Abstract: A method according to one embodiment includes monitoring a data transfer operation for detecting temporary errors; determining whether an error burst has occurred based on the monitoring; if an error burst has occurred, altering a condition of the data transfer operation; monitoring the data transfer operation having the altered condition for detecting temporary errors; determining whether another error burst has occurred based on the monitoring of the data transfer operation having the altered condition; and if another error burst has occurred, altering another condition of the data transfer operation. Additional systems and methods are also presented.

Abstract: In one embodiment, a data storage system includes a magnetic head having a main magnetic pole and a wrap around shield positioned around the main magnetic pole at an ABS thereof, a magnetic medium, a drive mechanism for passing the magnetic medium over the magnetic head, and a controlling mechanism electrically coupled to the magnetic head for controlling operation of the magnetic head that initiates rewriting of information of a recording track of the magnetic medium if a recording magnetic field applied to the recording track exceeds a threshold. In another embodiment, a method includes writing data to a first track of a magnetic medium using a magnetic head, determining characteristics consistent with data degradation from tracks adjacent to the first track and far tracks away from the first track using a controlling mechanism, and rewriting data in tracks determined to be degraded due to ATI and/or FTI.

Abstract: A method and apparatus are disclosed for detecting an address mark in a data stream having a preamble followed by the address mark. The end of the preamble is detected in the data stream, which is then used to open a window to search for the address mark. If the address mark is not detected during the window, the search for the address mark is restarted. The window can have a duration based on a length of the address mark. The address mark can be, for example, a servo address mark following a servo preamble or a read address mark following a read preamble. The preamble can have a 2T pattern and the preamble can be detected by determining if energy associated with a 2T frequency is greater than energy associated with a non-2T frequency. The end of the preamble can be performed by an EndOf2T detector that detects a break in an expected bit pattern.

Abstract: A low flying slider detector is disclosed. In one embodiment a surface is provided. In addition, a suspender is provided for receiving and flying a slider above the surface. A detector is also provided for detecting a low flying slider flying above the surface wherein the detector does not require measuring of the slider fly height to detect the low flying slider and wherein the detecting of the low flying slider is performed at least at a slider level of assembly.

Abstract: Systems, methods and computer program products for reducing or removing current spikes generated during a current recirculation period associated with phase switching in a spindle motor are described. In some implementations, the duty cycle of the drive signals applied to the windings of the spindle motor can be adjusted to reduce or eliminate the current surge resulting from current recirculation. In some implementations, the duty cycle of the drive signals during spin-up can be reduced based on a current limit, and the reduced duty cycle can then be used to drive the spindle motor taking into account of current surges in the supply current.

Abstract: According to one embodiment, a storage device includes a recording medium, a driving module, a head, a conductive body, a write-verify module, and a projection amount controller. A conductive body is mounted on the head, and changes a projection amount of the head by thermally expanding the head with heat from a current carried by the conductive body. The write-verify module executes a write-verify check to check whether content written in any location on the recording medium is correct when the driving module starts rotating the recording medium. The projection amount controller controls the projection amount of the head by adding a first value to a current in a steady state carried by the conductive body if the content is correct, and adding a second value with an absolute value greater than that of the first value to the current in the steady state if the content is not correct.

Abstract: A head assembly including one or more transducer elements for controlling head-media spacing is disclosed. The assembly includes detection circuitry configured to receive an input detection signal responsive to the spacing between the head and the data storage media and provide an output measure indicative of the head-media spacing. The output signal is utilized by control circuitry to provide a control input to one of a plurality of transducer elements on the head to protrude a localized portion of the head to adjust head-media spacing.

Abstract: Approaches for a testing device for selecting a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). The testing device comprises a continuous magnetic-recording disk, rotatably mounted on a spindle, which stores data using a continuous media format. The testing device also comprises a testing module configured to simulate reading data, stored using a discrete track media (DTM) format, from the continuous magnetic-recording medium. Advantageously, testing time and cost is reduced as both discrete track media (DTM) disks and expensive discrete track media (DTM) recording testing hardware are not required to select the optimal a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). In addition, embodiments may be used to optimize features of the tracks of the DTM disk, such as the land to groove ratio.

Abstract: According to one embodiment, a method of detecting contact of a magnetic head with a magnetic disk by changing the dynamic flying height of the magnetic head in a magnetic disk drive is disclosed. The method can change control of a spindle motor configured to rotate the magnetic disk, from feedback control to open loop control. The method can detect a change in rotational speed of the magnetic disk during the open loop control. The method can detect contact of the magnetic head with the magnetic disk based on the detected change in the rotational speed.

Abstract: A method of erasing a servo pattern of a hard disk drive includes reading a servo pattern recorded on a disk, generating an erase pattern to erase the servo pattern based on the servo pattern obtained in the reading of the servo pattern, and erasing the servo pattern by using the erase pattern while the disk is rotated. The servo pattern recorded on the hard disk drive may be uniformly erased. Also, a stabilization time to stabilize a read/write head after the position control of the read/write head that is needed when a servo writer is used may be avoided so that a time to erase a servo pattern may be reduced.

Abstract: In a magnetic recording device adopting a microwave assisted recording method, a microwave frequency on a positive polarity side and a microwave frequency on a negative polarity side are adjusted to be optimal. The magnetic recording device of the invention supplies to a magnetic head a write current of which a current waveform on the positive polarity side and a current waveform on the negative polarity side are asymmetric.

Abstract: The present invention enhances reliability by correcting a write error due to unstable oscillation of a spin torque oscillator. In the present invention, a resistance value of a spin torque oscillator is monitored to detect that oscillation becomes unstable during recording. When a measured resistance value is out of a predefined normal range, information for which the recording operation is already performed is rewritten.

Abstract: Various embodiments of the present invention provide systems and methods for medium utilization control. As an example, a method for identifying potentially damaged media regions is discussed that includes receiving a data set; performing a data detection process on the data set to yield a detected output and a status value corresponding to the data set; performing a data decoding process on the detected output to yield a decoded output; and identifying a region of a storage medium from which the data set was derived as failing based at least in part on the status value.

Abstract: Methods and systems for measuring variations in head-disk clearance in a hard disk drive. User generated data is randomly selected at a controller of the hard disk drive wherein the user generated data is stored on a disk associated with the hard disk drive. A reference point associated with the user generated data is stored on a storage medium associated with the hard disk drive. The user generated data is read at the controller. The user generated data is analyzed with the reference point using more than two frequencies, at the controller, to obtain a variation in measurement of the head-disk clearance.

Abstract: A tape drive device for storing data in a tape cartridge includes a comparison unit that compares a transfer speed of the data transmitted from a host machine to the tape drive device with a speed threshold, a speed determination unit that determines a writing speed to a tape cartridge using the speed threshold, and a data write unit that writes data to the tape cartridge, the data write unit writing data to the magnetic tape provided for the tape cartridge when the determined writing speed is higher than the speed threshold, and the data write unit writing subsequent data following data written to the magnetic tape to the non-volatile semiconductor memory provided for the tape cartridge when the determined writing speed is lower than the speed threshold.

Abstract: Techniques for performing metrology on magnetic media disk formations that are arranged in curvilinear patterns are disclosed. Small integrated test patterns having rectangular periodicity are integrated among the concentric circles of patterned media formations. The test patterns cover only very small areas of the disk so as to not significantly affect disk capacity. The periodicity of the test patterns allows their formations to be more readily measured by metrology technology than those having a curvilinear periodicity.

Abstract: A data storage device preamplifier circuit including (i) a write amplifier having an input and an output, and (ii) a read amplifier has an input and an output. The data storage device preamplifier circuit further includes a loopback circuit configured to selectively connect the output of the write amplifier to the input of the read amplifier.

Abstract: A method is disclosed of servo writing a disk drive comprising a first head actuated over a first disk surface, and a second head actuated over a second disk surface. A first repeatable runout (RRO) of the first disk surface is measured, and a seek is performed to seek the first head over the first disk surface in response to the measured first RRO while writing a first spiral track to the second disk surface using the second head. As a result, the first spiral track comprises a second RRO that substantially matches the first RRO of the first disk surface.

Abstract: A system and method of establishing write timing in a disk drive using bit patterned media and a magnetic head with read-write offset in which servoing and writing occur on different tracks with timing offsets. Initially, the distance between the servoing and writing tracks is determined for each track/head position in accordance with head geometry and skew angle. The relative timing errors are then measured by iteratively writing data at timing offset increments to determine the optimal timing offset for the servoing/writing track pair, and then writing the offset to sync fields on the servoing tracks of the disk.

Abstract: Disclosed are a method and system for distinguishing spatial and thermal defects on perpendicular media. The magnetic domains of the perpendicular media are oriented to have a first polarity, scanned using a read head, oriented to have a second polarity and scanned again. The signals from the read head are combined to produce output signals having improved signal to noise ratios from which the locations of spatial and thermal defects can be identified and distinguished.

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

Abstract: According to one embodiment, a magnetic head for perpendicular recording includes a first magnetic core includes a main pole configured to produce a recording magnetic field, and a return pole configured to reflux magnetic flux from the main pole to form a magnetic circuit in conjunction with the main pole, a first coil configured to excite magnetic flux in the magnetic circuit, side shields arranged individually on opposite sides of the main pole transversely relative to a track so as to be magnetically separated from the main pole and formed integrally with the return pole, a second magnetic core configured to form a physically closed magnetic path, a part of which comprises the return pole, and a second coil wound around the second magnetic core and configured to excite magnetic flux in the closed magnetic path.

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 SIN 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: A device is provided that, in one implementation, includes interpolators to generate interpolated phase shifted signals, and a precompensation circuit to provide precompensated versions of data bits in accordance with the interpolated phase shifted signals. Each of the interpolators is assigned a bit pattern different from that assigned to remaining ones of the interpolators.

Abstract: In a perpendicular magnetic recording system, the data that is being written by the write channel is fed back into the read channel. The read channel processes the data and decides if the written sequence is likely to have very poor DC characteristics. If that is the case, the write channel changes a scrambler seed and rewrites the data using the new scrambler seed. The data may also be inspected for patterns that might cause large baseline wander before being written to disk, i.e., in the write channel. A data sequence may be repeatedly scrambled and encoded until an acceptable level of estimated DC-wander has been achieved. The data sequence may then be written to disk.

Abstract: A tape drive assembly for data storage on a magnetic tape includes a tape head, a cartridge receiver and a controller. The cartridge receiver selectively receives a cartridge having a test tape formatted at a predetermined location with data errors with predetermined type, size and distribution representative of data errors in tape drives. The test tape is able to measure the quality of heads in suspect tape drives by comparing the ratio of the error count successfully recovered by the suspect head to that recovered by the reference drive while reading the same error distributions.

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

Abstract: According to one embodiment, a magnetic disk drive includes a grouping module and a refresh controller. The grouping module partitions a set of tracks on a disk into a plurality of groups. Each of the plurality of groups includes a plurality of tracks including at least two tracks with nonconsecutive physical positions. The refresh controller controls refresh process for each of the plurality of groups.

Abstract: A storage system is configured to determine a redundancy group configuration for a plurality of storage drives by grouping storage drives with a similar performance group designation together. When a storage drive is inserted, the storage system tests the performance of the storage drive. The storage drive may comprise a serial ATA (advanced technology attachment) (SATA) hard drive and/or a solid state drive. The storage system stores the result in a database. The storage system assigns the storage drive a performance group designation based on the result and groups the storage drive into a redundancy group. The storage system then displays the redundancy group configuration for the plurality of storage drives so that a storage administrator may configure the redundancy groupings of the storage drives of the storage system based on the redundancy group configuration displayed.

Abstract: A method for recording defects on a hard drive is provided. The method includes mapping a plurality of primary windows. Each primary window contains a respective plurality of data sectors on a disk of a hard drive. Each of the respective plurality of data sectors contains at least one defect. The method includes recording a location of each primary window in a defect log of the disk, and mapping a plurality of secondary windows if recording the location of each primary window fails. Each secondary window contains a respective plurality of data sectors containing at least one defect. The number of data sectors contained in each of the plurality of primary windows is different from the number of data sectors contained in each of the plurality of secondary windows. The method includes recording a location of each secondary window in the defect log of the disk.

Abstract: A head using heaters or actuators to control head media spacing is disclosed. In embodiments disclosed the heaters are selectively energized to control a close point of the head for read and/or write operations. As disclosed power is supplied to multiple heaters to generate heat induced protrusion data and the heat induced protrusion data is used to apply power to the multiple heaters for head media spacing control.

Abstract: Methods, systems and computer program products for performing hybrid defect detection are disclosed. A hybrid defect detection mechanism may be used to detect various classes of defects (e.g., long and shallow defects, and short and deep defects) while reducing the probability of a miss or false alarm. In some implementations, the hybrid defect detection mechanism may utilize defect detectors to each receive signal samples and apply a different set of parameters indicating a different respective window to the signal samples. Each defect detector may generate a corresponding output based on a count of signal samples within the corresponding window that are associated with abnormal signal quality.

Abstract: Methods for certifying data retained by a tape cartridge in a tape library are shown. Error rates that are encountered when the tape cartridge is being read by a tape drive can be accounted for without actually reading data for data content retrieval. A record of the error rate can be stored in a medium auxiliary memory device associated with the tape cartridge. An older record containing a formerly accounted for error rate of read errors when the tape cartridge was formerly read can be accessed and compared with the record presently assessed. If there is a difference between the presently found error rate and the formerly found error rate an action can be executed if the difference exceeds a predetermined threshold.

Abstract: A length of a separator to be skipped on the storage disk is compared with a threshold. The threshold is associated with a maximum value for which a timing loop is able to be paused without causing the timing loop to have inaccurate timing. If the length is greater than the threshold, a first split sector format is assigned to the split sector and that information is recorded. In such cases, a first portion and a second portion both include synchronization information. If the length is less than the threshold, a second split sector format is assigned to the split sector and that information is recorded. In such cases, the first portion includes synchronization information and the second portion of the split sector excludes synchronization information.

Abstract: A method of managing a defect of a hard disk drive includes calculating a number of ECC symbols of every sector which becomes an object of a defect scan and setting a defect reference value based on results of the calculation. The hard disk drive sets a sector as a defect sector having the number of ECC symbols greater than a set defect reference value.

Abstract: Embodiments of the invention broadly contemplate systems, methods and arrangements for managing Adjacent Track Interference (ATI) risk through intelligent management of a table that logs individual tracks creating a risk of ATI in tracks adjacent thereto. Embodiments of the invention provide that tracks considered being at low risk for creating ATI be ejected from the table in order to maintain a track-level log of manageable size.

Abstract: A method and apparatus for writing data to a tape is disclosed. A plurality of data tracks are written onto a tape simultaneously. Any data tracks written to the tape that needs to be rewritten are identified. Each re-write unit that contains a data track that needs to be re-written is accumulated. The accumulated rewrite units are written to tape when a full set of rewrite units have been accumulated.

Abstract: A disc drive system provides increased reliability by detecting and correcting errors associated with bit-patterned media. Write synchronization errors associated with bit-patterned media are addressed by including data storage for temporarily storing data that is being written to the disc drive. The data is read from both the disc drive and the storage medium and compared to detect write synchronization errors. The disc drive system utilizes the identified write synchronization errors for at least one of timing recovery, equalizer training detection, error correction code application, and error recovery.

Abstract: This application discloses a hard disk drive and a control circuit that are configured to determine touchdown by determining the SAGC for a track, removing the repeatable component of the SAGC to create the non-repeatable component and determining an indication of clearance irregularity and/or touch down when the standard deviation of the non-repeatable component spikes. These operations may create a defect map and/or a Flying height On Demand (FOD) control table in or for the hard disk drive as products of operating the hard disk drive.

Abstract: In one embodiment, a tape drive system includes a magnetic head having at least one servo sensor for track-following at least one defined servo track of a longitudinal tape, a tape motion controller configured to move the longitudinal tape past the magnetic head, a compound actuator configured to translate the magnetic head laterally with respect to the longitudinal tape, and a control configured to track-follow the at least one defined servo track by reducing a position error between the magnetic head and a desired position, transition from a write state to a monitor state when the position error is greater than a threshold, transition from the monitor state to a stop write state when the position error is greater than the threshold for a first period, and transition from the monitor state to the write state when the position error is less than the threshold for a second period.

Abstract: A tape drive system according to one embodiment includes a magnetic head having at least one servo sensor; a tape motion controller; a fine actuator; a skew actuator; a coarse actuator; and a control. The control is configured to perform various operations that help account for vibrations that effect track-following a servo track when operating a tape drive. Additional systems, methods and computer program products are also described.

Abstract: In one embodiment, a method includes sensing a servo sensor while a longitudinal tape is moved past a magnetic head, determining position error between the magnetic head and a desired position related to the at least one defined servo track; providing signals to operate a fine actuator to translate the magnetic head laterally in a manner to reduce the determined position error; transitioning from a write state to a monitor state when the determined position error is greater than a threshold error value; transitioning from the monitor state to a stop write state when the determined position error is greater than the threshold error value for a first predetermined period; and transitioning from the monitor state to the write state when the determined position error is less than the threshold error value for a second predetermined period.

Abstract: In a method of determining an iteration value for an iterative decoding process of a hard disk drive, a bit error rate (BER) of a digital signal is measured in multiple iterations. A difference is calculated between BERs of consecutive iterations, and the calculated differences are compared with a reference value. An adjusted iteration value is then determined based on the comparison.

Abstract: Various embodiments of the present invention provide systems and methods for servo data based harmonics calculation. For example, a circuit for determining harmonics is disclosed that includes an analog to digital conversion circuit that provides a series of digital samples corresponding to a pattern within a servo data region of a storage medium, and a harmonic calculation circuit. The harmonic calculation circuit is operable to calculate a first harmonic value for the series of digital samples, calculate a second harmonic value for the series of digital samples, and calculate a ratio of the first harmonic value to the second harmonic value.

Abstract: A method is disclosed for preserving data in a hard disk drive, in which data loss due to adjacent track erase (ATE) phenomenon can be minimized by relocating data, which is written in a zone where the ATE phenomenon is likely to occur since frequency of use is high, to another zone having a low TPI when writing the data in a disk.

Abstract: Shingled magnetic recording (SMR) devices according to embodiments of the invention include unshingled cache regions that can be used for storage of data. The unshingled cache regions can be used in a variety of flexible ways including in an implementation of write-twice caching or for opportunistic temporary storage to improve performance. The cache regions can be offset between top and bottom surfaces of the disk and staggered between disks to provide shorter seek times to the nearest cache region. Embodiments of the invention are adapted for use with symmetric or asymmetric heads.

Abstract: Systems and methods for improving accuracy of head positioning using existing servo patterns are provided. In one embodiment, a method for improving read head positioning is provided that comprises: writing a series of tracks over a range of read offsets to be calibrated; measuring a set of raw track profiles from the series of tracks; sampling the set of raw track profiles at a series of signal amplitude levels; constructing a reference track profile from the set of sampled track profiles; calculating a set of read offset deltas from each sampled track profile; merging the sets of read offset deltas into a set of average read offset deltas; and converting the set of average read offset deltas into a read offset correction table. A similar method for improving disk write head positioning is also provided which utilizes such a read offset correction table to eventually create write offset correction table.

Abstract: According to one embodiment, a magnetic disk drive includes a parameter management table, a parameter adjustment module and an interpolation module. The parameter management table stores a parameter used to write or read data to or from a disk in the parameter management table in association with each of a plurality of predetermined temperature divisions. The parameter adjustment module adjusts a first parameter stored in the parameter management table in association with a first temperature division to a second parameter adapted for the first temperature division if an ambient temperature detected by a temperature detector corresponds to the first temperature division and if the first parameter is unadjusted. The interpolation module updates an unadjusted third parameter corresponding to a third temperature division between the first temperature division and a second temperature division for which the parameter is adjusted based on a result of the adjustment of the first parameter.

Abstract: Systems and methods for performing refresh operations using write/read commands are provided. In one embodiment, a disk drive comprises a disk partitioned into a plurality of refresh zones, a head configured to write data to and read data from the disk, and a controller. The controller is configured to receive an access command, to read data from at least one of the refresh zones using the head in response to the access command, to check a condition of the read data, and to determine whether to refresh the at least one refresh zone based on the condition of the read data, wherein the read data includes data from a portion of the at least one refresh zone not being accessed by the access command.

Abstract: A disk drive is disclosed comprising a plurality of disks having a plurality of disk surfaces. The disk drive further comprises a head actuated over each disk surface, and a spindle motor for rotating the disks. A first fly height measurement is generated for a first disk surface, and a second fly height measurement is generated for a second disk surface. A positive correlation is detected in the first and second fly height measurements.