial head position on disk spin up and a head position during a read or write operation, one can increase a disk's data-storage capacity by reducing the number of, or altogether eliminating, spin-up wedges.
    Type: Grant
    Filed: November 5, 2001
    Date of Patent: November 23, 2010
    Assignee: STMicroelectronics, Inc.
    Inventor: Hakan Ozdemir
  • Patent number: 7839590
    Abstract: In a method of servo writing of a magnetic recording system and the magnetic recording system, the signal is recorded in a dummy area with a higher recording density than the burst signal. Also, the maximum bit length of the burst area is shortened as compared with the maximum bit length of the data area. A servo control method for perpendicular recording similar to that for longitudinal recording can be used to reduce the development cost. The anti-signal decay performance is also improved. Further, since the variations of the burst signal along the track width is suppressed, the positioning accuracy is improved. These effects combine to produce a reliable magnetic recording system of large capacity.
    Type: Grant
    Filed: September 9, 2008
    Date of Patent: November 23, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yasutaka Nishida, Takehiko Hamaguchi, Hideki Sawaguchi, Hisashi Takano
  • Publication number: 20100290153
    Abstract: The operational bandwidth of a servo control circuit can be increased using a plurality of servo processors that handoff between them the responsibility for controlling head positioning in response to sequentially occurring servo patterns.
    Type: Application
    Filed: May 18, 2009
    Publication date: November 18, 2010
    Inventor: Randall David Hampshire
  • Patent number: 7830635
    Abstract: On a magnetic recording medium, M sets of burst patterns are formed along a direction of rotation of a substrate in each burst pattern region. Each burst pattern is formed so as to include two types of burst signal units that have an equal length along a radial direction of the substrate. In a predetermined range (2·M) centers in the radial direction of the burst patterns are present at intervals of (1/N) times the track pitch in the radial direction. The predetermined range has a length along the radial direction of (2M/N) times the track pitch. M or N is a natural number of two or higher. The two types of burst signal units are formed of non-recording regions and facing end parts in the radial direction of the first type of burst signal units and the second type of burst signal units are separated via recording regions.
    Type: Grant
    Filed: April 30, 2009
    Date of Patent: November 9, 2010
    Assignee: TDK Corporation
    Inventors: Akimasa Kaizu, Yoshikazu Soeno, Makoto Moriya
  • Patent number: 7821738
    Abstract: Data track pattern regions, in which data track patterns are formed by concave/convex patterns, and servo pattern regions, in which servo patterns are formed by concave/convex patterns, are provided on a magnetic recording medium so as to be alternately disposed in a circumferential direction. At least one predetermined region that differs to the data track pattern regions is provided between two servo pattern regions that are adjacent in a circumferential direction. A concave/convex pattern including a plurality of first convex parts formed continuously in a radial direction is formed in each predetermined region.
    Type: Grant
    Filed: November 8, 2006
    Date of Patent: October 26, 2010
    Assignee: TDK Corporation
    Inventors: Kuniyasu Ito, Makoto Moriya, Kazuya Shimakawa
  • Patent number: 7813076
    Abstract: A hard disk drive with a controller that determines a position error signal gain. The position error signal gain is determined from a total servo loop gain and a function that is defined by a slope of a line of A and B servo bits measured at N off-track positions. The function determines an actual plant gain and thus provides a more accurate position error signal gain.
    Type: Grant
    Filed: September 3, 2008
    Date of Patent: October 12, 2010
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chang Ik Kang, Sang Hoon Chu
  • Patent number: 7813074
    Abstract: A mechanical transport device includes a system for transport; and a hard disk drive attached to the system. The hard disk drive comprises a magnetic recording disk to record data, a head to read or write the data to or from the disk, and a drop sensor designed to sense a shock condition. The system for transport may be a vehicle such as a car. Additional systems are also presented.
    Type: Grant
    Filed: April 21, 2008
    Date of Patent: October 12, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Susumu Shimotono, Tetsuya Noguchi, Mitsuru Ogawa, Akiyoshi Tanaka
  • Patent number: 7813065
    Abstract: Various embodiments of the present invention provide systems and methods for performing modified rate burst demodulation. For example, a method for performing modified rate burst demodulation is disclosed. The method includes receiving a data input that includes a synchronization pattern, an information pattern, and a demodulation pattern. A periodic boundary is established along with a phase and frequency of a sampling clock based at least in part on the synchronization pattern. The information pattern is processed using the sampling clock to determine a location fix. The sampling clock is phase shifted by a skew amount and a phase shifted sampling clock is provided. The demodulation pattern is processed using the phase shifted sampling clock.
    Type: Grant
    Filed: April 29, 2008
    Date of Patent: October 12, 2010
    Assignee: Agere Systems Inc.
    Inventors: Viswanath Annampedu, Venkatram Muddhasani, Xun Zhang
  • Publication number: 20100246056
    Abstract: In a disk drive, a wedge-based scheme is used to determine wedge offset correction values for a track of the disk drive. Correction values for the offset of each servo wedge are calculated wedge-by-wedge, based on the position error signal (PES) of the most recently measured servo wedge in combination with the measured PES of other servo wedges. To minimize transport delay of the servo, the majority of servo-control calculations may be pre-calculated prior to measuring the PES at the current wedge. Wedge offset correction values for a given servo wedge are corrected iteratively with each revolution of the storage disk.
    Type: Application
    Filed: March 30, 2009
    Publication date: September 30, 2010
    Inventors: Richard M. EHRLICH, Anton L. GERASIMOV
  • Patent number: 7800853
    Abstract: A disk drive is disclosed comprising a disk having a plurality of data tracks defined by a plurality of servo sectors, wherein each servo sector comprises a Gray coded address representing at least part of a track address. The disk drive further comprises a head actuated over the disk for detecting a first Gray coded address in a first servo sector. A second Gray coded address is generated in response to the first Gray coded address. The first Gray coded address is decoded into a first binary address, and the second Gray coded address is decoded into a second binary address. One of the first and second binary addresses closest to a target address is selected, and the head is positioned in response to the selected binary address.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: September 21, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Jie Yu
  • Patent number: 7800859
    Abstract: A recording/reproducing apparatus includes: a rotary-type magnetic recording medium including a track pattern with concentric or spiral data recording tracks; a composite magnetic head including a reproducing element that reads magnetic signals from the medium and a recording element that writes magnetic signals on the medium; a control unit that moves the magnetic head over the medium to carry out tracking servo control on the reproducing element or the recording element to keep the element on a desired track; and a storage unit that stores offset information that specifies offsets for calculating an adjustment used to adjust a head position of the magnetic head during tracking servo control. The stored offset information specifies at least two different offsets per revolution of the medium. During tracking servo control, the control unit changes the adjustment at least once per revolution of the medium in accordance with offsets specified based on the offset information.
    Type: Grant
    Filed: February 25, 2008
    Date of Patent: September 21, 2010
    Assignee: TDK Corporation
    Inventors: Makoto Moriya, Kazuya Shimakawa
  • Publication number: 20100226038
    Abstract: A data storage medium comprises a plurality of data regions, and a plurality of servo regions configured to provide positioning information to a reading device. Each of the plurality of data regions corresponds to more than one of the plurality of servo regions. The more than one of the plurality of servo regions are configured to provide positioning information to the reading device at discrete times corresponding to a data operation of a corresponding data region.
    Type: Application
    Filed: March 5, 2009
    Publication date: September 9, 2010
    Applicant: WESTERN DIGITAL (FREMONT), LLC
    Inventors: SHAOPING LI, JINSHAN LI, FENG LIU, KUOK SAN HO
  • Patent number: 7787208
    Abstract: Provided are a bit patterned medium having a super-track, a method of tracking a track of the bit patterned medium, a head appropriate for the bit patterned medium, and an information recording/reproducing apparatus including the bit patterned medium and the head. The bit patterned medium includes a substrate, and a recording layer comprised of a plurality of bit cells which are formed on the substrate by being separated from each other, along a plurality of tracks. Each of the plurality of tracks includes a super-track comprised of a plurality of sub-tracks. Bit cells formed on a sub-track from among the plurality of sub-tracks in the super-track are disposed so as to deviate from bit cells formed on another sub-track from among the plurality of sub-tracks in the super-track. A track ID (identification) for recognizing the super-track, and a servo burst generating a position error signal when a head tracks the super-track, are arranged in an area of each of the plurality of tracks.
    Type: Grant
    Filed: April 29, 2008
    Date of Patent: August 31, 2010
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Dong-ki Min, Seung-bum Hong
  • Patent number: 7787210
    Abstract: A magnetic hard disk drive includes a method for eliminating that portion of track following error by a read/write transducer that is caused by repeatable runout of the disk tracks. The repeatable runout is eliminated by application of an iterative algorithm that calculates feed-forward correction terms based on gain coefficients iteratively calculated from the amplitude and phase portions of a Bode plot characterizing the system. The corrective coefficients can be inserted into the hard disk drive at a summing junction that redefines the centerline of the track, or at a summing junction that causes the actuator to follow the repeatable runout and make non-repeatable runout corrections relative thereto.
    Type: Grant
    Filed: March 17, 2009
    Date of Patent: August 31, 2010
    Assignee: Headway Technologies, Inc.
    Inventors: David Drouin, Billy Wahng
  • Patent number: 7777983
    Abstract: A method of writing a servo pattern to a disk, wherein a servo pattern is generated in a processor. The generated servo pattern is then written to a disk. The servo pattern for a servo sector is preferably generated in a single routine.
    Type: Grant
    Filed: September 14, 2006
    Date of Patent: August 17, 2010
    Assignee: Xyratex Technology Limited
    Inventors: Keith Rowland Charles Brady, Alistair Malcolm Campbell, Mark John Newland
  • Patent number: 7773323
    Abstract: On a magnetic recording medium, M sets of burst patterns are formed along a direction of rotation of a substrate in each burst pattern region. Each burst pattern is formed so as to include two types of burst signal units that have an equal length along a radial direction of the substrate. In a predetermined range, (2M) centers in the radial direction of the burst patterns are present at intervals of (1/N) times the track pitch in the radial direction. The predetermined range has a length along the radial direction of (2M/N) times the track pitch. M or N is a natural number of 2 or higher. The two types of burst signal units are formed of non-recording regions and end regions of the burst signal units overlap in the radial direction in at least one part region of the substrate.
    Type: Grant
    Filed: March 27, 2009
    Date of Patent: August 10, 2010
    Assignee: TDK Corporation
    Inventors: Akimasa Kaizu, Yoshikazu Soeno, Makoto Moriya
  • Patent number: 7771852
    Abstract: A magnetic recording disk has patterned nondata regions that are used for read/write head positioning and data synchronization. The nondata regions contain nondata islands of magnetizable material separated by nonmagnetic spaces with the nondata islands having alternating magnetization polarity in the along-the-track direction. In each nondata region, every other nondata island in the along-the track direction has the same magnetization direction, with adjacent nondata islands having antiparallel magnetization directions. The disk may be either a horizontal magnetic recording disk, wherein the antiparallel magnetization directions are in the plane of the recording layer and parallel to the along-the-track direction, or a perpendicular magnetic recording disk, wherein the antiparallel the magnetization directions are “into” and “out of” the recording layer.
    Type: Grant
    Filed: June 9, 2005
    Date of Patent: August 10, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Thomas R. Albrecht, Zvonimir Bandic
  • Patent number: 7768735
    Abstract: In accordance with various embodiments, an angular location of a first servo field along an annular track is determined in relation to a difference between a first code value of the first servo field and a second code value of a second servo field along the track. A radial location of the track is obtained in relation to the determined angular location of the first servo field.
    Type: Grant
    Filed: August 28, 2007
    Date of Patent: August 3, 2010
    Assignee: Seagate Technology LLC
    Inventors: Stanley H. Shepherd, Bruce Liikanen
  • Patent number: 7768737
    Abstract: A mark information is recorded in an area which is on a circumference of a magnetic disk corresponding to a last track in which a servo information write is ended or a track, which is one or two in front of the last track in which servo information is not written and the mark information is detected by returning a magnetic head in a radial direction of the magnetic disk by a fine movement stage after the magnetic head is moved to a next aimed track by a coarse movement stage. The servo information write position is detected by the magnetic head and the servo information is written in a servo information write position of a next track by positioning the magnetic head therein by using the fine movement stage.
    Type: Grant
    Filed: September 4, 2008
    Date of Patent: August 3, 2010
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Yoshihiro Sakurai, Hitoshi Otani, Kunihito Higa, Yukio Yamamoto
  • Patent number: 7764458
    Abstract: An apparatus, method, and system for providing a fine adjustment for transducing head positioning in a hard disk drive (HDD). The apparatus, method, and system include reading a positioning error field wherein the resulting signal is a substantially sinusoidal position error signal (PES), filtering the PES to remove low frequencies and attenuate high frequencies, sample the filtered PES at a multiple of the channel frequency, filter the higher frequency harmonics, down sample the PES, and provide a signal proportional to the amplitude of the down sampled PES. This signal is the reference signal to the head positioning servo.
    Type: Grant
    Filed: August 25, 2009
    Date of Patent: July 27, 2010
    Assignee: Marvell International Ltd.
    Inventors: Pantas Sutardja, Michael B. Madden
  • Patent number: 7760459
    Abstract: Systems and techniques to select a framing and determine a waveform polarity of an encoded repeating pattern include, in at least one aspect, operations including: decoding an encoded repeating pattern using multiple framings of signal samples of a signal from a machine-readable medium; correlating the signal samples that indicate pattern transitions, for the multiple framings, with valid pattern transitions as defined by the encoding; accumulating the transition pattern correlations for the multiple framings; selecting one of the multiple framings as a correct framing for decoding based on the accumulated correlations; and determining a waveform polarity for the signal based on the repeating pattern and the selected correct framing.
    Type: Grant
    Filed: December 10, 2007
    Date of Patent: July 20, 2010
    Assignee: Marvell International Ltd.
    Inventors: Ke Han, Pantas Sutardja, Rui Cao