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.

The present disclosure generally relates to tape heads for use in a tape drive system. The tape head includes a plurality of servo elements and a plurality of data elements disposed between the servo elements. An electrostrictive material is present in the tape head. Electrodes are coupled to the electrostrictive material to permit a voltage to be distributed across the electrostrictive material. The voltage causes the electrostrictive material to expand, and thus expand the tape head. By expanding the tape head by adding voltage, or contracting the tape head by lowering voltage, the spacing between adjacent data elements can be adjusted to match the spacing between adjacent data tracks on a tape.

A tape drive may arrange timing-based-servo marks into a timing-based-servo pattern. The timing-based-servo pattern may be at least one M-pattern. The tape drive may select the at least one M-pattern. The tape drive may match at least two timing-based-servo marks in the at least one M-pattern. The tape drive may determine, from the matching, whether an alignment of the at least two timing-based-servo marks is demonstrative of tape-creep.

A tape drive may arrange timing-based-servo marks into a timing-based-servo pattern. The timing-based-servo pattern may be at least one M-pattern. The tape drive may select the at least one M-pattern. The tape drive may match at least two timing-based-servo marks in the at least one M-pattern. The tape drive may determine, from the matching, whether an alignment of the at least two timing-based-servo marks is demonstrative of tape-creep.

Concurrent standard/high resolution logging of critical performance metrics and functional data for various functional areas including servo system, dataflow, channel, read/write, speed matching, and error recovery is achieved by segregating one or more rows of the tape map array for the purpose of logging only high resolution data. As performance data is logged to the standard resolution tape map by wrap and regional offset down tape, the reserved high resolution row logs data sequentially in the order it was processed on magnetic tape and not by its position on magnetic tape. The high-resolution performance data is concurrently logged with normal-resolution performance data as a supporting view with more detailed tape processing data should the normal-resolution performance data have inconclusive or insufficient content. High-resolution storage is structured for shorter regional logging or per-dataset logging of critical performance metrics and functional data, referred to herein as performance data.

A methodology that enables, for example, tape drive operation at lower SNR and/or reduced rewrite area uses a first threshold T and a second threshold r for a rewrite condition. Codeword interleaves (CWIs) in a data set are written onto a plurality of simultaneously-written parallel tracks of a magnetic recording medium, read back and error correction decoded. A determination is made as to whether at least one of the C1 or C1 codewords in each decoded CWI contains more byte errors than the second threshold r of the rewrite condition. A number of CWIs in a rewrite buffer are according to the following criteria: b.sub.i=b.sub.iT when b.sub.i is greater than the first threshold T, and b.sub.i=0 when b.sub.i is less than or equal to the first threshold T.

A recording and reproducing apparatus includes: a magnetic head in which a servo band having a servo pattern and a data band having data tracks are alternately arranged along a width direction, the magnetic head including a recording and reproducing element that records or reproduces data with respect to the data track, and at least two servo reproducing elements that read servo patterns adjacent to each other in the width direction of the magnetic tape; a selection unit that selects a servo reproducing element from the servo reproducing elements according to a position of the data track, as a target of recording or reproducing of data in the data band, along the width direction; and a controller that controls positioning of the magnetic head along the width direction by using a result of reading of the servo patterns by the servo reproducing element selected by the selection unit.

A tape drive may calculate the slopes for three successive timing-based-servo marks in a timing-based-servo group. The timing-based-servo marks may be arranged in a one or more M-patterns. The three successive timing-based-servo marks may be across the one or more M-patterns. The tape drive may perform a parabolic fit of a gradient of the slopes. The tape drive may determine whether the gradient is demonstrative of tape-creep.

In an approach to HRTD recovery by writing the HRTD in a null data set, responsive to receiving a request to write a data set to a magnetic tape, a lead data set of a current wrap of a plurality of wraps of the magnetic tape is written, wherein the lead data set of the current wrap includes a current wrap HRTD that contains one or more directory records for each wrap of the plurality of wraps from a lead wrap of the plurality of wraps through a first prior wrap of the plurality of wraps, and further wherein the first prior wrap immediately precedes the current wrap.

Aspects of the present disclosure relate to managing index writes within a tape. A determination can be made that a change was made to at least one file stored within a tape medium while the tape medium was mounted within a tape drive. In response to the determination, an index can be written to a data partition of the tape medium. A determination can be made whether the change included any changes to a file at least equal to a threshold hierarchy level. In response to determining that the change did not include any changes to a file at least equal to the threshold hierarchy level, a first instruction can be issued to the tape drive to reposition the tape medium to the end of the tape. A second instruction can be issued to the tape drive to perform an unthread operation at low tension to rewind the tape medium.