Matches 151 - 200 out of 511 < 1 2 3 4 5 6 7 8 9 10 11 >
Match Document Document Title
6963462 Servo detection control system, servo detection control method and hard disk drive  
For the purpose of providing technique by which even when large skew of a disk or a head occurs due to a thermal shock, an outside shock, or the like, a servo signal area is not extended, and a...
6963466 Radial dependent low frequency repeatable run out compensation apparatus and method  
An apparatus and method for tracking radially-dependent repeatable run-out in a disc drive having a servo loop for positioning a head over a rotating disc is provided. The disc includes multiple...
6956711 Fractional-rate feedforward RRO compensator  
An apparatus and method of tracking repeatable runout in a disc drive servo loop is provided in which a feedforward signal having harmonic components that are updated at a sample rate that is a...
6956712 Head position demodulating method and disk apparatus  
A head position is demodulated by two-phase servo signals of PosN and PosQ from output of the head, so as to acquire a more accurate demodulated position. Saturation of PosN and PosQ is judged from...
6952321 Method for sensing run-out in data fields  
A method of determining run-out in a disc drive involving steps of performing a direct current erase, selecting a reference track, writing a sinusoidal signal into a first track at a first offset...
6952320 Virtual tracks for repeatable runout compensation  
The present invention relates to repeatable runout (RRO) compensation of servo control systems that can be used in disc drives or spin-stands. The RRO relates to eccentricity between servo tracks,...
6950274 Disk storage apparatus and disk storage apparatus control method  
A disk storage apparatus includes: an actuator positioning a head with respect to a disk; a drive device driving the actuator; a voltage detection device detecting a voltage signal induced in...
6947248 Method and apparatus for writing with head having spaced read and write elements  
An apparatus includes a unit that uses a head with spaced read and write portions to write and read information to and from an information storage medium. According to one feature, a desired...
6947852 Monitoring and correcting for non-translational motion in a resonance measurement apparatus  
A system and method for assessing and potentially correcting for non-translational motion in a resonance measurement apparatus is provided. The design measures the response of an article, such as...
6940679 Method and apparatus for increasing track density by adapting write fault gate to position error signal as it varies from ID to OD  
A disk drive utilizes a track dependent variable write fault gate for each of the transducers within the drive. By deriving a 3 sigma distribution across the repeatable run out (RRO) and the...
6937424 Repeatable runout (RRO) compensation methods and apparatus for data storage devices  
In one illustrative example, a method for use in reducing Repeatable Run Out (RRO) error in a data storage device involves obtaining an RRO measurement for each track of a limited number of N disk...
6937420 Determining repeatable runout cancellation information using PES information generated during self servo-writing operations  
Disclosed is a method for generating a repeatable runout (RRO) compensation value set for a circular track on a magnetic medium on a surface of a disk in a disk drive. The magnetic medium has a...
6930851 Guiding a sensor using a broadly-curved lateral profile  
Problems inherent in guiding a sensor via a piecewise-linear lateral parametric profile are generally avoided using at least one broadly curved, generally lateral profile ( 494 ). A sensor is...
6924959 Reducing estimation period for repeatable runout errors in a disk drive  
A method for reducing an estimation period for repeatable runout (RRO) errors in a disk drive comprising a head, a disk surface having a track partitioned by servo-wedges, and a servo control...
6922596 Efficient adaptive feedforward periodic disturbance compensation  
A system and method is given for minimizing periodic disturbances in electronic systems. Given the input-output characteristics of the system, the present method identifies and cancels the periodic...
6922304 Positioning control device  
In a positioning control apparatus, a distance between an actual position at which absolute values of N and Q head positioning signals whose amplitudes vary cyclically in accordance with a position...
6909574 Disk device conducting a disturbance compensation based on a time-interval measurement in reading servo sectors recorded on a disk  
A disk device comprises a disk having predetermined information sectors recorded at a constant interval; a head scanning the disk; and a disturbance-compensation unit obtaining an amount of a...
6906485 Spindle motor control using a current profile to taper current transitions  
Method and apparatus for operating a motor. During a commutation state current is applied to a motor while field effect transistors (FETs) are held in an enable or disable state to effect current...
6904010 Method of writing servo tracks for disk file apparatus using write start or stop sectors  
A method of STW (servo track write) for improving the quality of the servo tracks by suppressing the misalignment of the write start position caused by the asynchronous continuous vibration of a...
6898047 Magnetic disk drive for compensating repeatable runout error  
In order to achieve narrow track pitch by measuring, storing and compensating common average values for repeatable runout components between adjacent tracks in a head positioning control system for...
6898039 Positioning control device for two-stage actuator  
In a positioning control device for a two-stage actuator having a coarse-movement actuator and a fine-movement actuator, a notch filter having a cutoff frequency fn is provided to a coarse-movement...
6894862 Servo system with learning function for achieving servo compensation in a disk drive  
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,...
6891693 Apparatus and method for head positioning control in disk drive  
A memory section stores values of the runout component, which are obtained in respective predetermined radial positions on the disk. A determining section selects, from the memory section, a value...
6882497 Track closure error cancellation for a disc drive  
Track closure errors written into servo sectors of an information track of a disc of a disc drive are resolved from a position control signal generated by a servo control circuit of a data storage...
6879459 Positioning control mechanism for a magnetic head in a magnetic storage device  
A mechanism to allow accurate control of the position of a magnetic head even if the state of the magnetic head has changed due to instability.
6879460 Magnetic recording disk drive  
A magnetic recording disk drive can prevent the deterioration of the head off-track characteristics and the reduction of the drive performance even when an erase band asymmetry resulting from a...
6867943 Efficient feedforward compensation for repeatable runout in a disc drive  
Method and apparatus for more accurate track following. Control circuitry rotates a data storage surface containing thousands of annular tracks. A “measured” subset of the tracks is selected so...
6859341 Method and apparatus for feedforward repeatable runout compensation in a selected frequency range  
For runout compensation in a data handling system, a servo feedback loop is configured to control a head position relative to a corresponding disc surface. Operation of the feedback loop is...
6853514 Method for measuring PES noise of servo patterned media  
A method for measuring servo pattern irregularity and other servo information of pre-patterned servo media mounted on a spindle with the center of the pre-pattern tracks off center from the axis...
6850385 Repeated servo runout error compensation in a disc drive  
An apparatus and associated method are disclosed for compensating for repeated servo runout error in a disc drive. The disc drive includes a disc on which servo information is arranged as a...
6847503 Repeatable runout compensation in a disc drive  
A system and method for correcting repeatable runout errors during manufacture of a disc drive. The system includes a Kalman filter having a recursive learning gain input and includes a recursive...
6847502 Repeatable runout determination within a rotating media storage device  
A rotating media storage device (RMSD) includes a disk having at least one track with a plurality of servo wedges, a moveable head, and a microprocessor. The microprocessor receives a plurality of...
6831803 Repeatable runout identification device and method  
A repeatable runout (RRO) identification device for use with a disc drive having a rotatable disc is provided. The RRO identification device determines RRO values for servo fields of a first track...
6826006 Method for recursively determining repeatable runout cancellation values in a magnetic disk drive  
A method is disclosed for recursively determining repeatable runout (RRO) cancellation values in a disk drive having a head disk assembly (HDA) and a sampled servo controller. The HDA includes a...
6819521 Repeated runout position error compensation in a disc drive servo system  
An apparatus and method for compensating repeated runout position error in a disc drive data handling system having an actuator assembly which supports a head adjacent a recording surface. A servo...
6813227 Apparatus and method to compensate for disturbance using learning control in an optical recording/reproducing apparatus and optical recording medium drive servo system  
A disturbance compensation module using learning control generates a control input to compensate for track position errors due to a periodic disturbance occurring in an optical recording medium in...
6804079 Written-in repeatable run-out compensation in embedded servo disc drives  
An apparatus and method of correcting for written-in repeatable run-out in a disc drive having a servo loop for positioning a head over a rotating disc is provided. The rotating disc has at least...
6798611 Disk storage system employing a discrete-time sliding mode controller for servo control  
A discrete-time sliding mode controller (SMC) controls the motion of a read head actuated over a disk storage medium during tracking operations. The discret-time SMC comprises a linear signal...
6785073 Identification and cancellation of cage frequency in a hard disc drive  
Written-in runout due to vibration of the cage of a spindle motor of a disc drive is detected by identifying an initial cage frequency value of the motor. A written-in magnitude of successive servo...
6785084 Correction of dynamic track spacing errors in storage devices  
The present invention offers a time efficient means to determine and eliminate dynamic track squeeze error. The present invention can be used to correct imperfections in tracks written by a...
6775091 Repeatable run-out compensation for disk drive  
An apparatus and a process for positioning a read/write head in a hard disk drive, and more particularly for using the phenomenon of repeatable run-out to efficiently compensate a servo loop used...
6765747 Method and apparatus for reducing low frequency repeatable runout in hard disk drive  
A method and apparatus are disclosed which allow for compensation of repeatable runout in a disk drive when an actuator arm assembly has a relatively high friction to inertia ratio in a pivot...
6765748 Method of interleaving servo information fields for track following and seeking and a recording medium including interleaved servo information fields  
A method of interleaving servo information fields on a recording medium, and a corresponding recording medium having interleaved servo information fields, that reduce the amount of disk surface...
6765737 Variable track densities on a recording medium to compensate for non-repeatable runout (NRRO) error  
A disc drive includes a base and a disc rotatably attached to the base. The disc has an inner diameter and an outer diameter and a plurality of tracks. Information is written on the plurality of...
6762902 Time-varying, non-synchronous disturbance identification and cancellation in a rotating disk storage device  
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...
6760183 Servo system with runout compensation for disk drive  
A disk drive including a servo system that performs a learning operation for calculating a servo compensation value is disclosed. The servo system determines whether an initial learning value...
6760170 Servo test method  
A servo test is performed on a disc drive. The servo test includes performing a position error sample (PES) threshold test on tracks in the disc drive and identifying those tracks that fail the PES...
6754032 Method and system for radial and circumferential alignment of data tracks on patterned media  
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....
6751036 Tuning track density for data storage device  
A data storage device has a plurality of head/surface combinations with different data track densities on at least two surfaces. A minimum head quality is established for the data storage...
6751046 Writing servo data patterns on a data storage disk to account for repeatable and non-repeatable disturbances and thereby provide concentric data tracks  
A method for self-servo writing begins by calibrating at least one ruler formed on at least one storage disk. A ruler is a position-sensing pattern that defines the radial position of a recording...
Matches 151 - 200 out of 511 < 1 2 3 4 5 6 7 8 9 10 11 >