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.

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: Determining a parameter associated with whether a portion of a storage device is defective is disclosed. Determining comprises: obtaining known data associated with the portion; reading back from the portion to produce a read-back waveform; decoding the read-back waveform, including producing statistical information; and determining a parameter associated with whether the portion is defective based at least in part on the statistical information.

Abstract: In various embodiments, systems and methods to detect signal irregularity caused by defects in the read/write head element are disclosed. In some embodiments, an exemplary system comprises a memory and a processor. The processor is coupled to the memory and is configured to implement a filter module and a detector module. The filter module is configured to generate a test waveform based on data read from a medium by a storage device head to be tested. The detector module is configured to generate a signal quality value based on a property of at least a portion of the test waveform, compare the signal quality value to an event threshold, and generate an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head.

Abstract: According to one embodiment, there is provided a disk drive. In the disk drive, a calibration module calibrates a write condition using a first area in a sequential access area on a disk to which data is to be written next time as a calibration area if the calibration is required. A manager enters the calibration area in a management table in association with a physical address of the first area used as the calibration area. A sequential write module continues a sequential writing from a second area following the first area based on skipping the first area.

Abstract: Storing data in a hard disk drive may include determining a percentage of storage usage (SU %) of the data tracks. If the SU % is less than a first threshold percentage (TP1), the method may include storing data to Nth data tracks. If the SU % is greater than or equal to TP1, but less than a second threshold percentage (TP2), the method may include storing data to about N/2 data tracks between said Nth data tracks. If the SU % is greater than or equal to TP2, the method may include storing data to data tracks between said N/2 data tracks and said Nth data tracks.

Abstract: Apparatus and methods for performing defect scanning on a disk drive which includes a disk constructed to have tracks written on the disk for storing data. Test data is concurrently written in more than one track on the disk and the data written to the more than one track is read to detect defects on the disk.

Abstract: Various embodiments of the present invention provide systems, methods and media formats for efficiently determining a position error of a head in relation to a storage medium. In one case, a system is disclosed that includes a storage medium with a series of data. The series of data includes a first defined marker and a second defined marker located a distance from the first defined marker, and position location data. The systems further include a first detector circuit that is operable to detect the first defined marker and to establish a location of the first defined marker, and a second detector circuit that is operable to detect the second defined marker and to establish a location of the second defined marker. The systems further include an error calculation circuit and an interpolation circuit. The error calculation circuit is operable to calculate an interpolation offset based at least in part on the location of the first defined marker and the location of the second defined marker.

Abstract: A servo writer is disclosed operable to write servo sectors on a disk to define non-circular servo tracks. The servo writer comprises control circuitry including a servo control system operable to measure a position of a head over the disk to generate a position signal, generate a position error signal (PES) representing a difference between the position signal and a reference signal, process the PES with a servo compensator to generate a control signal, and position the head over the disk in response to the control signal. A disturbance is induced into the servo control system, and while positioning the head over the disk in response to the control signal, a plurality of servo sectors are written on the disk to define a servo track, wherein the disturbance induced into the servo control system causes the servo track to be non-circular relative to a rotation axis of the disk.

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; logic for periodically determining a stopwrite threshold based on a current position error signal sample; logic for determining whether the current position error signal sample exceeds the stopwrite threshold; logic for disabling writing when the current position error signal sample exceeds the stopwrite threshold; and logic for enabling writing when the current position error signal sample does not exceed the stopwrite threshold. Additional embodiments are also disclosed.

Abstract: In one embodiment, a data storage system includes a head; a drive mechanism for passing a medium over the head; a controller electrically coupled to the head; logic encoded in or available to the controller for: periodically determining a stopwrite threshold based on a standard deviation or a variance at a current position error signal sample, wherein a smoothing factor applied to a subsequent calculation of the standard deviation or variance is altered based at least in part on a current magnitude of the standard deviation or the variance; determining whether the current position error signal sample exceeds the stopwrite threshold; disabling writing when the current position error signal sample exceeds the stopwrite threshold; and enabling writing when the current position error signal sample does not exceed the stopwrite threshold. Other systems, methods, and computer program products are described according to more embodiments.

Abstract: According to one embodiment, a disk storage apparatus includes a first storage device, a second storage device, and a controller. The first storage device stores data for use in determining influence imposed on tracks peripheral to a designated track in which data should be written on a disk. The second storage device has a nonvolatile cache area for temporarily storing data. The controller performs a cache process of storing the data in the nonvolatile cache area if the influence is determined, from the data, to exceed a reference value, in preparation for writing the data in the designated track.

Abstract: Method and apparatus for identifying the track pitch capability of a recording device, such as but not limited to a recording system and/or a servo control system in a data storage device. In accordance with some embodiments, data are written to first and second tracks at an initial track pitch such that the second track at least partially overlaps the first track. Data are arranged on the first track in code words each having a fixed plurality of bits which are decoded as a group by a data channel. The code words are transferred from the first track to the data channel, and a final track pitch for subsequent tracks is responsive to a distance at which nominally half of the code words are undecodeable by the data channel.

Abstract: Approaches for determining the timing latency of a communication path are described. Some embodiments involve a method for testing timing latency. A signal is driven on a first data path and is returned through a second data path through a loop back element. The timing latency of at least a portion of the communication path that includes the first data path and the second data path is tested using the signal returned on the second data path. The gain of the second data path is adjusted to a test value during the testing of the timing latency.

Abstract: A method, apparatus, and system for implementing channel signal processing assist with an embedded contact sensor (ECS) in hard disk drives. An ECS signal is captured during write and idle operation of the hard disk drive. A read channel monitors changes in the ECS signal providing a clearance monitor function for insuring write integrity.

Abstract: A method, apparatus, and system are provided for implementing magnetic defect location detection on-the-fly for hard disk drives. A magnetic media readback signal of a hard disk drive is demodulated to generate phase modulation (PM) and amplitude modulation (AM) signals. A new coordinate plane defined by a combined phase modulation (PM) and amplitude modulation (AM) phasor-defect detector calculation function used to locate magnetic defects on-the-fly.

Abstract: An asymmetry is determined of a signal generated by a read transducer in proximity to a changing magnetic field of a magnetic media. In response to determining the asymmetry of the signal, a current flowing through a heater of the read transducer is adjusted to cause a change to a magnetic field generated by the current. The change to the magnetic field generated by the current reduces the asymmetry of the signal.

Abstract: A method of detecting a contact between a transducing head and a storage medium is provided. The method applies an input signal, having a select power level and known frequency, to an actuator for actuating the head. An output signal is obtained in response to the input signal. At least one signal component is extracted from the output signal at the same or a harmonic of the same known frequency as the input signal applied to the actuator. Whether the at least one extracted signal component indicates a contact between the head and the medium is determined. The power level of the applied wave pattern is increased incrementally until the extracted signal component indicates a contact between the head and the storage medium.

Abstract: A method and apparatus for detecting a touch-down and contact between a head and a storage medium by using a signal generated by a data storage device, specifically by a sensor installed in a slider. The method includes: separating a signal detected by a sensor into a direct current (DC) component and an alternating current (AC) component, wherein the sensor has an electrical characteristic that changes according to temperature; using the DC component to detect a touch-down state of the head during a touch-down test to determine a value of a control signal for adjusting the flying height of the head; and using the AC component to detect a contacting state between the head and the storage medium in an operating state of the apparatus.

Abstract: Cross-track deviation of a writer from a predetermined track on a recording medium is detected. A write current is adjusted based on the cross-track deviation of the writer from the predetermined track. The adjusted write current is applied to the writer to compensate for the cross-track deviation of the writer from the predetermined track.

Abstract: A method, apparatus and a data storage device are provided for implementing data track pitch adjustment for data written on a recordable surface of a storage device under operational vibration conditions. An operational vibration disturbance spectrum is detected during a write operation and the data track pitch is selectively adjusted based on the detected operational vibration disturbance spectrum. The adjusted track pitch information is saved and used during a read operation.

Abstract: A disk drive tester is disclosed operable to test a plurality of disk drives, each disk drive comprising a head actuated over a disk. The disk drive tester comprises a plurality of test slots, where each test slot is operable to receive one of the disk drives. The disk drive tester further comprises an interface for receiving vibration data from the disk drives, wherein the vibration data at least partially represents a vibration applied to each disk drive by the respective test slot. The disk drive tester further comprises control circuitry operable to detect when one of the test slots is defective in response to the vibration data.

Abstract: A disk drive is disclosed comprising a disk comprising a plurality of tracks, and a head actuated over the disk. The head is positioned over a track while writing a first frequency pattern substantially centered on the track at a first frequency. After writing the first frequency pattern, a second frequency pattern is written substantially centered on the track at a second frequency, wherein the second frequency pattern is written over the first frequency pattern. After writing the second frequency pattern over the first frequency pattern, the head is scanned across the track while reading the disk to generate a read signal. A first frequency component is extracted from the read signal representing the first frequency.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, and control circuitry including a shock detector. A shock threshold of the shock detector is initialized, and a first number of shock events is detected in response to the shock detector operating at the initial shock threshold. When the first number of shock events exceeds an upper event threshold, a control signal is adjusted in order to adjust a frequency spectrum of noise affecting the shock detector. After adjusting the control signal, a second number of shock events is detected in response to the shock detector operating at the initial shock threshold. When the second number of shock events exceeds the upper event threshold, the shock threshold is increased.

Abstract: In one embodiment, a tape drive system includes a read channel configured for performing a portion of a data transfer operation, logic adapted for monitoring the data transfer operation for detecting one or more temps within a sliding window spanning a last group of datasets processed, logic adapted for measuring interference between first tier and second tier recovery methods based on the monitoring, logic adapted for setting a backhitch delay based on conditions relating to the interference of first tier and second tier recovery methods as it relates to a determined error burst, and logic adapted for performing a backhitch and altering at least one condition of the data transfer operation after the backhitch delay.

Abstract: Methods for measuring media performance associated with adjacent track interference are provided. One such method includes iteratively writing data to a target track for each of a plurality of n frequencies, measuring a first signal amplitude and a first noise for each of the n sectors on the target track, writing an aggressor track pattern proximate the target track, measuring a second signal amplitude and a second noise for each of the n sectors on the target track, calculating a weighted sum for each of the signal amplitude measurements for each of the plurality of n frequencies, and calculating a weighted sum for each of the noise measurements for each of the plurality of n frequencies, and repeating the writing the aggressor track pattern, the measuring the second signal amplitude and the second noise, and calculating the weighted sums for preselected numbers of times.

Abstract: Described are embodiments of an invention for customizing the range of acceptable write conditions to a tape of a tape cartridge that contracts or expands laterally based on environmental conditions. The tape drive utilizes servo information to determine if the tape has expanded or contracted from the nominal dimension and to determine the magnitude of the expansion or contraction. In the case of expansion, the magnitude of the determined expansion and the stored maximum amount of contraction must be below a predetermined threshold value to allow a write. In the case of contraction, the magnitude of the determined contraction and the stored magnitude of expansion must be below the same predetermined threshold value to allow a write. If the determined magnitude of contraction or expansion is greater than the stored magnitude of contraction or expansion, respectively, then the new extreme is stored.

Abstract: A disk drive is disclosed that enables defect margining during disk drive burn-in testing. The disk drive comprises: a disk comprising a plurality of tracks; a head actuated over the disk; and a processor. The processor is configured to: perform disk drive burn-in testing to detect media defects; generate an initial defect list based upon detected media defects for sectors; generate an extended defect list that includes detected media defects and extended defect margins from the detected media defects; and utilize the extended defect list for burn-in, wherein a spare area of the disk allows for the detected media defects and the extended defect margins.

Abstract: According to one embodiment, there is provided a method for determining whether a defect on a disk in an apparatus includes head is a recess or a protrusion. The method detects a first defect on the disk using a read element provided in the head. The method detects a second defect on the disk using a head disk interference sensor provided in the head. The method further determines whether a third defect is a recessed defect or a protruding defect based on a ratio between a first width of the first defect in a radial direction on the disk and a second width of the second defect in the radial direction of the disk. The third defect is identified based on the first defect and the second defect.

Abstract: A disk drive is disclosed comprising a plurality of disk surfaces, and a head actuated over each disk surface. When a write command is received, the data is written to a selected disk surface in response to a measured environmental condition. For example, the heads may exhibit different write performance based on the ambient temperature, and therefore the head to write data may be selected based on a measured ambient temperature at the time of the write operation.

Abstract: Methods and apparatus are provided for validating a detection of RRO address marks. After a potential RRO address mark is detected, a disclosed RROAM validation metric evaluates the energy of the remaining RRO data bits in the servo sector, relative to a predefined energy threshold. In addition, the number of remaining RRO data bits in the servo sector is compared to an expected value. The detected RRO address mark is validated in an exemplary embodiment if the RROAM validation metric satisfies the predefined energy threshold and the proper number of remaining RRO data bits is detected in the servo sector. The potential RRO address mark can optionally be discarded if the potential RRO address mark is not validated.

Abstract: Apparatus and methods for managing data stored in a disk drive having at least one disk including a first zone of tracks for storing data and a second zone of tracks for storing data, with the second zone being adjacent the first zone. It is determined whether a write counter for the first zone exceeds a threshold value. The write counter for the first zone represents a number of times the first zone has been completely written with data. If it is determined that the write counter for the first zone exceeds the threshold value, the disk drive is controlled to rewrite data from at least a portion of the second zone.

Abstract: A system and method for monitoring fly height between a magnetic recording medium and a transducing head. In a first exemplary embodiment, magnetic spacing change value is calculated using media noise on the recording medium (instead of prerecorded tones) to provide a broadband frequency distribution that results in improved Wallace equation accuracy. In a second exemplary embodiment, a magnetic spacing change value is acquired by any suitable method but is adjusted as necessary to reflect transducing head wear, thus providing a methodology for calculating changes in fly height by taking into account the signal loss that is attributable to wear. In this way, a basic understanding of the mechanism causing changes in magnetic spacing is achieved.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes a read circuit and a combining circuit. The read circuit is operable to provide a first instance of a user data set, a second instance of the user data set, and a third instance of the user data set. The combining circuit is operable to: combine at least a first segment of the first instance of the user data set with a first segment of the second instance of the user data set to yield a first combined data segment; provide a second combined data set that includes a combination of one or more second segments from the second instance of the user data set and the third instance of the user data set; and provide an aggregate data set including at least the first combined data set and the second combined data set. The second combined data set does not incorporate a second segment of the first instance of the user data set.

Abstract: According to one embodiment, a magnetic disk device is configured to read data from and write data to a magnetic disk using a magnetic head and provided with a control module that controls initial operation of the magnetic disk device according to initial firmware. The magnetic disk device includes a reader, a retainer, a blocker, and a switch. The reader reads control firmware stored in the magnetic disk. The retainer fixes a servo control amount for the magnetic head after the control firmware is read, and retains the magnetic head at a predetermined position above the magnetic disk. The blocker blocks input of an interrupt signal to the control module. The switch switches the initial firmware to the control firmware after the servo control amount is fixed and the input of an interrupt signal is blocked.

Abstract: Described embodiments cancel inter-track interference (ITI) from one or more sectors read from a desired track of a storage medium. A read channel reads one or more sectors in the desired track and generates one or more groups of sample values corresponding to each of the sectors. An ITI canceller estimates an ITI response and an ITI signal for each sample value corresponding to (i) a next adjacent track and (ii) a previous adjacent track. If the estimated ITI response of the previous adjacent track reaches a predetermined threshold, the ITI canceller subtracts the estimated ITI signal corresponding to the previous adjacent track from each associated sample value of the desired track. If the estimated ITI response of the next adjacent track reaches a predetermined threshold, the ITI canceller subtracts the estimated ITI signal corresponding to the next adjacent track from each associated sample value of the desired track.

Abstract: A tape recording apparatus in communication with a tape medium, and includes a head and a controlling unit to control the head to read and write data to the tape medium, wherein the controlling unit performs operations, comprising: determining an overwrite starting position by skipping data units whose beginning position cannot be determined until a data unit is reached having a beginning position that can be determined; and performing an overwrite operation at the overwrite starting position at the data unit whose beginning position can be determined.

Abstract: Systems and/or methods for measuring latency in an electronic device such as, e.g., a storage device, may include coupling circuitry configured to capacitively couple an outbound or write data path to an inbound or read data path. A latency measurement signal may be driven on the write data path, the coupling circuitry may transmit at least a portion of the latency measurement signal from the write data path to the read data path, and the latency measurement signal may be sensed on the read data path to be used to determine communication path latency in the device.

Abstract: A process is disclosed for determining one or more edges of usable portions of a disk drive. Such knowledge can be used to determine the range of valid tracks of the disk and improve utilization of available disk space. The process can detect the edges by processing one or more disk controller signals, such as an adaptive feed-forward (AFC) injection signal, or a position error signal (PES).

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is discussed that includes an inter-track interference determination circuit operable to calculate an inter-track interference from a previous track data set based at least in part on the previous track data set and a current track data set. The previous track data set includes a gap. A portion of the data in the previous track data set corresponds to a previous track on a storage medium, and the data in the previous track data set corresponding to the gap corresponds to a track preceding a previous track.

Abstract: A data processing device includes a memory, an arithmetic circuit that accesses the memory by outputting an access control signal CTRL that controls access to the memory, a first data storage unit that stores first data used when a self-diagnosis is performed, a read-modify-write circuit that generates second data by replacing a part of the first data stored in the first data storage unit with modify data outputted from the arithmetic circuit, and a determination unit that diagnoses a failure of the read-modify-write circuit by comparing the second data with an expected value.

Abstract: A measuring circuit system in a magnetic field measuring apparatus of the invention has an amplifier and a band-pass filter connected in sequence on an output terminal side of the TMR element, the band-pass filter is a narrow-range band-pass filter such that a peak pass frequency of the filter that is a center is a basic frequency selected from a range of 10 to 40 GHz and a band width centered around the basic frequency is a narrow range of ±0.5 to ±4 GHz; and with the measuring circuit system, an S/N ratio (SNR) of 3 dB or greater is obtained, the SNR being defined by a ratio of an amplitude S of a high-frequency generated signal induced by the TMR element to a total noise N that is a sum of a head noise generated by the TMR element and a circuit noise generated by the amplifier. With such a configuration, an in-plane high-frequency magnetic field generated by a microwave-assisted magnetic head is reliably and precisely measured.

Abstract: The present inventions are related to apparatuses and methods for detecting and classifying media defects. For example, an apparatus for classifying a media defect is disclosed including a DFT circuit operable to yield real and imaginary components of a signal derived from data read from a storage medium, a calculation circuit operable to calculate an amplitude and a phase of the signal based on the real and imaginary components, and a classifier operable to detect the media defect based on the amplitude and to classify the media defect based on the phase.

Abstract: A “write-squeeze-verify” method is used for verification of the data that has been written in the annular bands of a shingled magnetic recording disk drive. The writing of data along a track overwrites a portion of the previously written track and thus “squeezes” the data of the previously written track to thereby form a “shingled data track” (SDT). The data in each SDT is read back and verified by an error correction check using error correction bits associated with the data written in the SDT, or by comparing the readback data with the data stored in memory. If the data read back is not verified, a write error counter is incremented and a write error frequency is calculated. One or more attempts to write the data can be performed. If the data in the SDT cannot be verified after the attempted rewrite(s), then a “re-try fail” is reported.

Abstract: A characteristic evaluation method of a perpendicular magnetic recording medium suitable for obtaining a perpendicular magnetic recording medium which can respond to much higher recording density is provided.

Abstract: Inter-track interference cancelation is disclosed, including: receiving an input sequence of samples associated with a track on magnetic storage; using a processor to generate inter-track interference (ITI) data associated with a first side track including by performing a correlation between the input sequence of samples and a sequence of data associated with the first side track.

Abstract: According to one embodiment, a method includes writing, to a regular recording region of a tape medium after having written a first data accumulated in a buffer to a temporary recording region of the tape medium without an accompanying backhitch, a first data group that includes the first data that has any gaps between data eliminated, predicting a second volume of a second data, to be written in response to a command that is sent after the first data has been written to the regular recording region, judging whether the first volume exceeds a first threshold and whether or the second volume exceeds a second threshold, and writing the second data to the regular recording region without an accompanying backhitch when it has been judged that the first volume exceeds the first threshold and the second volume exceeds the second threshold.

Abstract: A system for monitoring and analyzing operation of a tape infrastructure. The system includes a plurality of real and virtual tape libraries each including a plurality of tape drives and tape media. The system includes a server linked to the tape library. On the server, a storage tape analytics application is provided that functions to extract raw data sets from the tape library corresponding to operations of the tape library. The data pertains to use of the drives and media during data storage operations and data about the activities of the real or virtual tape libraries. The analytics application stores the extracted data sets in an analytics database. The analytics application provides a user interface for viewing data in the analytics database, e.g., a GUI operable by monitoring personnel to view and interact with the gathered and processed tape operations monitoring data to provide historical and user-driven analysis of data for an entire data center.

Abstract: A system includes a read channel circuit configured to output a write signal, and output a write enable signal that indicates a write operation. A preamplifier circuit includes a write amplifier configured to amplify the write signal and provide the amplified write signal to a read/write device. A read amplifier is configured to amplify a read signal received from the read/write device. A circuit is configured to receive the amplified write signal from the write amplifier, receive the amplified read signal from the read amplifier, receive the write enable signal from the read channel circuit, and provide, to the read channel circuit, a selected one of the amplified write signal and the amplified read signal based on the write enable signal.