Abstract: A Dynamic Wave-Shaping (DWS) write driver for use in a preamp in a disk drive is described. The DWS write driver includes a Dynamic Current Booster (DCB) that adds a current component (WDCB) to the standard write driver signal (including overshoot) that is a function of the bit spacing in the write data input waveform supplied to the write driver. The invention allows dynamic control of the bit-pattern dependent overshoot amplitude without requiring significant preamp overhead. Embodiments of the Dynamic Current Booster include a programmable analog feed-forward timer at the preamp level. The boost current amplitude is a function of the time between the transitions that represent bits. In embodiments, the polarity of the boost current WDCB can be programmed to be positive or negative.

Abstract: An apparatus comprising a preamplifier, a channel, and a controller. The preamplifier may be configured to read/write data to a drive with a read/write head, in response to (i) a plurality of digital control signals multiplexed to be sent/received over a first bus and (ii) one or more analog data signals sent/received over a second bus. The channel may be configured to (i) connect to the first and second bus, and (ii) send/receive the plurality of digital control signals through (a) a plurality of interconnects and (b) the first bus. The controller may be configured to send/receive the digital control signals over the interconnects. The apparatus may be configured to (i) read/write the analog data signals to the drive and (ii) generate the digital control signals, in response to one or more input/output requests received from a drive interface.

Abstract: Aspects of the disclosure pertain to a read channel system and method for providing sector prioritization for promoting improved sector processing performance. The system and method, during processing of sectors of data, prioritize each of the sectors for further processing based upon: a global iteration index of each sector, trapping set characteristics of each sector and processing latency of each sector.

Abstract: Aspects of the disclosure pertain to a system and method for providing zero gain start (ZGS) and gain acquisition based on an adaptive analog-to-digital converter (ADC) target. The adaptive ADC target is used to collect channel characteristics and based on the adaptive ADC target, an adjusted 2T amplitude target value is generated.

Abstract: Methods and systems for estimating MRA for a hard disk drive are described. The methods and systems described herein provide for real time estimating and correcting magneto-resistive head asymmetry (MRA) in a hard disk drive using analog-to-digital convertor (ADC) samples or counts. Generally, ADC outputs may be obtained by injecting MRA at known values, where an estimated MRA may be derived in real time by applying an equation using particular ADC output values. Once an estimated MRA is obtained, MRA correction may be performed when the estimated MRA is larger than a threshold value, such as by adjusting a channel MRA compensation coefficient.

Abstract: Embodiments of the present inventions are related to systems and methods for data processing, and more particularly to systems and methods for reducing inter-track interference in relation to processing data retrieved from a storage medium.

Abstract: A hard disk drive or other storage device comprises a storage medium, a read head configured to read data from the storage medium, and control circuitry coupled to the read head and configured to process data received from the read head. The control circuitry comprises read channel circuitry that includes a low-density parity check decoder or other type of decoder. Power management circuitry associated with the read channel circuitry is configured to detect a power control condition of the read channel circuitry and to control insertion of idle clock cycles in a clock signal supplied to the decoder responsive to the detected power control condition. For example, the read channel circuitry may comprise a clock generator configured to gate the clock signal responsive to a control signal from the power management circuitry.

Abstract: Records and filemarks read from data segments are aggregated into at least one single data segment. The records and the filemarks are reorganized and restructured in the single data segment such that buffer utilization is improved.

Abstract: A first data group in an access sequence is selected based on which data group in the data groups has a beginning closest to a current position of the tape medium. Those data groups located in specified regions of the tape medium are separated from other data groups located in alternative specified regions of the tape medium. The distance from the current position of the tape medium is set to be a logical distance value, determined by a calculation function, that is substituted for the physical distance value for the data groups that are located in the specified regions as compared with other data groups located in the alternative specified regions. A second data group in the access sequence is selected based on which remaining data group in the data groups has a beginning closest to an end of the first data group in the access sequence.

Abstract: A method, apparatus and a data storage device are provided for implementing track following and data recovery with readback of shingled data written in overlapping shingled data tracks on a recordable surface of a storage device. Positional information is identified with data readback of shingled data written in overlapping shingled data tracks. The identified positional information is used to selectively modify at least one predefined channel parameter, for example, to provide enhanced track following and enhanced data recovery.

Abstract: Methods and apparatus are provided for improved detection of servo sector data in a magnetic recording system using single bit error correction. Servo sector data is processed by detecting the servo sector data; determining whether a single bit error occurred in the detected servo sector data; and flipping a bit value of an individual bit in the detected servo sector data having a lowest amplitude sample among the samples of the detected servo sector data when a single bit error is detected in the detected servo sector data. The servo sector data comprises, for example, a servo address mark, Gray data, an RRO address mark and/or RRO data. For example, the bit value can be flipped by changing a binary value of one to a binary value of zero and changing a binary value of zero to a binary value of one.

Abstract: A write driver circuit for generating a write current pulse for use by a magnetic write head includes an output stage adapted for connection with the magnetic write head and a charge storage circuit connected with the output stage. The charge storage circuit is operative in a first mode to store a prescribed charge and is operative in a second mode to transfer at least a portion of the charge stored therein to the output stage to thereby enable an output voltage level of the output stage to extend beyond a voltage supply rail of the write driver circuit. A control circuit in the write driver circuit is operative to generate at least one control signal for selectively controlling a mode of operation of the charge storage circuit.

Abstract: The present inventions are related to systems and methods for data processing, and more particularly to data processing using distortion-correction loops with saturation-based assistance.

Abstract: A method of storing data in a storage medium includes determining a compensation unit for a portion of the storage medium, reading a first set of bit values from the portion of the storage medium, determining a compensation value based at least in part on an erroneous bit value of the first set of bit values and the compensation unit, and storing the compensation value in association with the portion of the storage medium.

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: Systems and methods are included for determining a presence of an upcoming reading field during a write mode of a storage device, and initiating a read-while write (RWW) mode of the storage device in response to the sensed reading field. Initiating the RWW mode comprises warming up the reader circuitry, generating a signal in response to an end to the write operation, and activating reader bias current in response to the generated signal.

Abstract: Selection of disk drive data tracks for the location of reserved area include providing a media disk with data tracks comprising a user data region. A location is assessed on the media disk with a highest frequency of adjacent track interference and far track interference-refresh potential. The location is then configured to be a reserved area where no user data is written. The reserved area has parameters that are read out first before the disk drive enters an operation enabled state for user interface.

Abstract: According to one embodiment, a magnetic disk device includes an initial calculation module and a simple determination module. The initial calculation module, in a simple determination expression describing a magnitude relation between a first value calculated from a first half part of the burst data and a second value calculated from a second half part of the burst data, starts a calculation of the first value before the reading of the second half part of the burst data is completed. The simple determination module performs a determination by the simple determination expression after the reading of the second half part of the burst data is completed.

Abstract: In accordance with one embodiment, a data storage system includes a tape channel for reading precoded data from a magnetic tape medium to produce a signal, a soft detector adapted for calculating first soft information about each bit of the signal and sending the first soft information to a soft decoder, and the soft decoder positioned subsequent to the soft detector, the soft decoder being adapted for calculating second soft information about each bit of the signal and sending the second soft information to the soft detector, wherein the precoded data includes a characteristic of being passed through at least one precoder prior to being written to the magnetic tape medium, and wherein the soft detector provides automatic compensation for the precoded data. Other systems, methods, and computer program products for reading data using an adaptive soft-output detector are described according to more embodiments.

Abstract: In one embodiment, a data storage system includes a tape channel for reading data from a magnetic tape medium to produce a signal, a noise whitening filter positioned subsequent to the tape channel adapted for receiving the signal, wherein the noise whitening filter is adapted for minimizing variance of its output signal, a soft detector adapted for receiving output from the noise whitening filter, the soft detector adapted for calculating first soft information about each bit of the signal and sending the first soft information to a soft decoder, and the soft decoder positioned subsequent to the soft detector, the soft decoder being adapted for calculating second soft information about each bit of the signal and sending the second soft information to the soft detector. Other systems, methods, and computer program products are described according to more embodiments.

Abstract: In one embodiment, a system includes a tape channel for reading data from a magnetic tape medium to produce a signal, a bank of noise whitening filters positioned subsequent to the tape channel adapted for receiving the signal, the bank of noise whitening filters being adapted for minimizing variance of noise affecting the signal at an output of the bank of noise whitening filters, wherein each noise whitening filter in the bank of noise whitening filters is dependent on a different possible data pattern, a soft DMAX detector adapted for calculating first soft information, dependent on the different possible data patterns, about each bit of the signal from the bank of noise whitening filters, and sending the first soft information to a soft decoder adapted for calculating second soft information about each bit of the signal and sending the second soft information to the soft DMAX detector.

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: The present inventions are related to systems and methods for transferring information to and from a storage medium, and more particularly to systems and methods for positioning a sensor in relation to a storage medium. For example, an apparatus for determining a sensor position is disclosed that includes a data stream processor operable to generate a number of data streams at different frequencies based on an input data stream, a number of servo preamble detectors each operable to process a different one of the data streams to detect a servo preamble, a selector operable to output one of the data streams in which the servo preamble was detected as a winning data stream, and a pattern detector operable to detect a pattern in the winning data stream.

Abstract: The present inventions are related to systems and methods for transferring information to and from a storage medium, and more particularly to systems and methods for positioning a sensor in relation to a storage medium. For example, an apparatus for determining a sensor position is disclosed that includes discrete Fourier transform calculators operable to process input data to yield a magnitude response of the input data at each of a number of candidate frequencies, a comparator operable to compare the magnitude responses to yield a winning candidate frequency, a servo controller operable to process at least one servo field in the input data to identify a position of a sensor based on the at least one servo field, and a servo frequency synthesizer operable to establish a frequency of operation in the servo controller based at least in part on the winning candidate frequency.

Abstract: A first parameter associated with a writer preamp is defined. A write current of the writer preamp is adjusted in accordance with the first parameter so that an asymmetric signal is applied at a write head. The asymmetric signal results in symmetric writing of bits to a medium.

Abstract: A method is provided. A first CMOS switch is deactivated while activating a second CMOS switch to cause the portion of the write signal to transition from a first direct current (DC) voltage to a first peak voltage. After a first interval, the second CMOS switch is deactivated while activating a third CMOS switch to cause the portion of the write signal to transition from the first peak voltage to a second DC voltage. After a second interval, the third CMOS switch is deactivated while activating a fourth CMOS switch to cause the portion of the write signal to transition from the second DC voltage to a second peak voltage After a third interval, the fourth CMOS switch is deactivated while activating the first CMOS switch to cause the portion of the write signal to transition from the second peak voltage to the first DC voltage.

Abstract: A magnetic recording device includes a magnetic disk and a magnetic head that performs magnetic recording to the magnetic disk. The magnetic head includes a main magnetic pole layer and a microwave generating element. The magnetic recording device further includes a microwave generating element driving current control circuit. The microwave generating element driving current control circuit, during the magnetic recording, applies a microwave generating element driving current at a first current level to the microwave generating element for a period that is from at the latest a polarity reversal of the recording current before a subsequent polarity reversal of the recording voltage, and thereafter applies another microwave generating element driving current at a second current level, which is smaller than the first current level, to the microwave generating element, or stops the application of the another microwave generating element driving current until the polarity reversal of the recording voltage.

Abstract: In one embodiment, a tape drive system includes a read channel, a write channel, logic adapted for accessing data sets using the read channel and/or the write channel, logic adapted for counting each data set access using the read channel that used error recovery procedure (ERP), logic adapted for counting each data set access using the read channel that did not use ERP, logic adapted for counting each data set access using the write channel that used ERP, logic adapted for counting each data set access using the write channel that did not use ERP, and logic adapted for accessing subsequent data sets using the read channel and/or the write channel, wherein any subsequent data set access that uses ERP is accessed using an initial ERP step characterized by a first tape speed, wherein the first tape speed is selected at least partially based on the counts.

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 method to compensate for spacing variations between a dynamic fly height (DFH) controlled read/write head and a rotating disk surface. Using a HDI sensor or equivalent indicator of touchdowns, a power profile is calculated for an arbitrary track on a disk. The profile tracks disk topography by recording touchdown power at each of a series of sectors into which the track is subdivided. The resulting power profile, smoothed and expressed as a function of sector position, substitutes for the usual constant TD power setting that provides only an uncompensated range of spacing variations. A fixed back-off spacing power is added to the power profile enabling the head to fly over the track at a constant spacing. The power profile can be calculated to account for various temperature and pressure conditions.

Abstract: The disclosure is related to systems and methods for servo Gray code error detection and correction. A device may include a circuit configured to 1) selectively implement a quality-based error correction system to determine an error in the servo Gray code and correct the error; 2) selectively implement a trajectory-based error correction system to determine an error in the servo Gray code and correct the error; or 3) implement any combination of a quality-based error correction system and a trajectory-based error correction system to determine an error in the servo Gray code and correct the error.

Abstract: A hard disk drive or other disk-based storage device comprises a storage disk, a read/write head configured to read data from and write data to the disk, and control circuitry coupled to or otherwise associated with the read/write head. The control circuitry comprises a write driver configured to generate a write signal for data to be written to the storage disk, and a multiple-slope transition controller associated with the write driver and configured to control a data transition in the write signal such that the data transition comprises at least two different segments each having a different slope, with the transition controller comprising separate slope control mechanisms for each of the segments. By way of example, the data transition may comprise a dual-slope transition having first and second segments arranged sequentially between a start point and an end point of the data transition.

Abstract: Servo pattern read-back signal processing for storage devices is described. In an example, a method of processing a read-back signal derived from a servo pattern on a storage medium in a storage device includes differentiating the read-back signal in an analog domain to produce a differentiated signal; and converting the differentiated signal into digital samples.

Abstract: An implementation of a system disclosed herein provides a method of deferring decoding of a data sector received at a read channel of a storage device, in response to determining that a data sector cannot be decoded by a first decoder and storing the data sector for further processing by a second decoder.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing system is discussed that includes: a buffer circuit, an equalizer circuit, a data processing circuit, and a retry determination circuit. The buffer is operable to store digital samples as a buffered output, and the equalizer circuit is operable to equalize the buffered output using a first equalization target to yield a first equalized output, and to yield a second equalized output using a second equalization target. The retry determination circuit is operable to select the second equalization target based at least in part on an occurrence of an error.

Abstract: A hard disk drive or other disk-based storage device comprises a storage disk, a read/write head configured to read data from and write data to the disk, and control circuitry coupled to the read/write head and configured to process data received from and supplied to the read/write head. The control circuitry comprises calibration circuitry configured to vary a phase of a clock signal as a test pattern is written to the storage disk as part of a calibration procedure, and disk locked clock circuitry coupled to the calibration circuitry and configured to obtain phase lock between the clock signal and a timing pattern on a surface of the storage disk. The calibration circuitry is further configured to determine an initial phase update value to be applied by the disk locked clock circuitry in a control loop as the phase of the clock signal is varied as part of the calibration procedure.

Abstract: According to one embodiment, a magnetic disk drive includes a disk and a controller. The disk includes a plurality of zones each having a plurality of tracks. The disk is formatted such that a plurality of servo frames are discretely recorded in each of the plurality of tracks. The plurality of servo frames include servo preamble data of a second length which corresponds to the zone having the track and which is less than or equal to a first length serving as a reference. The controller allows a head to read the servo frames from the disk via a read amplifier.

Abstract: According to one embodiment, there is provided a method of temporarily storing data in a buffer. The method determines whether data written based on sequential writing is of a first type or a second type in data type. The method stores the written data in association with the determined data type in the buffer. The method further controls the buffer so that the data of the first type stored in the buffer may be held in the buffer for a length of time twice as long as time T1 corresponding to one revolution of a disk and the data of the second type stored in the buffer may be held in the buffer for the time T1.

Abstract: According to one embodiment, there is provided an information recording apparatus that writes information onto a magnetic recording medium including a plurality of fine magnetic grains. The information recording apparatus includes a random number generation unit, a modulation unit, and a processing unit. The random number generation unit generates a random number bit value. The modulation unit modulates a period of a basic clock according to the random number bit value generated, and generates a modulated clock. The processing unit writes or reads information with respect to the magnetic recording medium in synchronization with the modulated clock generated.

Abstract: According to one embodiment, a magnetic disk includes a plurality of tracks each having a plurality of servo frames with servo burst data and repeatable runout correction data written thereto. The repeatable runout correction data includes a pattern repeated at a predetermined period and is written so that beginning of write is delayed by a time corresponding to a correction amount with respect to a base point corresponding to a synchronization timing position in the servo frame. A detector detects a phase delay amount corresponding to a time elapsed until the repeated pattern is read from the servo frame by a magnetic head, with respect to the synchronization timing position.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing system is discussed that includes: an analog to digital converter circuit, a data detector circuit, a filter circuit, an error generation circuit, and a target parameter adaptation circuit. The analog to digital converter circuit converts an analog input into corresponding digital samples. The data detector circuit applies a data detection algorithm to a data set derived from the digital samples to yield a detected output. The filter circuit convolves the detected output with a target parameter to yield a target output. The error generation circuit calculates an error value based on the digital samples and the target output. The target parameter adaptation circuit updates the target parameter based at least in part on the error value.

Abstract: A method of targeted corruption of user data in a shingled magnetic recording disk includes identifying user data on a Track_N targeted for corruption; identifying a readback centerline of the Track_N; identifying a readback centerline of an adjacent track to Track_N; acquiring user data of the adjacent track; and rewriting the user data of the adjacent track with an offset write centerline to overwrite magnetic material at the readback centerlines of both Track_N and the adjacent track.

Abstract: A magnetic recording disk drive has a fly-height sensor on the slider that supports the read/write head. The head-disk spacing signal from the fly-height sensor utilizes the existing read path between the arm electronics (AE) module and the channel electronics module. A variable gain amplifier (VGA) on the AE module receives as one input the head-disk spacing signal and as the other input an emulated read signal. The output of the VGA is thus an oscillatory signal that emulates the read signal but whose amplitude varies as the head-disk spacing varies. A multiplexer (MUX) on the AE module multiplexes the amplified read signal from the read amplifier with the VGA oscillatory output signal on the read path back to the channel electronics module.

Abstract: An extended servo mark word is used when an error is detected from a servo mark. For example, a servo mark associated with a disk drive track may be detected during a data access operation. In response to an error in detecting the servo mark, at least one adjacent bit is evaluated together with the servo address mark to overcome the error.

Abstract: Various embodiments of the present invention provide apparatuses, systems and methods for data detection in a detector with a pruning control system. For example, a data detector is disclosed that includes a first set of counters operable to distinguish prunable data from non-prunable data in the data detector, a second set of counters operable to generate initial values for the first set of counters, and a prune control signal generator operable to generate a prune control signal based on the first set of counters. The second set of counters is operable to generate the initial values at least in part before a syncmark is detected in a data sector. The initial values are used to initialize the first set of counters when the syncmark is detected in the data sector. The prune control signal controls whether the data detector is allowed to prune a trellis.

Abstract: Example methods and apparatus concern creating and/or manipulating a tape-specific layout for a tape based de-duplication repository. One example apparatus include a processor, a memory, a set of logics and an interface to connect the processor, the memory, and the set of logics. The apparatus may include a tape layout logic configured to determine the tape-specific layout for a de-duplication data set. The tape-specific layout may be based on forensic data acquired for the de-duplication data set. The apparatus may also include a write logic configured to write the de-duplication data set to a tape according to the tape-specific layout. The forensic data may identify, for example, the order in which sub-blocks are accessed, reference counts, access frequency, access groups, and other access information.

Abstract: A magnetic recording system configured for recording to a bit patterned media using both hypertrack recording and shingled recording. The magnetic recording system includes a write pole with a notched trailing edge that results in a write bubble with a trailing edge that has two outer convex lobes separated by a centrally disposed concave region. By locating one of the lobes over first and second data tracks of a hypertrack, a proper alignment of the relative phase of the two tracks can be maintained. Further adjustment to the alignment can be achieved by adjusting the radial location of the write head.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing system is disclosed that includes Various embodiments of the present invention provide data processing systems that include an analog to digital converter circuit and a phase and gain computation circuit. The analog to digital converter circuit is operable to convert an analog input into a series of digital samples. At least a portion of the series of digitals samples represent a periodic signal from a servo data region. The phase and gain computation circuit is operable to: determine an approximate amplitude of the periodic signal based at least in part upon the digital samples representing the periodic signal from the servo data region; determine a gain based at least in part on the approximate amplitude; and determine a phase based at least in part on the approximate amplitude.

Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator (STO) sensing with a demodulator for hard disk drives. The demodulator measures an instantaneous phase of the readback signal from a STO sensor and converts the readback signal into a signal that is proportional to the magnetic field affecting the STO frequency during a bit time. The converted signal is used for processing by conventional data detection electronics.

Abstract: A disk drive is described that uses a vibration sensor to generate a compensating feed-forward control signal to synchronize the write clock frequency with the modulated data island frequency. A linear vibration sensor is positioned with its sensitivity axis aligned with the tangential direction of a track at the radial position of the write head. The tangential component of the external linear vibration is measured by the sensor. The feed-forward control signal derived from the linear vibration sensor modifies the control voltage input to VCO (voltage controlled oscillator) in the write clock generator to adjust the write clock frequency to compensate for the modulated data island frequency caused by the tangential component of the linear vibration.