Abstract: A method includes determining an error after attempting to read, via a first read transducer and a second read transducer, a data sector in a first data track. The method further includes calculating a weight ratio associated with the data sector and determining a read offset direction of the data sector based, at least in part, on the calculated weight ratio.

Abstract: Disclosed is a method of generating electrical signal waveforms by a generator. The method includes storing phase points of first and second digital electrical signal waveforms in first and second lookup tables. The first and second digital electrical signal waveforms are represented by a predetermined number of phase points that define wave shapes. At each clock cycle, a digital synthesis circuit retrieves phase points from the first and second lookup tables and the digital processing circuit combines phase points from the first and second lookup tables. A digital-to-analog converter (DAC) circuit converts the combined phase point into an analog signal. The analog signal is configured to drive a first and second ultrasonic transducer.

Abstract: A method may generate a demodulated sine component for a sequence of samples of a servo burst window of a position error signal using a sine weight look up table and generate a demodulated cosine component for the sequence of samples of the servo burst window of the position error signal using a cosine weight look up table. The sine weight and the cosine weight look up tables may have indexes representing a phase range. The method may generate a demodulated phase component signal and a demodulated amplitude component signal for the sequence of samples of the servo burst window of the position error signal based on the demodulated sine component and the demodulated cosine component using a Coordinate Rotation Digital Computer at least in part by iteratively rotating a vector based on the demodulated sine component and the demodulated cosine component and summing angular changes in the vector.

Abstract: An envelope tracking (ET) bias circuit includes an envelope tracking (ET) bias circuit includes an envelope detection circuit, an envelope amplifier circuit, and an envelope output circuit. The envelope detection circuit is configured to detect an envelope of an input signal, and output an envelope signal based on the detected envelope of the input signal. The envelope amplifier circuit is configured to differentially amplify the envelope signal in response to a first control signal and cancel a direct current (DC) offset of the envelope signal to output an amplified signal from which the DC offset is canceled. The envelope output circuit is configured to generate an ET bias current by selecting either one of a negative signal of the amplified signal and a positive signal of the amplified signal in response to a second control signal.

Abstract: In a self-synchronous transmission scheme, received data is accurately acquired. A timing signal generating unit generates timing signals indicating different timings in synchronization with a timing at which a status of a reception signal transitions. A first data signal generating unit generates a first data signal from statuses of the reception signal before and after a timing at which a predetermined first timing signal becomes a specific value, and outputs the first data signal in synchronization with a second timing signal different from the first timing signal. A second data signal generating unit generates a second data signal from statuses of the reception signal before and after a timing at which the second timing signal becomes the specific value, and outputs the second data signal in synchronization with a timing signal different from the first timing signal.

Abstract: First and second read channel logic circuits are configured to process first and second signals communicated from respective first and second readers that simultaneously read from a magnetic disk. A first servo detection circuit generates a primary servo gate based on timing data from the first reader. The primary servo gate is used for processing the first signal via the first read channel logic. A second servo detection circuit that generates a secondary servo gate based on the primary servo gate and an adjustment value. The secondary servo gate is used for processing the second signal via the second read channel logic.

Abstract: In response to determining that a first write operation is to be performed on a portion of tape, writing data to a data track with a tape head element spacing at a nominal value. A tape width of one or more tape positions at which data is written is recorded. In another aspect, a tape width value associated with a tape is retrieved. A current tape width value associated with the tape is determined, and the tape head element spacing is set based on a difference between the retrieved tape width value and the determined current tape width value.

Abstract: 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.

Abstract: A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module servo module comprises two servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted metric and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. A first multiplying node receives a first unweighted metric and a first weight signal and is operable to output a first weighted metric. A second multiplying node receives a second unweighted metric and a second weight signal and outputs a second weighted metric. A summing node receives the first and second weighted metrics and outputs a combined weighted metric to an LPOS word decoder.

Abstract: A system and method for identifying signal degradation in a tape drive is disclosed in which a data signal read from the tape drive and the signal characteristics of the undecoded portion of the data stream are compared with a set of known values. The undecoded portion of the data may comprise the preamble portion of the signal and the comparison set of known values may be saved to local storage on the tape drive. If the comparison of the signal characteristics of the undecoded portion of the data stream and the known set of signal values indicates that data signal is degraded, a notification is generated that indicates that the signal at the tape drive is degraded.

Abstract: In a servo control loop, the rate of change of filter coefficients used by an adaptive filter to counteract external disturbances to head position is regulated in response to a characteristic of an acceleration signal. Regulating the rate of change of the filter coefficients may improve the stability of the servo control loop.

Abstract: A system and method for identifying signal degradation in a tape drive is disclosed in which a data signal read from the tape drive and the signal characteristics of the undecoded portion of the data stream are compared with a set of known values. The undecoded portion of the data may comprise the preamble portion of the signal and the comparison set of known values may be saved to local storage on the tape drive. If the comparison of the signal characteristics of the undecoded portion of the data stream and the known set of signal values indicates that data signal is degraded, a notification is generated that indicates that the signal at the tape drive is degraded.

Abstract: Methods and systems for sensing a position of a transducer head with respect to a storage medium. One method includes generating a read signal from a servo track stored on a magnetic storage medium. The servo track includes servo frames of magnetic flux transitions forming detectable servo marks, the servo marks forming a tone field of repeating servo marks oriented at a first azimuth angle and a mid-frame synchronization mark incorporated within the tone field, wherein the tone field provides a metric reference for dimensional measurements between features within the servo frame(s). The number of servo marks in the tone field of each servo frame along a longitudinal direction of the servo track before the mid-frame synchronization mark and after the mid-frame synchronization mark varies with lateral position.

Abstract: Methods and systems for sensing a position of a transducer head with respect to a storage medium. One method includes generating a read signal from a servo track stored on a magnetic storage medium. The servo track includes servo frames of magnetic flux transitions forming detectable servo marks, the servo marks forming a tone field of repeating servo marks oriented at a first azimuth angle and a mid-frame synchronization mark incorporated within the tone field, wherein the tone field provides a metric reference for dimensional measurements between features within the servo frame(s). The number of servo marks in the tone field of each servo frame along a longitudinal direction of the servo track before the mid-frame synchronization mark and after the mid-frame synchronization mark varies with lateral position.

Abstract: A recording/reproducing apparatus includes: a rotary-type magnetic recording medium including a track pattern with concentric or spiral data recording tracks; a composite magnetic head including a reproducing element that reads magnetic signals from the medium and a recording element that writes magnetic signals on the medium; a control unit that moves the magnetic head over the medium to carry out tracking servo control on the reproducing element or the recording element to keep the element on a desired track; and a storage unit that stores offset information that specifies offsets for calculating an adjustment used to adjust a head position of the magnetic head during tracking servo control. The stored offset information specifies at least two different offsets per revolution of the medium. During tracking servo control, the control unit changes the adjustment at least once per revolution of the medium in accordance with offsets specified based on the offset information.

Abstract: Processing wherein a measurement signal and an erasure signal are recorded on adjacent tracks of a recordable tape 10 by one recording head HWi of n (i=1 to n) recording heads is effected on n recording heads, and measurement signals are recorded on n tracks substantially simultaneously by n recording heads HW1 to HWn in standard operation state. Then, reproducing heads with respect to thus obtained two kinds of tracks are displaced in track width directions, characteristic curves of reproduced signal waveform amplitudes of measurement signals displacement (off-track) amounts of tracks are obtained, half widths of these characteristic curves are assumed to be expedient track width and a variable Ri optimum and a variable Ri now corresponding to track widths of two kinds of tracks are obtained. Then, deviation between the variable Ri optimum and the variable Ri now is adjusted to become smaller than a desired value.

Abstract: According to an aspect of an embodiment, a magnetic device comprises a head for writing data into or reading data from a medium, the head having an actuator for changing a flying height of the head over the medium, a storage for storing characteristic information of areas of the medium and a controller for controlling the actuator on the basis of the characteristic information of the areas of the medium when writing data into or reading data from the areas of the medium.

Abstract: Methods and systems for data recording and reading for increasing overall tape data storage density, especially for data written in azimuth style. The principles of the invention provide servo formats and systems that allow accurate on track guidance for higher density applications and that are less sensitive to off track error. Preferred embodiments of the invention offer servo formats and systems of the invention that allows positive track and group identification at the beginning, end, and optionally periodically along the length of a tape.

Abstract: A fully synchronous servo channel for a data tape drive is provided which includes the initial acquisition of synchronous servo channel parameters, generation of a timing basis for signal interpolation, generation of a tape velocity estimate and a y-position estimate and an optimum detection of longitudinal position (LPOS) symbols embedded in servo bursts.

Abstract: Methods and systems for data recording and reading for increasing overall tape data storage density, especially for data written in azimuth style. The principles of the invention provide servo formats and systems that allow accurate on track guidance for higher density applications and that are less sensitive to off track error. Preferred embodiments of the invention offer servo formats and systems of the invention that allows positive track and group identification at the beginning, end, and optionally periodically along the length of a tape.

Abstract: When the head of a data pack that can be a start point of consecutive recording is included in an ECC (error correcting code) bank, data indicating this is set in an ECCTB (error correctly code two-B picture). When the head of a data pack that can be a start point of consecutive recording is not included in the ECC bank, data indicating this is set in the ECCTB. Thus, when performing consecutive recording, a recording apparatus refers to contents of the ECCTBs to detect a consecutive recording start, thereby allowing selection of the point closest to a point where a user desires to start consecutive recording, and the user starts the consecutive recording at the detected point.

Abstract: Provided is an apparatus and method of adjusting reference clock frequency in a disk drive. The reference clock frequency adjustment method includes; measuring each servo sector detection time interval, generating an error signal by subtracting initially set reference time interval information between servo sectors from the measured servo sector detection time interval information, and adjusting the reference clock frequency using the error signal such that a constant number of reference clock pulses are generated in each servo sector detection time interval regardless of variation in each servo sector detection time interval.

Abstract: Methods and systems for sensing a position of a transducer head with respect to a storage medium. One method includes generating a read signal from a servo track stored on a magnetic storage medium. The servo track includes servo frames of magnetic flux transitions forming detectable servo marks, the servo marks forming a tone field of repeating servo marks oriented at a first azimuth angle and a mid-frame synchronization mark incorporated within the tone field, wherein the tone field provides a metric reference for dimensional measurements between features within the servo frame(s). The number of servo marks in the tone field of each servo frame along a longitudinal direction of the servo track before the mid-frame synchronization mark and after the mid-frame synchronization mark varies with lateral position.

Abstract: Track thinning at an IN point of consecutive recording is prevented by doing a head-track one-edge coincidence tracking by using a head of a larger width than the track width. ATF control unit (15) makes a control during reproduction of pre-roll of consecutive recording according to a pilot signal out of the reproduction output from heads (1a, 1c) so that centers of the heads (1a, 1c) may scan the center line of the track. A positioning signal (6g) during the control and a phase of HSW are detected by a detecting circuit (16), and a desired phase having a predetermined advanced amount is set by a desired phase setting unit (18) and stored in a storage unit (19). After this, a tracking method switching control unit (23) switches the tracking method into another by which a control unit (20) controls the difference in phase between the positioning signal (6g) and the HSW to a desired value stored in the storage unit (19).

Abstract: Servo positioning systems, methods, formats, and data recording media used in association with the same, employing additional timing reference information to improve immunity to time-based errors caused by instantaneous speed variations.

Abstract: In a recording and reproduction method for recording digital data on magnetic tape by a helical scanning method or for reproducing digital data recorded on magnetic tape by the helical scanning method, a plurality of sectors are generated in each track on the magnetic tape and various types of data, such as video data and audio data, and track-synchronization data are recorded. Pilot signals for tracking control are recorded on the various types of data in a superposition manner by the use of three different frequencies such that the frequency changes every track in a predetermined repetition manner. The pilot signal is recorded so as to have a higher level at least in two blocks in a sector where the track-synchronization data is recorded than in the other portion of each track.

Abstract: In a helical scan recording system, magnetic tape (31) is transported by a tape transport (98) proximate a rotating scanner (85). The scanner has a pair of read heads (82) mounted thereon, e.g., a first read head and a second read head, which travel in a helical direction on the magnetic tape in view of the transport of the tape and rotation of the scanner. A synchronization detection system (38) determines a first synchronization mark detection time at which a first synchronization mark is read by the first read head from the first track, and a second synchronization mark detection time at which a synchronization mark read by the second read head from the second track. A position error signal generator (100) develops a position error signal (PES) based upon a difference between the first synchronization mark detection time and the second synchronization mark detection time.

Abstract: In a system having an input signal set with at least two signals having mutually exclusive frequencies f1 and f2 being part of the input signal set, whose amplitude is represented in an input digital representation, the amplitudes of each of the at least two signals are digitally represented. A digital representation of the frequency of each of the signals is derived. A digital representation of the sine function and of the cosine function of the frequency of each of the signals is derived based on the digital representation of the frequency. The digital representations of each of the sine and cosine functions is mixed with the input digital representation to derive digital representations of the sine and cosine functions of each of the signals. The digital representations of the sine and cosine functions of each of the signals are processed to derive a digital representation of the amplitude of each of the signals.

Abstract: A disk drive has a channel circuit for demodulating data sectors and servo sectors stored on a rotating medium to provide data-sector data and servo-sector data. The channel circuit transmits the data-sector data and servo-sector data to a disk controller circuit in an order which is different than the order in which they are stored on a rotating medium to allow for demodulation latency while maintaining real-time updates of embedded servo information.

Abstract: The present specification discloses a preferred method, apparatus, and system for calibrating a magnetic tape system. The magnetic tape system comprises at least one head mounted within a head drum, a magnetic tape that has a data region and a no data region, the magnetic tape being contiguous with the head, and a device for providing a relative motion between the magnetic tape and the head. A preferred embodiment of the present invention has the following. A reference track provided on the magnetic tape. The reference track is located in the no data region, at a constant distance from the data region. A processor programmed to determine the time required for the head to travel from the provided reference track to the data region.

Abstract: A signal detecting device for detecting a pilot signal component from a modulated digital signal which contains information data and the pilot signal component, comprises a digital converter for performing bit-quantization of the modulated digital signal, a detector for detecting the pilot signal component and a restoring circuit for restoring the information data, the detector and the restoring circuit both using an output of the converter. The detecting device is digital throughout since the pilot signal component is detected by using an output of the digital converter.

Abstract: In order to easily discriminate a recording mode of a magnetic tape even when the fast feeding/rewinding reproducing operation is set to the odd number times speed or even number times speed, a standard pilot signal for generating the tracking error signal is set to a fixed frequency when the fast feeding/rewinding reproducing operation is performed in the even number times speed of the ordinary reproduction speed and the standard pilot signal is set in the rotational frequencies when the fast feeding/rewinding reproducing operation is performed in the odd number times speed. Thus, the recording mode is discriminated by making reference to the time series pattern of an output obtained by sampling the tracking error signal obtained on the basis of the reproduced pilot signal and the standard pilot signal in the predetermined timing.