Abstract: Embodiments in accordance with the present invention provide a magnetic disk drive with reduced noise during seek operation without causing any delay in control response. According to one embodiment of the present invention, a control circuit of a magnetic disk drive controls the drive power supplied to a voice coil motor during a seek operation adapted to move a magnetic head over a target track formed on a magnetic disk so as to bring the travel speed of the magnetic head close to a predetermined target speed. The control circuit determines a provisional current according to the difference between the predetermined target speed and an actual travel speed in an acceleration zone adapted to accelerate the magnetic head to the predetermined target speed. If the provisional current exceeds a limit specified in relation to an elapsed time from the start of acceleration, the control circuit sets the limit as the current of the drive power supplied to the voice coil motor to control the motor.

Abstract: Embodiments in accordance with the present invention provide a disk drive that ensures quieter rotational acceleration of a recording disk. Certain embodiments relate to a hard disk drive that detects the vibration of an enclosure by monitoring, via a driver, a counter electromotive voltage generated in a voice coil motor. If the hard disk drive detects a predetermined level of vibration or higher in the enclosure, it switches the status of a drive signal applied to a spindle motor so as to reduce the current level or smooth the waveform. This ensures reduced vibration of the enclosure.

Abstract: Embodiments of the invention reduce the noise occurring when the lubricating layer on the magnetic disk is smoothed. In one embodiment, a magnetic disk drive has a read/write mode parameter table for generating an electric current to be supplied to a voice coil motor when the magnetic head performs data read/write operations on the magnetic disk. The magnetic disk drive also has a smoothing mode parameter table for generating another electric current to be supplied to the voice coil motor when neither a data read nor a write operation is performed on the magnetic disk. The CPU refers to either the read/write mode parameter table or the smoothing mode parameter table and controls the electric current to be supplied to the voice coil motor.

Abstract: Detection capability of a servo timing mark (STM) is improved. Long STM is configured by pseudo-STM forming part of an AGC/PLL pattern and intrinsic STM. When a system can not recognize the intrinsic STM, it keeps a state that a sector detection window is opened, and is operated in a long STM detection mode to recognize the long STM, thereby generates an STM detection signal. After the STM detection signal has been generated, an STM detection window is closed, and the system is operated in an intrinsic STM detection mode. Since the long STM has longer bit length than the intrinsic STM, it has high discriminating power with respect to other bit patterns. Therefore, even if the sector detection window is remained to be in an opened state, bit strings of data sector, address information in a servo sector or the like is not falsely recognized.

Abstract: Embodiments of the invention provide control of a disk data storage device to prevent off-track writing. In one embodiment, the SA acquires the CYLIDs and ADC Values generated from the SERVO SIGNALs acquired previously, and generates DACOUT which defines a driving current of the VCM driver. The SA monitors the DACOUT generated and determines whether the DACOUT is within a predefined range. If the DACOUT is outside the predefined range, data writing is inhibited. By monitoring the DACOUT, it is possible for the VCM driver to detect supply of an overcurrent to the VCM driver 210 beforehand, and off-track writing can thus be prevented.

Abstract: Embodiments of the invention provide a data storage apparatus and its control method capable of accurately reading/writing data.

Abstract: Embodiments of the invention provide a data storage apparatus and its control method capable of accurately reading/writing data.

Abstract: Embodiments of the invention provide a data storage apparatus and its control method capable of accurately reading/writing data.

Abstract: Embodiments of the invention provide a data storage apparatus and its control method capable of accurately reading/writing data.

Abstract: Embodiments of the invention reduce the noise occurring when the lubricating layer on the magnetic disk is smoothed. In one embodiment, a magnetic disk drive has a read/write mode parameter table for generating an electric current to be supplied to a voice coil motor when the magnetic head performs data read/write operations on the magnetic disk. The magnetic disk drive also has a smoothing mode parameter table for generating another electric current to be supplied to the voice coil motor when neither a data read nor a write operation is performed on the magnetic disk. The CPU refers to either the read/write mode parameter table or the smoothing mode parameter table and controls the electric current to be supplied to the voice coil motor.

Abstract: A method (and structure) senses a rotational vibration of a disk drive. The disk drive includes a rotating disk. The disk includes a plurality of reference bits across a surface thereof. The method (and structure) includes detecting the reference bits across a pattern on the rotating disk, and analyzing a time interval between adjacent ones of the reference bits.

Abstract: Embodiments of the invention provide control of a disk data storage device to prevent off-track writing. In one embodiment, the SA acquires the CYLIDs and ADC Values generated from the SERVO SIGNALs acquired previously, and generates DACOUT which defines a driving current of the VCM driver. The SA monitors the DACOUT generated and determines whether the DACOUT is within a predefined range. If the DACOUT is outside the predefined range, data writing is inhibited. By monitoring the DACOUT, it is possible for the VCM driver to detect supply of an overcurrent to the VCM driver 210 beforehand, and off-track writing can thus be prevented.

Abstract: A disk drive (HDD) (and method) subject to linear and rotational vibration, includes an independent sensing unit for sensing a rotational velocity component of the rotational vibration in a predetermined frequency range, and an optimal filter combination for receiving an output from the sensing unit.

Abstract: Non-linearity in a position error signal (PES) for a data storage device is precisely characterized during a calibration phase in the manufacturing process. From this characterization of the PES non-linearity, the data storage device can be programmed with the necessary data to perform accurate, real-time linearization calculations of the PES in order to compensate for non-linearity in the PES during operation. The sequence of calibration steps includes a PES gain calibration, a first servo loop gain calibration, a PES linearization calibration, and an optional second servo loop gain calibration.

Abstract: A method (and structure) senses a rotational vibration of a disk drive. The disk drive includes a rotating disk. The disk includes a plurality of reference bits across a surface thereof. The method (and structure) includes detecting the reference bits across a pattern on the rotating disk, and analyzing a time interval between adjacent ones of the reference bits.

Abstract: A disk drive (HDD) (and method) subject to linear and rotational vibration, includes an independent sensing unit for sensing a rotational velocity component of the rotational vibration in a predetermined frequency range, and an optimal filter combination for receiving an output from the sensing unit.

Abstract: Non-linearity in a position error signal (PES) for a data storage device is precisely characterized during a calibration phase in the manufacturing process. From this characterization of the PES non-linearity, the data storage device can be programmed with the necessary data to perform accurate, real-time linearization calculations of the PES in order to compensate for non-linearity in the PES during operation. The sequence of calibration steps includes a PES gain calibration, a first servo loop gain calibration, a PES linearization calibration, and an optional second servo loop gain calibration.

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: 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 disk drive system, includes a head, a controller for controlling an operation of the head, at least one feedback filter coupled in relation to the controller, and a mechanism for keeping a function of the at least one of the feedback filter active during any of an absence of a valid position error signal (PES) and a position error signal being unavailable due to a defect during an operation of the head.