International Business Machines Corporation

Broadcom Corporation

Globalfoundries Inc.

Other

Simeon Furrer

Mark Alfred Lantz

Giovanni Cherubini

Roy Daron Cideciyan

Jens Jelitto

Robert Allan Hutchins

Keisuke Tanaka

Johan B C Engelen

Nhan Xuan Bui

Hugo Eric Rothuizen

Steven Ross Bentley

Angeliki Pantazi

Kevin Bruce Judd

Wolfgang H Schott

Kevin Dale Butt

Kazuhiro Tsuruta

Ernest Stewart Gale

Laurent A Dellmann

Pedro E Coronel

Robert G Biskeborn

Marcel A Kossel

Joachim S Hammerschmidt

Edwin Ralph Childers

Masayuki Iwanaga

Paul Merril Greco

Kenji Ohtani

Beat Eugen Weiss

Hazar Yüksel

Icko E T Iben

Thomas Helmut Toifl

Walter Haeberle

George Dionyssios Kondylis

Dietrich G Maiwald

Luzius Kronig

Arya Behzad

Jason A Trachewsky

Robert Fontana

Rajendra Tushar Moorti

Jason Liang

Randy Clark Inch

Ilias Iliadis

David Lee Swanson

Pierre-Olivier Jubert

Armando Jesus Argumedo

Rohit Gaikwad

David Harper

Amit Goutam Bagchi

Scott Jeffrey Schaffer

Chunyu Hu

Keith Andrews Carter

Martin Petermann

Hazar Yuksel

Johan Bc Engelen

Venkateswara Rao Kodavati

Arash Behzad

Hazar Yueksel

Stella Brach

Georg Lothar Lauhoff

Wolfgang Schott

Provided are a computer program product, device, system, and method for compensating for a nonlinear deformation field of a tape of a tape storage system. In one embodiment, a head beam of a tape head module of a tape drive employing active skew-based TDS compensation, is segmented into linear segments which are pivotally coupled to each other. Each linear beam segment carries a portion of the transducer array of the tape head module to form a tape head module segment. The pivot angle between a pair of pivotally coupled head module segments of the tape head may be controlled by a controllable pivot actuator to provide an independently adjustable skew angle for each module segment with respect to the direction of travel of tape. As a result, it is believed that registration between the transducers of each module segment and data tracks of the tape may be improved.

Segmented tape head

An apparatus for a reworkable tape track following actuator includes a spring actuator, a head module, a voice coil, and a mounting body, where the spring actuator is coupled to the mounting body and the mounting body is removable from a tape drive assembly. The apparatus further includes the head module being coupled to a middle section of the spring actuator and the voice coil being positioned beneath the head module.

Reworkable tape track following actuator

Provided are a tape head controller, tape drive, and method for adjusting a skew angle and lateral position of a tape head to reduce track placement errors. A tape head is rotated at a nominal skew with respect to a tape medium to position servo readers in servo patterns. Data writers are located in a first plane of the tape head and the servo readers are located in a second plane in the tape head. The first and the second planes are separated by a distance. Repeatedly determining a skew angle comprising the nominal skew adjusted by a delta angle, at which to rotate the tape head to position the servo readers in the servo patterns. Repeatedly determining a lateral position error based on the distance and the delta angle. Repeatedly adjusting a lateral position of the tape head using the lateral position error to position the data writers in target data track locations at which to write data.

Adjusting a skew angle and lateral position of a tape head to reduce track placement errors

Provided are a computer program product, device, system, and method for write data management. In one embodiment, a write management controller calculates an order for writing data and parity blocks of write data code words on tape media in a variable interleaved fashion which ensures a minimum physical longitudinal separation along the length of tape between data and parity blocks of the same code word. The calculated write order information may be provided back to a host or other data source so that the write data is eventually transmitted to the tape drive for writing on tape media in accordance with the calculated write order. In this manner, a minimum physical longitudinal separation along the length of tape between data and parity blocks of the same code word may be achieved to increase the reliability of the data storage.

Write data management

In response to a rotation of timing-based servo (TBS) patterns of a first servo band and a second servo band, heights of top and bottom portions of servo stripes of servo frames of the TBS patterns are adjusted to compensate for changes in a usable height of the servo stripes caused by the rotation.

Servo pattern for skew based tape dimensional stability compensation

The present disclosure includes systems and methods for reducing rewrite overhead in a sequential access storage system. The method may comprise writing a data set to a sequential access medium using a magnetic head, wherein the data set comprises a plurality of encoded data blocks, classifying each of the plurality of encoded data blocks on the sequential access medium into one of at least three classes of write quality, and rewriting the encoded data blocks in a rewrite area of the sequential access medium based at least in part on the write quality class. In some embodiments, the at least three classes of write quality may comprise a hard rewrite class for which rewrites are necessary to prevent data loss, a soft rewrite class for which rewrites are desirable but not necessary, and a no rewrite class for which no rewrite is needed or desired.

Selective hard and soft rewrites

In one aspect of the present disclosure, the degree of side erasure occurring in neighboring tracks is controlled by controlling the skew angle of the tape head, relative to the longitudinal direction of motion of the tape past the head as a track is written. In one embodiment, the tape head is rotated relative to the longitudinal direction of tape travel, and the trailing edge of the tape head which forms an acute angle with the edge of a track being written, is used for writing tracks at a desired track pitch. Other aspects and advantages may be provided, depending upon the particular application.

Side erasure control for track writing in a system

Provided are a tape guide roller and tape drive having a guide roller having magnets and bushings to stabilize a roller barrel for a tape medium. The tape guide roller has a roller barrel extending around a vertical axis. The tape medium passes across the roller barrel to guide the tape medium on a tape path. A plurality of magnets positioned with respect to the vertical axis provide an axial force to stabilize the tape guide roller axially.

Guide roller having magnets and bushings to stabilize a roller barrel for a tape medium

In one general embodiment, a data storage product includes a magnetic recording tape having written thereon at least two servo tracks extending along a longitudinal axis of the tape. Each servo track has a timing-based servo (TBS) pattern comprising a series of servo frames arranged to enable lateral positioning of a magnetic head relative to the servo tracks as well as tape dimensional stability (TDS) compensation via head skew. Each frame comprises a sequence of pairs of leading and trailing servo stripes. Midpoints between the servo stripes in each pair, at all points having a same relative lateral height on the tape, are located along a virtual median line oriented at an angle β from perpendicular to the longitudinal axis of the tape, the angle β being greater than 1 degree.

Magnetic recording tape having servo pattern for tape dimensional stability compensation via head skew

Mechanisms are provided to receive encoded header information stored on a tape of a tape drive, wherein the encoded header information has been generated by: generating, for a plurality of tracks of the tape of the tape drive, a header information in a plurality of symbols, wherein the plurality of symbols is comprised of a first set of symbols and a second set of symbols, wherein the first set of symbols include identical information across all tracks of the plurality of tracks, and wherein the second set of symbols are configurable to include different information across all tracks of the plurality of tracks; and modifying, for writing to the tape of the tape drive, the first set of symbols of the plurality of tracks to include parity information corresponding to information included in the second set of symbols of the plurality of tracks. The received encoded header information is decoded.

Header decoding mechanism for tape storage

A data storage system comprises: a head configured to produce a signal representing data stored on a storage medium; an estimator configured to determine an estimated signal comprising a superposition of an estimated linear portion of a partial-response equalizer output and an estimated nonlinear portion of the signal; a bank of noise whitening filters configured for filtering a difference between the signal and the estimated signal; a branch metric calculator configured to calculate branch metrics based on the filtered signal; and an adaptive data-dependent noise-predictive maximum likelihood sequence detector configured to generate an output stream representing the data based on the one or more branch metrics.

Adaptive data detection on a nonlinear channel

An apparatus includes an array of write transducers. Each write transducer includes a lower yoke, a lower write pole piece comprising a lower base layer in magnetic communication with the lower yoke and a lower high moment layer above the lower base layer. Each write transducer includes a write gap above the lower write pole piece and an upper write pole piece above the write gap. The upper write pole piece includes an upper high moment layer above the write gap and an upper base layer above the upper high moment layer. Each write transducer includes an upper yoke above the upper base layer. A media facing side of the lower pole piece and at least a portion of a media facing side of the upper pole piece extend along a plane and the remainder of the media facing side of the upper pole piece is recessed from the plane.

Write transducer with recessed portion to improve track shingling performance

Methods and apparatus are provided for calculating branch metrics, associated with possible transitions between states of a trellis, in a sequence detector for detecting symbol values corresponding to samples of an analog signal transmitted over a channel. For each sample and each transition, the method calculates a plurality of distance values indicative of distance between that sample and respective hypothesized sample values for that transition. In parallel with calculation of the distance values, the sample is compared with a set of thresholds, each defined between a pair of successive hypothesized symbol values arranged in value order, to produce a comparison result. An optimum distance value is selected as a branch metric for the transition in dependence on the comparison result.

Sequence detection

A computer-implemented method, according to one embodiment, includes: receiving a first timestamp in response to a first servo reader detecting a stripe of a first servo burst on the magnetic tape, and receiving a second timestamp in response to a second servo reader detecting a stripe of a second servo burst on the magnetic tape. A third timestamp is received in response to the first servo reader detecting a stripe of a third servo burst on the magnetic tape, while a fourth timestamp is received in response to the second servo reader detecting a stripe of a fourth servo burst on the magnetic tape. The first, second, third, and fourth timestamps are used to determine the skew of the magnetic tape. Further still, the first and third servo bursts are in a same first servo sub-frame, while the second and fourth servo bursts are in a same second servo sub-frame.

Accurate skew determination for magnetic tapes experiencing the effects of tape dimensional instability

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Altdorf, Switzerland

Simeon Furrer