Quantum Corporation

Seagate Removable Storage Solutions LLC

Hewlett-packard Development Company, L.P.

Certance LLC

Ming-Chih Weng

Turguy Goker

Ashok Babubhai Nayak

James Mark Decot

Umang Mehta

Ryan Taylor

Jerry Hodges

Carl R Hoerger

John Anthony Hamming

Kempton William Redhead

Charles E Kinney

John Ycas

Jeff McAllister

Minh Vu

Matt Barsotti

A media drive includes a head, a servo signal processing circuit, an actuator and a processor. The head is positioned near a data storage medium, and includes a servo element. The servo signal processing circuit is coupled to the servo element to output a position error signal. The actuator controls a position of the head relative to the data storage medium. The processor communicates with the actuator and the servo signal processing circuit. The processor provides a filtered position error signal to the actuator to compensate for a position displacement between the head and the data storage medium. The filtered position error signal includes a sum of outputs from a first compensation filter and a second compensation filter that is each applied to the position error signal output. The compensation filters attenuate disturbance frequencies that contribute to the position displacement. Each of the compensation filters has a sampling rate relating to the respective disturbance frequency. In one embodiment, the disturbance frequencies are fixed frequencies. Alternatively, the first disturbance frequency is a fixed frequency and the second disturbance frequency is a dynamic frequency. Still alternatively, the disturbance frequencies are dynamic frequencies.

Adaptive disturbance compensation with multi-rate synchronized sampling

A head rotator assembly () for dynamically compensating for a tape skew of a storage tape that moves over a head () in a tape drive () comprises a head supporter () that is coupled to and supports the head (), and a supporter mover assembly (). The supporter mover assembly () includes a first actuator (A) that indirectly rotates a portion of the head supporter () about an axis to move the head () in an azimuth direction relative to the storage tape to dynamically compensate for the tape skew as the storage tape moves over the head (). Additionally, the supporter mover assembly () can include a first lever (A) moved by the first actuator (A) to rotate the portion of the head supporter () so that the head () moves in the azimuth direction relative to the storage tape to dynamically compensate for the tape skew.

Head rotator assembly for tape drive

A head rotator assembly for positioning a head of a tape drive relative to a storage tape that moves over the head comprises a head supporter and a supporter mover assembly. The head supporter is coupled to and supports the head. The supporter mover assembly includes a first actuator that indirectly rotates a portion of the head supporter about an axis to move the head in an azimuth direction relative to the storage tape as the storage tape moves over the head. The supporter mover assembly can further include a first lever. The first actuator moves the first lever to rotate the portion of the head supporter so that the head moves in the azimuth direction relative to the storage tape.

An apparatus and method for providing adaptive disturbance compensation with multi-rate synchronized sampling is disclosed herein. The dynamic disturbance occurring in a media drive during read/write operations is attenuated using the adaptive disturbance compensation scheme. A plurality of compensation filters are used, each of the compensation filters configured to attenuate a disturbance caused by a particular source within the media drive. Each of the compensation filters is computed based on a sampling rate relevant to the respective disturbances.

A tape drive () that receives a tape cartridge () having a tape () comprises a tape head () and a control system (). The tape head () transfers data between the tape drive () and the tape (). The control system () utilizes linear parameterization to control the position of the tape head () relative to the tape (). The control system () can include a compensator (J) and a filter (Q). The compensator (J) is a combination of the information contained in a nominal control system (A) and the information contained in a model of the servo system (B). The model of the servo system (B) estimates system disturbances that affect the tracking ability of the control system (). The filter (Q) filters the estimated system disturbances to generate a filtered system disturbance signal. The filtered system disturbance signal is then used to adjust the output of the compensator (J). Additionally, the control system () can utilize Youla-Kucera parameterization to control the position of the tape head () relative to the tape (). Further, the control system () controls the position of the tape head () relative to the tape () without the use of a feed-forward sensor.

Control system for tape drive to compensate for system disturbances without use of feed-forward sensor

A head rotator assembly () for positioning a head () of a tape drive () relative to a storage tape includes a head supporter () and a supporter mover assembly (). The head supporter () is coupled to and supports the head (). The supporter mover assembly () rotates a portion of the head supporter () about an axis () to move the head () in an azimuth direction relative to the storage tape as the storage tape moves over the head (). The head rotator assembly () includes a controller () that controls movement of the supporter mover assembly () based on a positioning signal. The supporter mover assembly () can include a first actuator (A) that moves a first lever (A) to rotate the head supporter () to move the head () in the azimuth direction. The first actuator (A) biases the first lever (A) to rotate part of the head supporter () to move the head in the azimuth direction.

In a method of electronically measuring reader/writer offset in a tape drive head, a plurality of sequentially adjacent data tracks are written on a tape with a write head. Error rate information is measured while reading a data track of the plurality of sequentially adjacent data tracks with a read head of the tape drive. A bathtub shaped curve is built from a set of the error rate information which is accumulated by reading the data track at a plurality of offsets of the read head relative to the data track. Offset of the read head relative to the write head is measured by determining an offset of the read head which correlates to a magnetic center of the data track as represented by a center point between edges of the bathtub shaped curve.

Measuring reader/writer offset in a tape drive head

An actuator assembly () for positioning a head () of a tape drive () relative to a storage tape that moves along a tape path () includes a first actuator (), a second actuator () and a controller (). The actuators () move the head () in a direction that is substantially perpendicular to the tape path. The first actuator () is mounted to the second actuator () at a location that is based on a position of a resonance node () of the second actuator (). The controller () controls linear positioning of the first actuator () and the second actuator () relative to the storage tape on a closed-loop basis. The actuators () can each include voice coils (). The second actuator () can include two positioner guides (A,B) that are configured in a substantially collinear configuration or in a triangular configuration with the head (). The first actuator () can include an isolation boot () that decreases vibration of the first actuator () caused by vibration of the second actuator (). The actuators () can have resonance frequencies that are different from one another. The first fundamental resonance frequency can be tuned based on the second resonance frequency to decrease a correlation between the resonances of the actuators ().

Dual stage head actuator assembly for tape drive

In a method of electronically measuring reel off-center run-out and reel hub mismatch, tape speed data related to a tape coupled with an operating drive reel is electronically measured. The tape speed data is correlated with drive reel rotation angles. The correlated tape speed data is translated to drive reel hub radii variations with respect to the drive reel rotation angles. The drive reel hub radii variations comprise an operational measure of reel off-center run-out and reel hub mismatch of the drive reel.

Electronic measurement of off-center run-out and reel-hub mismatch

In a method of multi-rate tracking with a multi-actuator servo control, a track position error is sampled at an asynchronous sample rate for operating a first actuator. The track position error is also sampled at a synchronous sample rate for operating a second actuator. The sampling from the synchronous sample rate is utilized to reduce a delay associated with the sampling at the asynchronous sample rate.

Multi-rate tracking with a multi-actuator servo control

A servo-controlled, head actuator design that has low profile characteristics in both the height and width dimensions. The low height allows the actuator to fit into a half-high tape drive form factor. Additionally, in some implementations, the actuator comprises a smaller, concentrated moving mass coupled with a flexure construction having a narrowed width with added ribs for torsional stiffness. These aspects of the actuator provide a higher second mode of vibration compared to the flexure designs of the prior art. The actuator includes a coarse actuator assembly for larger movements of the head, and a fine actuator, including a Voice coil motor, responsive to analysis of servo signals. In some embodiments, the voice coil motor of the fine actuator and the coarse actuator shafts are in line. Since the centerlines of the shafts are in-line with the voice coil motor, the resonance response of the shaft spring-mass system is reduced.

Narrow width actuator for tape drive systems

The present invention, in particular embodiments, is directed to methods, apparatuses and systems that facilitate recording of servo signals on a recording medium such as magnetic tape with high accuracy. Variation of inter-frame and intra-frame placement is substantially reduced by writing successive frames or sub-frames based on a detection of a previously-written frame or sub-frame by a read element. Appropriate placement of the read element in relation to servo write elements, on a multi-gap servo write head, ensures the correct placement of subsequent frames on the recording medium.

Servo writing and decoding position error signal for linear tape drives

The claimed embodiments provide methods, apparatuses and systems directed to a servo-actuated positioner for a read/write head that uses a piezoelectric super fine actuator that moves the read/write head to maintain alignment with data tracks on a magnetic tape. The servo-actuated positioner, in one implementation, uses flexures to mechanically support the read/write head. Piezoelectric elements are attached to the flexures in strategic locations to effect movement of the read/write head when the elements are actuated. This configuration achieves a large actuator motion using small piezoelectric elements. Additionally, manufacturability is improved since the piezoelectric elements, which are typically brittle, are attached to the mechanically robust flexures.

Piezoelectric micro-actuator for magnetic tape read/write head

An example embodiment provides for an apparatus and method, for use in a tape drive system, that supplies tape azimuth error information transduced from servo read elements that are located on differing bumps of a magnetic read/write head. Non-azimuth error information is also transduced from servo read elements located on a read bump. The azimuth error and non-azimuth are utilized to correctly place the magnetic head at a currently selected track of the tape for which data is being written. In one implementation, the servo read elements utilized for transducing the azimuth information are substantially aligned with each other relative to a tape path and disposed on separate bumps. In another implementation, the servo read elements utilized for transducing the azimuth information are not substantially aligned with each other and are disposed diagonally on opposite bumps.

Azimuth compensation using combination bump pes detection

A tape drive is provided having a pair of stationary guide assemblies disposed symmetrically about the magnetic read/write head. Each of the stationary guide assemblies has a mounting portion and a separate guide surface portion mounted on the mounting portion. The mounting portion may be made of a plastic and the guide surface portion of a ceramic, for example. A spring arrangement with pressure pads is mounted directly on the mounting portion, and applies pressure to a top edge of a tape during guiding of the tape.

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Los Angeles, CA, United States of America

Ming-Chih Weng