For Rotary Carrier (e.g., Disc) Patents (Class 360/78.04)
  • Patent number: 6778343
    Abstract: A method and apparatus is disclosed for providing a track pitch on a recording surface that is associated with the width of the tracks written by the write element of a head therefore reducing the number of heads that are discarded when a fixed relationship between track pitch of storage media in a storage device is desired. The method includes the steps of calculating the width of a write element to be associated with a storage medium and determining the track pitch for the storage medium based upon the calculated width of the write element. The step calculation of the width of the read/write element includes writing a pattern on a storage medium at a predetermined radius using the write element associated with the storage medium to form a written track, moving the head across the written track to read an amplitude sensed from the written track by the head, and ascertaining the width of the write element based upon the sensed amplitude.
    Type: Grant
    Filed: March 25, 1998
    Date of Patent: August 17, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands BV
    Inventor: Lewis L. Nunnelley
  • Patent number: 6768607
    Abstract: A disk drive comprises an actuator servo control system including at least one disk, an actuator structure comprising at least transducer head for writing and/or reading data from the disk and providing a transducer head position error signal (PES), and a servo compensator applying a servo control algorithm to the PES to produce a servo control signal. An adaptive elliptic notch filter controller is adapted to analyze the PES for a transducer head at a disk track radii, identify resonant disturbances present in the PES, select two adjacent resonant disturbances having first and second frequencies, ascertain coefficients of at least a fourth-order elliptic notch filter transfer function having first and second zero-notches with frequencies substantially at the first and second resonant frequencies, apply the at least fourth-order elliptic notch filter transfer function with the ascertained coefficients in the servo system to thereby substantially attenuate the selected adjacent resonant disturbances.
    Type: Grant
    Filed: August 22, 2001
    Date of Patent: July 27, 2004
    Assignee: Hitachi Global Storage TEchnologies Netherlands B.V.
    Inventors: Hal Hjalmar Ottesen, Gordon James Smith
  • Patent number: 6765749
    Abstract: An attenuating filter for the servo control processor of a disc drive data storage device. The filter is constructed by determining the peak resonance in the structure frequency response above a preselected magnitude and computing a digital notch filter to attenuate that peak resonance. The notch filter domain is then summed with the structure frequency response to derive a modified structure frequency response. The modified structure frequency response is substituted for the unfiltered structure frequency response and again the peak resonance in the modified structure frequency response above a preselected magnitude is determined and a notch filter is computed as necessary. This process of summing the structure frequency response with the latest computed notch filter domain to derive a modified structure frequency response continues until the peak resonance of the latest modified structure frequency response is less than the preselected magnitude.
    Type: Grant
    Filed: January 24, 2002
    Date of Patent: July 20, 2004
    Assignee: Seagate Technology LLC
    Inventors: Paul A. Galloway, Mohammad A. Miah
  • Publication number: 20040136109
    Abstract: On the basis of the position of a first target track specified by a command from a host, a CPU calculates a first offset value reflecting a track pitch that enables the adverse effects of crosstalk to be suppressed. The first offset value indicates an offset of a target position at which a head is to be actually positioned from a predetermined position on the first target track. The CPU determines a second target track, to which the target position belongs, and a second offset value on the basis of the position of the first target track and the calculated first offset value. The second offset value indicates an offset of the target position from the predetermined position on the second target track. The CPU positions the head at the target position on the determined second target track on the basis of the determined second target track position and second offset value.
    Type: Application
    Filed: December 23, 2003
    Publication date: July 15, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tatsuharu Kusumoto, Koji Yaegashi
  • Patent number: 6762571
    Abstract: A method and apparatus for controlling acoustic noise generated by a seek operation in a disc drive by using a feedback control system to control the seek operation. The feedback control system is excited by a feed-forward signal during execution of the seek operation. An acoustic factor, which defines a seek operation noise level, is selected. The feed-forward signal is generated based, at least in part, upon the selected acoustic factor. The feed-forward signal has a first derivative having a maximum value. The selected acoustic factor is used to select the maximum value of the first derivative of the feed-forward signal.
    Type: Grant
    Filed: May 10, 2002
    Date of Patent: July 13, 2004
    Assignee: Seagate Technology LLC
    Inventors: ShuangQuan Min, MingZhong Ding, KianKeong Ooi
  • Patent number: 6762902
    Abstract: A method, apparatus, or product for a rotating disk storage device. In one embodiment, the apparatus includes a disk, a spindle motor that rotates the disk, a transducer, an actuator arm that can move the transducer, and a controller. The controller can control the movement of the actuator arm to move the transducer across the disk surface from a first track to a second track, and determine a position error signal (PES) at one or more positions between the first and second tracks, where the PES includes a non-repeatable disturbance signal. The controller can iteratively generate a disturbance correction signal at the one or more positions based on the PES, combine the disturbance correction signal with the PES to minimize the non-repeatable disturbance signal to provide a corrected PES, and vary, at the one or more positions, the movement of the transducer as a function of the corrected PES.
    Type: Grant
    Filed: October 9, 2001
    Date of Patent: July 13, 2004
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Kok-Kia Chew
  • Patent number: 6762901
    Abstract: A power driver for driving a signal on a load using voltage-mode driver. A system processor generates commands indicating a programmed drive signal desired from the voltage-mode driver. A VBEMF compensator determines a compensated command to compensate for the back electromotive force voltage produced by the load. The compensated commands are coupled to the voltage-mode driver, such that the voltage-mode driver generates a voltage output based upon the compensated command.
    Type: Grant
    Filed: July 23, 2001
    Date of Patent: July 13, 2004
    Assignee: STMicroelectronics, Inc.
    Inventor: John P. Hill
  • Publication number: 20040130817
    Abstract: The servo data writing device has a simple system and small structure. The servo data writing device, to which a magnetic disk drive unit, which includes: a magnetic disk attached to a spindle; a magnetic head for writing data onto and reading data from the magnetic disk; and an inner actuator for moving an arm holding the magnetic head in the radial direction of the magnetic disk, is attached and which writes servo data in each track of the magnetic disk with the magnetic head, comprises a non-contact position sensor for detecting a position of the arm from outside of the magnetic disk drive unit without contact. The servo data writing device detects the position of the arm by the non-contact position sensor and controls an inner actuator control circuit, which is assembled in the magnetic disk drive unit, so as to position the magnetic head.
    Type: Application
    Filed: December 18, 2003
    Publication date: July 8, 2004
    Applicant: Fujitsu Limited
    Inventors: Masanori Fukushi, Masaru Ishijima
  • Patent number: 6760174
    Abstract: A method of recovering data from a data sector through adaptive fly height to improve reliability of a disc drive is disclosed. Encountering a data error in a data sector initializes an error recovery routine that increases a fly height of the read/write head for asperity encounters, or decreases the fly height of the read/write head for low amplitude read signal encounters. In the case of asperity encounters, when the increased fly height fails data recovery, the read/write head is positioned off track, then lowered to burnish the asperity and the data sector is re-read.
    Type: Grant
    Filed: January 25, 2002
    Date of Patent: July 6, 2004
    Assignee: Seagate Technology LLC
    Inventor: Monty A. Forehand
  • Patent number: 6760180
    Abstract: A servo track writer for writing a servo track signal to a disk medium in a disk drive including the disk medium, a head for reading/writing information from/to the disk medium, and an internal actuator for moving the head across tracks formed on the disk medium. The internal actuator has a rotatable carriage for supporting the head. The servo track writer includes an external actuator having an arm, a solid deformation element provided in relation to the arm, and an effector mounted on the arm; an internal actuator control unit for controlling the internal actuator; an external actuator control unit for controlling the external actuator; a solid deformation element control unit for controlling the solid deformation element; and an arm position detecting device for detecting a position of the arm. The solid deformation element is divided into a first segment functioning as an actuator for minutely displacing the carriage, and a second segment functioning as a sensor for detecting a position of the effector.
    Type: Grant
    Filed: August 30, 2001
    Date of Patent: July 6, 2004
    Assignee: Fujitsu Limited
    Inventors: Seiji Kino, Hirofumi Ohsawa, Yukio Ozaki
  • Publication number: 20040125498
    Abstract: Clock speed of the processor in a hard disk drive is controlled during run time to optimize the trade-off between minimizing power consumption and maximizing performance. Processor clock speed is increased during processing of code more performance critical to the disk drive system, while processor clock speed is reduced when less performance critical code is processed. An example of more critical code where processor clock speed is increased is the code executed by the processor from the start of a servo interrupt until output of resulting servo current command is provided from the processor to the actuator controller. To enable changing processor clock speed, an ASIC containing the disk drive processor is selected which provides the ability to switch clock rates of the processor during processor run time.
    Type: Application
    Filed: April 14, 2003
    Publication date: July 1, 2004
    Inventor: Thorsten Schmidt
  • Patent number: 6757129
    Abstract: In a magnetic disk storage apparatus, when a drive current of the voice coil motor is small, the head drive control circuit executes the linear drive mode under which the voice coil motor is driven in a linear control manner, whereas when the drive current is large, the head drive control circuit executes the pulse drive mode under which the voice coil motor is driven in a pulse width control manner. Both modes are carried out by employing a commonly-used output amplifier that is arranged as a push-pull type output circuit made of both a push-driving output transistor and a pull-driving output transistor. An operation mode of this output amplifier is set to an AB-class operation during the linear drive mode, whereas the operation mode of this output amplifier is set to a B-class operation during the pulse drive mode.
    Type: Grant
    Filed: February 25, 2002
    Date of Patent: June 29, 2004
    Assignees: Renesas Technology Corporation, Hitachi Ulsi Systems Co., Ltd.
    Inventors: Hiroshi Kuroiwa, Yasuhiko Kokami
  • Patent number: 6757126
    Abstract: A magnetic recording medium having a magnetic layer includes a plurality of tracks formed on the magnetic layer. The tracks have information magnetically recorded thereon. A magnetization change area for tracking control is formed on the magnetic layer adjacent to and along a length of each of the tracks. The magnetization change area has magnetic flux which changes along the length of the tracks.
    Type: Grant
    Filed: April 16, 1999
    Date of Patent: June 29, 2004
    Assignee: Fujitsu Limited
    Inventors: Sumio Kuroda, Koichi Iida
  • Publication number: 20040120068
    Abstract: A detector detects, in read data, a servo address mark of a type indicated by a register. Every time a SAM is detected during a self servo process, a CPU carries out tracking control in accordance with corresponding servo data. The CPU causes a head to write a corresponding type of additional servo data item in a disk at a position offset from the position of servo data containing the detected SAM, by a predetermined distance in a circumferential direction of the disk. Every time sets of servo data, each consisting of various types of data items, are written in the disk, the head is moved by a predetermined pitch in a radial direction of the disk.
    Type: Application
    Filed: July 23, 2003
    Publication date: June 24, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Takahiro Koyanagi
  • Patent number: 6754035
    Abstract: The temperature of an actuator voice coil in a disc drive is regulated so as to prevent outgassing. In a preferred embodiment, coil temperature is calculated at the beginning of each long seek. If the temperature is determined to be at or below a predetermined “safe” level, temperature rise is not limited and power may be applied to the coil without additional limitations. If, however, coil temperature is determined to be above the “safe” level, proportional control is used to scale back power generation so as to prevent the coil temperature from exceeding the coil's specified temperature limit.
    Type: Grant
    Filed: January 31, 2001
    Date of Patent: June 22, 2004
    Assignee: Seagate Technology LLC
    Inventors: Stuart Kevin Francis, Mitchell Ray Rose, Bijan Tehrani
  • Patent number: 6754032
    Abstract: Radial correction factors are calculated for each ruler on a patterned media in a data storage system. A ruler is a position-sensing pattern that defines the radial position of a recording head. Rulers are patterned onto each disk before the disks are assembled into a storage system. The radial correction factors are then added to the measured position information during read and/or write operations of the data storage system. The radial correction factors correct for any radial misalignment created by disturbances in the data storage system. Circumferential correction factors are calculated for each patterned media in the data storage system. A corrected sector number is then determined by redefining the original sector numbers using the circumferential correction factors.
    Type: Grant
    Filed: October 23, 2000
    Date of Patent: June 22, 2004
    Assignee: Seagate Tech. LLC
    Inventors: Gabor Szita, Karl A. Belser
  • Patent number: 6747833
    Abstract: The position information of the magnetic head is generated also from the data area to improve the positioning accuracy. The magnetic disk drive has a function of oscillating the magnetic head in the radial direction in the data area at a specific frequency and a function of detecting a read signal during the execution of the oscillation function and detects position information of the magnetic head from the detected read signal. The magnetic head position control can be performed in the data area. The magnetic head position signal not dependent on the frequency of a sampling signal generated from the servo information area can be generated. This in turn improves the data recording density and allows a highly precise position control of the magnetic head, thus improving the reliability of the magnetic disk drive.
    Type: Grant
    Filed: June 25, 2001
    Date of Patent: June 8, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Masayoshi Shimokoshi, Takeshi Doi
  • Publication number: 20040105186
    Abstract: In a disk drive, a disk medium includes servo areas on which servo data is recorded and data areas on which data is recorded. In each of data tracks in, e.g., an outer radius of the disk medium, the inclination &thgr;2 of the servo data recorded on the servo areas is smaller than the inclination &thgr;1 of the data recorded on the data areas.
    Type: Application
    Filed: November 18, 2003
    Publication date: June 3, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Koji Yano
  • Patent number: 6744589
    Abstract: A disc drive including a rotatable data track, a dual-stage actuator with a primary actuator motor supporting an actuator arm, a read/write head supported by the actuator arm and communicating with a secondary actuator motor, and steps for controlling range of motion of the secondary actuator motor. The controlling steps include supplying and sustaining a bias signal to a single-sided unipolar device driver that then apply a bias voltage the secondary actuator motor to induce the secondary actuator motor to expand substantially one half of its expansion capabilities. And, confining correction signals provided by a control circuit of the disc drive, used in correcting mechanical position of the secondary actuator motor, to a voltage ranging substantially between a positive “+” and negative “−” voltage substantially equal to the applied bias voltage.
    Type: Grant
    Filed: May 2, 2001
    Date of Patent: June 1, 2004
    Assignee: Seagate Technology LLC
    Inventors: John C. Morris, Reed D. Hanson
  • Patent number: 6741914
    Abstract: A method for optimizing the attenuation of mechanical resonances of actuator driving energy of a disc drive is presented. The method generally involves determining a resonant frequency range of the disc drive, comparing the resonant frequency range to a filter coverage limit, failing the disc drive if the resonant frequency range exceeds the filter coverage limit, and storing notch filter constants in servo flash memory of a servo control processor if the filter coverage limit is not exceeded by the range of resonant frequencies. The notch filter constants configure the notch filter to attenuate the frequencies of the driving energy produced by the servo control processor that are within the resonant frequency range. The notch filter is implemented by the servo control processor each time the disc drive is used. Also presented is a disc drive and a program that are capable of implementing the above-described method.
    Type: Grant
    Filed: December 30, 1999
    Date of Patent: May 25, 2004
    Assignee: Seagate Technology LLC
    Inventor: Jimmy Tze Ming Pang
  • Publication number: 20040095671
    Abstract: Disclosed is a data storage device to provide servo patterns of a track pitch individually consistent with head characteristics (writing width, and reading width) in a recording medium of a hard disk device. The data storage device is provided with a disk having pitch information indicating a track pitch recorded in a predetermined area, and a head for scanning the disk to read the TPI ID and reading/writing data from/in the disk by being subjected to seeking control based on the TPI ID. The TPI ID is recorded as a part of a servo pattern in a TPI ID embedded area provided in an outer periphery of a data area of the disk.
    Type: Application
    Filed: June 19, 2003
    Publication date: May 20, 2004
    Applicant: Hitachi Global Storage Technologies
    Inventors: Masaomi Ikeda, Nobuyuki Kitazaki, Kenji Ogasawara, Atsushi Takeichi, Hirofumi Yanase
  • Patent number: 6738220
    Abstract: A disk drive control system that compensates for mechanical bias torques present in disk drives. A transducer, commonly referred to as a head, is attached to an actuator arm that is subjected to mechanical bias torques, including flex bias torque and bearing friction. The net bias torque has a mechanical memory that is manifested as hysteresis whose magnitude depends on the size of the stroke length between inflection points of the transducer in seek operations. The dependence of the net bias torque includes location of the transducer, direction of the seek, and the history of previous seeks. The dependence may further include operating temperature of the disk drive. The disk control system determines and applies these corrections to the disk drive to enhance the seek performance.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: May 18, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventor: Raffi Codilian
  • Patent number: 6738219
    Abstract: A seek pattern formation circuit includes a seek pattern generation circuit for generating a seek pattern formed of a predetermined pulse train every time a step pulse is applied and a seek pattern shaping circuit for shaping the seek pattern and supplying the shaped seek pattern to a stepping motor driver. When the period for which the step pulse is supplied is shorter than the period for which the seek pattern is generated, and when at least one of pulses included in the seek pattern is very narrow, the seek pattern shaping circuit selectively eliminates the narrow pulse. As a result, narrow pulses which may induce noise are not supplied to the stepping motor driver, and hence a malfunction in the stepping motor driver does not occur.
    Type: Grant
    Filed: September 4, 2001
    Date of Patent: May 18, 2004
    Assignee: Alps Electric Co., Ltd.
    Inventor: Munehisa Haitani
  • Patent number: 6735032
    Abstract: A multi-actuator disk storage device has at least two actuators respectively mounting plural product heads. Servo writing is performed using the product heads themselves. A first servo write operation is performed that includes operating a product head of the first actuator as a first clock head to generate first clock reference information for the product heads of the second actuator, which are operated as servo write heads to perform servo writing of disk areas associated with the second actuator using the first clock reference information. To servo write disk areas associated with the first actuator, a second servo write operation is performed. This operation includes operating a product head of the second actuator as a second clock head to generate second clock reference information for the product heads of the first actuator, which are operated as a servo write heads to perform servo writing using the second clock reference information.
    Type: Grant
    Filed: April 16, 2001
    Date of Patent: May 11, 2004
    Assignee: International Business Machines, Inc.
    Inventors: George Anthony Dunn, Scott Arthur Thomas
  • Patent number: 6731453
    Abstract: A disc drive comprises a drive motor mechanically coupled to a disc and a voice coil motor mechanically coupled to a read/write head on the disc. A power integrated circuit is electrically coupled to the drive motor and the voice coil motor. The power integrated circuit includes an integrated temperature sensor that provides a temperature output. A control circuit receives the temperature output and provides a voice coil motor control output to the power integrated circuit as a function of the temperature output.
    Type: Grant
    Filed: June 27, 2001
    Date of Patent: May 4, 2004
    Assignee: Seagate Technology LLC
    Inventors: Garry E. Korbel, Brian R. Pollock
  • Publication number: 20040080854
    Abstract: A dual GMR or dual spin valve sensor has a self-pinned layer which has its magnetic moment pinned perpendicular to an air bearing surface by sense current fields from conductive layers in the dual spin valve sensor when a sense current is conducted therethrough. This scheme eliminates one of the antiferromagnetic pinning layers which is typically employed in a dual GMR or dual spin valve sensor. The self-pinned layer is thin so that its demagnetization field will not be greater than the sense current fields acting thereon. Because of the thinning of the self-pinned layer the spin valve effect of the spin valve sensor is degraded by scattering of conduction electrons at the boundary of the self-pinned layer.
    Type: Application
    Filed: June 30, 2003
    Publication date: April 29, 2004
    Applicant: Hitachi Global Storage Technologies
    Inventor: Hardayal Singh Gill
  • Publication number: 20040080860
    Abstract: A position detection means generates a position error signal corresponding to a current position of a head, a position control means generates a position control signal from the position error signal, a voltage detection means detects a voltage signal generated when driving an actuator by a driving means, a disturbance estimation means generates a disturbance estimation signal from a driving signal and the voltage signal, and a correction means outputs the driving signal from the disturbance estimation signal and the position control signal.
    Type: Application
    Filed: September 26, 2003
    Publication date: April 29, 2004
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO,, LTD.
    Inventors: Toshio Inaji, Hiroshi Kohso, Keizo Miyata
  • Publication number: 20040075936
    Abstract: A method of reproducing data and a control device using a controllable dummy read gate. In the method of reproducing data, at least one of a pulse width, a pulse generating location and a number of pulses is controlled so that a dummy read gate is generated. Then, a read gate for reproducing a target sector is generated, and data is reproduced using the read gate. According to the method, the pulse width of the dummy read gate is generated, a location of the defect sector is avoided and error estimation is decreased. Further, in a case where it is determined that the defect sector or signal distortion exists, the read error is prevented by adjusting the pulse generating location of the dummy read gate.
    Type: Application
    Filed: August 29, 2003
    Publication date: April 22, 2004
    Applicant: Samsung Electronics Co., Ltd.
    Inventor: Jae-Sung Lee
  • Publication number: 20040075935
    Abstract: There is disclosed a self-supporting-type servo writing apparatus in which a head of a disk drive is used to write a servo pattern on a disk. In the disk drive, the disk is incorporated in which a clock pattern is pre-written as a signal pattern for position detection in a rotation direction. The servo writing apparatus uses the servo pattern written on the disk by a write head device to successively add the servo pattern into the whole surface on the disk.
    Type: Application
    Filed: July 30, 2003
    Publication date: April 22, 2004
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Masahide Yatsu
  • Patent number: 6724562
    Abstract: A method for writing servo patterns on at least one disc in a disc drive that has a first set of tracks and a second set of tracks on a major surface of the disc includes stepping between the tracks of the first set of tracks at a first constant angle, and stepping between the tracks of the second set of tracks at a second constant angle. Stepping between tracks in the first group or the second group includes selecting two adjacent tracks from either the first group of tracks or the second group of tracks, and determining the angle through which an actuator assembly must be rotated between the two adjacent tracks selected to produce a selected track pitch. The method produces a disc for a disc drive with a first set of tracks, and a second set of tracks in which the track pitch varies across the set of tracks.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: April 20, 2004
    Assignee: Seagate Technology LLC
    Inventors: Chiap Heok Ang, Niroot Jierapipatanakul, Beng Theam Ko, Myint Ngwe, Beng Wee Quak, Choonkiat Lim
  • Patent number: 6724564
    Abstract: A disk drive and methods for preventing a coil in a voice coil motor from overheating due to the application of excess current. The disk drive comprises a servo control system. The servo control system is adapted for applying a current to a coil of the voice coil motor thereby causing the voice coil motor to move the head according to a seek distance. The servo control system generates a plurality of seek profiles for each of a plurality of seek distances and a plurality of current limits for the plurality of seek profiles. Each of the plurality of seek profiles defines a plan for controlling the current to be applied to the coil while the voice coil motor is operated over the seek distance. The plurality of current limits each define a maximum current allowed while controlling the current to be applied to the coil.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: April 20, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventors: Raffi Codilian, David D. T. Nguyen, David L. Whitaker
  • Patent number: 6724162
    Abstract: A device for controlling a motor intended to set an arm provided with a head for reading/writing information in motion with respect to a surface carrying information. The device having a controller for enabling the power supply of the winding of the motor to be managed and a measurer for measuring the value of a counter-electromotive force induced in the winding by the movement of the rotor when the power supply of the winding is interrupted. This device enables the angular speed of the arm to be measured and controlled during an emergency return phase of the arm towards a rest position.
    Type: Grant
    Filed: September 12, 2001
    Date of Patent: April 20, 2004
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Jannis Pieter van der Linde, Henricus Marinus van Hout
  • Patent number: 6717763
    Abstract: A disk drive includes at least one disk having a disk surface and at least one transducer head for writing and/or reading data from the disk surface. The disk drive performs a power-saving idle operation including reducing a rotational speed of the disk, and continuously moving the transducer head at varying radial velocity components relative to the disk surface in a repeating sweeping pattern between a selected inner disk diameter and a selected outer disk diameter. The radial velocity components are varied as a function of the transducer head's radial position in relation to the disk surface, such as with a radial velocity idle sweep profile representing a relationship between the radial velocity component of the transducer head and its radial location relative to the disk surface that optimizes head-disk interaction (HDI) when the disk is rotating at a given reduced rotational speed.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: April 6, 2004
    Assignee: Hitachi Global Storage Technologies, Netherlands B.V.
    Inventors: Hal Hjalmar Ottesen, Gordon James Smith
  • Publication number: 20040061970
    Abstract: An information handling system includes a processor and a disk drive coupled to receive information from the processor. The disk drive is configured to write the information to a first location on a platter. The disk drive is further configured to write the information to n locations on the platter such that a phase difference between successive locations is approximately (360 divided by n) degrees where n is an integer greater than or equal to two.
    Type: Application
    Filed: September 30, 2002
    Publication date: April 1, 2004
    Applicant: Dell Products L.P.
    Inventors: Thomas L. Pratt, Raymond Farrell Dumbeck
  • Patent number: 6714373
    Abstract: A magnetic disk device has an improved seek control in which a waiting time occurred in a first magnetic head while it is scanning a first track, is utilized efficiently and effectively by activating a second magnetic head such that the second magnetic head scans a second track during the waiting time of the first magnetic head.
    Type: Grant
    Filed: June 26, 2000
    Date of Patent: March 30, 2004
    Assignee: Fujitsu Limited
    Inventor: Kiyotaka Sasaki
  • Patent number: 6714378
    Abstract: A positioning method and a positioning device are disclosed for controlling an actuator and moving it to a target position. The positioning method generates a random wave signal RN and detects a position error from the target position. The servo control signal CV is generated to position the actuator back to the target position, and the random wave signal RN is added to the servo control signal CV to generate a control signal. Since a random, minute vibration is constantly applied to the actuator to avoid the assumption of a static state by bearings of the actuator, the actuator is affected only by dynamic friction, and relative to the control value, its movement is representative of a linear characteristic. As a result, the positioning accuracy is enhanced, and since the random wave is employed, there is no deterioration of the positioning accuracy of the servo system.
    Type: Grant
    Filed: July 20, 2000
    Date of Patent: March 30, 2004
    Assignee: Fujitsu Limited
    Inventors: Hiroshi Uno, Nobuyoshi Yamasaki, Kiichiro Kasai
  • Publication number: 20040057151
    Abstract: Provided is a data storage device in which read and write heads can be desirably located with respect to servo tracks from the viewpoint of linearity of a PES on the premise that a read write offset exists. A read write offset value, which is a deviation amount between write and read heads in a radial direction of a disk-shaped storage medium, is set equivalent to an integer number N of servo tracks.
    Type: Application
    Filed: June 19, 2003
    Publication date: March 25, 2004
    Applicant: Hitachi Global Storage Technologies
    Inventors: Manabu Saikawa, Hirofumi Yanase
  • Publication number: 20040051993
    Abstract: A method and an apparatus to control a disc drive, and more particularly, a method and an apparatus to control a disc drive using a counter-electromotive force, prevents collision and malfunction of a transducer and a disc by determining external vibrations and magnitude of a shock without installing an additional shock sensor in the disc drive. The method of controlling the disc drive using a counter-electromotive force includes detecting a voltage applied to a voice coil during a predetermined mode, performing an operation of a value of the counter-electromotive force using the detected voice coil voltage comparing the value of the counter-electromotive force operated with a predetermined threshold, and when the value of the counter-electromotive force is equal to or larger than the predetermined threshold, controlling a voice coil motor and a spindle motor so that a current mode is stopped and a parking or unloading mode is executed.
    Type: Application
    Filed: August 28, 2003
    Publication date: March 18, 2004
    Applicant: Samsung Electronics Co., Ltd.
    Inventor: Sang-chul Shin
  • Publication number: 20040047065
    Abstract: A disturbance compensation signal is produced by estimating the magnitude of disturbance acting upon an actuator based on a driving signal and a voltage signal generated when driving the actuator. A control signal is produced by multiplying the disturbance compensation signal by a gain adjustment coefficient. A head position error signal is produced based on the target position of a magnetic head and the current position of the magnetic head that is detected based on servo information recorded in advance on a magnetic disk. A gain adjuster obtains the driving signal by adding together the control signal and a position control signal. The actuator is driven with the driving signal output from the gain adjuster.
    Type: Application
    Filed: June 26, 2003
    Publication date: March 11, 2004
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Keizo Miyata, Toshio Inaji
  • Publication number: 20040047066
    Abstract: A problem to be solved is to calculate, at a high speed, a control amount for a magnetic head in an eccentricity control method for magnetic disk of a magnetic disk apparatus and thereby avoid the degradation of control performance due to control delay caused by a long calculation time. Another problem to be solved is to realize stable control performance even when a variation in the position error of the magnetic head relative to a target position is large, for example, in the seek and the settling of the magnetic head.
    Type: Application
    Filed: June 13, 2003
    Publication date: March 11, 2004
    Inventor: Norio Shigematsu
  • Publication number: 20040042114
    Abstract: Disclosed herein is a servo system for performing head positioning control in a disk drive, thereby to move the head to a desired position on a disk. The servo system perform a learning operation, thereby calculating a learned value relating to a disk-runout, and effects servo compensation to suppress a disk-runout, by using the learned value. Further, the servo system abandons erases the learned value in a memory when an impact applied to the disk drive and exceeding a tolerance value is detected during the learning operation.
    Type: Application
    Filed: September 3, 2003
    Publication date: March 4, 2004
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Tatsuharu Kusumoto
  • Publication number: 20040036998
    Abstract: In a disk storage apparatus, an micro processing unit (MPU) as an upper unit calculates a positional relationship between a head section and storage disks using disk management data indicating the positional relationship of servo information among the storage disks to complete a servo lock based on the result of calculation. The servo lock can thereby be executed at high rate without waiting for a disk controller as a lower unit to complete a servo lock.
    Type: Application
    Filed: January 24, 2003
    Publication date: February 26, 2004
    Applicant: FUJITSU LIMITED
    Inventor: Hidekazu Masuyama
  • Publication number: 20040036999
    Abstract: A method of driving an electrical load having a complex electrical impedance, such as a voice-coil motor controlling the position of a read/write head in a data storage disk drive system, comprises providing a voltage-mode driver generating drive signals for the electrical load in response to drive commands. Compensated commands for the voltage-mode driver are generated filtering the drive commands, compensating for a phase shift between electrical quantities delivered to the electrical load. The voltage-mode drive thus emulates a conventional, but more expensive, current-mode drive. In a preferred embodiment, the method comprises estimating characteristic parameters of the electrical load during the operation, and adapting the filtering to the estimated characteristic parameters. The estimation comprises implementing a Kalman filtering algorithm, particularly an extended Kalman filtering.
    Type: Application
    Filed: June 16, 2003
    Publication date: February 26, 2004
    Applicant: STMicroelectronics S.r.I.
    Inventors: Francesco Chrappan Soldavini, Roberto Oboe, Paolo Capretta
  • Publication number: 20040036997
    Abstract: A method for writing streaming audiovisual data to a disk drive is performed by organizing the data into clusters and commencing writing the clusters to the first physical sector encountered after the read/write head has settled to the desired track on the rotating disk. A cluster contains a number of data blocks corresponding to the number of physical sectors in an integer number of tracks on the disk, so that the writing of a single cluster is the writing to an integer number of full tracks on the disk. Even though the disk drive may have a physical index to identify the first physical sector in all the tracks, the writing of cluster data takes place-without regard to index position.
    Type: Application
    Filed: August 23, 2002
    Publication date: February 26, 2004
    Inventors: Steven R. Hetzler, Daniel F. Smith
  • Patent number: 6697210
    Abstract: In a disk device, in a state where no access to the disk is permitted, instead of permitting the head to be driven stepwise whenever step pulses are fed in, the head is inhibited from being driven stepwise until a predetermined period of time elapses after the disk starts being rotated. This helps reduce electric power consumption in such a state. Moreover, when the head has been retracted to its initial position because of an error in the stepwise driving thereof, instead of waiting for step pulses to be fed in from the host and thereby losing much time before the head is moved back to the track at which it was located before the error, the position of the head before the error is stored so that the head can be, by self recovery, moved back to the position before the error without waiting for an instruction from outside the disk device.
    Type: Grant
    Filed: December 21, 2000
    Date of Patent: February 24, 2004
    Assignee: Rohm Co., LTD
    Inventor: Shinichi Hirano
  • Publication number: 20040032688
    Abstract: In a disk storage a command controller issues a seek command and transmits it to a seek command manager. A head position controller performs a seek operation. If the head position controller is not busy with the seek operation, the seek command manager transmits the seek command to the head position controller. If the head position controller is busy with the seek operation, the seek command manager queues the seek command in a memory and transmits the seek command to the head position controller after the head position controller has finished the seek operation.
    Type: Application
    Filed: January 24, 2003
    Publication date: February 19, 2004
    Applicant: FUJITSU LIMITED
    Inventor: Hiroshi Tsurumi
  • Patent number: 6693754
    Abstract: Aspects of the invention include a method and apparatus to optimize the location of data on a disc drive storage system by optimizing the physical location of the file to allow the read ahead memory cache to operate more efficiently. In one aspect, the disc drive uses a reserved area on the media to hold files during the optimization process. In another aspect, the drive includes an optimization table that stores optimized file access data to further enhance the drive performance.
    Type: Grant
    Filed: May 24, 2001
    Date of Patent: February 17, 2004
    Assignee: Seagate Technology LLC
    Inventors: Gayle L. Noble, Rick S. Shimizu, Jason P. Hanlon
  • Patent number: 6690536
    Abstract: A disk drive is disclosed comprising a disk, a head, an actuator arm for actuating the head radially over the disk, a fixed object, and a voice coil motor (VCM) for rotating the actuator arm about a pivot, the VCM comprising a coil comprising a VCM resistance R. A back EMF voltage detector measures a back EMF voltage across the coil, and a current detector detects a current I flowing through the coil. An IR voltage detector, responsive to the current I detected by the current detector, detects an IR voltage proportional to the current I times the VCM resistance R. A voltage compensator substantially cancels the IR voltage from the measured back EMF voltage to generate a compensated back EMF voltage. A control voltage generator, responsive the compensated back EMF voltage, generates a control voltage applied to the coil to generate the current I flowing through the coil.
    Type: Grant
    Filed: October 31, 2000
    Date of Patent: February 10, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventor: Robert P. Ryan
  • Patent number: 6690537
    Abstract: A read/write head servo control system for data recording devices, wherein a method of compensating initial values is utilized to generate a control signal to move the head from an initial position to a target position. The method estimates and stores multiple position compensation values. A first control signal moves the head from an initial position to a target position. Head position values are sampled as the head moves. Head position deviation values are calculated for the sampled position values. The head position values are utilized to select a set of estimated position compensation values. These values are in turn utilized to generate a second control signal, which is then utilized to control the position of the head.
    Type: Grant
    Filed: July 13, 2001
    Date of Patent: February 10, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Naoyuki Kagami, Akira Tokizono, Hiroshi Uchida
  • Patent number: 6687081
    Abstract: A disk drive uses seek profile manipulation to provide enhanced transducer fly height control. The maximum seek velocity that is used during a seek operation is made dependent upon, among other things, the direction associated with the seek operation (i.e., either radially inward or radially outward with respect to the disk). In a preferred embodiment, the maximum seek velocity in a direction that normally results in a fly height loss is made less than the maximum seek velocity in the opposite direction. Thus, a minimum transducer fly height can be maintained with minimal effect on average seek time in the disk drive. In one approach, the maximum seek velocity values are stored within a lookup table within the disk drive.
    Type: Grant
    Filed: May 15, 2000
    Date of Patent: February 3, 2004
    Assignee: Maxtor Corporation
    Inventors: Matthew O'Hara, Don Brunnet, Yu Sun, David M. Sigmond