Abstract: An apparatus comprises read channel circuitry and signal processing circuitry associated with the read channel circuitry. The signal processing circuitry is configured to: equalize a digital data signal; align the equalized digital data signal; determine a detector reliability metric based at least in part on the aligned equalized digital data signal; perform an iterative decoding process to determine a decoded digital data signal using the detector reliability metric; adjust the aligned equalized digital data signal using the decoded digital data signal; and repeat at least determining the detector reliability metric and performing the iterative decoding process using the adjusted equalized digital data signal.

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: Systems, methods and apparatus for archive verification including the verification of media in a library, are disclosed. More specifically, a method of archive verification may include performing an initial verification on a first media in a first drive and performing a subsequent verification on the first media in a second drive not used for the initial verification, and comparing the results of the initial verification and the subsequent verification. Embodiments may further perform an initial verification of the readability of a second tape media and subsequent verification of the readability for the second tape media, and compare the results of the initial verification to the results of the subsequent verification to determine the tape drive health, the efficacy of the first tape media or the second tape media, the efficacy of the first tape drive or the second tape drive, or whether to replace a tape media.

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

Abstract: User level data associated with a location adjacent to a desired location on a magnetic disk storage is received. Media level data associated with the adjacent location is generated based at least in part on the user level data associated with the adjacent location; a processor which is configured to generate the media level data associated with the adjacent location is a same processor which is configured to generate media level data based at least in part on user level data during a write process. The media level data associated with the adjacent location is used to remove inter-track interference (ITI) associated with the adjacent location from a signal read back from the desired location.

Abstract: Various embodiments of the present invention are related to methods and apparatuses for decoding data, and more particularly to methods and apparatuses for multi-level layered LDPC decoding with out-of-order processing.

Abstract: A method, apparatus, and system are provided for implementing magnetic defect classification using phase modulation for hard disk drives. A magnetic media readback signal of a hard disk drive is processed to identify predefined phase modulation (PM) characteristics to implement magnetic defect classification of magnetic media bump and pit defects.

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: 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 system provides tape having at least one longitudinal data track and a tape head operative to move along a single axis line lateral to the data track. The storage tape moves across the tape head. The tape head moves along the axis line such that a write element of the tape head intersects the data track and writes data to a section of the data track. A controller determines that the storage tape is skewed. In response to determining that the storage tape is skewed, the controller determines a position along the axis line and a time to move the tape head such that the read elements intersects the section of the data track. At the determined time, the tape head pauses writing of data and moves to the position along the axis line. The tape head reads the section of the data track to verify the written data.

Abstract: A method includes, in at least one aspect, receiving a data set to be written onto a medium, identifying an index associated with the medium, identifying a first sector and a second sector of the medium, the first sector preceding the second sector, generating an error code for the data set based on the index and the first sector, and writing at least one of the data set or the generated error code into the second sector.

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: A storage device includes a storage medium having a plurality of tracks of data. Reading apparatus for reading a current track of data that has been subject to previous encroachment to an extent from at least one adjacent track of data includes a write head that writes interfering data to the adjacent track of data while intentionally encroaching at least to that extent onto the current track of data, and circuitry that recovers data on the current track of data using the interfering data. A method for reading a current track of data, that has been subject to previous encroachment to an extent from at least one adjacent track of data, includes writing interfering data to the adjacent track of data while intentionally encroaching at least to that extent onto the current track of data, and recovering data on the current track of data using the interfering data.

Abstract: A method of writing data to a storage device includes writing current data to a first track of data, monitoring write head position, and on detection of encroachment of the write head position on a second track of previously written data, using the current data to recover the previously written data on the second track, and rewriting the current data to the first track. A storage controller includes a device controller that writes data to a current track of data on a storage device. The device controller monitors write head position. On detection of encroachment of the write head position on a second track of previously written data uses the current data to recover the previously written data on the second track, and rewrites the current data to the first track. A storage system includes a storage medium having a plurality of tracks of data thereon, and a storage controller.

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: Various embodiments of the present invention provide systems and methods for determining contact between a head and a storage medium.

Abstract: A disk drive is disclosed comprising a first disk surface comprising multiple zones, each comprising multiple tracks, a first head actuated radially over the first disk surface to write data to and read data from the first disk surface, and control circuitry coupled to the head. The control circuitry sets the first head to a first fly height over a first zone, writes a data pattern on a first track in the first zone, reads the data pattern to determine a first value of a first metric, writes a first frequency pattern on the first track, determines an initial amplitude of the first frequency pattern, writes a second frequency pattern over the first frequency pattern, determines a first value of a second metric for the first frequency pattern, and determines a first fly height value for the first zone by utilizing the first values of the first and second metrics.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a pattern detection circuit is discussed that includes a distance calculation circuit and a comparator circuit. The distance calculation circuit is operable to calculate a noise whitened distance between a reference signal and a received input to yield a comparison value. The comparator circuit is operable to compare the comparison value with a threshold value.

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

Abstract: 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: Various embodiments of the present inventions are related to initialization of decoder-based filter calibration, and in particular to initially using either a detector output or unconverged data from the decoder to train filter coefficients in a noise predictive calibration engine until data sectors converge in the decoder and can be used to train filter coefficients.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes: a data detector circuit, a data decoder circuit, and a multi-path circuit. The data detector circuit is operable to apply a data detection algorithm to a data input and a decoder output to yield a detected output. The data decoder circuit is operable to apply a decoding algorithm to a decoder input to yield the decoder output and a status input. The multi-path circuit is operable to provide the decoder input based at least in part on the detected output and the status input.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing circuit is discussed that includes: a data detector circuit, a low latency detection circuit, and an error calculation circuit. The data detector circuit is operable to perform a data detection process on a first signal derived from a data input to yield a detected output, and to provide a loop error as a difference between the detected output and the first signal. The low latency detection circuit operable to process a second signal derived from the data input to yield a fast detector output, and to provide a generated error as a difference between the fast detector output and the second signal. The error calculation circuit is operable to calculate an error value based at least in part on the generated error and the loop error.

Abstract: Disclosed is a method of storing data on a tape medium in at least one data recording session employing a tape drive apparatus operable to record the data in accordance with a format specifying an unused area of the tape medium. The method comprises formatting the tape medium according to the format, and recording a tape medium identifier in the specified unused area of the tape medium.

Abstract: A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.

Abstract: In one embodiment, a tape drive system includes a soft detector for executing a first forward loop of a detection algorithm on a first block of signal samples during a first time interval; and logic for executing forward and reverse loops during several time intervals; and logic adapted for outputting a first decoded block of signal samples based on the executing the decoding algorithm on the first block during a sixth time interval, wherein a sum of second, third, fourth, fifth, and sixth time intervals are about equal in duration to the first time interval.

Abstract: A method in one embodiment includes receiving a command to perform at least one of a refresh operation and a verification operation on a media cartridge having a tape wrapped around a spool; mounting the media cartridge in a tape drive; starting execution of the refresh and/or verification operation; aborting execution of the refresh and/or verification operation upon occurrence of a predetermined event. A method in another embodiment includes receiving an instruction to perform a verification operation on a media cartridge having a tape wrapped around a spool; unwrapping at least some of the tape from the spool; after the unwrapping, wrapping at least some of the tape back onto the spool; during at least one of the unwrapping and wrapping, performing a verification operation; terminating execution of the verification operation when a drive error is detected; outputting an indication of a media error when a media error is encountered.

Abstract: Testing procedure (Integrated Head Spiral Testing) for disk media utilizes a single head with both write and read elements that are offset to allow spiral testing. The offset allows a write element to write one portion of a spiral track while a read element simultaneously reads a previously written portion of the spiral track.

Abstract: According to one embodiment, an information recording device includes: a recording controller configured to control recording of information on a magnetic recording medium having tracks by a recording method; a managing module configured to manage two or more counters corresponding to each of plural track groups that are adjacent to each other; an updating module configured to update a count of one of the two or more counters corresponding to a second track group that is adjacent to a first track group of the plural track groups when information has been recorded on the first track group; a determining module configured to determine an attribute of the second track group based on the updated count of the one counter; and a rewriting module configured to rewrite information recorded in the second track group based on the determined attribute.

Abstract: A system including a detection module, a reconstruction module, and a correlation module. The detection module receives first signals from a medium and detects data bits from the first signals. The reconstruction module reconstructs the data bits and generates second signals. The correlation module generates first correlation values by correlating the first and second signals and generates second correlation values by self-correlating the second signals. In response to at least one of the first and second signals including a floating number having a plurality of bits and a sign bit, the correlation module generates at least one of the first and second correlation values based on a plurality of most significant bits of the floating number and the sign bit of the floating number. The first and second correlation values indicate whether the data bits detected from the first signals include errors due to defects in the medium.

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: 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: Embodiments of the present invention help to reduce damage of a head element portion or a magnetic disk in a procedure for specifying a heater power value for adjusting a clearance between the head element portion and the magnetic disk. In an embodiment of the present invention, an HDC/MPU sequentially performs data writing and reading while increasing heater power. The HDC/MPU further determines whether or not a head slider has retrieved the data properly. When the data cannot be retrieved properly, the HDC/MPU specifies a heater power value in a normal operation based on the heater power value at which the data could not be retrieved properly.

Abstract: A method for certifying data on tape cartridges for a library with a first tape cartridge that possesses a medium auxiliary memory device, a medium auxiliary memory reader/writer, a first tape drive and a second tape drive, a shelf system, and access to a memory device containing a media lifecycle management data base. After a period of time from when data was originally stored on the tape first cartridge, a portion of data residing on the first tape cartridge is read. The portion of data is assessed as to whether a percentage of the portion contains an expected data structure and if the percentage exceeds a predetermined threshold, a data recovery sequence is initiated.

Abstract: A method for testing a hard drive includes determining a first partial bit error rate (PBERT) value of a hard drive at a first temperature and a second PBERT value of the hard drive at a second temperature. The method includes determining a PBERT minimum based on the first and second PBERT values, and comparing the PBERT minimum to a first PBERT minimum limit. The method includes determining a PBERT ratio based on the first and second PBERT values if the PBERT minimum is greater than or equal to the first PBERT minimum limit. The method includes comparing the PBERT ratio to a PBERT ratio limit, and comparing the PBERT minimum to a second PBERT minimum limit if the PBERT ratio is greater than the PBERT ratio limit. The method includes generating a failure indicator if the PBERT minimum is less than the first and/or second PBERT minimum limit.

Abstract: A method of refreshing data on a hard disk drive configured to carry out commands issued by a host that comprises tracking run-time conditions related to patterns of host command activity on the hard disk drive; selecting an entry from a high priority pool that is configured to hold a predetermined maximum number of entries, each entry comprising a plurality of tracks having been designated as being eligible for a high priority refresh operation as a result of the host command activity; refreshing data stored on at least one track of the selected entry; pausing the refreshing for a period of time equal to a throttle interval to process at least one command issued by the host before returning to the selecting or to the refreshing, and periodically modifying a value of the throttle interval depending upon the tracked run-time conditions.

Abstract: A hard disk drive (HDD) minimizes the effects of far track erasure (FTE) by counting the number of writes to the data tracks and incrementing counters based on the known effect of FTE on each track. The extent of the FTE effect is determined for each track within a range of tracks of the track being written, and based on the relative FTE effect for all the tracks in the range a count increment (CI) is determined for each track within the range. A counter is maintained for each track. For every writing to a track, a count for each track within a range of the track being written is increased by the CI value associated with the track number within the range. When the count value for a track reaches a predetermined threshold the data is read from that track and rewritten, preferably to the same track.

Abstract: According to one embodiment, an information reproducing apparatus is configured to obtain, from a read sample value sequence obtained by sampling a read signal read from a first recording track of a magnetic recording medium, an interference-component-removed read sample value sequence, from which an interference component from a second recording track adjacent to the first recording track is removed. The apparatus includes a decoding module. The decoding module is configured to generate a first interference-component-removed read sample value sequence based on a cancellation weight column which varies according to a difference in polarity between a first bit of the first recording track and a second bit of the second recording track adjacent to the first bit.

Abstract: Methods and apparatus describe processing of data for recording to a storage device. An apparatus includes, in at least one aspect, a plurality of buffers and circuitry configured to encode data stored in one buffer of the plurality of buffers concurrently with storing data in another buffer of the plurality of buffers and to write the encoded data from the one buffer to a storage device concurrently with encoding the stored data in the other buffer.

Abstract: A method of storing data includes receiving general purpose (GP) data and special Error Tolerant or Streaming (ETS) data, storing the GP data using a data storage method, and storing the ETS data using a different data storage method which affects the access rate, resilience to errors, data integrity, storage density, or storage capacity. The storage medium, which can include a disk drive, flash memory, or holographic memory, is utilized differently depending on the required Quality of Service in aspects including block size, storage of error correction codes, utilization of error correction codes, storage area density, physical format pattern, storage verification, or reaction to failed storage verification. For disk drives these differences include spacing between tracks; overlap between tracks; spiral track formatting; concentric track formatting, and size of blocks, and for flash memories these differences include levels per cell and number of cells.

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: The present disclosure describes apparatuses and techniques of improved sequential-access of storage media. In some aspects an indication that a media disk interface failed to read a sector of a sequential-read during a revolution of the media disk is received and the media disk interface is caused to attempt to read a next sector of the sequential-read subsequent the sector failed to be read during a same revolution of the media disk.

Abstract: In a controller of a tape drive, a command processing unit receives a request to write new data, an offset determination unit determines whether old data is not partially overwritten with new data, and if old data is not partially overwritten with new data, a head position management unit makes a write head offset toward the unoverwritten portion. Then, a channel input/output unit reads pattern data that disables old data from a pattern storage unit and outputs the data to the write head to thereby overwrite the old data with the pattern data. After that, a tape transport management unit rewinds a tape and the head position management unit returns the write head to the original position to overwrite the old data with the new data as usual.

Abstract: A method performed by a disk drive, comprising: receiving a plurality of signal samples over a channel in the disk drive; executing a forward pattern-dependent noise prediction (PDNP) operation on the plurality of the signal samples; generating, based on execution of the forward PDNP operation, a first detection of recorded data bits in the plurality of received signal samples; executing a backward PDNP operation on the plurality of the received signal samples; generating, based on execution of the backward PDNP operation, a second detection of recorded data bits in the plurality of received signal samples; comparing the first detection to the second detection; identifying, based on comparing, one or more erasures in the received plurality of signal samples; and generating one or more sequences of bits that promote correction of the one or more erasures.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of segments. A cluster of defective segments is identified, and a margin rectangle of segments is defined around each defective segment in the cluster. A margin map representing the margin rectangles is generated. The margin map may comprise start and end segment numbers, or run-length encoding, or any other suitable encoding for identifying consecutive segments that extend across multiple, overlapping margin rectangles.

Abstract: A method for efficiently rewriting data to tape is disclosed herein. In one embodiment, such a method includes writing a data set to tape, the data set comprising S sub data sets of fixed size, each sub data set comprising N code word interleaves (CWIs). The method further includes reading the data set while writing it to the tape to identify faulty CWIs. While reading the data set, the method buffers the faulty CWIs (such as by storing, identifying, and/or marking the faulty CWIs) for later retrieval. When the end of the data set is reached, the method writes corrected versions of the faulty CWIs to the end of the data set. A corresponding apparatus is also disclosed and claimed herein.

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

Abstract: A method and apparatus for writing data to a tape is disclosed. A plurality of data segments are written onto a tape simultaneously. Any data segments written to the tape that needs to be rewritten are identified. Each data segment that needs to be re-written is accumulated. The accumulated data segments are written to tape when a full set of data segments have been accumulated. The re-written data segments each have a first field in a header that designates itself and a second field in the header that designates a second re-written data segment.

Abstract: The present disclosure is directed to selectively protecting a portion of a track including a plurality of data sectors. The data sectors include a plurality of user sectors and one or more parity sectors. Protected bits are designated in each of the of data sectors. The protected bits are selected to have matching bit indices across the data sectors resulting in a parallel alignment of the protected bits across the user and parity sectors. One or more selections of protected bits of the user sectors are encoded across matching bit indices to generate data values in the corresponding protected bits of the parity sectors. At least one portion of at least one failed sector is recoverable by decoding at least one selection of the protected bits when a sector error occurs at a protected bit.