International Business Machines Corporation

Other

David Lee Swanson

Alex Chliwnyj

Ernest Stewart Gale

Randy Clark Inch

Steven Carter Wills

Kevin Bruce Judd

Nhan Xuan Bui

Gilbert Trick

Icko E T Iben

Said Abdullah Ahmad

Jason Liang

Tomoko Taketomi

Illarion Borisevich

Eiji Ogura

James Mitchell Karp

Raymond Yardy

Pamela Ruth Nylander-Hill

Paul Merril Greco

Scott Milton Fry

David Michael Davis

Khanh V Ngo

Shawn Owen Brume

Fahnmusa Christian Jangaba

Christine Renee Knibloe

Gilbert L Smith

Christopher Robert Pandolfo

Mark Alfred Lantz

Simeon Furrer

Hugo Eric Rothuizen

Lee Curtis Randall

David H F Harper

Josephine F Bayang

Wlodzimierz Stanley Czarnecki

Edward George Butt

Mark Edward Hill

Josephine Faith Bayang (Kubista)

Georg Lothar Lauhoff

Stella Brach

Renee Marshall

A tape head adapted to 32-, 64-, and 128-channel operation is provided. A plurality of elements is provided, numbering N, comprising first and second sets of 64 evenly-spaced elements, each set comprising at least a first element and a last element. A plurality of servos is provided, comprising at least a first through sixth servo. The 64 evenly-spaced elements of each set are separated by an element pitch (W). The evenly-spaced elements and plurality of servos are spaced as set forth herein.

Tape head wafer design for multiple formats using same tape

Provided are a computer program product, device, system, and method for single data band data storage. In one embodiment, a tape head module has an array of four servo transducer elements for each servo band of a tape and an array of reader/writer transducer elements extending over most of the width of the tape. In another embodiment, a data storage tape has a top servo band positioned adjacent a top edge guard band of the tape, a bottom servo band positioned adjacent a bottom edge guard band of the tape, and a single data band positioned between the top and bottom servo bands and configured to receive tracks of data written by a tape head wherein the single data band width extends over most of the tape width.

Single data band data storage

A method, in accordance with one aspect of the present invention, includes writing, by a tape drive, data tracks to a data band of a magnetic tape having servo bands flanking the data band, the writing being performed using a magnetic head that is not designed for a format of the magnetic tape. An effective pitch of servo readers of the magnetic head used simultaneously during the writing matches a servo reader pitch specification of the format of the magnetic tape. An average effective pitch of write transducers of the magnetic head is greater than a data track pitch specification of the format of the magnetic tape.

Magnetic tape reuse across products

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

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

In one general embodiment, a method for selecting parameters of an error recovery procedure includes detecting an error during performance of a data operation on a data storage medium by an apparatus. In response to detecting the error, parameters of an error recovery procedure are selected based at least in part on: (a) first information about previous interactions between the apparatus and multiple data storage media, and (b) second information about previous interactions between the data storage medium and other apparatuses.

Adjusting error recovery procedure (ERP) in data drive based on historical ERP information

A tape may be mounted into a tape drive. Mounting the tape into the tape drive may include loading the tape from a storage slot. The tape drive may request a first record of the tape from a tape storage subsystem. The tape drive may determine whether the first record of the tape exists in the tape storage subsystem. The tape drive may load the first record of the tape in random access memory (RAM) of the tape drive. The first record may include one or more data entries. The tape drive may append a new data entry to the first record. The first record may be transitioned to a second record upon being appended with the new data entry. The tape may be unmounted from the tape drive.

Automatic volume statistical and performance information tracking

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

Provided are a tape drive, tape drive controller, and method for measuring amplitudes of written tracks to determine errors in read and write elements. The write element writes a data pattern and erase pattern to the tape medium to provide the data pattern and the erase pattern on sides of the data pattern. The read element is positioned to measure amplitudes at offsets in the data pattern. The offsets and the amplitudes at the offsets are processed to estimate a maximum amplitude read while the read element is estimated to be positioned entirely in the data pattern and estimate an offset at which the read element reads a fixed percentage of the maximum amplitude. A width of the read element is estimated based on the estimated offset. The estimated width of the read element is outputted to determine whether the estimated width of the read element is acceptable.

Measuring amplitudes of written tracks in a tape drive to determine errors in read and write elements in the tape drive

A method includes determining whether a tunneling magnetoresistance (TMR) sensor is corroded using resistance, amplitude and signal to noise ratio (SNR) measurements of the sensor. A method to determine whether a TMR sensor is corroded includes determining an expected initial resistance value, Rand measuring a resistance value, R, of the sensor. The method includes calculating a ratio of the Rvalue and the expected initial resistance value, Rand determining whether the ratio is in a predefined range for the TMR sensor. In response to determining that the ratio of the sensor is within the predefined range, the method includes outputting an indication that the TMR sensor is corroded. In response to determining that the ratio of the sensor is outside the predefined range, the method includes outputting an indication that the TMR sensor is not corroded.

Setting bias currents and limiting corrosion in TMR sensors

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

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 computer-implemented method includes: determining a reading performance of a head at a commanded lateral reading location; adjusting a location of the head relative to a medium by moving the head in a first lateral direction to an adjusted lateral reading location; determining a reading performance of the head at the adjusted lateral reading location, and determining whether the reading performance at the adjusted lateral reading location is better than the reading performance at the commanded lateral reading location. In response to determining the reading performance is better at the adjusted reading location, the method includes iteratively repeating the adjustment of the location of the head until the reading performance of the head at a current iteration is worse than the reading performance of the head at an immediately previous iteration. Corresponding systems and computer program products are also disclosed.

Dynamically optimizing read performance by adjusting servo-based head location

A method, according to one embodiment, includes writing a plurality of shingled tracks using an array of writers. The array of readers is repositioned to various locations between first and second positions and data is read from the shingled tracks at the various locations. A read offset point where read performance is about the highest during the reading performed when repositioning the array of readers between the first and second positions is determined. The method includes computing, using the read offset point, data describing a lateral writing position to use during writing such that shingled tracks are written in a location specified by a format. As a result, methods according to the present embodiment are able to provide desirable track alignment and reduced readback error rates for data of shingled tracks written to magnetic medium.

Growing community of inventors

Tucson, AZ, United States of America

David Lee Swanson