Abstract: A method and system for rewriting data on a tape when an error occurs during an initial write operation. When the initial write error occurs, the data is rewritten at a location that is a pre-defined block gap distance from the last valid write location on the tape. By measuring the length of the pre-defined block gap distance, the cause or causes of the write error or errors are known. Thus, the pre-defined block gap not only ensures that the data is not re-written in a no-write zone of the tape, due to the zone known to be error prone, but a historical record of past write errors is logged based on the length of the block gaps.

Abstract: A servo write head for magnetic tape is provided. The invention includes first and second non-magnetic substrates and first and second magnetic layers deposited between the non-magnetic substrates. A middle non-magnetic substrate is then deposited between the first and second magnetic layers and forms the magnetic gap. In one embodiment, non-magnetic protective layers are placed between the middle substrate and magnetic layers and form part of the gap. A contoured top layer of magnetic material is deposited across the other layers and substrates and has at least one recording gap, and wherein the top layer forms a magnetic pattern for writing a servo pattern to the tape.

Abstract: A method of positioning a selected recording channel on a recording head relative to an optical servo system includes positioning the optical servo system at a first position relative to the selected recording, processing an alignment tape to determine a lateral offset between the optical servo system and the selected recording channel and positioning the optical servo system at a second position relative to the selected recording channel using the lateral offset. An alignment tape is also provided, which includes an elongated continuous web of flexible plastic substrate material having two edges and defining a front major surface and a back major surface, a magnetic storage medium formed on the front major surface, an inert medium formed on the back major surface and a track of alignment voids for indicating actual lateral displacement of the selected recording channel relative to the optical servo system.

Abstract: In a magnetic tape system, during lateral repositioning of a tape head between servo bands, the servo head is not on a servo band and is unable to provide servo position information. Hence, information about the lateral position may be lost. A control system selectively senses data read transducers of the tape head; and, upon detecting a servo signal of a servo band from a sensed data read transducer, determines the lateral position of the tape head with respect to the detected servo band based upon the position of the data read transducer that sensed the detected servo signal.

Abstract: Disclosed are a system, a method, and article of manufacture to provide for filtering a servo signal in a tape drive using a matched filter that is optimized for the operating tape velocity of the tape drive. A servo controller for track following on a tape uses a digital filter implementation of the matched filter to produce a filtered servo signal. The digital filter is optimized for different tape velocities by selecting digital filter coefficients for the digital filter that depend upon the tape velocity presently in use. The filtered servo signal is used by the servo controller to provide improved track following in a tape drive.

Abstract: In magnetic tape having separate longitudinal servo bands of servo information with superimposed data information, the separate servo bands have selected different superimposed data information, to identify the separate servo bands for independent addressability. The servo information comprises non-parallel laterally extending transitions to indicate lateral positioning, and the selected different superimposed data information may comprise a lack thereof in portion(s) of the servo bands. Where the superimposed data information is longitudinal position information of the tape, the selected different superimposed data information may comprise different longitudinal position information of one or more servo band(s). The selected different superimposed data information may comprise a band identifier in the superimposed data information of one or more of the servo bands.

Abstract: A head-track alignment system and method. An embodiment of the system comprises: a head assembly capable of detecting arrival of servo frames in a first and second servo track of a tape; an alignment processor coupled to the head assembly generating a head-track alignment signal based on a comparison of the arrival times of the servo frames in the first and second servo tracks; and wherein the head-track alignment signal can be generated while accessing the tape. An embodiment of the method comprises: determining tape tilt with respect to a head assembly of a tape drive while accessing a tape, and compensating for the tape tilt.

Abstract: A timing based servo alignment system that uses a set of band identification marks to determine which data band is being currently read. The system uses a read module having a plurality of band identification read elements. The band identification read elements are placed on the read module such that each band identification read element is aligned only to the band identification marks when a corresponding data band is aligned to the data read element.

Abstract: A method, system and program for mitigating the effects of one or more inoperable servo readers used for data track positioning on a tape drive are disclosed. A track following servo system can compensate for an inoperable servo reader by collecting and measuring tape distortion information from the tape involved. The track following servo system can quantify the tape distortion information and produce a tracking offset value. The track following servo system can then position an operable servo reader over the tape with the compensating offset value applied.

Abstract: 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.

Abstract: A servo control method controlling the position of a magnetic head in order to record/reproduce a data on/from a magnetic tape having a number of servo tracks, is performed along the following manner. First, a servo signal is written to each servo track of the magnetic tape. Next, a position in the with direction of the magnetic head is adjusted based on the servo signal written on the magnetic tape when performing the record/reproduce of a data on/from the magnetic tape. Next, the servo signal written on each of two servo tracks is read simultaneously. Here, the two servo tracks are selected among a plurality of servo tracks provided in the magnetic tape. Finally, the position in the width direction of the magnetic head is determined based on two servo signals, which are written on one servo track and another servo track of the above selected two servo tracks, respectively.

Abstract: 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.

Abstract: A method to erase a magnetic tape, where the magnetic tape is first mounted in a magnetic tape in a tape drive, where that magnetic tape includes a physical beginning of tape (“PBOT”), a physical end of tape (“PEOT”), and information written thereon between the PBOT and the PEOT. The method then establishes one or more critical areas located on the magnetic tape, attempts to erase the information, and determines if each of the one or more critical areas have been erased. In the event each of said one or more critical areas have not been erased, Applicants' method provides an error message.

Abstract: A system, method and an article of manufacture to provide more accurate magnetic tape servo operation are disclosed. Accurate measurements of the width of the servo pattern written on the magnetic tape are accomplished in the presence of relatively large motion of the magnetic tape. The accurate measurements of the width of the servo pattern are used to produce a corrected position error signal that provides improved servo track following to maintain the tape head at an optimal alignment for writing and reading data tracks on the tape.

Abstract: A device for precision alignment of a write element of a tape head to a transport direction of a media that is transported across the tape head is disclosed. The tape head includes at least one alignment element that is cofabricated with the write element so that both the write element and the alignment element have a fixed orientation with respect to a magnetic axis of the tape head. The alignment element and the write element can be fabricated on the tape head using standard microelectronic photolithographic processes. Preferably, the tape head includes a plurality of alignment elements. Those alignment elements are operative to write alignment transitions onto the media. The alignment transitions can be observed to determine if they are indicative of the write element having a predetermined orientation with respect to the transport direction.

Abstract: A method and apparatus to calibrate a servo sensor disposed on a tape head located adjacent a moving magnetic tape is disclosed where that magnetic tape includes at least one servo edge comprising an interface between a first recorded signal and a second recorded signal, and where the servo sensor provides a servo signal, and where an independent position sensor provides an IPS signal. The method first samples the servo signal and the IPS signal, calculates a transfer function, and forms a first calibration curve. The method then forms an average residual error value. If that average residual error exceeds the maximum allowable residual error, then the method applies an offset to the first calibration curve to form a second calibration curve. That second calibration curve is saved for subsequent use during, for example, read/write/erase operations.

Abstract: The servo signal recording device records a servo signal onto a magnetic tape. The device includes a transporting unit for transporting the magnetic tape along its lengthwise direction, a recording unit for recording the servo signal onto the transported magnetic tape, a detecting unit for detecting an edge of the magnetic tape at a time when the servo signal is recorded and an adjusting unit for adjusting a recording position of the servo signal along a crosswise direction of the magnetic tape in accordance with a detection result of the edge of the magnetic tape by the detecting unit. The servo signal verifying device verifies a servo signal recorded onto a magnetic tape.

Abstract: A method of aligning a magnetic read/write head to data tracks on a magnetic surface of a digital linear tape. The method includes writing a signal over a track of optical servo marks located on the magnetic surface of the tape with a servo channel writer, generating a position error signal from read back signals obtained from a servo channel reader and positioning the magnetic read/write head in accordance with the position error signal.

Abstract: A servo track configuration includes at least one servo track having a width. A servo pattern is repeatedly recorded in the at least one servo track. Repeatedly recording the servo pattern includes repeating the simultaneous recording of first and second reference pattern lines and a track pattern line in the at least one servo track. Each of the first and second reference pattern lines has an identical predetermined geometry and extends across the width of the at least one servo track. Further, the track pattern line has a predetermined geometry that is different than the predetermined geometry of the first and second reference pattern lines and extends across the width of the at least one servo track.

Abstract: A method to calibrate a transducer, whereby the transducer provides a first signal, and whereby a reference provides a reference signal. The first signal is sampled at a sampling rate comprising a reference frequency, and a digital measured first signal waveform is formed. The reference signal is sampled at the sampling rate, and a digital measured reference signal waveform is formed. The real and imaginary components of the measured first signal waveform are determined at (P) harmonics of the reference frequency. A filtered first signal waveform is formed using those real and imaginary components. The real and imaginary components of the measured reference signal waveform are determined at (P) harmonics of the reference frequency. A filtered reference signal waveform is formed using those real and imaginary components. A transfer function is formed using the filtered first signal waveform and the filtered reference signal waveform. A calibration curve is formed using that transfer function.

Abstract: A head-track alignment system and method. An embodiment of the system comprises: a head assembly capable of detecting arrival of servo frames in a first and second servo track of a tape; an alignment processor coupled to the head assembly generating a head-track alignment signal based on a comparison of the arrival times of the servo frames in the first and second servo tracks; and wherein the head-track alignment signal can be generated while accessing the tape. An embodiment of the method comprises: determining tape tilt with respect to a head assembly of a tape drive while accessing a tape, and compensating for the tape tilt.

Abstract: The invention is directed to a magnetic storage medium recorded with an amplitude-based servo pattern in which one or more first servo windows positioned above a centerline of a servo track have a different width than one or more second servo windows positioned below the centerline. The first servo windows may be larger or smaller than the second servo windows. In either case, by detecting the widths of the servo windows and detecting signal amplitude as a servo head passes relative to the servo track, servo tracking can be achieved without the use or need for additional synchronization marks in the servo pattern.

Abstract: A method to calibrate a servo sensor disposed on a magnetic tape head disposed adjacent a magnetic tape, where that magnetic tape includes at least one servo edge comprising an interface between a first recorded signal and a second recorded signal, whereby the servo sensor is capable of detecting that first recorded signal and that second recorded signal, and whereby an independent position sensor provides an IPS signal comprising the position of the tape head with respect to the tape path. Applicants' method determines and uses initial servo signal information and initial IPS signal information to determine an initial transfer function. That initial transfer function is used to determine a positioning signal where the tape head is alternatingly moved in a first direction and an opposing second direction along a first axis as the tape moves along a tape path such that the position of the magnetic head along the first axis as a function of time comprises a periodic function having the positioning signal.

Abstract: A method to calibrate a servo sensor disposed on a magnetic tape head disposed adjacent a magnetic tape moving along a tape path. The method measures a maximum and a minimum servo signal ratio, establishes target maximum and minimum servo signal ratios, and determines if the measured servo signal ratios include the target ratios. If the measured servo signal ratios include the target servo signal ratios, then the method forms a filtered servo signal waveform using the measured servo signal waveform. The method then uses the filtered servo signal waveform to calculate a transfer function which is saved for subsequent track following.

Abstract: An apparatus and method to read and/or write information from and/or to a moving magnetic tape comprising one or more servo edges using a tape head comprising (N) servo sensors. Bach servo edge comprises an interface between a first recorded signal and a second recorded signal, where each of the (N) servo sensors detects that first recorded signal and that second recorded signal. The method calculates (N) target PES signals and provides (N) measured PES signals. Using the target and the measured PES signals, the method forms (N) weighted PES signals and averages those (N) weighted PES signals to form a Composite PES signal. That Composite PES signal is used to position the tape head.

Abstract: A magnetic tape drive has a servo head for performing the tracking control and a head unit. The head unit includes a recording head group composed of a plurality of recording heads, which are lined up along the width directions with respect to a magnetic tape. In this head unit, the distance between the recording heads is the same distance as the distance between adjacent data tracks to be formed on the magnetic tape, and the azimuth angle of each recording heads differs with each other. A plurality of data tracks are simultaneously formed on the magnetic tape using a plurality of recording heads, respectively, when performing the recording of data on the magnetic tape.

Abstract: An arrangement and method for compensating for the written-in tracking error for a linear tape drive filters out spatial error components of a position error signal (PES). The position information contained within A, B pairs of servo stripes, and within C, D pairs of stripes is preserved. The timing between the A and C bursts and the C and A bursts is filtered, such as by low pass filtering, to filter out the error that can be written-in by a servo writer. The timing signal for the A, B bursts and C, D bursts are divided by the filtered timing signals for the AC and CA timing signals, respectively. This ratio provides the filtered PES signal used by a head positioner to precisely position the head with respect to the tape.

Abstract: The invention provides a method, apparatus and software for detecting mechanical faults in tape drives. The invention is especially suited to detecting collisions against a read/write head in a tape drive that occurs during tape threading operation. According to embodiments of the invention the read/write head is located at a predetermined position with a predetermined effective holding force, and an independent position sensor that senses the position of the read/write head is used to detect collisions against the read/write head. According to embodiment of the invention the relative frequency with which mechanical faults are detected over the course of multiple tape threading operations is evaluated to determine if there is a mechanical fault in a particular tape drive.

Abstract: A system, method and an article of manufacture to provide more accurate magnetic tape servo operation are disclosed. Accurate measurements of the width of the servo pattern written on the magnetic tape are accomplished in the presence of relatively large motion of the magnetic tape. The accurate measurements of the width of the servo pattern are used to produce a corrected position error signal that provides improved servo track following to maintain the tape head at an optimal alignment for writing and reading data tracks on the tape.

Abstract: A servo write head assembly comprises an AC demagnetizing head that slides in contact with a magnetic tape all of which surface is magnetized in one direction of longitudinal directions thereof, and demagnetizes a data band of the magnetic tape; a servo write head that slides in contact with the magnetic tape, magnetizes a servo band of the magnetic tape in a reverse direction, and writes a servo signal; and a guide for regulating a movement in lateral directions of the magnetic tape that is running, wherein the AC demagnetizing head and the servo write head are integrally configured and the guide is provided between the AC demagnetizing head and the servo write head.

Abstract: A staggered calibration track comprising a plurality of calibration tracks for use positioning a tape drive tape head for reading and writing data to and from multiple data tracks. The staggered calibration track is written by positioning the write head to a predetermined location and moving the tape media horizontally as the vertical position of the tape head is incremented in a stepwise alignment. Locating one of the plurality of calibration tracks is accomplished by positioning the read head at the predetermined location corresponding to the edge of the particular calibration track and moving the tape media horizontally as the read head output is recorded. The particular calibration tracks vertical position is derived using the average read head output.

Abstract: Calibration of magnetic tape servo index positions, which are laterally offset from edges and measured by ratios of dissimilar servo signals. A defined signal is injected into the track following servo to modulate the lateral position of the servo sensor, which is detected by an independent position sensor. Logic converts the detected lateral positions and servo signals to frequency components; selects injected signal frequency components; converts the selected frequency components to lateral positions and servo signals, and fits a curve to the converted lateral positions with respect to the converted servo signals to calibrate the index positions.

Abstract: Initially, from an off-track position at a known side of, and displaced from, a servo track pattern of a tape subject to lateral movement, servo loop logic slews a tape head servo sensor laterally toward the pattern at a rate greater than the maximum rate of lateral movement of the tape. Upon detecting sensed servo signals, the logic decelerates the slewing rate. Upon detecting that the sensed servo signals are within a lock window tolerance, the logic locks a servo loop to a position error signal representing the current lateral position of the servo sensor, thereby acquiring the servo pattern.

Abstract: The invention presents techniques for marking data storage media and responding to disturbances in the marking process. In one embodiment, the invention presents a system that uses a laser to emit a beam to ablate physical marks in a data storage medium. The system includes a sensor such as an optical sensor, configured to detect the position of the data storage medium and to generate a position signal as a function of the position of the data storage medium. An optical device, controlled by an actuator, directs the beam from the laser to an ablation site on the data storage medium as a function of the position signal.

Abstract: The invention combines the benefits of sectored servo data with the benefits of time-based servo data. Recording media such as magnetic tape, magnetic disks, optical tape and optical disks can store servo data in a time-based sectored servo format.

Abstract: Magnetic tape experiencing transverse distortion may be read by selecting between longitudinally offset read elements to read a data track. The read elements are part of a tape head having an azimuth angle relative to the tape which creates a transverse offset between the data read elements. This transverse offset is exploited to minimize the effects of any transverse tape distortion.

Abstract: A method and system are described for preventing data loss from an off-track write condition in a disk drive. In accordance with exemplary embodiments of the present invention, the disk drive comprises a disk surface comprising a first track and a second track adjacent to the first track, and a head for writing data to and reading data from the first and second tracks. The method of recovering from the off-track write condition comprises the steps of receiving a write command to write a first series of data blocks on the first track. Before writing the first series of data blocks, a second series of data blocks stored in the second track is read and stored in a data buffer.

Abstract: A lateral tape sensor for a tape drive having a tape head that is not capable of moving vertically as quickly as tape media, wherein the sensor senses lateral movement of tape media as it moves along a tape path between a storage reel and a take-up reel. The lateral tape motion sensor comprising a means for sensing the position of at least one edge of the tape media and a means for comparing the at least one edge position to predetermined thresholds to determine if the tape media moved laterally. When the lateral movement exceeds predetermined thresholds, the tape drive processor and control circuits respond to prevent accidentally overwriting data previously written on an adjacent track during a write operation, to adjust the tape head to locate data being read following lateral tape motion that occurs during a read operation or to warn the user of poor tape media quality.

Abstract: Nonlinearities in the interaction between a servo read head and a servo track are considered to more accurately determine the position error or offset between the servo read head and the servo track. A position error expression is determined based on a track profile for the servo read head. A servo track signal is generated by reading a servo track with the servo read head. The position error is determined based on the servo track signal and the position error expression.

Abstract: Embodiments of a data storage tape control system are disclosed that works to prevent or reduce frequency of off-track errors. The invented method slows tape speed in response to the writing head or writing element moving transversely away from a track center a predetermined distance, called an “off-center limit,” wherein the off-center limit is part of the way to an off-track error limit. The off-center limit is close enough to the center of the track that the writing operation is still effective, but wherein further movement out from the center would result in an off-track error and possible overwriting or unreadable data. The tape speed reduction is preferably done in increments until the writing head/element is closer to the center of the track than the off-center limit. Speed reduction is preferably done concurrently with writing, so that writing is not interrupted.

Abstract: A system and method of controlling tape tension during operation of a tape drive by making use of pre-existing timing based servo patterns formatted on the media. Changes in servo pattern timing are read at regular intervals and used to calculate changes in tension, with the torque of the tape reel motors being adjusted accordingly.

Abstract: A method and apparatus for performing position error signal conditioning of LTO media servo format written-in velocity variation is disclosed. According to the present invention only the signals demonstrating velocity deviations are filtered. A magnetic recording tape includes servo signal bursts of flux transitions recorded thereon. The servo bursts include a configuration of stripes of A spacings and B spacings and a servo head disposed proximate to the magnetic recording tape senses the flux transitions of the servo signal bursts. A servo controller, coupled to the servo head, receives the sensed signals from the servo head. The servo controller further includes a filter for filtering the B time interval servo signal components. Then a position error signal according to: PES=ref−A/(B filtered), wherein A represents unfiltered A time interval servo components and B filtered is filtered B time interval servo components.

Abstract: Width of a write track for a magnetic tape head is measured by writing a foreground magnetic track signal on a magnetic tape having a dissimilar background signal. A magnetic tape read head is moved from beyond one edge, laterally across, and beyond the opposite edge of the foreground track signal. Logic detects the read head encountering the one edge and the opposite edge of the foreground track signal; and determines, from an independent position sensor, the width of the foreground track signal as the lateral distance between the lateral position of the read head at one edge, and at the opposite edge of the foreground track signal.

Abstract: A system and method to minimize the contribution of head channel spacing to the negative effects of transverse changes in dimensions of recording media having prerecorded servopositioning tracks. Multiple channels on the recording head are separated into multiple groups of head channels, and each group of heads is independently positioned relative to the pre-written servo tracks. The head comprises an actuator for each pair of head groups. The actuator adjusts the relative spacing between members of the pair in response to position error signals indicating misalignment between the heads and the pre-written servopositioning tracks on the medium.

Abstract: Time-based servopositioning systems, methods, formats, and data recording media used in association with the same, employing full amplitude recording signals to improve the available signal as media thicknesses decrease.

Abstract: A multi-channel head position control apparatus and a method of controlling the position of the multi-channel head in which even if the width of a tape-like recording medium is changed, each of unit recording heads constituting a multi-channel head can be aligned with corresponding track centers. The multi-channel head having a plurality of unit recording heads arrayed in the longitudinal direction is disposed so that the alignment direction of the unit recording heads forms an azimuth angle relative to the running direction of the tape-like recording medium. The position of the multi-channel head is controlled by a supporting section in accordance with a control signal recorded on the tape-like recording medium and detected by a detecting section so that the alignment between each of the unit recording heads and corresponding track center is maintained.

Abstract: A system for recording and/or reproducing information, including a magnetic tape formatted by a magnetic write head which is movable in a longitudinal direction (x) and which forms “buried” servo tracks of different widths. The amplitude of the servo read signals, as a function of the position of the magnetic read/write head of the apparatus with respect to the “buried” servo tracks of the magnetic tape in the width direction (y), is substantially the same for the all the read/write units of the read/write head in spite of the width differences.

Abstract: A tape movement constraint is provided for a tape drive system which moves a tape longitudinally along a tape path across a tape head, the tape having longitudinal tracks. The tape head has a track following servo system for moving the head laterally for following lateral movement of the tracks, where the tape is subject to lateral transient movement. A tape roller bearing closely adjacent the tape head is rotatable about a central axis parallel to the cylindrical peripheral surface, allowing the tape freedom of movement in the longitudinal direction. The tape roller bearing has a frictional cylindrical peripheral surface for contacting and engaging the surface of the tape and constraining movement of the tape in the lateral direction, thereby reducing the rate of the lateral transient movement of the tape to allow the track following servo system to follow the reduced rate lateral transient movement of the longitudinal tracks.

Abstract: A device for precision alignment of a write element of a tape head to a transport direction of a media that is transported across the tape head is disclosed. The tape head includes at least one alignment element that is cofabricated with the write element so that both the write element and the alignment element have a fixed orientation with respect to a magnetic axis of the tape head. The alignment element and the write element can be fabricated on the tape head using standard microelectronic photolithographic processes. Preferably, the tape head includes a plurality of alignment elements. Those alignment elements are operative to write alignment transitions onto the media. The alignment transitions can be observed to determine if they are indicative of the write element having a predetermined orientation with respect to the transport direction.

Abstract: 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.