Abstract: Methods, systems and computer program products for performing hybrid defect detection are disclosed. In some implementations, an apparatus includes a signal module to process data signals corresponding to data on a storage medium to generate signal samples. The apparatus includes a first defect detector to identify a first portion of the signal samples, determine a number of the signal samples in the first portion that are associated with abnormal signal characteristics, and generate a first output based on the number of the signal samples in the first portion that are associated with abnormal signal characteristics. The apparatus includes a second defect detector to identify a second portion of the signal samples different from the first portion, and generate a second output based on a correlation between data bits and signal samples in the second portion.

Abstract: A method and system for estimating a zero gain start (ZGS) bias in a read channel is disclosed. The method may include: receiving preamble samples within a fixed-length window selected for ZGS calculation; calculating an energy associated with a 2T frequency in the preamble samples; calculating an energy associated with non-2T frequencies in the preamble samples; and calculating the ZGS bias based on the energy associated with the 2T frequency in the preamble samples and the energy associated with non-2T frequencies in the preamble samples.

Abstract: A system and method for recording data to a perpendicular magnetic recording media having a highly ordered granular structure. The method includes the synchronization of write frequency and write phase to the granular structure of the magnetic media optimize performance of the magnetic data recording system by minimizing bit error rate.

Abstract: A data storage device includes a storage medium on which data is stored in overlapping tracks, and a medium controller that directs storage of data on, and reading of data from, the storage medium, including encoding data being stored and decoding data being read. The decoding includes, when reading a first track, cancelling interference from a second track that overlaps the first track. The data storage device also includes a host controller in communication with the medium controller. The host controller includes memory that stores data decoded, and data to be written, by the medium controller. Communication between the medium controller and the host controller includes signals derived from data on said first and second tracks for facilitating the cancelling. A method of operating a data storage device includes, when reading a first track, facilitating the cancelling by communicating signals derived from the data on the first and second tracks.

Abstract: According to one embodiment, a magnetic disk device includes a first magnetic head corresponding to a first disk surface; a second magnetic head corresponding to a second disk surface; a skip processor which performs skip processing to prevent selection of the second magnetic head when the first magnetic head performs writing; a write data saving unit which selects the second magnetic head based on a result of the detection of ae write environment, and writes write data to the second disk surface through the second magnetic head; and a write data write-back unit which selects the first magnetic head based on a result of the detection of the write environment, and writes the write data written to the second disk surface to the first disk surface through the first magnetic head.

Abstract: The disclosure is directed to monitoring changes in fly height for a plurality of read heads. Readback signals based upon a first periodic data sequence and a second periodic data sequence are detected using at least a first read head and a second read head at a first point in time corresponding to a first fly height of each read head and at a second point in time corresponding to a second fly height each read head. The difference between the first fly height and the second fly height of the first read head and the difference between the first fly height and the second fly height of the second read head are determined by comparing the respectively detected readback signals. A summation of the difference values, each having been multiplied by a fusion coefficient, is then used to estimate a global change in fly height.

Abstract: A disk drive component flow fixture is described including a base fixture, and one or more child fixtures. Each of the one or more child fixtures is configured, for example, for removable insertion into the base fixture, and to receive a disk drive component. In an embodiment, a method for analysis of disk drive components is described using the disk drive component flow fixture, the method including inserting a first child fixture into a base fixture, placing a first disk drive component for a first type of disk drive onto the first child fixture, and performing an analysis of the first disk drive component.

Abstract: A system including a first circuit, a second circuit, an amplifier, and a summer. The first circuit is configured to (i) select a first portion of a signal, and (ii) generate a first compensation for asymmetry in the first portion of the signal using a first function, where the first function is a modulus function. The second circuit is configured to (i) select a second portion of the signal, and (ii) generate a second compensation for asymmetry in the second portion of the signal using a second function, where the second function is different than the first function. The amplifier amplifies the signal and provides an amplified output. The summer is configured to add (i) the first compensation, (ii) the second compensation, and (iii) the amplified output, where (i) the first circuit, (ii) the second circuit, and (iii) the amplifier are connected in parallel to the summer.

Abstract: A data storage system according to one embodiment includes a head; a drive mechanism for passing a medium over the head; and a controller electrically coupled to the head. The system calculates a kurtosis value, using the current position error signal sample or derivative thereof, and adjusts a threshold value using the kurtosis value. The standard deviation or variance is compared to the threshold value, and writing is enabled when the standard deviation or variance does not exceed the threshold value.

Abstract: The location of a load/unload ramp in a disk drive is calibrated by monitoring servo spirals that are crossed by a magnetic read/write head during an unload process. Monitoring the number servo spirals crossed allows an accurate velocity of the read/write head to be determined. Based on this unload velocity and the time elapsed during the unload operation, a distance between an ID crash stop position and the load/unload ramp can be calculated quickly and accurately.

Abstract: A data storage system according to one embodiment includes a head, a drive mechanism for passing a medium over the head, a controller electrically coupled to the head, and logic integrated with and/or executable by the controller. The logic is configured to: update a first value based on a current position error signal sample, determine whether the first value exceeds a predetermined threshold, determine a stopwrite threshold based on the first value when the first value exceeds the predetermined threshold, determine whether the current position error signal sample exceeds the stopwrite threshold, disable writing when the current position error signal sample exceeds the stopwrite threshold, and enable writing when the current position error signal sample does not exceed the stopwrite threshold.

Abstract: In a magnetic recording disk drive, a disk with equally angularly spaced regions that have topography different from the other regions of the disk is used to detect head-disk contact. In one embodiment of a bit-patterned media (BPM) disk, equally angularly spaced servo sectors have topography different from the data regions of the disk. A head-disk spacing sensor detects the topography of the servo sectors as the servo sectors pass the sensor during rotation of the disk. This results in the head-disk spacing sensor generating an output signal with a fundamental frequency f0=NX/60 Hz, where N is the number of servo sectors and X is the disk rotation rate in RPM. A second or higher harmonic or harmonics of the fundamental frequency f0 are filtered from the output of the head-disk spacing sensor and used to identify the initiation of head-disk contact.

Abstract: There is disclosed a hard disk drive and an operation method thereof. A method of operating a hard disk drive according to the present invention may include (a) loading drive data required to drive the hard disk drive from a maintenance cylinder area contained in a disk to a memory; and (b) writing test data output from a head into a spare area contained in the maintenance cylinder area, wherein the steps (a) and (b) are carried out within a ready time.

Abstract: A method according to one embodiment includes measuring a current position error signal; calculating a standard deviation or a variance using the current position error signal sample; calculating a kurtosis value, using the current position error signal sample or derivative thereof; adjusting a threshold value using the kurtosis value; comparing the standard deviation or variance to the threshold value; enabling writing when the standard deviation or variance does not exceed the threshold value.

Abstract: Embodiments of the present disclosure provide for reading data from a physical storage medium, transferring the data between a data channel and a test interface over a parallel data bus, and providing the data from the test interface at a serial port in a serial format.

Abstract: Calibrating a read channel is disclosed. Previously written user data is read from an auxiliary memory. The previously written user data is processed through a plurality of write channel stages. The output of at least one of the plurality of write channel stages is compared to the output of a corresponding read channel stage to generate an error signal.

Abstract: Testing and compensating for fly height of a head in a storage device during settling time using a head for use on a storage medium and a processor to idle the head for an idle time, unload the head from idle, and compensate for any unsettled fly height of the head using the idle time and at least a pre-determined clearance settling function over time from idle.

Abstract: In one general embodiment, a magnetic head includes a slider having a media-facing surface; and a device coupled to the slider and being selectively extendible for selectively contacting a magnetic medium at a frequency of between about 200 and about 600 kHz. Other magnetic heads and methods of use are described according to additional embodiments.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing system is disclosed that includes: a data detector circuit, a pseudo-random sequence generator circuit, a decoder circuit, and a pseudo-random sequence reconstitution circuit. The data detector circuit is operable to apply a data detection algorithm to a first data set to yield a detected output. The pseudo-random sequence generator circuit is operable to generate an interim data sequence and to generate a second data set based upon a combination of the detected output and the interim data sequence. The decoder circuit is operable to apply a data decode algorithm to a derivative of the second data set to yield a third data set.

Abstract: Determining a polarity of a piezoelectric (PZT) actuator of a disk drive including a disk for storing data and a head for reading and writing data. A test signal is injected into the PZT actuator and a position signal is received which indicates a position of the head over the disk resulting from the test signal. A test compensation signal is generated based on the received position signal and the polarity of the PZT actuator is determined based on a phase of the generated test compensation signal.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing system is disclosed that includes: a data detector circuit, a filter circuit, and a mean squared calculation circuit. The data detector circuit is operable to apply a data detection algorithm to a data set to yield a detected output. The filter circuit is operable to filter the detected output to yield a filtered output. The mean squared calculation circuit is operable to calculate a mean squared error value based at least in part on the data set and the filtered output. A quality indicator is generated at least in part on the mean squared error value.

Abstract: In one embodiment, a method includes updating a standard deviation or a variance based on a current position error signal sample, where a smoothing factor applied to a subsequent calculation of the standard deviation or variance is dynamically altered based at least in part on whether a current value of the standard deviation or the variance is above or below a specified value. A determination is made as to whether the standard deviation or the variance exceeds a predetermined threshold. A stopwrite threshold is determined based on the standard deviation or the variance when the standard deviation or the variance exceeds the predetermined threshold. A determination is made as to whether the current position error signal sample exceeds the stopwrite threshold. Writing is disabled when the current position error signal sample exceeds the stopwrite threshold. Writing is enabled when the current position error signal sample does not exceed the stopwrite threshold.

Abstract: A magnetic recording element records information by applying a recording magnetic field to a magnetic recording medium having an information recording area to form a plurality of recording columns extending in a first direction. Recording by the magnetic recording element is performed so that a first recording column and a second recording column formed before the first recording column partially overlap each other in a second direction perpendicular to the first direction, and that a recording start position of the first recording column is positioned upstream, relative to the recording direction, of a recording start position of the second recording column.

Abstract: A magnetic media tester comprising a Laser Doppler Vibrometer (LDV) head; and a magnetic read head; the LDV head and the magnetic read head being configured for obtaining correlatable data of a region on a magnetic disk.

Abstract: A shingled magnetic recording hard disk drive that uses writeable cache tracks in the inter-band gaps between the annular data bands minimizes the effect of far track erasure (FTE) in the boundary regions of annular data bands caused by writing to the cache tracks. Based on the relative FTE effect for all the tracks in a range of tracks of the cache track being written, a count increment (CI) table or a cumulative count increment (CCI) table is maintained. For every writing to a cache track, a count for each track in an adjacent boundary region, or a cumulative count for each adjacent boundary region, is increased. When the count value for a track, or the cumulative count for a boundary region, reaches a predetermined threshold the data is read from that band and rewritten to the same band.

Abstract: According to embodiments of the present invention, a data storage device is provided. The data storage device includes a recording channel configured to carry a signal; a detector configured to detect the signal from the recording channel; and a noise prediction circuit configured to predict noise affecting the recording channel and the detected signal based on a noisy channel model. According to further embodiments of the present invention, a method of processing a signal in a data storage device is also provided.

Abstract: A disk drive is disclosed comprising a head actuated over a disk surface, the head comprising a fly height actuator for controlling a fly height of the head, and a ramp for parking the head. A ramp procedure is executed by applying a control signal to the fly height actuator to decrease the fly height and receiving a corresponding fly height signal, and detecting whether the head is on the ramp in response to the fly height signal.

Abstract: An assembly and method to determine adjacent track coherence is disclosed. The assembly includes coherence circuitry configured to receive phase and frequency offsets from timing recovery circuitry and determine an inter-track phase and frequency coherence between the encoded data on a first track and the encoded data on a second track adjacent to the first track utilizing the frequency and phase offsets from the timing recovery circuitry for the output signals corresponding to the first and second tracks.

Abstract: A computer program product includes a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code being executable by a processing circuit to cause the processing circuit to perform the following process. A data transfer operation is monitored for detecting one or more temps. A backhitch delay is set based at least in part on a post-recovery condition of a tape drive performing a portion of the data transfer operation. A backhitch is caused to be performed. At least one condition of the data transfer operation is altered after the backhitch delay.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, some embodiments of the present invention provide clock generation systems that include: a first clock multiplier circuit, a second clock multiplier circuit, a modulus accumulator circuit, and a data clock phase control circuit. The first clock multiplier circuit is operable to multiply a reference clock by a first multiplier to yield a first domain clock, and the second clock multiplier circuit is operable to multiply the reference clock by a second multiplier to yield a second domain clock. The modulus accumulator circuit is operable to yield a value indicating a fractional amount of the second domain clock that an edge of the second domain clock is offset from a trigger signal. The data clock phase control circuit is operable to phase shift the second domain clock by a phase amount corresponding to the fractional amount.

Abstract: Techniques to determine particular bad tapes or tape drives. All tape and tape drive combinations within a system may be obtained. A read error or a write error that occurs with each tape and tape drive combination may be detected, and the read error, the write error, or a parameter may be analyzed to determine the particular tape or the particular tape drive that is bad.

Abstract: Tuning a skew between a read head and a write head, may include setting a center value of a track according to a track density of a storage medium; writing data having a certain pattern to at least one target track and at least two tracks adjacent to the target track, while following the center value of the track; reading the data having a certain pattern from the target track by using a plurality of off track values in an off track range based on the center value of the track; and detecting an off track value having a minimum error occurrence number among error occurrence numbers with respect to the read data having a certain pattern corresponding to each of the plurality of off tracks, as an optimum off track value of the target track.

Abstract: A tape cartridge library that is equipped with a cleaning device is described. The tape cartridge library essentially includes a plurality of tape cartridges each possessing recording tape media. A plurality of tape drives that read and write data to and from each of the tape cartridges. A tape cleaning drive incapable of transferring data to and from the recording tape media which is independent of the tape drives, the tape cleaning drive disposed entirely within the tape cartridge library. The tape cleaning drive automatically receives one of the tape cartridges and cleans its respective recording tape medium when a predetermined reason for cleaning the tape cartridge is justified.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of normal servo tracks each comprising a plurality of normal servo sectors storing head position information, and a fly height calibration servo track comprising fly height calibration servo sectors, each fly height calibration servo sector comprising head position information and a spacing pattern. After positioning the head over the fly height calibration servo track, the head is servoed over the fly height calibration servo track in response to the fly height calibration servo sectors. A dynamic fly height (DFH) setting is calibrated for the DFH actuator in response to the spacing pattern in the fly height calibration servo sectors. After calibrating the DFH setting, the control circuitry seeks the head to a data track defined by at least one of the normal servo tracks, and startup data is read from the data track.

Abstract: A contact event between a sensing device and a storage medium is detected by receiving a signal indicating a physical proximity between the sensing device and the storage medium; generating a plurality of frequency bin outputs; comparing one or more frequency bin outputs to a corresponding first level threshold to yield a corresponding comparator output; summing the comparator output with at least one prior instance of the comparator output to yield an aggregated value; comparing the aggregated value to an aggregate threshold to yield an aggregate output; and generating a contact event output if one or more of a first group of the plurality of frequency bin outputs has an associated aggregate output set to a predefined binary value and a predefined minimum number of a second group of the plurality of frequency bin outputs has an associated aggregate output set to a predefined binary value.

Abstract: In one embodiment, a read/write chip for a hard disc drive has at least one on-chip, in-channel, hardware-based optimization processor that is part of one or more channels (e.g., read, write, and/or servo) of the read/write chip. The optimization processor can iteratively evaluate the performance of a channel for different values of one or more different parameters that control channel processing by generating an appropriate metric value for each different parameter value. The optimization processor can then select an optimal parameter value for subsequent channel processing.

Abstract: Tape media life is increased by dynamically controlling a turn around point (TAP) on the tape media for either an end of a tape wrap or a directional change from a first longitudinal position tape section to a second longitudinal position tape section for reducing damage to the tape media caused by debris by monitoring the TAP for all tape media motion and adjusting tape deceleration for maintaining the TAP to be located at the second longitudinal position tape section.

Abstract: Various embodiments of the present invention provide systems and methods for calibrating write pre-compensation values.

Abstract: A method or apparatus for changing a performance level of a disk drive from an initial performance level to a target performance level, wherein the disk drive includes a profile table. The method including determining an initial performance level, determining a target performance level, determining constant offset values that cause the performance level of the disk drive to match the target performance level, and programming a constant offset table of the profile table with the constant offset values.

Abstract: The data recording apparatus for recording data to a recording medium having one or more tracks arranged in parallel comprises a data recorder configured to record data to the one or more tracks, a memory configured to store data, and a controller configured to control the data recorder. The controller determines whether or not the one or more tracks include a data defective region in which the data has not been recorded properly, stores in the memory the data that has not been recorded properly, designates a position corresponding to the data defective region, which is in a track arranged in parallel to the data defective region, and reads from the memory the data that has not been recorded properly, and records that data to the position corresponding to the data defective region.

Abstract: Magnetoresistive (MR) bias is dynamically controlled in a tape drive using a processor device. Upon determining head amplitude is below a threshold value, the MR bias is adjusted for increasing the head amplitude and extending the useful life span of the tape drive.

Abstract: A system and method for predicting the likelihood of failure of the individual sectors of a magnetic storage disk based upon the monitoring of adjacent sector performance in responding to access requests. The prediction for a specific target sector's fidelity can be made through the gathering of sector performance data that occurs during normal read/write actions to the adjacent sectors, without a recent access request necessarily being made to the target sector. Scrubbing of the sectors can also be directed based upon the needed sector access data for target sector fidelity prediction.

Abstract: A computer-implemented method, apparatus and computer-program product for writing data to a tape data storage medium. The method comprises providing a system service that an application invokes to handle data synchronization events associated with writing a group of files to the tape medium; keeping track of the files and data blocks in each file while writing the files to the tape medium based on file boundaries; and responsive to a data writing failure, invoking the system service to determine the files affected by the data writing failure.

Abstract: Systems and methods related to writing data to a storage medium. In some cases, a heat assisted loopback circuit is used that includes: a read circuit, a magnetic write circuit, a heat write circuit, and a loopback circuit. The loopback circuit is operable to selectively couple a derivative of a heat output to a read output and to selectively couple a derivative of a write output to the read output.

Abstract: In one embodiment, a system includes a medium, a magnetic head having a write element adapted for writing data to the medium, a MAMR element and/or a TAMR element adapted for assisting recording on the medium, the MAMR element having a microwave-generating portion that receives current for operation thereof, the TAMR element having a localized heat-generating portion that receives current for operation thereof, and a read element adapted for reading data from the medium, a device adapted for measuring environmental conditions relating to the TAMR/MAMR elements and the medium, and a controller adapted for controlling operation of the magnetic head and adjusting operating parameters of the system based on the environmental conditions. The environmental conditions include temperature, a reproduced signal of the read element, and/or clearance between the TAMR/MAMR elements and the medium. The operating parameters include the clearance, amount of current injected to the TAMR/MAMR elements, and/or write current.

Abstract: Embodiments provide a method for a method comprising causing data to be written on a first track located on a disk; while writing the data on the first track, buffering, in a buffer module, the data; determining that while writing the data on at least a portion of the first track, a portion of a write head was offset with respect to the first track, such that at least the portion of the write head infringed on a second track; determining a direction of movement of the write head; and based on determining that the portion of the write head was offset and determining the direction of movement of the write head, selectively performing one of (i) using the data buffered in the buffer module to recover data of the second track, or (ii) discarding the data buffered in the buffer module.

Abstract: Disclosed is a magnetic recording/reproduction device 2 including: a recording/reproduction head 7; and a recording/reproduction head 7 for detecting a leakage magnetic field of each of the plurality of magnetic recording cells 1 so as to reproduce information, the recording/reproduction head 7 carrying out the recording on the magnetic recording medium 4 so that the magnetic recording medium 4 includes continuous recording regions that (i) satisfy Nmin?2 and that (ii) include a continuous recording region that satisfies N?n×Nmin, where N represents a number of magnetic recording cells 1 in a continuous recording region; Nmin represents a minimum value for N; and n represents a positive integer, the continuous recording regions each being a region on a reproduction track in which region magnetic recording cells 1 sharing an identical magnetization direction are sequentially arranged in a circumferential direction of the magnetic recording medium 4.

Abstract: Disk drives are described with a write inhibit control system with an adaptive head position predictor, e. g. an adaptive FIR filter, that includes a set of coefficients (weights) that are updated for each iteration based on the difference between past predictions and actual location measurement. Standard PES signals are used as the measure of the actual head position. The adaptive head position predictor uses a sequence of the most recent PES measurements and a corresponding set of coefficients (weight values) to calculate a predicted (future) PES value during each iteration. The write inhibit decision is then made by determining whether either a) the absolute value of the current measured PES is less than predetermined value L; or b) the absolute value of the estimated future PES is less than predetermined value L.

Abstract: According to one embodiment, a disk storage apparatus includes a magnetic head, a detector, a calculator, and a decision module. The magnetic head has a high-frequency assisted element disposed close to a main magnetic pole that generates a recording magnetic field for perpendicular magnetic recording, the high-frequency assisted element applying a high-frequency magnetic field onto a magnetic disk during data recording. The detector detects an electrical resistance of the high-frequency assisted element. The calculator calculates time axis data indicative of a variation, on a time axis, in the electrical resistance value detected by the detector. The decision module determines whether the high-frequency assisted elements is malfunctioning based on the time axis data.

Abstract: A system and method for recording data to a perpendicular magnetic recording media having a highly ordered granular structure. The method includes the synchronization of write frequency and write phase to the granular structure of the magnetic media optimize performance of the magnetic data recording system by minimizing bit error rate.