Abstract: Aspects of the present disclosure relate to rewinding a tape medium. Data is written to the tape medium under a first tension. An end data region of the tape medium is identified, where the end data region is not the end of the tape medium. An indication that the tape medium is to be unmounted is received. The position of the tape medium is moved to the end data region. The tape medium is then rewound from the end data region under a second tension, the second tension being lower than the first tension.

Abstract: A magnetic tape drive includes a head assembly with a write head and a read head. The read head is positioned ahead of the write head, so that as a magnetic tape is moved across the head, the read head is able to read data that is about to be overwritten by the write head. When a client computer system commands the tape drive to write data to the magnetic tape, the tape drive writes the data to the tape but preserves any data that is overwritten by reading the data before it is overwritten. The preserved data is returned to the client computer system. In various examples, the returned data can be written back to the tape, discarded, or stored elsewhere under the control of the client computer system.

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. The controller is configured to read first data written on the disk, measure a first read error rate of the first data, determine a difference in the first read error rate from a previously determined read error rate of the first data, determine a current read error rate for second data written on the disk based on the difference in the first read error rate from the previously determined read error rate, and determine whether a refresh process is performed on the second data based on the current error rate.

Abstract: A first drive volume formed on a disk within a drive enclosure. The first drive volume is read from and written to by a first head that is moved by a first actuator, A second drive volume is formed on the one or more disks. The second volume is read from and written to by a second head that is moved via a second actuator within the drive enclosure. The second actuator is separate and independent from the first actuator. Data of the first drive volume is duplicated onto the second drive volume, Background validation operations are performed on the second drive volume instead of the first volume.

Abstract: A set of patterns written to a magnetic recording medium are found that result in a relatively high and/or low error when read back. Upon writing subsequent to the determining of the set of patterns, one pattern of the set of the patterns is identified within a data segment ready to be written to the magnetic recording medium. The data segment is written with a changed bit spacing in response to identifying that the one pattern of the set of the patterns is within the data segment.

Abstract: In a data storage device having a storage medium, wherein data is written to tracks on the storage medium, data for each track including a preamble, and wherein the preamble in any current track is orthogonal to the preamble in any track adjacent to the current track, and wherein data accumulated in a multi-dimensional space is representative of a relationship between signals from the current track and signals from at least one adjacent track, the relationship between the signals from the current track and the signals from the at least one adjacent track is calibrated by, for each respective position out of a plurality of positions in the multi-dimensional space, accumulating a plurality of data values for the respective position, and determining, from the plurality of data values for the respective position, an inverted covariance matrix without performing a matrix inversion operation, either during run-time or prior to run-time.

Abstract: According to one embodiment, a magnetic disk device, includes a disk including a track including a plurality of servo sectors, a head including a write head which writes data to the disk and a plurality of read heads which read the data from the disk, and a controller configured to simultaneously acquire a plurality of pieces of correction data for repeatable runout of the disk by the read heads, acquire a first correction data and a second correction data based on the correction data, write the first correction data and the second correction data to the disk, and correct a position of the head based on the first correction data and the second correction data.

Abstract: Technologies are provided for using an index in one region of a storage device to track modifications to data stored in another region of the storage device. The index can be stored in a first storage region using a first storage format, and data items can be stored in a second storage region using a second storage format. The index can map logical identifiers for data items to locations in the second storage region where the data items are stored. Instead of modifying a data item in the second storage device region, an entry in the index can be updated to mark the data item as deleted. Requests for data items can be reconciled using the index before returning the requested data items. Storage locations in the second region that are associated with index entries that are marked as deleted can be reclaimed and used to store additional data items.

Abstract: In one embodiment, a drive-implemented method includes determining, by a tape drive, that a magnetic recording tape is compatible with a first format, the tape drive having an array of transducers including subarrays of the transducers positioned on opposite sides of an inner transducer, reading from or writing to the magnetic recording tape using the array in a first mode of operation corresponding to the first format, processing data using only transducers in the subarrays in the first mode of operation, and processing data using only a portion of transducers in each subarray in a second mode of operation corresponding to the second format. The first format specifies locations of data and a contiguous spare area on the tape and compatibility with a second format. The second format specifies a set of second active channels different than a set of first active channels specified by the first format.

Abstract: An optical disc device includes a first error correction coding circuit that codes the recording data according to a first error correction coding format, a second error correction coding circuit that codes the recording data according to a second error correction coding format, and a recorder that converts the recording data into a recording signal and records it on an optical disc. The second error correction coding format is different in an arrangement of the recording data from the first error correction coding format. The second error correction coding format is configured to generate a second parity code with a higher degree of redundancy. The recorder records the recording data coded by the first error correction coding circuit and only the second parity code in the recording data coded by the second error correction coding circuit.

Abstract: An apparatus according to an embodiment includes an array of transducers including an inner transducer and subarrays of the transducers positioned on opposite sides of the inner transducer, and a controller coupled to the transducers. The controller is configured to process data using only the transducers in the subarrays in a first mode of operation. Moreover, the controller is configured to process data using only a portion of the transducers in each of the subarrays in a second mode of operation, where the inner transducer is inactive in the second mode of operation.

Abstract: According to one embodiment, a magnetic disk device includes a disk, a first head, a second head, an actuator configured to position the first head and the second head over the disk, and a controller configured to control the actuator based on a first value having a first waveform suppressing a disturbance component, wherein the controller is configured to invert, in the first waveform, a polarity of a third waveform succeeding a first timing with respect to a polarity of a second waveform preceding the first timing in a case where the first head is changed to the second head at the first timing.

Abstract: An apparatus according to one embodiment includes an array of 2N+1 transducers and a controller directly electrically coupled to each of the transducers, where the controller is configured to use transducers on only one side of a centerline of the array in a first mode of operation.

Abstract: A disk device includes a recording medium on which data is recorded, a decoding circuit configured to decode data read from the recording medium, and a control circuit. The control circuit is configured to cause first data associated with a target sector referenced in a read request to be read from a target track of the recording medium, second data associated with a non-target sector that is not referenced in the read request to be read from the recording medium after the first data is read from the recording medium, and decoding of the first data to be completed by the decoding circuit after the second data is read from the recording medium.

Abstract: Devices that have an air bearing surface (ABS), the device includes a near field transducer (NFT) that includes a disc configured to convert photons incident thereon into plasmons; and a peg configured to couple plasmons coupled from the disc into an adjacent magnetic storage medium, wherein the disc includes a disc material that includes gold or an alloy thereof and the peg includes a peg material, wherein the disc material is different from the peg material and wherein the peg material has a real part of the permittivity that is not greater than that of gold.

Abstract: A data storage device is disclosed comprising a first disk surface comprising a plurality of data tracks, and a first head actuated over the first disk surface. First data is written to the first disk surface based on a first format. At least part of the first disk surface is reformatted based on a second format, wherein the second format defines a lower recording density for the first disk surface as compared to a recording density defined by the first format. After reformatting the at least part of the first disk surface, second data is written to the first disk surface based on the second format and the first data is read from the first disk surface based on the first format.

Abstract: A near-field transducer has an enlarged portion with a layer of soft plasmonic material. A peg is embedded in a lower part of the enlarged portion that faces a media-facing surface. The peg has an elongated outer part that extends from a lower edge of the enlarged portion towards the media-facing surface and an embedded part that is embedded within the enlarged portion. The embedded part could be any shape. The peg is formed of a thermally robust plasmonic material.

Abstract: A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a spin torque oscillator (STO). A first bias signal is applied to the STO during a first interval preceding a write operation to write data to the disk, wherein the first bias signal causes the STO to protrude toward the disk. After the first interval, a second bias signal is applied to the STO during a second interval spanning at least part of the write operation, wherein an amplitude of the first bias signal is in the range of 1.1 to 1.5 times an amplitude of the second bias signal.

Abstract: Some embodiments are directed to computer program products for use with tape drives that oscillate the relative transverse position of a tape and magnetic head during seek operations (for example, by moving the magnetic head in the transverse direction). Some embodiments are directed to methods and computer program products for use with tape drives that select relative transverse position of the tape and magnetic head to counter uneven wear (for example, observed uneven wear, uneven wear predicted based on historical tape and drive usage data).

Abstract: An optical disc apparatus includes: a controller configured to acquire information of an access result and access positions on an optical disc when an optical disc drive unit configured to optically access an optical disc optically accesses the optical disc; and a storage configured to store the information acquired by the controller.