Abstract: According to one embodiment, a magnetic disk device includes a disk, a head that writes data to the disk and reads data from the disk, and a controller that executes error correction on a first sector which is unreadable in a first track from an initial reading time of initially one-round reading the first track of the disk based on first parity data corresponding to the first track.

Abstract: According to one embodiment, a magnetic disk device includes a disk having a first sector including first servo data, first user data, and first correction information used to correct a data error, a head that writes data to the disk and that reads data from the disk, and a controller that changes, according to a first defect length of a defect generated in the first sector in a circumferential direction of the disk, a first sector length of the first sector in the circumferential direction.

Abstract: Storage pools having categorized archival storage tapes according to content of files stored on each tape. Archiving new files into the storage pools according to content of the new files for efficient retrieval of files from storage tapes organized by category of content. Recall of multiple files from archival storage tapes to primary storage of an hierarchical storage management system is efficiently performed such that tape mounting operations are minimized.

Abstract: A multi-actuator storage device includes separate actuators that can be used to access a storage medium. A property of a request can be analyzed to determine which actuator to use to access data associated with the request. For example, high-priority requests can be handled by an actuator designated for random I/O requests, whereas low-priority requests can be handled by an actuator designated for sequential I/O requests. Writes can be treated as low-priority requests. In a particular embodiment, a priority bit can be used to determine which actuator is used to access the data.

Abstract: A magnetic recording medium includes a substrate, an underlayer disposed above the substrate, and a first magnetic layer disposed above the underlayer. The first magnetic layer has a granular structure including magnetic grains having a L10 structure, and grain boundaries. A content of the grain boundaries is in a range of 25 volume percent to 50 volume percent, and the grain boundaries include a chalcogenide-based layered material.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a storage unit, a magnetic head, an error correction unit that, in a case where an error is detected in user data read by the magnetic head, performs error correction on a sector in which the error is detected in track units and acquires error correction data, and a control unit. The control unit controls reading/writing of user data, management data for managing a sector on which the error correction is performed in the track units, and the error correction data, and in a case where there is no host access, rewrites data on the track including the sector on which the error correction is performed, based on the user data stored in the track and the error correction data of the sector, in which the error is detected, of the track.

Abstract: A packet forwarding method and apparatus pertaining to the field of communications technologies are disclosed. The method includes: determining whether a current to-be-sent target packet is a header packet or a following packet in a burst sequence; when the target packet is the following packet in the burst sequence, obtaining port information of an egress port used to send the burst sequence, where the port information of the egress port is determined and stored when the header packet in the burst sequence is sent, and the burst sequence is a sequence including a plurality of packets that belong to a same service flow; and sending the target packet through the obtained egress port.

Abstract: In examples, a list of elements may be divided into spans and each span may be allocated a respective memory range for output based on a worst-case compression ratio of a compression algorithm that will be used to compress the span. Worker threads may output compressed versions of the spans to the memory ranges. To ensure placement constraints of a data structure will be satisfied, boundaries of the spans may be adjusted prior to compression. The size allocated to a span (e.g., each span) may be increased (or decreasing) to avoid padding blocks while allowing for the span's compressed data to use a block allocated to an adjacent span. Further aspects of the disclosure provide for compaction of the portions of compressed data in memory in order to free up space which may have been allocated to account for the memory gaps which may result from variable compression ratios.

Abstract: In accordance with one implementation, a method for mitigating cache transfer time entails reading data into memory from at least two consecutive elliptical data tracks in a main store region of data storage and writing the data read from the at least two consecutive elliptical data tracks to a spiral data track within a cache storage region.

Abstract: A magnetic tape drive for writing data to a magnetic tape that includes a first data band, a second data band, and a servo band that is positioned between the first data band and the second data band, each of the data bands including a plurality of wraps including a first wrap and a last wrap, includes a drive controller and a tape head. The drive controller defines at least a first partition and a second partition within the magnetic tape. The tape head is configured to write data to the first partition of the magnetic tape and subsequently write data to the second partition of the magnetic tape. The drive controller defines an end of the first partition to be directly after the last wrap of the first data band. The drive controller controls the tape head to write data to all of the plurality of wraps of the first data band.

Abstract: A processing device of a system receives a request to access a selected sector in a memory component. The selected sector is associated with a sector number. The processing device determines a virtual block corresponding to the selected sector. The virtual block is associated with a misalignment factor and a misalignment counter. The processing device determines if the misalignment counter satisfies a threshold criterion. In response to the misalignment counter satisfying the threshold criterion, the processing device generates an updated sector number by shifting the sector number by the misalignment factor and performs the access to the selected sector using the updated sector number. In response to the misalignment counter not satisfying the threshold criterion, the processing device updates the misalignment counter and performs the access to the selected sector using the sector number.

Abstract: A storage device and a method of operating a storage device including a non-volatile memory. The method includes selecting a first task from among a plurality of tasks queued in a task queue of the storage device; determining whether a mode of the first task is identical to a mode of a previously-executed task; and determining an execution order of the first task according to a result of determination. The modes and the region addresses of tasks may be utilized to group tasks to permit interleaving of programming data.

Abstract: A victim feedforward signal is added to a microactuator control signal of the victim actuator in response to a voice-coil motor (VCM) control signal that is applied to the aggressor actuator, where the victim feedforward signal is configured to compensate for disturbances to a victim head caused by assertion of the aggressor VCM control signal. Each aggressor VCM control signal is asserted at a specific time by the aggressor actuator, for example in response to the aggressor head passing over a first servo wedge. A feedforward signal that compensates for the effect of the aggressor VCM control signal is then determined based on the aggressor VCM control signal, stored, and asserted via the victim microactuator at a predetermined time relative to when the aggressor VCM control signal is asserted.

Abstract: A computer-implemented method can include obtaining tape data for one or more tapes. The tape data can include pointer data corresponding to a first file. The method can further include determining, based on the tape data, that the first file is stored on a first tape of the one or more tapes. The first tape can have an export status. The method can further include determining that the pointer data includes a pointer to the first tape and a pointer to a second tape. The second tape can have a non-export status. The method can further include storing at least a portion of the tape data. The method can further include initiating, based on the first tape having the export status, a deactivation of the pointer to the first tape.

Abstract: According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, and a controller. The magnetic disk has a plurality of tracks. The magnetic head performs reading and writing from and to the magnetic disk. The controller controls write operations to a first region and a second region of the magnetic disk in different manners. The second region is narrower in track pitch than the first region.

Abstract: A data storage device is disclosed comprising at least one head configured to access a magnetic tape comprising a plurality of data tracks, wherein each data track comprises a plurality of data segments and a plurality of servo sectors. The head is used to read one of the servo sectors to generate a first read signal. The first read signal is processed to generate a position error signal (PES) of the head relative to the magnetic tape, wherein the head is positioned relative to the magnetic tape based on the PES. The head is used to read one of the data segments to generate a second read signal, wherein the second read signal is processed to detect user data recorded in the data segment.

Abstract: An apparatus in one embodiment comprises a host device that is configured to communicate over a network with at least one storage system comprising a source logical storage volume and a target logical storage volume. Responsive to a reboot of the host device during a migration of a plurality of chunks of data from the source logical storage volume to the target logical storage volume, the host device is configured to determine, based at least in part on an entry of a copy migration journal, the entry corresponding to a given chunk of the plurality of chunks, that the migration of the given chunk was in progress prior to the reboot. Responsive to determining that the migration of the given chunk was in progress prior to the reboot, the host device is configured to resume the migration of the plurality of chunks from the given chunk.

Abstract: A servo pattern recording method according to an embodiment of the present technology is a servo pattern recording method of recording a servo pattern on a tape-like magnetic recording medium including a magnetic layer including five or more servo bands, the method including: determining at least three first servo bands in which first servo band identification information constituted by a plurality of bits is to be recorded, and at least two second servo bands in which second servo band identification information constituted by a plurality of bits is to be recorded, the second servo band identification being different from the first servo band identification information; and recording each of the first servo band identification information and the second servo band identification information in the first servo band and the second servo band on the same phase.

Abstract: According to one embodiment, a magnetic disk device includes a disk including a servo sector including burst data, a head including a write head which writes data to the disk, and a read head which reads data from the disk, and a controller which generates a first normal servo gate for applying servo read to the servo sector, wherein when a short servo gate for at least applying servo read to the burst data is generated, the controller generates the short servo gate and the first normal servo gate, and when the short servo gate is not generated, the controller generates the first normal servo gate and a second normal servo gate different from the first normal servo gate.

Abstract: A memory system includes a first nonvolatile memory, a first bridge circuit connected to the memory, a second nonvolatile memory, a second bridge circuit connected to the second memory and connected to the first circuit, and a controller connected to the first circuit and configured to output, to the first circuit, first data to be stored in the first memory and second data to be stored in the second memory, the first and second data being mapped to multiplexing symbols. The first bridge circuit is configured to, upon receipt of the multiplexing symbols, extract the first data from the symbols, store the first data in the first memory, generate third data based on the second data to insert the generated third data into the multiplexing symbols where the first data was mapped, and output to the second circuit the multiplexing symbols into which the third data has been inserted.

Abstract: Storage device self-servo-write includes generating a time base frequency signal, generating a sampled frequency signal by sampling the time base frequency signal at a sample rate to obtain a first set of samples, decimating those samples at a decimation rate to obtain a second set of samples at a spiral frequency of which the time base frequency is a first integer multiple, detecting a spiral track based on the spiral frequency, and writing a servo pattern based on the spiral track and the time base frequency. A generated sampled frequency obtained by sampling the time base frequency signal at the sample rate is used as the servo write frequency, of which the time base frequency is a second integer multiple. Alternatively, the time base frequency is multiplied by a first rational multiple so that the time base frequency is a second rational multiple of the servo write frequency.

Abstract: An access operation performed by a tape drive is detected. The access operation is performed on a tape medium. The access operation has one or more performance characteristics. The performance characteristics of the detected access operation are compared with one or more predefined performance thresholds. The comparison is in response to detecting the access operation. An operation performance of the tape medium is determined. The determination is based on comparing the performance characteristics with the predefined performance thresholds. A table associated with the tape medium is updated based on the operational performance of the tape medium. The table is stored in a non-volatile storage.

Abstract: A method for data storage tape access optimization is provided. The method identifies a plurality of data segments stored on a data storage tape. Each segment having a location and a size on the data storage tape. The method determines a subset of data segments stored on the data storage tape selected for retrieval. The method determines an access order for the subset of data segments. The access order represents a minimized tape cycle time for retrieving the subset of data segments. The method retrieves the subset of data segments from the data storage tape based on the access order.

Abstract: Apparatuses, systems, methods, and computer program products are disclosed for key-value stores with partial data access. An interface module is configured to receive a data object for storage in a key-value store. The data object may include a key and a value. A block object module is configured to generate a plurality of block objects smaller than the data object. A block object may include a new key and a new value. The new key may be based on the key for the data object and on metadata for the new value. The new value may be based on at least a portion of the value for the data object. A storage module is configured to store the block objects in the key-value store.

Abstract: In one embodiment, a guide layout creating apparatus includes a selection module that selects a first point as a point on which a guide to array a plurality of particles in a first array is arranged. The apparatus further includes a calculation module that calculates first free energy when the plurality of particles are arrayed in the first array by the guide arranged on the first point, and second free energy when the plurality of particles are arrayed in a second array by the guide arranged on the first point, a type of the second array being different from a type of the first array. The apparatus further includes a determination module that determines whether the first point is employed as the point on which the guide is arranged on the basis of the first free energy and the second free energy.

Abstract: According to one embodiment, a magnetic disk device includes a disk having a first region to which data is written by normal recording and a second region to which data is written by shingled recording, a head configured to write the data to the disk and read the data from the disk, and a controller configured to, when first data and second data is to be sequentially written to a third region of the second region, reserve a fourth region corresponding to the first data and the second data in the first region, write the first data to the fourth region, write the second data after the first data in the fourth region, and sequentially write the first data and the second data read from the fourth region to the third region.

Abstract: A magnetic tape reading apparatus comprises an acquisition unit that acquires information on linearity of a servo pattern to be recorded on a servo band of a magnetic tape, a reading element unit in which at least two reading elements each of which reads data from a specific track region included in the magnetic tape are disposed, a servo reading element that reads the servo pattern, a control unit that performs control of positioning the reading element unit, a derivation unit that derives a deviation amount, and an extraction unit that extracts data recorded on the reading target track by performing a waveform equalization process on each reading result for the reading elements in accordance with the deviation amount.

Abstract: A data storage device is disclosed comprising a head actuated over a non-volatile storage medium. A plurality of access commands are received from a host and sored in a host queue and a pending queue. A first access command is selected from the host queue, wherein the first access command having a first execution time needed to execute the first access command. When a second access command in the pending queue can be executed within the first execution time, the second access command is executed, and after executing the second access command, the first access command in the host queue is executed. After selecting the first access command from the host queue, a third access command is transferred from the pending queue to the host queue based on a first-in-first-out (FIFO) order of the pending queue.

Abstract: A magnetic tape and servo elements of a magnetic head for reading and writing to the magnetic tape can ascertain servo band signals from different servo bands that are vertically aligned and adjacent to one another. When operating in a write or read mode, at least two servo elements can be activated to respond to a write/read operation based on a determined position across a width of the servo bands in the magnetic tape. The determined position is based on various pattern combinations from different servo band identifiers from the servo band signals.

Abstract: Disclosed are a communication method and communication apparatus using an ambient backscatter communication. A transmission apparatus may include generating a plurality of bitsets by fragmenting data based on a predetermined bitset length, mapping the plurality of bitsets to a plurality of switching patterns based on a data size, and controlling a reflection of a background radio frequency (RF) signal based on a corresponding mapped switching pattern, a total number of the plurality of switching patterns may be determined based on the bitset length, and each of the plurality of switching patterns may have a different length.

Abstract: According to one embodiment, a magnetic disk device includes a disk including a first servo sector including a first preamble, a first servo mark, a first gray code, and first burst data, a head including a write head which writes data to the disk and a read head which reads data from the disk, and a controller which stops write processing, based on a write mask gate different from a first servo gate executing read processing of the first servo sector and a write gate executing the write processing to the disk.

Abstract: A data transmission method according to one aspect of the present disclosure includes: generating a plurality of MPUs, reference clock time information, and leading clock time information indicating a leading PTS that is a clock time at which a leading access unit in the MPU is presented, transmitting the generated plurality of MPUs, reference clock time information, and leading clock time information, wherein the leading clock time information indicates the leading PTS of the plurality of MPUs of which presentation is started after the leading clock time information is transmitted in the generated plurality of MPUs, and each of the generated plurality of MPUs indicates a time point at which each access unit that does not exist in a head of the MPU is presented as a relative value to a time point of another access unit in the MPU.

Abstract: Data set groups are determined, wherein each data set group includes a plurality of data sets and each data set includes error-correcting information for content user data of the data set. One or more versions of data set group level error-correcting information for each data set group are calculated. The data set groups on stored a tape storage media. After the data set groups are stored, an amount of storage available on one or more regions of the tape storage media associated with one or more tape edges is identified. An instruction is provided to store at least a partial amount of the calculated one or more versions of data set group level error-correcting information for the data set groups able to be stored in the amount of storage available on the one or more regions of the tape storage media associated with the one or more tape edges.

Abstract: A system and method are disclosed for detecting and handling volume creation failures. In one implementation, a request to create a new volume in a volume chain for a virtual machine is received. A processing device creates a first metadata file for the new volume, where the first metadata file has a first filename indicating that creation of the new volume has not completed. A reference to a parent volume of the new volume is stored in the first metadata file, along with an indication that the new volume is a leaf of the volume chain. A second metadata file that is associated with the parent volume is updated in view of the new volume. The processing device creates a data file for the new volume and renames the first metadata file to a second filename indicating that creation of the new volume has completed.

Abstract: A computer-implemented method for incrementing a tape write pass (WP) value includes identifying an action that requires incrementing a tape WP value on a magnetic tape storage device. The computer-implemented method further includes, in response to identifying the action that requires incrementing the tape WP value on the magnetic tape storage device: assigning a new tape WP value to a dataset based, at least in part, on a partition number corresponding to the data partition in which the dataset is written to.

Abstract: The magnetic tape includes a non-magnetic support and a magnetic layer, in which the magnetic layer has a timing-based servo pattern, an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference between a value L99.9 of a cumulative distribution function of 99.9% and a value L0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and a difference between a spacing S0.5 measured, after n-hexane cleaning, on a surface of the magnetic layer under a pressure of 0.5 atm by optical interferometry and a spacing S13.5 measured, after n-hexane cleaning, under a pressure of 13.5 atm is 3.0 nm or less, and S0.5 is 5.0 nm or more.

Abstract: According to one embodiment, there is provided a magnetic disk drive comprising a magnetic disk, a magnetic head configured to read/write data from/to the magnetic disk, a signal processing circuit configured to convert data to be recorded on the magnetic disk into a write signal, and to output the write signal to the magnetic head that generates a recording magnetic field corresponding to the write signal, and a recording control circuit configured to control the signal processing circuit and the magnetic head to record, in a target recording area of the magnetic disk, first data in the target recording area with a recording magnetic field having a first frequency, and to write, second data different from the first data over the first data with a recording magnetic field having a second frequency higher than the first frequency.

Abstract: Systems and methods for servo zone transition optimization are described. In one embodiment, the storage system device includes a disk drive and a controller. In some embodiments, the controller may be configured to assess at least one operation of a read/write head of the disk drive; and format, based at least in part on the assessing of the read/write head, a disk surface of the disk drive with a first servo zone, a second servo zone, and an overlap region extending between a start point of the second servo zone and an end point of the first servo zone. In some cases, the overlap region starts towards a disk inner diameter (ID) and ends towards a disk outer diameter (OD).

Abstract: A storage device includes a disk, a head configured to write data to and read data from the disk, and a controller. The controller is configured to, for each of a plurality of unexecuted commands, carry out a calculation of an amount of time that is required for the head to start accessing the disk to begin execution of the non-executed command upon completion of a currently-executed command, until the earlier of i) a number of unexecuted commands for which the calculation has been carried out reaches a threshold value or ii) the completion of the currently-executed command, select a next command to be executed from one or more unexecuted commands for which the calculation has been carried out, based on the calculated amount of time for each of the one or more unexecuted commands, and execute the selected next command.

Abstract: Computer image clustering systems and methods for conducting effective media searches by grouping multimedia documents tagged by keywords into a hierarchy of images configured to: (1) maintain a first database, (2) maintain an initial occurrence matrix, (3) maintain an occurrence matrix, (4) maintain a media file activation score for each media file in the first database, (5) generate a log version of the occurrence matrix, (6) maintain an inverse media file frequency value for each descriptive term in the first database, (7) generate a descriptive term frequency matrix and generate a list of document vectors in multidimensional space (list), and (8) organize and process each media file in the list into a high activation score category and a low activation score category.

Abstract: An implementation of a system disclosed herein provides a method for managing data streams of sequential nature, wherein the method provides for determining that a sequence of incoming write commands are associated with an LBA range mapped to a source band and writing data of the incoming write commands to physical blocks of a destination band assigned to the LBA range of the source band such that the data of the incoming write commands is written according to a sequential order of data receipt and in a forward write direction to sequentially fill physically-consecutive blocks in the destination band.

Abstract: A computer-implemented method may include obtaining position information of a susceptible zone of a tape. The susceptible zone may be a section of the tape where a stress value of the tape exceeds a threshold. The method may further include storing a block of data to the tape in a first storage zone. The method may further include determining that the first storage zone is positioned within the susceptible zone. The method may further include storing, based at least in part on the determining, a duplicate block of data in a second storage zone.

Abstract: The method, computer program product, and computer system may include a computing device which may generate a list of data to be copied from a plurality of source media to a target medium. The computing device may identify a first type of data in the generated list of data with the first type of data being pre-migrated data. The computing device may reclaim the first type of data from a primary storage tier to the target medium with the target medium being associated with the first drive. The computing device may identify a second type of data in the generated list of data, the second type of data being migrated data, and reclaim the second type of data from at least one secondary source medium to the target medium using the first drive and a second drive. The secondary source medium may be associated with the second drive.

Abstract: The present disclosure describes aspects of pulse-based writing for magnetic storage media. In some aspects, a pulse-based writer of magnetic storage media determines that a string of data bits having a same polarity corresponds to a magnet longer than a threshold associated with a magnetic media writer. The pulse-based writer inserts, into the string of data bits, a transition to a polarity opposite to the same polarity of the string of data bits. The string of data bits including the inserted transition is then transmitted to the magnetic media writer to cause a write head of the writer to pulse while writing the magnet to magnetic storage media. Various aspects may also implement a control signal to mask a transition or control polarity of the magnetic media writer. By so doing, magnets may be written to the magnetic storage media more efficiently or with less distortion to neighboring tracks.

Abstract: In one embodiment, a method includes receiving a number of notifications of one or more activities relevant to a user. Each notification has an associated receipt time and type of notification. The method also includes aggregating one or more of the notifications based on the type of notification; determining a sending time to send the aggregated notifications based at least in part on determining that a pre-determined amount of time that has elapsed from a receipt time of a most recent one of the aggregated notifications; and sending the aggregated notifications to the user based on the sending time.

Abstract: A method includes writing first data to a first track of a magnetic recording medium of a storage device. First parity sectors corresponding to the first data are written. The first parity sectors have a first size. Second parity sectors corresponding to the first data are written. The second parity sectors have a second size. Second data is written to a second track of the magnetic recording medium. The second track is adjacent to the first track. It is determined whether an unrecoverable data error has occurred on the second track. After writing to the second track and determining that no unrecoverable data error has occurred, the first and second parity sectors corresponding to the first data are released.

Abstract: In one embodiment, a data storage system includes a tape drive configured to: write a plurality of files to a first partition of a magnetic recording tape; and write an index to a second partition of the magnetic recording tape, the index including information about locations of data of the plurality of files in the first partition of the magnetic recording tape. In another embodiment, a magnetic recording tape includes: a plurality of files to written to a first partition of the magnetic recording tape using a tape drive; and an index written to a second partition of the magnetic recording tape using the tape drive, the index including information about locations of data of the plurality of files in the first partition of the magnetic recording tape.

Abstract: A system for performing a computation includes a tenant associated processor; a commingling associated processor; an interface; and a processor. The interface is configured to receive an indication of a computation. The processor is configured to determine a set of computational steps for performing the computation; determine a preprocessing subset, wherein the preprocessing subset comprises a subset of the set of computational steps for execution by the tenant associated processor; and determine a main processing subset, wherein the main processing subset comprises the set of computational steps for execution by the commingling associated processor.

Abstract: Methods, devices and systems to make compressed backup copies of in-use compressed database indices are described. In general, an “oldest” time at which index pages in working memory had been updated is identified. Compressed index pages may be directly copied without the need to bring them into working memory or uncompressing them. The identified “oldest” time is then associated with the compressed backup copy. In some embodiments, an entire compressed backup copy may be associated with a single point in time (e.g., the identified “oldest” time). In other embodiments, a compressed backup copy may be associated with multiple points in time (e.g., one time for each portion of the compressed index that is being backed-up). Compressed indices copied in accordance with the invention may be used during restore operations to reconstruct database indices using the identified “oldest” time and database log files.

Abstract: A technique for managing cache in a data storage system is disclosed. Data storage system cache memory is arranged into multiple input/output (IO) cache macroblocks, where a first set of IO cache macroblocks are configured as compressed IO cache macroblocks, each compressed IO cache macroblock storing a plurality of variable sized compressed IO data blocks, and a second set of IO cache macroblocks are configured as non-compressed IO cache macroblocks, each non-compressed IO cache macroblock storing a plurality of fixed sized non-compressed IO data blocks. A write request is receive at the data storage system. If the IO data associated with the write request is determined to be compressible, the IO data is compressed in-line and written to an IO data block in a compressed IO cache macroblock, otherwise non-compressed IO data is written to an IO data block in a non-compressed IO cache macroblock.