Minnesota Mining and Manufacturing Company

Imation Corporation

Robert J Youngquist

Theodore A Schwarz

Hung Thien Tran

Richard W Molstad

Durkee B Richards

James S Anderson

Bennett G Dy

Christopher L Hill

Michael E Hamerly

Robert W Tapani

Richard E Jewett

John Eric Heinz

Leroy A Kuta

Gary D Moeller

Robert E Wolff

Alan R Olson

John A McCracken

Michael J Kelly

Noel L Allen

Tim Ngo

George L Chavez, Jr

Harvey J Richardson

Richard S Mansfield

Michael Kelly

A tape servo system includes tape having bands of tracks including at least one data band having a plurality of data tracks of track pitch P and a servo band dedicated for servo information. The servo band includes two or more noncontiguous servo tracks with each pair of adjacent servo tracks of the two or more noncontiguous servo tracks having a center to center separation equal to M*P, wherein M for each pair of adjacent servo tracks may be any integer&gE;2. The system may further include a head assembly having a single magnetoresistive read element tapped to provide at least (K&plus;1) tapped servo read elements for use in reading servo information written to the servo band; wherein K is equal to the integer M for the pair of adjacent servo tracks having the greatest center to center separation and a repositioning assembly for repositioning the head assembly as a function of the servo information. Further, the center to center separation between pairs of adjacent servo tracks of the two or more noncontiguous servo tracks may be different for at least two pairs of adjacent servo tracks. A servo tracking data recording tape with two or more noncontiguous servo tracks having center to center separation between pairs of adjacent servo tracks being different for at least two pairs of adjacent servo tracks is also provided along with a method for servo track identification for use therewith. Further, track read/write head assemblies wherein the servo read and write elements are along the same gap lines as the data read and write assemblies, respectively, are provided.

Head assembly having a single pass servo writer

A servo track recording tape includes a plurality of data tracks and a servo band dedicated for servo information. The servo band includes substantially uniformly written servo carrier information across a predetermined servo carrier width along the length of the tape with at least one encoded track pitch defined therein. Each encoded track pitch has alternating erased and non-erased portions along the length of the tape for defining servo tracks. The alternating erased and non-erased portions of the at least one encoded track pitch include encoded information provided by varying the length of one or more of the erased portions. The encoded information may be representative of tape locations along the length of the tape. The servo band may include two or more encoded track pitches defined in the substantially uniformly written servo carrier information with each encoded track pitch defining corresponding servo tracks. The alternating erased and non-erased portions of each of the two or more encoded track pitches may include encoded information uniquely identifying the corresponding servo tracks. Another servo tracking data recording tape includes a servo band including at least one single frequency servo track written in an erased width of the servo band along the length of the tape. The single frequency servo track includes encoded blocks of information along the length of the tape representative of at least one characteristic of the tape. Systems, head assemblies and encoding methods for use in providing such encoded servo track recording tape configurations are also described.

Encoded servo track configurations, servo writer and systems/method

A tape servo system includes tape having bands of tracks including at least one data band having a plurality of data tracks of track pitch P and a servo band dedicated for servo information. The servo band includes two or more noncontiguous servo tracks with each pair of adjacent servo tracks of the two or more noncontiguous servo tracks having a center to center separation equal to M * P, wherein M for each pair of adjacent servo tracks may be any integer .gtoreq.2. The system may further include a head assembly having a single magnetoresistive read element tapped to provide at least (K+1) tapped servo read elements for use in reading servo information written to the servo band; wherein K is equal to the integer M for the pair of adjacent servo tracks having the greatest center to center separation and a repositioning assembly for repositioning the head assembly as a function of the servo information. Further, the center to center separation between pairs of adjacent servo tracks of the two or more noncontiguous servo tracks may be different for at least two pairs of adjacent servo tracks. A servo tracking data recording tape with two or more noncontiguous servo tracks having center to center separation between pairs of adjacent servo tracks being different for at least two pairs of adjacent servo tracks is also provided along with a method for servo track identification for use therewith. Further, track read/write head assemblies wherein the servo read and write elements are along the same gap lines as the data read and write assemblies, respectively, are provided.

A method for providing information about the characteristics of a length of magnetic tape to a tape drive without the use of a separate sensor. The drive has a scanning read/write head that is capable of reading/writing on data tracks on the tape which span at least a portion of the width of the tape. A pattern of magnetically polarized stripes is provided on the tape. The stripes extend along the length of a portion of the tape and are polarized substantially transversely to their length. As the tape is driven past a read/write head, the head reads the pattern on the tape, and decodes the information in the pattern. The drive can then respond as appropriate to the information to facilitate the reading/writing of data on the tape.

Method of identifying magnetic tape characteristics

A tape servo system includes tape having bands of tracks including at least one data band having a plurality of data tracks of track pitch P and a servo band dedicated for servo information. The servo band includes two or more noncontiguous servo tracks with each pair of adjacent servo tracks of the two or more noncontiguous servo tracks having a center to center separation equal to M*P, wherein M for each pair of adjacent servo tracks may be any integer .gtoreq.2. The system may further include a head assembly having a single magnetoresistive read element tapped to provide at least (K+1) tapped servo read elements for use in reading servo information written to the servo band; wherein K is equal to the integer M for the pair of adjacent servo tracks having the greatest center to center separation and a repositioning assembly for repositioning the head assembly as a function of the servo information. Further, the center to center separation between pairs of adjacent servo tracks of the two or more noncontiguous servo tracks may be different for at least two pairs of adjacent servo tracks. A servo tracking data recording tape with two or more noncontiguous servo tracks having center to center separation between pairs of adjacent servo tracks being different for at least two pairs of adjacent servo tracks is also provided along with a method for servo track identification for use therewith. Further, track read/write head assemblies wherein the servo read and write elements are along the same gap lines as the data read and write assemblies, respectively, are provided.

Tape servo system and methods, write/read heads, and servo track

A track pitch error compensation system for tape drives of the type configured for reading data from and/or writing data to magnetic tape having adjacent servo tracks with apparent centerlines spaced about a tracking axis. The tape drive includes a multichannel head assembly having a plurality of channels of read gaps which produce position error signals (PES) representative of positions of the read gaps on the tracking axis with respect to the apparent centerlines of servo tracks on the tape, a positioner responsive to positioner drive signals for driving and positioning the head assembly on the tracking axis with respect to the servo tracks, and a servo control system connected between the head assembly and positioner for generating positioner drive signals causing a servoing read gap to be servo locked to a desired servo track as a function of the PES when operated in a closed-loop servo mode. The method includes determining and storing one or more track pitch error values for each magnetic tape, and determining a gain constant of the servo system. PES correction offsets representative of the magnitudes of positioner drive signals causing the positioner to drive the head assembly distances sufficient to compensate for the track pitch errors are calculated as a function of the track pitch errors and the gain constant, and stored. During closed-loop servo mode operation the PES correction offset is summed with the PES to cause the servoing read gap to be servo locked to the desired centerlines of the servo tracks.

Track pitch error compensation system for data cartridge tape drives

A track control method for a data cartridge tape drive which includes a multichannel head assembly, a positioner for controllably positioning the multichannel head assembly transversely to a transport path for a tape driven by the drive, and drive electronics responsive to a carrier servo signal. The track control method initializes the data cartridge tape drive by operating the positioner to move the head assembly to a preselected transverse position. Next, the tape is moved along the transport path and the positioner is moved to substantially minimize a feedback signal derived from the carrier servo signal. The head assembly is stepped a first predetermined number of steps in a first transverse direction until the carrier servo signal is not detected. If the carrier servo signal is not detected, then the positioner is stepped so as to move the head assembly a second predetermined number of steps in a second transverse direction to locate a reference track.

Track servo control method for data cartridge tape drives

A direct file access system for a magnetic tape where all data files begin at a designated location on the tape. The direct file access system may be used with a reduced rewind data configuration to decrease data access time. The reduced rewind data configuration divides data files into generally equal portions so that data files begin and end at the designated location on the tape, eliminating rewind sequences. A method and system for reducing the number of tape retensioning passes is included to further decrease access time.

Direct file access system for magnetic tape

A head-track orienting system for use in magnetic recording tape drives is disclosed which automatically corrects for misalignment between the head assembly and a recorded servo track on the tape. Using a servo control loop, the system calculates head-track alignment error during operation of the tape drive and either pivots the head assembly or adjusts the tape cartridge to compensate for the error. Transverse head-track positioning mechanisms are also included in the system to locate and maintain a centered position of the heads on the servo track.

Head-tape alignment system and method

A mechanism for accurately positioning a recording/playback head on the center of a track including a stepper motor and coil assembly in combination controlling coarse and fine transverse head position. The coil is attached to a pivoting actuator arm which provides a mounting member for a recording/playback head. A torsion spring is attached to the actuator arm and to a stage which is driven by a stepper motor lead screw to incrementally position the actuator arm. The coil assembly operates to pivot the recording/playback head transversely, thereby providing fine position control, and is mounted together with other members at either sides of a pivot axis to provide a dynamically balanced structure.

Balanced cantilevered head positioning mechanism for multitrack tape

This invention relates to a magnetic recording head assembly and method enabling an end user to record a unique servo control track on a magnetic recording tape while the tape is in the recorder to be used for recording and playback of computer data. Previously, most such control tracks were applied only at the time of manufacture of preformatted media. The head assembly includes, in addition to a plurality of sets of read/write transducers, a servo write head having an extended transverse width for uniformly recording a servo signal across the width of a servo track section, and a servo erase head having a plurality of alternating erasing and non-erasing sections adapted to controllably erase portions of the previously recorded servo signal, resulting in unique servo control tracks.

Servo positioning system for magnetic recording media

A digital recording system utilizing a magnetoresistive transducer in a magnetic recording head. The system measures the amplitude of an output signal, E.sub.o, from the transducer for various bias currents as a recorded magnetic media passes by the head. The system then determines the bias current for which the output signal, E.sub.o, is maximized and multiplies that bias current by a suitable factor. The system then operates at the calculated bias current level, thereby minimizing the error rate of the system.

Method and system for minimizing the error rate of a digital recording

An adjustable write-equalized recording circuit for recording data onto a magnetic tape. The circuit variably adjusts the amplitude of write-equalization pulses relative to the data waveform by an amount that can be either preset or determined during operation.

Method and apparatus for amplitude compensated write equalization

A mechanism for accurately following the center of a track includes a voice coil, or a voice coil and stepper motor in combination. The voice coil and stepper motor combination operate to variably position a recording head transversely with respect to the width of the recording tape. The mechanism enables head positioning with very close tolerances due to the ability of the voice coil to finely position the head very accurately on the center of a track.

Combined stepper motor and voice coil head positioning apparatus

This invention relates to a magnetic recording head assembly and method enabling an end user to record a unique servo control track on a magnetic recording tape while the tape is in the recorder to be used for recording and playback of computer data. Previously, most such control tracks were applied only at the time of manufacture of preformatted media. The invented head assembly includes, in addition to a plurality of sets of read/write transducers, a servo write head having an extended transverse width for uniformly recording a servo signal across the width of a servo track section, and a servo erase head having a plurality of alternating erasing and non-erasing sections adapted to controllably erase portions of the previously recorded servo signal, resulting in unique servo control tracks.

Growing community of inventors

White Bear Lake, MN, United States of America

Robert J Youngquist