Abstract: A magnetic disk drive includes a magnetic disk and a femto slider. The magnetic disk has a minimum track linear velocity of 1 to 5 m/s. In one embodiment, the magnetic disk drive includes a negative pressure type femto slider and adopts a load/unload method. A gram load “GL” of a head suspension assembly HSA is set at a value exceeding about 3 mN and smaller than about 15 mN and a pitch static attitude “PSA” (deg) and pitch stiffness “Kp” (Nm/deg) satisfy the expression ((PSA×Kp)/GL)<0.25 mm. As a result, it is possible to prevent the femto slider from assuming a meta-stable flying high state referred to as a bi-stable height. Further, by setting the pitch static attitude “PSA” at a value of larger than 0 deg, it is possible to prevent the slider from assuming a state of meta-stable contact with the magnetic disk surface referred to as semi-stable drag.

Abstract: Embodiments of the present invention relate to detecting a flying high state in which a head/slider is flying stably at a high flying position, and then to restore the head/slider to a normal flying position. The detection is made by detecting a read output of a head using a head output detector, and by detecting a gain of a VGA using a gain detector. A control unit uses a value measured in a normal flying state as a reference value to compare a detected value with the reference value. If the compared values differ from each other, the control unit judges that a flying high state has occurred. The control unit, therefore, moves the head/slider to the vicinity of the innermost circumferential track of the disk, or unloads the head/slider.

Abstract: A hard disk device includes a servo control unit that constitutes a servo loop for a head seek for performing read/write of data from/to a recording medium, a correction signal generation unit for generating a correction signal for correcting a control by the servo control unit based on an output of a predetermined sensor, and a correction signal control unit for estimating an effect of supplying the correction signal to the servo loop and for controlling whether or not the correction signal is to be supplied to the servo loop in response to a result of the estimation. Moreover, the gain of the sensor is dynamically controlled in response to the above estimation result.

Abstract: A method and apparatus for use with a rotating storage device. The rotating storage device includes a storage medium driven to rotate, a head for reading and writing information on the storage medium and a ramped loading mechanism in which the head is stored. In accordance with the method of the present invention, the head is loaded from the ramped loading mechanism onto the storage medium. Next, determining whether or not a write operation on said storage medium is performed within a predetermined amount of time after loading said head on said storage medium and in response to said determination, setting a verification flag to indicate a data verification is required immediately after said write operation.

Abstract: A magnetic disk drive includes a magnetic disk and a femto slider. The magnetic disk has a minimum track linear velocity of 1 to 5 m/s. In one embodiment, the magnetic disk drive includes a negative pressure type femto slider and adopts a load/unload method. A gram load “GL” of a head suspension assembly HSA is set at a value exceeding about 3 mN and smaller than about 15 mN and a pitch static attitude “PSA” (deg) and pitch stiffness “Kp” (Nm/deg) satisfy the expression ((PSA×Kp)/GL)<0.25 mm. As a result, it is possible to prevent the femto slider from assuming a meta-stable flying high state referred to as a bi-stable height. Further, by setting the pitch static attitude “PSA” at a value of larger than 0 deg, it is possible to prevent the slider from assuming a state of meta-stable contact with the magnetic disk surface referred to as semi-stable drag.

Abstract: In a hard disk drive where data is read from and written to a magnetic disk by a magnetic head in accordance with a command from a host computer, a moving distance of the magnetic head in a radial direction is detected within a predetermined period of time. The magnetic head is moved for seeking by a predetermined distance when the moving distance detected is small. The system and method of the present invention reduces write failures due to the undulation of a lubricant film on the magnetic disk by effectively preventing undulation.

Abstract: Embodiments of the present invention relate to detecting a flying high state in which a head/slider is flying stably at a high flying position, and then to restore the head/slider to a normal flying position. The detection is made by detecting a read output of a head using a head output detector, and by detecting a gain of a VGA using a gain detector. A control unit uses a value measured in a normal flying state as a reference value to compare a detected value with the reference value. If the compared values differ from each other, the control unit judges that a flying high state has occurred. The control unit, therefore, moves the head/slider to the vicinity of the innermost circumferential track of the disk, or unloads the head/slider.

Abstract: A control arrangement having a feedforward system and a feedback system, a control model for generating reference position data from a feedforward control signal is separated into an original control model and a compensation filter. Gain of the feedforward control signal is compensated by a gain compensation circuit to form a feedforward control signal after compensation. The reference position data is input to a feedback controller, and a feedback control signal and feedforward control signal are input to a control object. Coefficients of the compensation filter and the gain compensation circuit are compensated on the basis of a head position trajectory obtained by actual seek operation.

Abstract: A method and apparatus for use with a rotating storage device. The rotating storage device includes a storage medium driven to rotate, a head for reading and writing information on the storage medium and a ramped loading mechanism in which the head is stored. In accordance with the method of the present invention, the head is loaded from the ramped loading mechanism onto the storage medium. Next, location information stored in said storage medium via said head is read. A location of the head is then retained for a predetermined period above a track of a region other than a valid storage region of said storage medium after successfully reading the location information.

Abstract: An improved system and method for implementing a rotary memory device, including a host system and a disk-shaped memory medium storing position information, or a servo address mark (SAM). If a head fails to read a valid SAM, a dummy SAM is generated to prevent an arm with a read/write head from entering a neutral state. If the normal state cannot be restored within a fixed number of intervals, the system goes into the emergency brake control mode. In this emergency brake control mode, the direction of the head is determined, and the VCM current is applied in such a way drive the arm in the opposite direction. Damage to the magnetic medium and subsequent data loss problems are reduced because the velocity of the head is reduced to a safe level.

Abstract: A method and apparatus for use with a rotating storage device. The rotating storage device includes a storage medium driven to rotate, a head for reading and writing information on the storage medium and a ramped loading mechanism in which the head is stored. In accordance with the method of the present invention, the head is loaded from the ramped loading mechanism onto the storage medium. Next, location information stored in the storage medium via the head is read. A location of the head is then retained for a predetermined period above a track of a region other than a valid storage region of the storage medium after successfully reading the location information.

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.

Abstract: A hard disk device includes a servo control unit that constitutes a servo loop for a head seek for performing read/write of data from/to a recording medium, a correction signal generation unit for generating a correction signal for correcting a control by the servo control unit based on an output of a predetermined sensor, and a correction signal control unit for estimating an effect of supplying the correction signal to the servo loop and for controlling whether or not the correction signal is to be supplied to the servo loop in response to a result of the estimation. Moreover, the gain of the sensor is dynamically controlled in response to the above estimation result.

Abstract: A method and system for utilizing a digital filter for actuator positioning control in a disk device. In accordance with the method and system of the present invention multiple selectable filter modules are provided. Each of the multiple selectable filter modules functions in a serial or parallel filtering mode when selected. Multiple configurable registers are also provided wherein the configuration of each of the multiple configurable registers determines a selection of at least one of the multiple selectable filter modules. Particular ones of the multiple configurable registers are selected, such that a configuration of the digital filter is dynamically selectable in order to achieve a predetermined filter output.

Abstract: In a hard disk drive where data is read from and written to a magnetic disk by a magnetic head in accordance with a command from a host computer, a moving distance of the magnetic head in a radial direction is detected within a predetermined period of time. The magnetic head is moved for seeking by a predetermined distance when the moving distance detected is small. The system and method of the present invention reduces write failures due to the undulation of a lubricant film on the magnetic disk by effectively preventing undulation.

Abstract: Methods and systems for detecting and correcting for undesirable vibrations impacting the servo systems in data storage devices. A detection technique is provided wherein a detection filter is configured to scan a position signal of the servo system across a range of frequencies, and, at each respective scanned frequency, record an amplitude associated therewith. The recorded amplitudes are examined to determine whether any exceed a threshold, thereby locating a peak frequency of the vibration. Using the detected peak frequency of the vibration, a corrective filter is configured to operate about the peak frequency of vibration, thereby reducing its impact on the position signal in the servo system.

Abstract: A method and system for compensating head positioning servo in a storage device. In accordance with the method and apparatus of the present invention, an open-loop gain of a head positioning servo is calculated when the head positioning servo causes a head to follow a predetermined position of a target track of a storage media surface by generating a position detecting signal utilizing a position detecting signal gain. A compensated position detecting signal gain is generated by compensating the position detecting signal gain according to a difference between a first predetermined value and the open-loop gain of the head positioning servo, such that variability of the position detecting signal and the open-loop gain is reduced to achieve stability in a head positioning servo.

Abstract: In control means having a feedforward system and a feedback system, a control model for generating reference position data yr from feedforward control signal Uff0 is separated into an original control model 22 and a compensation filter 23. Gain of feedforward control signal Uff0 is compensated by gain compensation means 24 to form feedforward control signal Uff after compensation. Data yr is input to a feedback controller 25, and feedback control signal Ufb and Uff are input to a control object 26. Coefficients of the compensation filter 23 and the gain compensation means 24 are compensated on the basis of a head position trajectory obtained by actual seek operation.

Abstract: A storage device with a disk-shaped recording medium having servo areas in which servo sectors are recorded and data areas in which data sectors are recorded; a read/write head to read and write the data sectors, and to read the servo sectors on the disk-shaped recording medium; a head actuator to control the position of the read/write head; a storage controller to control data sector read and write operations by the read/write head; a servo controller to determine a position of the read/write head from the servo sector output read by the read/write head; a servo assist unit, separate from the storage controller, to calculate servo data for controlling the head actuator based on position information extracted by the servo controller and read/write head; and an interrupt generator to generate interrupt requests to the storage controller as determined by results of calculations by the servo assist unit.

Abstract: A method and apparatus for use with a rotating storage device. The rotating storage device includes a storage medium driven to rotate, a head for reading and writing information on the storage medium and a ramped loading mechanism in which the head is stored. In accordance with the method of the present invention, the head is loaded from the ramped loading mechanism onto the storage medium. Next, location information stored in said storage medium via said head is read. A location of the head is then retained for a predetermined period above a track of a region other than a valid storage region of said storage medium after successfully reading the location information.