Abstract: A method of recovering data from one or more failed data sectors includes estimating a reader offset position from a first or a second read attempt of the one or more failed data sectors at a current set of channel parameters and basing the estimated reader offset position on, at least in part, a position error signal generated during the first or second read attempt. At least one read is performed on the one or more failed data sectors at the estimated reader offset position to obtain one or more samples. The one or more samples are processed to obtain a processed sample. Iterative outer code recovery is performed on the processed sample.

Abstract: According to an embodiment, a controller of a magnetic disk device executes control such that detection of touchdowns of one or more first magnetic heads and detection of touchdowns of one or more second magnetic heads are executed at different timings. In addition, the controller executes control such that touchdowns of the one or more first magnetic heads are detected at different timings and touchdowns of the one or more second magnetic heads are detected at different timings.

Abstract: Systems and methods are disclosed for synchronous writing of a grain patterned medium. The systems and methods can be implemented within a data storage device having a grain patterned medium. Further, a calibration process to determine a count of bits between servo wedges can be implemented in manufacturing, within the data storage device, or both. In some examples, the data storage device, during operation, can utilize the count of bits to perform synchronous writing, determine write errors, or both. Further, the servo wedge of the grain patterned medium may be patterned with a same or similar grain pattern as the data area that follows the servo wedge. Such a data storage device can implement a single clock for reading a servo wedge and writing a data area.

Abstract: According to one embodiment, in a disk device, a first pattern cut out from a burst region at a certain servo track by a first length and with a first start position, does not match a second pattern cut out from the burst region at an adjacent servo track by the first length and with an arbitrary second start position including first timing. The burst region at the servo tracks includes a first burst pattern including a first magnetized portion where a first value is recorded and a second magnetized portion where a second value reverse to the first value in polarity is recorded, the second magnetized portion being adjacent to the first magnetized portion in a down track direction. A width of the first magnetized portion in the down track direction and a width of the second magnetized portion in the down track direction are different from each other.

Abstract: According to one embodiment, a magnetic disk device includes a disk including two first servo sectors and at least a second servo sector, a head, and a controller, wherein the first servo sector includes burst data and a first data pattern written before the circumferential direction of the burst data, the second servo sector includes the burst data, the first data pattern, and a second data pattern written after the circumferential direction of the burst data, a first frequency of the first data pattern is different from a second frequency of the second data pattern, and a first length of the first data pattern is different from a second length of the second data pattern.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising servo data for defining a plurality of data tracks, wherein each data track comprises a plurality of data segments. First data is written to data segments of a first data track, and second data is written to data segments of a second data track. After writing the second data, the first data is read at multiple off-track offsets of the first data track to measure an average off-track read capability (OTRC) of the first data track. A cross-track profile is generated for a first data segment of the first data track, and at least part of the cross-track profile is correlated with the measured average OTRC.

Abstract: A method of countering a residual resonance experienced by an electronic communication device due to an activation of an actuator within the housing of the electronic communication device. The method includes determining an effective vibration behavior of the electronic communication device when activating the actuator according to a predetermined pattern, determining, based on the effective vibration behavior, a desired counter actuation signal, activating the actuator according to the predetermined pattern for a predetermined period of time, and upon expiration of the predetermined period of time, activating the actuator according to the desired counter actuation signal to counter an residual resonance experienced by the electronic communication device.

Abstract: A data storage device is disclosed comprising a top head actuated over a top surface of a first disk, a bottom head actuated over a bottom surface of the first disk, a top head actuated over a top surface of a second disk, and a bottom head actuated over a bottom surface of the second disk. A dual channel preamp circuit is coupled to the top and bottom heads of the first and second disks, wherein a selection signal is applied to the dual channel preamp circuit to select between the first disk and the second disk. A concurrent access operation of the top and bottom surface of the selected disk is executed using the dual channel preamp circuit.

Abstract: A method for scheduling data transfer commands between a first actuator or a second actuator across an interface is disclosed. The method includes balancing data transfer commands between the first actuator and the second actuator by applying a first rule for read commands and a second rule for write commands.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising servo data for defining a plurality of data tracks, wherein each data track comprises a plurality of data segments. First data is written to a first data segment of a first data track, and second data is written to a second data segment of a second data track. After writing the second data, a quality metric is measured for at least two off-track offsets of the first data segment. A track pitch is estimated between the first data segment and the second data segment based on the quality metrics, and a track trajectory is generated for the second data segment based on the estimated track pitch. Third data is written to the second data segment based on the track trajectory.

Abstract: A system and method for monitoring hard disks includes a displaying unit, a hard disk controlling unit, and a complex programmable logic device (CPLD). The displaying unit displays status of hard disks. The hard disk controlling unit obtains statuses and outputs information as to status. The CPLD decodes the status information and determines whether the status of a hard disk is predictive failure analysis (PFA) according to the decoded signal. The CPLD controls the displaying unit to output PFA warning and delays other status displays for priority of the PFA. A method for monitoring is also provided.

Abstract: A method according to one embodiment includes generating a y-position estimate based on a servo readback signal from a servo reader reading a servo band, retrieving or calculating a nonlinearity-correction value corresponding to the y-position estimate, adjusting the y-position estimate using the nonlinearity-correction value, and outputting the adjusted y-position estimate. A computer program product for compensating for nonlinearity in a timing based servo pattern according to one embodiment includes a computer readable storage medium having program instructions embodied therewith. The computer readable storage medium is not a transitory signal per se. The program instructions are readable and/or executable by a controller to cause the controller to perform the foregoing method.

Abstract: The disclosed technology provides a method that improves SMR throughput in vibration in storage systems. In one implementation, the method comprises receiving a write command to write data on a first track in a band of a storage medium, performing a vibration detection scheme to identify vibration events, determining if a number of vibration events is above a predetermined threshold, skipping the first track responsive to determining the number of vibration events is above a predetermined threshold, seeking to a second track adjacent to the first track, increasing an OCLIM on the second track adjacent to the first track from a default OCLIM to an increased OCLIM, and shifting the writer center on the second track adjacent to the first track.

Abstract: A data processing system is disclosed including a data detector, a data decoder and an alignment detector. The data detector is operable to apply a data detection algorithm to generate detected values for a data sector. The data decoder is operable to apply a data decode algorithm to a decoder input derived from the detected values to yield decoded values. The alignment detector is operable to calculate an offset between multiple versions of the data sector by correlating the multiple versions.

Abstract: A data storage device is disclosed comprising a head actuated over a disk surface comprising a plurality of servo tracks, wherein the head comprises at least two read elements including a first read element and a second read element, and at least two of the read elements are offset radially relative to a center of the two read elements by at least a width of a servo track at all radial locations of the head over the disk surface. First servo data recorded in a first servo track is read using the first read element to generate a first read signal, and second servo data recorded in a second servo track is read using the second read element to generate a second read signal. The head is servoed over the disk surface based on at least the first read signal and the second read signal.

Abstract: A storage device includes read circuitry having a read head having a detector that outputs signals representing data from a first track and an adjacent track. The read head is subject to off-track excursions during which the read head detects signals from both the first track and an adjacent track. Data on each track includes a preamble including a repeating pattern. The repeating pattern in any first track is orthogonal to the repeating pattern in any track adjacent to the first track. The read circuitry also includes respective Discrete Fourier Transform circuits to identify components in the signals corresponding to respective frequencies characteristic of the repeating pattern on the first track and the repeating pattern on the second track, and computation circuitry to determine from the components a ratio by which the read head is off-track. Corresponding methods are provided for operating such a storage device and for reading data.

Abstract: A reference spiral is written on a recording surface of a hard disk drive. By launching writing of fine guide spirals from a launch point that is disposed on a pre-existing coarse guide spiral, writing of the fine guide spiral can be launched in response to a write head crossing the pre-existing coarse guide spiral, rather than in response to a precisely timed event. To enable launch points being disposed on pre-existing coarse guide spirals, launch points are not all located at the same radial position on the recording surface.

Abstract: According to one embodiment, a magnetic disk drive in the present embodiment includes a disk including tracks, each including servo sectors, a head, and a controller configured to acquire first correction data for repeatable runout occurring in a first direction, and second correction data different from the first correction data, to write the first correction data within a first permitted range in the first direction, to write the second correction data within a write permitted range including the first permitted range and a second permitted range in a second direction opposite to the first direction, to read at least one of the first correction data and the second correction data, and to correctly place the head.

Abstract: An output is generated in response to an indication associated with movement of a moveable part in a storage device. The output is for reducing a noise component associated with the movement of the moveable part.

Abstract: A magnetic storage medium is formed of magnetic nanoparticles that are encapsulated within nanotubes (e.g., carbon nanotubes).

Abstract: Method and apparatus for controlling the position of a control object in a closed loop control system, such as a servo control system used in a data storage device. In some embodiments, spaced apart first and second data tracks are written to a rotatable data recording medium without using repeated runout (RRO) compensation values to correct for RRO error in servo data written to the medium. A third data track is subsequently written so as to be interspersed between and partially overlap the first and second data tracks. The third data track is written using a set of RRO compensation values to correct for the RRO error in the servo data.

Abstract: Implementations described and claimed herein provide a method and system for managing execution of commands for a storage device, the method comprising determining a plurality of commands to be executed for the storage device and while a storage device is executing at least one command, determining an execution order for at least two of the plurality of commands. Alternate implementation described and claimed herein provide a computer readable memory for storing a data structure, the data structure comprising a cost table comprising a number of cells, each cell containing one or more cost values related to one of a plurality of traversals between two locations on a storage device wherein each of the plurality of traversals is related to completion of one of a plurality of commands and a benefit array comprising a number of cells, each cell containing a benefit value related to completion of one of the plurality of commands.

Abstract: An offset from track center of data is determined in a data storage device. The data is written to a heat-assisted magnetic recording medium of the device, and the offset compensates for degradation of an optical component of a read/write head when writing the data. The offset is stored in a memory of the storage device. Using the offset, a track alignment is changed during subsequent writes via the read/write head.

Abstract: Systems and methods are disclosed for using track misregistration values, representing an amount of off-track deviation of a write element, to dynamically increment error scan counters for proximate storage areas. In certain embodiments, an apparatus may comprise a processor configured to perform a write operation to record data to a target track of a data storage medium using a write element, determine an amount of deviation of the write element from a center line of the target track, and increment an error scan counter for an area of the data storage medium proximate to the target track based on the amount of deviation.

Abstract: Various embodiments of the present invention provide systems and methods for determining changes in fly-height. For example, various embodiments of the present invention provide storage devices that include a storage medium having servo data thereon. A read/write head assembly is disposed in relation to the storage medium. A servo based fly-height adjustment circuit receives the servo data via the read/write head assembly, and calculates a first harmonics ratio based on the received data and compares the first harmonics ratio with a second harmonics ratio to determine an error in the distance between the read/write head assembly and the storage medium.

Abstract: A patterned magnetic media having offset servo and data regions. The media can be constructed by a method that allows both a data region and a servo region to be patterned without the patterning of one region adversely affecting the patterning of the other region. The method results in a patterned data region a patterned servo region and intermediate regions between the servo and data regions. The intermediate regions, which are most likely, but not necessarily, asymmetrical with one another indicate that the method has been used to pattern the media.

Abstract: According to one embodiment, a position demodulation apparatus is provided which demodulates a first demodulated signal and a second demodulated signal, based on a servo-pattern read signal read out by a head from a medium, acquires a plurality of sets of a vector length and phase angle of vectors on a phase plane denoting the first and second demodulated signals, detects a phase angle for which the vector length is greatest based on the sets acquired, and executes rotational correction using the difference between the detected phase angle and a particular reference angle as a correction amount.

Abstract: Digital optical tape archival storage systems and methods are disclosed. A digital optical tape recorder may simultaneously write data and two or more guide tracks onto a digital optical tape recording medium. A digital optical taper reader may include a camera to capture a two-dimensional image of the digital optical tape recording medium, and an image processor to extract the data from the two-dimensional image.

Abstract: Disclosed is a technique of providing a perpendicular magnetic recording medium in which high-quality servo information enabling high-density recording of 500 kTPI or more is recorded, and a magnetic storage device of an adaptive track formatting type having large capacity, high reliability and high performance with high device manufacturing yield. At a servo area of the perpendicular magnetic recording medium, a servo sequence such as a burst pattern for positioning in a servo track is recorded in a seamless manner without big recording footprint (several times longer than the servo bit) and in a magnetization pattern such that a total amount of the recording magnetization is substantially zero.

Abstract: A method of operating or calibrating a storage device having a storage medium platter includes writing servo data to the storage medium platter, where the servo data include, for each track on the storage medium platter, a servo sync mark, and a repeating pattern. For each pair of adjacent tracks on the storage medium platter, the repeating patterns, which may be orthogonal, are compared to determine relative phase of the repeating patterns on adjacent tracks. The relative phase for each pair of adjacent tracks is recorded. In another calibration method, first and second repeating patterns may compared to determine whether relative phase of the first and second repeating patterns exceeds a threshold, in which case the second servo data are erased, new second servo data are written, and the comparing and erasing are repeated until the relative phase of the first and second repeating patterns is less than the threshold.

Abstract: Determining the radial position of a first read head of a storage device includes reading servo data from a storage media platter surface using the first read head, deriving from that servo data a first positron error signal representing a first estimate of the radial position of the first read head, reading the servo data from the storage media platter surface using a different read head, deriving from that servo data a second position error signal representing an estimate of the radial position of the different read head, and combining the first estimate of the radial position of the first read head and the estimate of the radial position of the different read head to obtain a revised estimate of the radial position of the first read head. The combining could include taking account of a known positional offset between the first read head and the different read head.

Abstract: An apparatus includes a controller configured to be coupled to a read/write head. The controller is configured to perform various operations including detecting a change in a time interval difference between servo sectors of a servo marked recording medium, converting the change to an offset signal that compensates for the change, and positioning the read/write head relative to the servo mark recording medium in response to the offset signal. The change in the time interval difference is representative of disk slip.

Abstract: A pattern of features of a storage medium includes first features having a first logical state and second features having a second logical state, wherein a cross track dimension of the first features is different from a cross track dimension of the second features. A transducer of a memory device senses the pattern of features and generates a transducer signal. Read circuitry samples the transducer signal at a frequency of a sampling clock signal and generates a read signal from the sampled transducer signal. Servo electronics includes a demodulator that demodulates at least first and second orthogonal frequency components of the read signal. Timing circuitry synchronizes a phase of the sampling clock signal with a phase of the pattern of features using the first orthogonal frequency component. Position error circuitry generates a signal indicating a cross track positional offset of the transducer relative to the features using the first and second orthogonal frequency components.

Abstract: Methods including determining a distribution of a position error signal (PES) of a magnetoresistive head by obtaining PES data from a servo controller associated with the magnetoresistive head; determining an encroachment function of a storage disc; and determining a track density of the storage disc by considering both the PES distribution and the encroachment function.

Abstract: Servo data of one or more tracks of a disk are collected using first and second read transducers co-located on a slider. Redundant portions of the servo data collected by the first and second read transducers are compared, and at least part of the servo data validating or corrected based on comparing the redundant portions.

Abstract: A magnetic head includes a main pole, a write shield, and first and second nonmagnetic layers. The main pole has a top surface including an inclined surface portion. The write shield includes an inclined portion facing toward the top surface of the main pole. The first nonmagnetic layer is interposed between the inclined surface portion and the inclined portion. The second nonmagnetic layer is interposed between the first nonmagnetic layer and the inclined portion. The first nonmagnetic layer has a first front end located in a medium facing surface. The second nonmagnetic layer has a second front end that is located closest to but at a distance from the medium facing surface.

Abstract: A magnetic head includes a coil, a main pole, a write shield, a first insulating film, and a second insulating film. The coil includes a specific coil element. The main pole has a top surface including an inclined surface portion and a flat surface portion. The write shield includes an inclined portion. The inclined portion includes a first portion opposed to the inclined surface portion, and a second portion located farther from a medium facing surface than the first portion. The specific coil element includes an interposition part interposed between the flat surface portion and the second portion. The first insulating film is interposed between the inclined surface portion and the first portion of the inclined portion, and between the interposition part and the second portion of the inclined portion. The second insulating film is interposed between the first insulating film and the second portion of the inclined portion.

Abstract: According to various embodiments, a recording medium may be provided. The recording medium may include a dedicated servo layer configured to provide servo information. The dedicated servo layer may include a plurality of tracks. A first track may include a first servo signal. The first servo signal may include first servo bursts of a pre-determined frequency. A second track adjacent to the first track may include a second servo signal. The second servo signal may include second servo bursts of the pre-determined frequency.

Abstract: A disk drive is disclosed including a disk having a plurality of sectors, and a head actuated over the disk. A defect threshold is initialized, and a first sector is read to generate a first read signal. The first read signal is processed to detect a defect in the first sector relative to the defect threshold. After detecting the defect, the defect threshold is adjusted and the first sector is reread to generate a second read signal. The second read signal is processed to detect the defect in the first sector relative to the adjusted defect threshold.

Abstract: According to one embodiment, a head position demodulating method and a magnetic disk device switch a demodulation window such that an amplitude of a fundamental wave component of a null-type burst pattern transitions from a decreasing direction to an increasing direction along with an increase in seek speed during demodulation of the null-type burst pattern recorded on a magnetic disk.

Abstract: According to one embodiment, a head position demodulating method and a magnetic disk device switch a demodulation window such that an amplitude of a fundamental wave component of a null-type burst pattern transitions from a decreasing direction to an increasing direction along with an increase in seek speed during demodulation of the null-type burst pattern recorded on a magnetic disk.

Abstract: A disk drive is disclosed comprising a disk comprising tracks defined by servo sectors, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk in response to the servo sectors. The servo control system is configured into a first state, and a position error signal (PES) representing a difference between a target location for the head and a measured location for the head is generated. An actuator control signal is generated in response to the PES, a feed-forward control signal is adapted in response to the servo sectors, and the actuator control signal is adjusted using the feed-forward control signal. The servo control system is configured from the first state to a second state, and a phase of the adaptation of the feed-forward control signal is adjusted based on the second state.

Abstract: A disk drive is disclosed comprising a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones, where a servo data rate of servo sectors in a first servo zone is different than a servo data rate of servo sectors in a second servo zone. A servo control system servos a head over the disk. An estimated servo state of a servo control system is generated, and when the head crosses from a first servo zone to a second servo zone, the estimated servo state is adjusted to compensate for a transient in a circumferential distance between a servo sector in the first servo zone and a servo sector in the second servo zone.

Abstract: According to one embodiment, there is provided a method for generating address data. The method generates a first code corresponding to a cylinder number. The cylinder number is divided and recorded on servo sectors in association with an identification of a cylinder on a disk. The first code is formed of some codes obtained by dividing the cylinder number based on a number of each of the servo sectors. The method generates a second code corresponding to address data for each of the servo sectors, by encoding the first code based on the servo sector number and a servo format number. The servo format number is used to identify a format of each of the servo sectors.

Abstract: A hard disk drive uses a second, reference burst field in a preamble to estimate burst phase and burst magnitude. Such estimations are used for position error signal integration and repeatable runout correction. Gain error is also derived from such estimations. Information contained in a preamble field is used in conjunction with the reference burst phase estimation to synchronize servo address marks.

Abstract: A magnetic disk device according to an embodiment includes a head and a disk with a recording surface, the head including a reader configured to perform data reading, and a writer configured to write data. A method of correcting a read/write offset, according to the embodiment, is applied to the above magnetic disk device. This method includes reconstructing position data read by the reader, using a spline function, and correcting a read/write offset due to the distance between the writer and the reader, using the reconstructed position data.

Abstract: At least three servo burst frequencies are simultaneously detected during a rotation of a disk using a read head. A position of the read head during the rotation is determined based on simultaneously reading at least two of the at least three servo burst frequencies.

Abstract: Techniques are provided for performing bit-locked operations on media. A first control signal is received from a first source, and a second control signal is generated at a second source in response to receiving the first control signal. The media is accessed according to the second control signal. One or more synchronization markers are located during the accessing of the media, and bit-level synchronization between the second source and the media is achieved based, at least partially, on the one or more synchronization markers. A control operation is performed on the media with bit-level synchrony between the second source and the media.

Abstract: A bit patterned media (BPM) encoded recordable medium includes a servo control field including servo bits. Each servo bit is represented by a servo bit pattern of dots and gaps on the recordable medium. In the servo bit patterns, substantially no two dots are placed immediately next to one another, and substantially all servo bit patterns start with a gap and/or substantially all servo bit patterns end with a gap.

Abstract: According to one embodiment, a system for processing data includes an equalizer configured to use servo coefficients for processing servo data and data coefficients for processing non-servo data, wherein the equalizer includes a finite impulse response (FIR) filter configured to process data read with a magnetic tape channel using the servo coefficients to generate equalized data, one or more low-pass filters with aggressive frequency characteristics configured to filter the equalized data to output filtered data, the one or more low-pass filters with aggressive frequency characteristics being configured to remove high frequency noise from the equalized data, a peak detector configured to process peaks in a waveform of the filtered data, and at least one servo pattern detector configured to detect a servo pattern in the filtered data. Other systems and methods for processing data are described in more embodiments.