International Business Machines Corporation

Randy Clark Inch

Nhan Xuan Bui

Kevin Bruce Judd

Eiji Ogura

Kazuhiro Tsuruta

Reed Alan Hancock

Ernest Stewart Gale

Mark Alfred Lantz

David Lee Swanson

David H F Harper

Pamela Ruth Nylander-Hill

Tomoko Taketomi

Kevin Dale Butt

Steven Michael Wallace

Dale A Christiansen

Angeliki Pantazi

Paul Merril Greco

Junichi Fukuda

Tsuyoshi Miyamura

Armando Jesus Argumedo

David Harper

Giovanni Cherubini

Simeon Furrer

James Mitchell Karp

Hirokazu Nakayama

Paul Merrill Greco

John Alexander Koski

Shawn Owen Brume

Jonathan Edward Bosley

David Franklin DeHaan

James J Howarth

Shuhei Nadehara

Katherine S Tyldesley

Carlos Jacobo Lujan

John Struble

Provided are a controller, tape drive, and method for determining a lateral position at which to move a tape head. The tape head, comprising a first module having a first servo reader and a second module having a second servo reader, is rotated to rotate the second servo reader at skew angles with respect to the first servo reader. A determination is made of estimated lateral positions of the second reader at the skew angles. Expected lateral positions of the second servo reader at the skew angles are calculated from a calculated distance between the first and the second servo readers and the skew angles. Lateral error offsets, comprising differences of estimated lateral positions and expected lateral positions at the skew angles, are added to an error offset data structure used to adjust a target lateral position at which to position the tape head.

Determining lateral error offsets to adjust a lateral position at which to move a tape head with respect to a tape medium

A method for characterizing a magnetic recording tape, according to one approach, includes measuring, using a magnetic head having servo readers of known pitch, a servo band difference at various locations along a length of a magnetic recording tape. The servo band difference measurements and/or derivatives thereof are stored in association with the magnetic recording tape. This procedure creates a characterization of the magnetic recording tape that is useful for assessing aging of the magnetic recording tape, as well as improving subsequent reading and/or writing operations.

Management of head and media dimensional stability

In one embodiment, a method includes writing, using a magnetic head, a set of parallel shingled tracks onto a magnetic recording tape using specified drive parameters, changing one of the specified drive parameters, reading a set of selected data tracks on the magnetic recording tape using the changed drive parameter, changing a lateral head position while reading the set of selected data tracks using the changed drive parameter, comparing track error rates observed during reading at the different lateral head positions, selecting a reader offset value based on the comparing, and performing a further action using the selected reader offset value.

Calibration of writer offset using media dimensional stability

An apparatus, according to one embodiment, includes a magnetic head having servo readers of known pitch, a drive mechanism for passing a magnetic recording tape over the magnetic head, and a controller electrically coupled to the magnetic head. The controller is configured to measure, using signals from the magnetic head, a servo band difference at various locations along a length of the magnetic recording tape. The controller is also configured to cause storage of servo band difference information about the servo band difference measurements in association with the magnetic recording tape.

A tape drive-implemented method, according to one embodiment, includes: detecting a read error, and sending one or more instructions to perform a first re-read attempt on a portion of a magnetic tape corresponding to the read error. In response to determining that the first re-read attempt was unsuccessful, a range of tension settings is selected. A range of lateral offsets is also selected. Moreover, one or more instructions are sent to apply each unique combination of a tension setting from the range of tension settings and a lateral offset from the range of lateral offsets. For each of the unique combinations applied, one or more instructions are sent to perform a second phase re-read attempt on the portion of the magnetic tape corresponding to the read error. Furthermore, a determination is made as to whether the second phase re-read attempt was performed successfully for any of the unique combinations.

Behavioral model for dynamic tension compensation

A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether a temperature within the tape drive storage unit exceeds a threshold value. In response to determining that the temperature within the tape drive storage unit exceeds the threshold value, a determination is made of a direction of travel of a tape media within the tape drive storage unit. In response to determining that the direction of travel is a forward direction, a first cooling device is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the tape media passing by a read/write head within the tape drive storage unit.

Tape drive bearing temperature control

In one general embodiment, a method includes calculating a differential position value based on readback signals from at least two servo readers of a magnetic head reading servo tracks of a magnetic recording tape. The differential position value is compared to a previously-calculated differential position value. An action is performed in response to determining that the difference between the differential position value and the previously-calculated differential position value is in a predefined range. In another general embodiment, an apparatus includes a magnetic head having at least two servo readers, and a controller in communication with the servo readers. The controller is configured to detect a sudden change in a width of a magnetic recording tape based on a differential position value derived from relatively more current servo readback data and a second differential position value derived from relatively older servo readback data.

Tape damage detection

An apparatus configured to characterize a magnetic recording tape of a tape cartridge, according to one embodiment, includes a magnetic head having servo readers of known pitch, a drive mechanism for passing a magnetic recording tape over the magnetic head, and a controller electrically coupled to the magnetic head. The controller is configured to measure, using signals from the magnetic head, a servo band difference at various locations along a length of the magnetic recording tape of a tape cartridge. The controller is also configured to store the servo band difference measurements and/or derivatives thereof in association with the tape cartridge.

A method for characterizing a magnetic recording tape of a tape cartridge, according to one approach, includes measuring, using a magnetic head having servo readers of known pitch, a servo band difference at various locations along a length of a magnetic recording tape of a tape cartridge. The servo band difference measurements and/or derivatives thereof are stored in association with the tape cartridge. This procedure creates a characterization of the magnetic recording tape that is useful for assessing aging of the magnetic recording tape, as well as improving subsequent reading and/or writing operations.

A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether an absolute value of a channel offset exceeds a threshold value. In response to determining that the absolute value of the channel offset exceeds a threshold value, a direction of travel of the tape media is determined. In response to determining that the direction of travel of the tape media is a forward direction, a determination is made whether the channel offset is positive. In response to determining that the channel offset is positive, a left cooling device within the tape drive storage unit is powered on. The left cooling device lowers the temperature of a left guide roller and the tape media coming off a left tape storage reel prior to the media passing by a read/write head.

Tape drive temperature control for media dimensional stability

A determination is made whether read/write is enabled within the tape drive storage unit. In response to determining that read/write is enabled, a determination is made whether an absolute value of a channel offset exceeds a threshold value. In response to determining that the absolute value of the channel offset exceeds a threshold value, a direction of travel of the tape media is determined. In response to determining that the direction of travel of the tape media is a forward direction, a determination is made whether the channel offset is positive. In response to determining that the channel offset is positive, a first cooling device within the tape drive storage unit is powered on. The first cooling device lowers the temperature of a first guide roller and the tape media coming off a first tape storage reel prior to the media passing by a read/write head.

In one general embodiment, a method includes calculating a differential position value based on readback signals from at least two servo readers of a magnetic head reading servo tracks of a magnetic recording tape. The differential position value is compared to a previously-calculated differential position value. An action is performed in response to determining that the difference between the differential position value and the previously-calculated differential position value is in a predefined range. The differential position value is an average of differential position values for a set of samples, wherein the previously-calculated differential position value is an average of previously-calculated differential position values for a set of previously-obtained samples. In another general embodiment, an apparatus includes a magnetic head having servo readers and a controller in communication with the servo readers. The controller is configured to detect a sudden change in a width of a magnetic recording tape.

A tape drive-implemented method, according to one embodiment, includes: detecting a read error, determining whether a current tension setting of the magnetic tape is accurate, determining whether the read error is part of an error burst in response to determining that the current tension setting of the magnetic tape is accurate, sending instructions to perform a first re-read attempt in response to determining that the read error is not part of an error burst, determining whether the first re-read attempt was performed successfully, selecting a range of tension settings in response to determining that the first re-read attempt was not performed successfully, selecting a range of lateral offsets, sending instructions to apply each unique combination of tension settings and lateral offsets, for each of the unique combinations applied, sending instructions to perform a second phase re-read attempt, and determining whether the second phase re-read attempt was performed successfully.

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Tucson, AZ, United States of America

Randy Clark Inch