Storage Technology Corporation

Oracle International Corporation

Sun Microsystems, Inc.

Oracle America, Inc.

Steven Gregory Trabert

Ronald Dean Gillingham

John Paul Mantey

James C Cates

Richard Lewis O'Day

Keith Gary Boyer

Mark Lee Watson

William Joseph Vanderheyden

Richard A Gill

Darryl Yeakley

Mark Hennecken

Steven Michael Kientz

Richard H Dee

Matthew P Wojciechowski

Kevin Dale McKinstry

Edward Virgil Denison

Forest Dillinger

Robert G Brocko

Matthew Tucker

Gerald M Grammens

Steven M Kientz

Hubert O Hayworth

Philip L Lloyd-Davies

James C Faulk

Kevin S Curran

Kevin D Mckinstry

A device for recording and/or reading data to and/or from a magnetic tape includes a read/write head which has a first device set including a first plurality of magnetic data write and/or read elements and a second device set including a second plurality of magnetic data write and/or read elements. The device also includes a lateral positioning actuator and an azimuth actuator. The lateral positioning actuator and azimuth actuator are used together to position both device sets on the magnetic tape. The lateral positioning actuator laterally positions the read/write head such that during write and/or read operations the first and second pluralities of magnetic data write and/or read elements align laterally to first and second pluralities of recordable and/or readable data tracks on the magnetic tape. The azimuth actuator rotates the read/write head about an azimuthal angle. such that the elements align to lateral spacings.

Azimuth actuated dual device set positioning

A system and method for verifying a servo pattern in tape media include a tape drive unit which moves the tape media lengthwise across a read head. The tape drive unit is adapted to use a tape comprising at least one servo band, each servo band including at least one servo pattern. The tape drive unit scans the read head across the servo band in a widthwise direction relative to the tape media. The system and method also include an electronic control unit that is adapted to verify the servo pattern.

Method and device for verifying a servo pattern in tape media

A recording head assembly that includes two side-by-side and separately actuated heads. To increase tape capacity while controlling tape mis-registration, write elements are provided in two subsets with a first subset provided on a first of the two heads and a second subset provided on the second of the two heads. The two subsets are offset a distance along the direction of travel for a tape (or horizontal offset) while the two subsets of write elements are also offset along the longitudinal axes of the heads (or bumps on the heads) such that a first subset acts as the upper half of the write element set and a second subset acts as the lower half of the write element set. The subsets of write elements simultaneously writes data, and a similar arrangement can be provided for two subsets of read elements that are aligned with the write elements.

Tape drive with head assembly having dual offset devices

Systems and methods (e.g., 'utilities') of measuring errors in the positioning of tape head assembly data write and read elements of a tape drive and utilizing obtained calibration data to accurately align the data write elements with a desired position while writing data tracks and data read elements while reading previously written and aligned data tracks. The disclosed utilities independently determine a degree to which a tape drive write head is to be offset from a nominal write position of the write head over a tape and independently determine a degree to which a tape drive read head is to be offset from a nominal center position of previously written data track of the tape, each to collectively account for the various types of non-idealities in the write or read head of the tape drive (e.g., positioning errors between the data write/read elements and servo readers, etc.).

Calibration system for limiting tape head assembly positioning errors during data writing and reading of tape in tape drive

A servo writing method is provided for use with unoriented magnetic tape media. A biasing zone is formed, such as between a pair of permanent block or disk magnets, with a strong DC magnetic field that is substantially free of perpendicular components. The method includes feeding the tape through the magnetic biasing zone to form a longitudinal magnetic bias in the magnetic layer of the tape media. The method includes using a write head to write a servo pattern on the tape media after the forming of the longitudinal magnetic bias in the tape media, and the servo pattern produces an output that is substantially symmetric with high amplitudes. In one embodiment, the biasing zone is formed or defined as the gap between first and second magnetic assemblies oriented with a single direction of magnetization, such as in the same direction as the tape travel through the biasing zone.

Servo writer providing a pre-writing, longitudinal magnetic bias in a magnetically unoriented tape supply

In an embodiment, a method is provided for improving signal and transducer alignment in a magnetic tape drive. The method includes writing a first track and a second track to a tape. Each track has an associated track characteristic, which may include fundamental frequency and test binary pattern, among other characteristics. The tracks are adjacent and substantially parallel to one another, and each track has a differing track characteristic value. Each track is read at multiple tracking positions to collect values corresponding to each position. An optimal offset is determined based on the collected values and the corresponding tracking positions. In another embodiment, a magnetic tape drive includes a data reader, a data writer, a processor, and a computer readable medium. The medium has stored instructions, executable by the processor, for carrying out the described method.

Technique for signal and transducer alignment in a tape drive

A tape has a component of magnetization pointing out of a plane of the tape. To write a pulse of a servo pattern to the tape, the tape is passed over a write head with a conventional write gap. Current having a fixed polarity is provided to the write head. Once the current achieves a desired value, the current is no longer provided to the write head.

Method for writing a servo pattern in tape

Systems, computer implemented methodology, and computer readable media for measuring position error signal differential nonlinearity in timing based servo patterns. A set of two or more reading heads, positioned at various locations along a servo stripe and orientated transverse to the longitudinal motion of the tape, collect PES data concerning servo stripes. A differential between the two reading heads is examined at various locations along the servo stripe of the servo pattern to ascertain differential PES data regarding an area of interests along the servo stripe. Examination of the differential data is thereafter conducted to isolate systematic PES readings from nonsystematic PES readings. The nonlinearity of the systematic PES readings at the various locations along the servo stripe is measured so as provide the ability to compensate for the nonlinear differential PES associated with the non-ideal shape of servo stripes.

Detection and measurement of position error signal linearity in timing based servo patterns using differential nonlinearity

Pulses generated from servo stripes of a servo tape system are narrowed by using non-linear gain enabling precise position of the read head. Non-linear gain based on the amplitude of each pulse is applied to each pulse to reduce jitter and distortion so as to more accurately position the read head. A non-linear gain device comprising multipliers apply a non-linear gain to a normal servo pulse signal prior, in one embodiment, to the signal being applied to a qualifier. The non-linear gain device further comprises a limiter so as to limit the gain beyond a certain threshold to 1.0. The limitation of the gain to 1.0 renders the actual amplitude of the pulse unchanged while narrowing the pulse and flattening the baseline. The resulting pulse possesses less jitter and less distortion qualities rendering the positioning of the read head more precise.

Pulse-slimming for a tape servo system using non-linear gain

Method and system of measuring and optimization of noise in a servo system. The method and system including features to optimize filtering otherwise reducing noise in the system so as to permit improved system operation.

Method and system of measurement and optimization of noise in servo systems

Identification of servo tracks is provided by adding one or more additional symbols to the write elements of at least some tracks on a servo recording head. The additional symbols are ignored for timing purposes, as they are not necessarily symmetrical, but the added symbols provide identification by their alterations on the otherwise identical patterns.

Timing based servo pattern incorporating band encoding

A method for correcting data track placement in a magnetic tape drive is provided. The invention comprises writing at least one data track on a magnetic tape, wherein the data track is written in a location determined by tracking a servo track on the tape. The tape drive reads the data track(s) at a plurality of offset positions, wherein each offset position is determined by deviating the servo track a specified distance from a servo reader. An optimal offset position is then determined based on collected read error data versus offset position data. During subsequent write operations, tapes are offset according to the optimal offset position.

Method for write track placement correction

A system and method for recovering from write errors during writing of a moving storage medium suspend write current while allowing the storage medium to continue moving. The system and method continue to format data for writing while the write current is suspended and resequence the data for subsequent storage. Information is recorded to distinguish previously written data from current data with error correction pointers adjusted accordingly. Write errors may be detected in a track following streaming tape system based on data errors from a read back check or based on positioning errors of a read/write head servo system, for example. By allowing the storage medium to continue moving through the error event, the system and method improve speed, capacity utilization, and throughput of the storage and retrieval process.

System and method for recovery from writing errors during data storage

A magnetic tape head assembly comprised of read and write elements and servo readers placed asymmetrically about the center of the head taken perpendicular to the direction of tape motion is provided. The tape head is capable of reading and writing in two directions of tape motion.

Asymmetric servo reader placement in bi-directional tape head

A servo track write head writes low frequency transitions for fine transverse positioning and high frequency fields providing additional information. The servo track write head includes a first write gap with at least one gap section at a first angle relative to a tape direction. A second write gap has at least one gap section at a second angle, not equal to the first angle. The first and second write gaps write low frequency transitions in each servo frame. A third write gap writes high frequency transitions in each servo frame.

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Boulder, CO, United States of America

Steven Gregory Trabert