Abstract: A magnetic tape control apparatus includes a control device that executes a process including: detecting an occurrence of speed fluctuations of a running magnetic tape for each recorded area from which a synchronization error is detected, when the synchronization error of a bit signal of a track is detected with a time lag between any of tracks of the running magnetic tape partitioned in units of recording areas; and setting the recording area as an unavailable area in accordance with a state where the speed fluctuations in the recording area occur.

Abstract: In one embodiment, a system includes a controller configured to: determine a reference velocity at various intervals, receive or determine a secondary velocity based at least in part on a parameter associated with a drive mechanism motor, determine a value representative of a difference between the reference velocity and secondary velocity, adjust a speed of the motor of the drive mechanism for minimizing the difference between the reference velocity and secondary velocity, receive/determine a primary velocity based on reading information encoded on a magnetic tape, at a switching point, make the reference velocity about equal to the primary velocity, after the switching point, determine the reference velocity at various intervals, after the switching point, determine a value representative of a difference between the reference velocity and primary velocity, and adjust the speed of the motor of the drive mechanism for minimizing the difference between the reference velocity and primary velocity.

Abstract: In accordance with the present invention, a method of operating a magnetic tape drive, a magnetic tape drive and a servo control system are provided for obtaining and maintaining velocity control in a magnetic tape drive. In one embodiment, a method is provided for operating a magnetic tape drive. The tape drive includes a plurality of DC motors, and each DC motor has a plurality of Hall sensors. The DC motors are under the control of a servo system which is configured to read location information from the magnetic tape, and compute a primary tape velocity from the location information, and sense a secondary and tertiary velocity signal and compute a tape velocity based on one of the sensed secondary velocity signal and tertiary velocity. The method includes detecting if the primary velocity location information is available. In response to detecting that the primary velocity location information is available the primary velocity is employed to control the servo system.

Abstract: 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.

Abstract: Provided are techniques for determining a reel motor angle. An estimate of an interval to degrees translation factor that represents a measurement angle interval divided by a first pulse count is calculated, wherein the first pulse count represents format transitions counted during an angular measurement interval. A reel motor angle is determined using the estimate by: receiving an indication that a rotating reference point has crossed a stationary reference point, wherein the indication is recognized as indicating that an angle between a motor rotor and a motor stator is a reference angle; determining a second pulse count, wherein the second pulse count represents format transitions counted since the indication was received to a given point in time; and at the given point in time, multiplying the second pulse count by the estimate to generate a first value and adding the reference angle to the first value to generate the reel motor angle.

Abstract: Provided are techniques for determining an angular position of a tape reel. A first edge of a hall sensor is identified. A number of format transitions on a timing based servo formatted tape are counted until detecting a predetermined edge of the hall sensor. A reel circumference is determined. A radius is determined using the determined reel circumference. A new circumference of a next revolution is determined using the determined radius and a tape thickness. A current angular position is determined using the determined new circumference and the counted format transitions.

Abstract: An apparatus for transporting a magnetic tape includes a writing head, a unit for generating pulse signal, a reading head and a unit for calculating transport speed. The writing head has at least two parallel and linear magnetic gaps spaced a predetermined distance in a tape transport direction. The unit for generating pulse signal cyclically sends a pulse signal to the writing head to write a magnetic pattern corresponding to the magnetic gaps on the magnetic tape. The reading head detects the magnetic pattern to generate a resulting pulse signal. The unit for calculating transport speed calculates a transport speed of the magnetic tape based on the pulse signal sent by the reading head. The unit incorporates a first time interval which is obtained from two parallel and linear pattern components within a magnetic pattern, and a second time interval obtained from adjacent magnetic patterns.

Abstract: A recording apparatus of a tape-shaped magnetic recording medium includes a transfer unit, a recording head, a signal-processing unit and a control unit. The transfer unit transfers a tape-shaped magnetic recording medium having an anisotropic property oblique with respect to the thickness direction in a forward or reversed direction. The recording head is positioned in such a way that a recording track is formed on the traveling tape-shaped magnetic recording medium, which is transferred by the transfer unit, in a direction parallel to the transfer direction of the tape-shaped magnetic recording medium. Connected to the recording head, the signal-processing unit receives a signal to be recorded onto the tape-shaped magnetic recording medium. The signal-processing unit then carries out signal processing required for an operation to write the signal to be recorded onto the tape-shaped magnetic recording medium.

Abstract: A drive and method of identifying write velocity during reading are provided. When a track is being read, the data signal is processed prior to determining the data stream to identify the velocity with which the track data were written. The read channel is adjusted based on the identified velocity to compensate for write channel transfer function variation.

Abstract: A tape drive and method of identifying write velocity during reading are provided. When a track is being read, a lead-in code of the data signal is processed prior to determining the data stream. The lead-in code identifies the velocity with which the track data were written. The equalization/detection channel is adjusted based on the identified velocity to compensate for write channel transfer function variation. The lead-in code is coded in a way that is reasonably immune to write channel transfer function variation such that the lead-in code is comprehended prior to adjusting the equalization/detection channel.

Abstract: A servo writer which writes a servo mend on a tape by the write head is characterized by being equipped with a pay-off side motor paying off the tape from tie payoff reel by rotating the pay-off reel; a winding side motor winding the tape on the winding reel by rotating the winding reel; a first capstan roller and second capstan roller which are provided at an upstream side and down stream side of the write head, respectively, and by rotating the capstan rollers, run the tape in a state pinched between respective pinch rollers and the capstan rollers; a first tension detector which is provided between the first capstan roller and second capstan roller and detects running tape tension; and a capstan roller controlling unit controlling a rotation speed of the first capstan roller and second capstan roller so that tension detected by the tension detector becomes constant.

Abstract: Calibration logic separately operates DC motors of a tape drive at a steady state estimated velocity (Omega C) for at least one full revolution without a tape; senses Hall sensor(s) to indicate a full revolution of each motor, measuring the time of the full revolution; determines the actual velocity (Omega A) of each motor employing the measured time; compares Omega C to Omega A to determine a calibration constant (K calib) for each motor; to calibrate the motor velocity of each motor, for determining the velocity for a mounted tape by averaging the tape velocity generated by each motor based on the calibrated motor velocity.

Abstract: Calibration logic separately operates DC motors of a tape drive at a steady state estimated velocity (Omega C) for at least one full revolution without a tape; senses Hall sensor(s) to indicate a full revolution of each motor, measuring the time of the full revolution; determines the actual velocity (Omega A) of each motor employing the measured time; compares Omega C to Omega A to determine a calibration constant (K calib) for each motor; to calibrate the motor velocity of each motor, for determining the velocity for a mounted tape by averaging the tape velocity generated by each motor based on the calibrated motor velocity.

Abstract: A magnetic recording and reproducing device according to the present invention operates with steps of moving a magnetic tape having a plurality of tracks per frame and a plurality of control signals recorded thereon, keeping count of the pulses of a frequency generator signal corresponding to the rotation of a capstan motor by a frequency generator counter, resetting the count of the frequency generator pulses by the control signal reproduced by a fixed magnetic head, detecting the track number by the control signal counter reset by a frame reference signal, controlling, at the start, the start timing on the basis of the tape stop position detected by the frequency generator pulse counter and control counter and the reference frame signal from the reference frame signal generator. The device prevents thinning of tracks at the editing point in after-break recording and the disturbance of images immediately after the start.

Abstract: An apparatus for calibrating a tape drive that includes a rotating scanner for reading the tracks on the tape and a tape drive servo for transporting the tape in response to a control signal. The apparatus includes a signal generator and a controller. The signal generator generates an indexing signal based on the rotational position of the scanner. The controller is coupled to the scanner, the tape drive servo and the signal generator, and provides a control signal to the tape drive servo causing the tape drive servo to transport the tape at either above or below a nominal speed. The controller detects an envelope for each of a plurality of scanned signals and the sub code data within each of the scanned signals, determines an envelope measurement for each envelope based on at least one sample magnitude of the envelope and measures a delay time for each of the scanned signals. The delay time is based on the indexing signal and the detection of the sub code data.

Abstract: A servo control apparatus controls operation of a to-be-controlled object through execution of software based on control data and reference data. An operation-signal generating portion generates an operation signal having a frequency representing the operation of the to-be-controlled object. A clock-signal generating portion generates a clock signal having a frequency controlled in accordance with the control data. A counting portion measures a time corresponding to the period of the operation-pulse signal by counting pulses of the clock signal, and generates a count value. A controlling portion controls the operation of the to-be-controlled object through execution of software based on the count value and the reference data.