Class / Patent application number | Description | Number of patent applications / Date published |
360770040 | By memory storage of repeatable error or correction | 36 |
20080278843 | Apparatus, system, and method for repeatable runout cancellation using ring of integrators - An apparatus, system, and method are disclosed to cancel repeatable runout signals. A linear causal system having an impulse response receives a cancellation signal and outputs a position error signal. An inverse matrix module multiplies the position error signal by an inverse matrix and outputs an intermediate cancellation signal. One or more impulse integration modules each integrate at least one sample of the intermediate cancellation signal in one or more predefined periods and output the cancellation signal. | 11-13-2008 |
20090002874 | REPEATED RUNOUT COMPENSATION USING SCALED POSITION SIGNALS - In accordance with various embodiments, a radial separation distance between first and second servo seams on a storage medium is determined, and a scaled position signal is generated in relation to the determined radial separation distance and a measured position signal. An error runout correction (ERC) value is obtained from the scaled position signal, and the ERC value is thereafter used to compensate for repeated runout (RRO) error. | 01-01-2009 |
20090059420 | SEAM TO SEAM EMBEDDED RUNOUT CORRECTION PROPAGATION - Various embodiments of the present invention are generally directed to propagating repeated runout (RRO) correction values for radially concentric servo seams on a storage medium in relation to an RRO correction value for an adjacent seam and a radial separation between the seams. | 03-05-2009 |
20090073600 | POSITIONING CONTROL SYSTEM AND POSITIONING CONTROL METHOD - There is provided with a positioning control system including: a head moving unit; a position detecting unit detecting a head position at predetermined time intervals; an error detecting unit detecting a position error of the head for a target position; a disturbance detecting unit detecting a non-periodic disturbance; a modifying unit modifying a first position error signal corresponding to a first head position detected in a first rotation period based on a second position error signal corresponding to a second head position detected one period length before; and a feedback controller, wherein the modifying unit modifies the first signal after reducing an amplitude of the second position error signal when a detected timing of the second head position is included in a predetermined time range with respect to a detected timing of the non-periodic disturbance detected in a second rotation period which is one period before the first rotation period. | 03-19-2009 |
20090073601 | Magnetic disk drive and control method thereof - Embodiments of the present invention provide a magnetic disk drive capable of easily suppressing degradation of position error caused by disturbance resulting from vibration from the outside. According to one embodiment, the magnetic disk drive acquires, during a period of time of track following control, data necessary for determining a filtering characteristic required to newly be specified in a peak filter; in association with the start of subsequent seek control, determines the filtering characteristic required to be specified in the peak filter; and specifies the determined filtering characteristic in the peak filter. | 03-19-2009 |
20090086364 | PER WEDGE WORF DETERMINATIONS FOR DISK DRIVE - A method for locating a track on a disk surface having a plurality of wedges of servo information includes demodulating servo information for a first servo wedge, and determining a correction factor for a written in repeatable runout for the servo information for the first servo wedge before demodulating servo information for a second servo wedge. A machine-readable medium provides instructions that perform the above method. A disk drive includes a processor disk that performs the above method and generates a signal to position a transducer over a desired track. | 04-02-2009 |
20090086365 | Read write offset error correction using geometric reference in self servo write process - A hard disk drive having a self servo write offset error correction mechanism to improve self servo write process is disclosed. In accordance with certain aspects of the present invention, there is provided a self servo write method that can measure an accurate position offset between the read-head element and write-head element incorporated in a disk drive before servo data is recorded on the disk provided in the disk drive. | 04-02-2009 |
20090122440 | REPEATED RUNOUT ERROR COMPENSATION USING ITERATIVE FEEDBACK - Various embodiments of the present invention are generally directed to adaptively determining an updated repeated runout (RRO) correction value to correct for RRO error in the placement of a servo seam, by iteratively combining a weighted initially estimated RRO correction value for the seam with a position error signal (PES). | 05-14-2009 |
20090161248 | METHOD AND APPARATUS FOR DETERMINING DISK-RUNOUT INFORMATION IN A DISK DRIVE - According to one embodiment, a disk drive has a disk, a CPU and a memory. The CPU measures servo intervals between the servo areas provided on the disk, and calculates changes of the servo intervals, which have resulted from a temperature change. The CPU detects a disk shift from the changes of the servo intervals. The CPU updates the disk-runout information stored in the memory, in accordance with the disk shift detected. | 06-25-2009 |
20090168226 | Repair of defective servo tracks - A method for repairing at least one defective servo segment of a servo sector having at least one defective servo track written on a magnetic recording media. The method comprises mapping the magnetic recording media for locations of the defective servo segment of the servo sector. A non-defective segment of the servo sector is replicated at least once on the magnetic recording media in a customer data zone, thereby creating at least one good servo segment copy of the servo sector. The good servo segment copy is propagated through the customer data zone associated with the defective servo segment. The good servo segment copy is copied onto the magnetic recording media previously occupied by the defective servo segment of the servo sector. | 07-02-2009 |
20090213487 | EFFICIENT METHOD TO DETECT DISK WRITE ERRORS - A write error detection mechanism for a computer data disk drive or storage controller writes and then verifies data to detect disk write errors. It allows the heads to be moved to other tracks to do other jobs in the time it takes the disk to rotate from the point the data was written and to return there again so it can be read to verify the write. The data written is temporarily stored in feature table memory outside the disk, so it can be used as in the comparison later when the written data can be read for the verify. In the interim, other write-and-verify and read operations can be pipelined, or multitasked using the same head, even on different tracks. | 08-27-2009 |
20090244768 | MAGNETIC HEAD POSITIONING CONTROL METHOD AND MAGNETIC HEAD POSITIONING CONTROL APPARATUS - N groups of servo patterns, each corresponding to the predetermined number of servo sectors, are recorded in a magnetic disk. The magnetic head positioning control apparatus of the present invention produces an RRO current correction table corresponding to each group of servo patters and selects the group of servo patterns that is the best in transferred quality of the sevro pattern as SPopt. For servo sectors (target servo sectors) corresponding to other groups of servo patterns and existing between two adjacent servo sectors corresponding to the SPopt, the magnetic head positioning control apparatus calculates an RRO current correction amount corresponding to the target servo sector by a linear interpolation calculation using the RRO current correction amount corresponding to each of the adjacent servo sectors in the RRO current correction table corresponding to the SPopt to perform the magnetic head positioning control based on the calculated RRO current correction amount. | 10-01-2009 |
20090296266 | Apparatus, system, and method for repeatable runout cancellation - An apparatus, system, and method are disclosed for the cancellation of repeatable runout signals. A signal processing module receives a position error signal and outputs a position compensated signal. A feed forward module receives the position error signal and outputs one or more cancellation signals to cancel one or more repeatable runout components from the position error signal when combined with the position compensated signal. A combining module combines the position compensated signal and the cancellation signals into a position command signal. A feedback module receives the position command signal and outputs the position error signal. | 12-03-2009 |
20090310250 | Magnetic Disk Drive Having Dual Actuator - In a dual-stage actuator magnetic drive having a coarse actuator and a fine actuator, an amplitude level of a command signal for the fine actuator during a decoupling-path control depends on a gain of an applied fine actuator model. The fine actuator model gain depends on the amplitude level of the fine actuator command signal and needs to be calibrated to avoid performance degradation. The gain is calibrated by determining a deviation of the fine actuator model gain from the fine actuator gain during decoupling-path control. This deviation is obtained by comparing gain values of the open-loop transfer functions measured for the decoupling-path control case and the single coarse actuator control case with respect to the feedback loop of the coarse actuator at an excitation signal frequency, when the excitation signal is added to the coarse actuator. | 12-17-2009 |
20100053799 | METHOD FOR ESTIMATING POSITION ERROR GAIN FOR HARD DISK DRIVES - 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. | 03-04-2010 |
20100103555 | SELF SERVO WRITING DISK CONTROLLER AND METHODS FOR USE THEREWITH - A self servo writing disk controller detects a plurality of spiral sync marks and a plurality of spiral bursts corresponding to one of a plurality of servo spirals from a read signal from the read/write head. A timing reference signal is generated based on timing of at least one of the plurality of the spiral sync marks. A position error signal is generated based on timing of at least one of the plurality of spiral sync marks and a magnitude of at least one of a plurality of spiral bursts. The timing reference signal and the position error signal are used by the disk drive for timing and positioning in self writing initial servo wedges to the disk. | 04-29-2010 |
20100128385 | INFORMATION STORAGE DEVICE AND COMPUTER PRODUCT - According to one embodiment, an information storage device includes a recording/reproducing head, a positioning controller, a position detector, a storage module, and a position error detector. The position detector detects the position of the recording/reproducing head. The storage module stores servo control filters. The position error detector generates a new position error signal from a target position and the position of the recording/reproducing head when the positioning controller performs positioning control with control current obtained from a position error signal having passed through each servo control filter. Upon occurrence of a recording/reproducing error, learning to calculate a vibration amount from the position of the recording/reproducing head is sequentially performed for the servo control filters for a predetermined time. The positioning controller performs the positioning control with control current obtained from the position error signal having passed through one of the servo control filters where the vibration amount is smallest. | 05-27-2010 |
20100142085 | MAGNETIC RECORDING DISK AND DISK DRIVE WITH ALTERNATING SINGLE-POLARITY POSITION ERROR SIGNAL (PES) BLOCKS FOR READ/WRITE HEAD POSITIONING - A magnetic recording disk drive has a position-error-signal (PES) servo pattern divided into at least two circumferentially adjacent fields that extend radially across the data tracks and include PES blocks that are DC magnetized in one direction, with each PES block having a magnetization opposite to the magnetization of its radially adjacent neighboring PES blocks. Each PES field is contiguous with and shifted radially relative to its circumferentially adjacent neighbor PES fields. Each PES block has a single DC magnetization, and the length of the magnetization is substantially longer than the length of the magnetizations in the other fields of the servo pattern. | 06-10-2010 |
20100149684 | DATA-STORAGE DEVICE AND ANALYSIS METHOD FOR DATA-STORAGE DEVICE - A data-storage device with a security function for user data stored in a data-storage medium. The data-storage device includes: the data-storage medium for storing data; an authentication processing section for performing an authentication process with a key obtained from a host; an error correction circuit for performing error correction in reading data at an address designated by a read command from a host which has been recognized as an authorized user for analysis access by the authentication processing section; and an analysis processing section for generating data indicating the positions of the error correction and transferring the data to the host. | 06-17-2010 |
20100238588 | FEED-FORWARD METHOD FOR REPEATABLE RUNOUT CANCELLATION - 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. | 09-23-2010 |
20100246055 | STORAGE DEVICE - A magnetic disk device includes a head that reads position information, a position-information correction value for correcting the position information, and an error correcting code for the position-information correction value from a storage medium; an MCU and an ECC circuit for correcting an error in the position-information correction value based on the error correcting code; and an SVC that performs position control based on either one of the position-information correction value read by the head and the position-information correction value with the error corrected by the MCU and the ECC circuit, and the position information read by the head so that the head is located at a target position on the storage medium. | 09-30-2010 |
20100302676 | CIRCUITS THAT USE A POSTAMBLE SIGNAL TO DETERMINE PHASE AND FREQUENCY ERRORS IN THE ACQUISITION OF A PREAMBLE SIGNAL - 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 phase error and frequency error in the timing of servo burst fields. | 12-02-2010 |
20100328813 | DISK-ENCLOSURE COVER FOR LOW-PROFILE, HARD-DISK DRIVE - A disk drive. The disk drive includes a head, a motion mechanism, and a controller. The head is configured to access a disk configured to store data. The motion mechanism is configured to move the head. The controller is configured to determine a seek direction when an error occurred; and, the controller is configured to repeat a seek as a repeat seek to a target radial position from a direction opposite to the seek direction in an error-recovery process for the error which occurred in the seek in which the head moved to the target radial position. | 12-30-2010 |
20110069411 | HEAD SERVO CONTROL SYSTEM AND HEAD SERVO CONTROL METHOD - A servo control system configured to position a head in accordance with position error signals between servo data on a disk read by the head in a servo sampling cycle and a target position. The system includes a plurality of adaptive peak filters connected in parallel configured to filter the position error signals and configured to change filter coefficients adaptively, and an estimator configured to estimate head vibration caused by disturbances using the servo data read by the head. The system further includes a selector configured to select a portion of the plurality of adaptive peak filters at preset occasions, and a setter configured to update coefficient settings of the portion of the adaptive peak filters selected by the selector in accordance with an estimation by the estimator. | 03-24-2011 |
20110075292 | LOG-STRUCTURE FILE SYSTEM FOR DISK DRIVES WITH SHINGLED WRITING - Data is written to a hard disk drive using shingled writing principles, i.e., each data track is partially overwritten when an immediately contiguous data track is written. One or more contiguous data tracks establish a hand, and a band establishes a respective segment in a log-structured file system. | 03-31-2011 |
20110085262 | DLC-Head Offset Compensation While Writing - In described embodiments, effects of frequency and phase error introduced at the outer diameter or inner diameter of the disk when a read head is used to maintain timing lock while the write head is used to write new data might be eliminated with a simple compensation circuit. Compensation circuits, modules or methods receive as input information i) write head radial position (e.g., from a wedge number that indicates the circumferential position of the heads), and ii) read head and write head relative physical offset. The timing error is measured by the system and might be automatically adjusted by the appropriate amount in order to reduce or to eliminate the differential head error when a write event (as opposed to a read event) is activated | 04-14-2011 |
20120087036 | Patterned media with offset PES servo segments with length encoded track position - Patterned discrete track magnetic media compatible with the constraints imposed by the use of self-assembly technology are described in which the PES servo portion of each servo sector has at least one offset segment used for the position error signal (PES). The downtrack length of the PES offset segment systematically varies according to the track position to encode information about the track position usable by the servo system. The downtrack length of the offset segment and, therefore, the time between the corresponding signal shifts is systematically varied from the inner diameter (ID) to the outer diameter (OD) according to the track position to provide coarse information to the servo system even if part of the track ID code cannot be read. Alternative embodiments include a preamble timing mark formed by another offset segment. A self-servo writing method is described using the preamble timing marks. | 04-12-2012 |
20120154949 | BIPOLAR POSITION ERROR BURSTS WITH UNIPOLAR SERVO FIELDS - A storage medium has a first servo field having magnetic lands separated by nonmagnetic areas, the magnetic lands of the first servo field having a unipolar pattern. The medium further includes a second servo field having magnetic lands separated by nonmagnetic areas, the magnetic lands of the second servo field having a bipolar pattern. | 06-21-2012 |
20120200954 | Systems and Methods for Off Track Error Recovery - Various embodiments of the present invention provide systems and methods for recovering data from a storage medium. As an example, a data recovery circuit is disclosed that includes: a controller circuit, a data processing circuit, a selector circuit, and a combining circuit. The controller circuit is operable to position a sensor over a track of the storage medium at a first distance from the center of the track to yield a first data set, and to position the sensor over the track of the storage medium at a second distance from the center of the track to yield a second data set. The data processing circuit is operable to process a processing data set, and the selector circuit is operable to select between the first data set and a combined data set as the processing data set. The combining circuit is operable to combine the first data set with at least the second data set to yield the combined data set. | 08-09-2012 |
20120250181 | DATA STORAGE SYSTEM WITH SELF-SERVO-WRITING AND METHOD OF OPERATION THEREOF - A method of operation of a data storage system includes: providing a disk having a reference servo; and positioning a read/write head over the disk with the reference servo including: collecting a raw phase error, estimating a phase delay error, estimating an estimated written-in error with the phase delay error subtracted from the raw phase error, calculating a remaining error based on the estimated written-in error, and adjusting a self-servo-writing clock based on the remaining error. | 10-04-2012 |
20120275050 | DISK DRIVE ADJUSTING ROTATIONAL POSITION OPTIMIZATION (RPO) ALGORITHM TO COMPENSATE FOR REPEATABLE RUNOUT (RRO) - A disk drive is disclosed comprising a first disk surface comprising a plurality of tracks, wherein each track comprises a number of data sectors and a number of servo sectors, and a second disk surface comprising a plurality of tracks, wherein each track comprises a number of data sectors and a number of servo sectors. A first repeatable runout (RRO) sinusoid is generated representing an RRO of the first disk surface, and a second RRO sinusoid is generated representing an RRO of the second disk surface. A plurality of access commands are received from a host which are stored in a command queue, and one of the access commands is selected to execute in response to the first and second RRO sinusoids. | 11-01-2012 |
20130222943 | REPEATABLE RUN OUT COMPENSATION - An apparatus can include a disk drive controller that includes at least one repeatable run out (RRO) compensator corresponding to a RRO component, the disk driver controller configured to change a head assembly position, and to disable the at least one RRO compensator in response to the head assembly position changing from one predetermined area of a disk to at least one other predetermined area of the disk | 08-29-2013 |
20150109700 | SHINGLED MAGNETIC RECORDING SYSTEM WITH ADAPTIVE WRITE BUFFER AREA - Techniques for writing data to a buffer region of a magnetic disk are described. In one example, a hard disk drive comprises a magnetic disk comprising a data buffer region including a first zone and a second zone. Data may be written to the magnetic disk using shingled magnetic recording (SMR) and the buffer region may be an exception region (E-region). A hard disk drive may be configured to calculate a position accuracy value associated with a data writing head. The hard disk drive may select one of the zones based on the position accuracy value. Further, a selected zone may have a determined zone format. The hard disk drive may be configured to write data to the selected zone using the determined zone format. | 04-23-2015 |
20150302876 | DATA STORAGE APPARATUS AND METHOD FOR CORRECTING REPEATABLE RUNOUT - According to one embodiment, a data storage apparatus includes a disk configured to be recorded correction information corresponding to radial positions of the disk and variation information corresponding to the correction information, each of the correction information being information for correcting a repeatable runout, and each of the variation information being information corresponding to a variation amount of a repeatable runout, and a controller configured to correct a first repeatable runout at a first radial position by using a first correction information and a first variation information which are recorded at a second radial position of the disk, when the head is controlled to be positioned at the first radial position on the disk. | 10-22-2015 |
20160012842 | METHOD AND APPARATUS FOR DETERMINING READ-HEAD DEVIATION USING ORTHOGONAL PREAMBLES | 01-14-2016 |
20160049168 | Methods and Apparatus for Improved Pattern Detection - Improved pattern detection is provided for a predefined pattern in data. A detection threshold employed by a Euclidean detector to detect a pattern (such as a Servo Address Mark) may be adjusted based upon data gathered that corresponds to an indication of a detected pattern by one of a plurality of pattern detectors. | 02-18-2016 |