Abstract: A disk drive is disclosed employing either back electromotive force (BEMF) spindle speed control or wedge spindle speed control. The BEMF spindle speed control is used to calibrate a reference time period representing an accumulation of a predetermined number of wedge-to-wedge times. During wedge spindle speed control, a wedge time period representing an accumulation of a predetermined number of wedge-to-wedge times is measured, and a wedge speed error is computed as the difference between the reference time period and the wedge time period.

Abstract: A method and apparatus are provided for implementing intelligent spin-up for a disk drive. When a command is received, checking for a disk drive start command is performed. Responsive to identifying the disk drive start command, a no-start flag is checked. Responsive to identifying the no-start flag being set, an error code is returned without starting the disk drive. The disk drive is started only when the no-start flag is not set. During operation of the disk drive, the disk drive is monitored to identify a drive fault condition. Responsive to identifying a disk drive fault, the identified disk drive fault is checked to identify a predefined inoperative drive or dead device fault. When a predefined dead device fault is identified, the no-start flag is set and an error code for the predefined dead device fault is stored. Also a no-load flag is set that is used when the disk drive is running to stop the disk drive and return an error code before the transducer heads are loaded.

Abstract: A spindle motor control circuit for controlling a motor; including a control circuit to control the motor during at least a low state, a pulse state and a high state, the motor braking during said low state, the control circuit receiving a flyback voltage from the motor during the pulse state and the control circuit receiving a reduced flyback voltage from the motor during the high state.

Abstract: Each of slave recorders includes a rotary drum, heads mounted on the rotary drum at positions spaced from a phase reference position on the rotary drum by different angular intervals respectively, and an arrangement for selecting at least one from the heads as an active head in accordance with a designated recording mode. Non-delayed stream data are delayed by a delay time interval to form delayed stream data. A distributor operates for distributing the delayed stream data to the slave recorders. Each of the slave recorders records the delayed stream data on a slave recording medium by the active head. The delay time interval corresponds to the angular interval between the phase reference position and the position of the active head.

Abstract: A method for controlling the rotational speed of a disk player includes first calculating the proportion of time which the disk player is reading data from the disk during a unit time T. Thereafter, the method increases the rotational speed of the disk player if the proportion of time that the disk player spends reading data from the disk is greater than a first threshold during each of m consecutive units of time T, and decreases the rotational speed of the disk player if the proportion of time that the disk player spends reading data from the disk is less than a second threshold during each of n consecutive units of time T.

Abstract: A disk drive apparatus reproduces a signal from a disk and/or records an signal on the disk. A position detecting part produces a position signal in response to a rotation of a rotor. An activation operation block controls active operation of first and second power amplifying parts in response to the position signal. A signal producing part produces a slope signal which repeats a slope waveform a plural times during one period of the position signal. The shaping part produces first and second activation control signals which responds with the slope signal. The activation operation block controls the first and second power amplifying parts responding with the first and second activation control signals. Therefore, an excellent disk drive apparatus with reduced acoustic noise and reduced vibration can be realized by using only one position signal of one position sensor.

Abstract: A method for calibrating a tape transport servo system for a tape drive is disclosed. The tape reel motors are excited when the tape drive is not being controlled by the tape transport servo system. Then, calibration data is collected for the motor torque, motor friction, DAC offsets, and pulse width modulator control signal timing.

Abstract: A tape roller bearing is provided that prevents the development of an air film between the roller surface and the tape. The spool surface is made from porous material so that air flows through the spool surface. The porous material vents air uniformly over the roller surface, and the tape remains in direct contact with the roller, even at high speed. The speed of the tapes movement can be determined by measuring the speed of movement of the spool surface using an encoder disk and an encoder module.

Abstract: A power driver for driving a signal on a load using voltage-mode driver. A system processor generates commands indicating a programmed drive signal desired from the voltage-mode driver. A lead compensator determines a compensated command to compensate for an admittance function of the load. The compensated commands are coupled to the voltage-mode driver, such that the voltage-mode driver generates a voltage output based upon the compensated command.

Abstract: A method and apparatus are provided for implementing intelligent spin-up for a disk drive. When a command is received, checking for a disk drive start command is performed. Responsive to identifying the disk drive start command, a no-start flag is checked. Responsive to identifying the no-start flag being set, an error code is returned without starting the disk drive. The disk drive is started only when the no-start flag is not set. During operation of the disk drive, the disk drive is monitored to identify a drive fault condition. Responsive to identifying a disk drive fault, the identified disk drive fault is checked to identify a predefined inoperative drive or dead device fault. When a predefined dead device fault is identified, the no-start flag is set and an error code for the predefined dead device fault is stored. Also a no-load flag is set that is used when the disk drive is running to stop the disk drive and return an error code before the transducer heads are loaded.

Abstract: Techniques are provided herein for reducing vibrations in various modes of a dynamic system. One such technique comprises incorporating vibration limiting and sensitivity constraints into a partial fraction expansion equation model of the system so as to reduce vibrations to specific levels. Another technique comprises shaping a command determined using the partial fraction expansion equation model to produce a desired output. The entire command may be shaped or only selected portions thereof which produce vibrations. Another technique involves commanding in current to produce saturation in voltage. By doing this, it is possible to command voltage switches. The times at which the switches occur can be set to reduce system vibrations. Other techniques are also provided. These include varying transient portions at the beginning, middle and/or end of a move and using Posicast inputs, among others.

Abstract: A method for controlling a stepping motor that moves an object from an initial position by a target distance. The method includes calculating a moved distance of the object, calculating a remaining moving distance of the object, updating a first velocity value until the moved distance exceeds a first reference value, updating a first position value indicating the present position of the accelerated object by adding the updated first velocity value to the first position value, updating a second velocity value when the remaining distance is less than the second reference value by subtracting a second acceleration value from the second velocity value, and updating a second position value indicating the present position of the decelerated object by adding the updated second velocity value to the second position value.

Abstract: A disk drive for use with interchangeable flexible magnetic disks of potentially different weights, comprising a disk drive motor for imparting rotation to a disk loaded therein, and a stepper motor for moving a transducer across the track turns on the disk. Since the current consumption of the disk drive motor is subject to change according to the weight of each disk being driven, a current detector circuit is provided for detecting the magnitude of the current being consumed by the disk drive motor. A current control circuit controls the magnitude of the current supplied to the stepper motor in inverse proportion to the detected magnitude of the disk drive motor current. The stepping pulse rate is also varied for making the rotational speed of the stepper motor higher with a decrease in the magnitude of the disk drive motor current. Thus the seek speed is made progressively higher as the disk weight grows less, without increasing the total current requirement of the disk drive.

Abstract: A method for calibrating a tape transport servo system for a tape drive is disclosed. The tape reel motors are excited when the tape drive is not being controlled by the tape transport servo system. Then, calibration data is collected for the motor torque, motor friction, DAC offsets, and pulse width modulator control signal timing.

Abstract: An apparatus and method are disclosed for detecting the velocity of a tape in a tape transport system having a write head and a read head separated by a known distance and formatting the tape using marks. The tape transport system generates a write signal indicating when one of the marks is written to the tape by the write head and a read signal indicating when one of the marks is read from the tape by the read head. An accumulator determines the amount of time between the write signal and the read signal. A velocity detector determines the velocity of the tape based on the time determined by the accumulator and the known distance between the write head and the read head.

Abstract: A capstan controlled tape transport mechanism that includes a tape tension controller for preventing tape slack in the tape path is presented. The transport mechanism includes a capstan, a spinnable reel, and a reel motor which controls the speed of revolution of the reel in response to a reel motor voltage/current. The spinning of the reel results in the winding of the tape around the reel to generate a tape stack whose radius varies according to the amount of tape wound around the reel hub. Each revolution of the reel generates a fixed number of reel tach pulses per reel revolution. The spinnable capstan controls the transport of tape across the capstan in the direction of the reel, generating a fixed number of capstan tach pulses per capstan revolution.

Abstract: An apparatus for parking a read/write head during power interruptions and methods of operating the same result in a hard disk drive apparatus that reduces the time to steady state the operating hard disk drive. The apparatus for reducing the time to steady state the operating disk drive having an actuator arm coupled to a voice coil for latching the actuator arm when power is interrupted comprises a Y-winding spindle motor having a first winding, a second winding, and a third-winding, and a spindle motor controller coupled to the Y-winding spindle motor configured to dynamically short the first winding and the second windings to produce a retarding force against the Y-winding motor and to direct power produced by the third winding in series with the first two windings in parallel to the voice coil for moving the actuator arm to a latched position and to maintain sufficient power to the spindle motor to provide greater operating range (headroom).

Abstract: Techniques are provided herein for reducing vibrations in various modes of a dynamic system. One such technique comprises incorporating vibration limiting and sensitivity constraints into a partial fraction expansion equation model of the system so as to reduce vibrations to specific levels. Another technique comprises shaping a command determined using the partial fraction expansion equation model to produce a desired output. The entire command may be shaped or only selected portions thereof which produce vibrations. Another technique involves commanding in current to produce saturation in voltage. By doing this, it is possible to command voltage switches. The times at which the switches occur can be set to reduce system vibrations. Other techniques are also provided. These include varying transient portions at the beginning, middle and/or end of a move and using Posicast inputs, among others.

Abstract: Apparatus is adapted for recording and reproducing compressed video data in a selected one of two recording formats, of which a first format is for recording the compressed video data in N (N≧3, and representing an integer) number of tracks on a magnetic tape by dividing the video data into N number of groups, and a second format is for recording data, as auxiliary data independent from the compressed video data, in two of the tracks at both ends, and the compressed video data in (N−2) number of the tracks. In the second recording format, the recording is carried out by setting a data length of an error correction code for sync blocks longer than a data length of another error correction code for sync blocks in the first recording format.

Abstract: An apparatus and method for minimizing the effects of rotational vibration upon a disc drive having a base deck supporting a rotatable disc and an actuator having a moveable data head. A fixed head is supported over the disc at a predetermined radius and transduces a circumferentially extending frequency pattern written to the disc at a constant frequency to generate a readback signal. A frequency modulation (FM) demodulator generates a rotational velocity signal indicative of application of rotational vibration to the base deck in relation to changes in frequency of the readback signal. A servo circuit controllably positions the moveable data head in response to the rotational velocity signal and servo information readback by the moveable data head. The servo circuit interrupts a data transfer operation between the moveable data head and a host device when a magnitude of the rotational velocity signal exceeds a predetermined threshold.

Abstract: A system for tracking vehicle and driver location, mileage and time and generating reports therefrom is provided. The system includes a device connected to a vehicle which includes a mileage tracking component connected to a central processor having suitable memory associated therewith for receiving and storing an input from the mileage tracking component as input data corresponding to mileage traveled on the vehicle. The device further includes operating software thereon and low power use detector operably connected to a battery on a vehicle for supplying power to said system in one of a normal power use mode and a low power use mode. Also, operably connected to the power supply and the mileage signal generating device is a detector which indicates when the vehicle is in a generally non-mobile state and causing the system to enter into said low power use mode.

Abstract: The object of the present invention is to provide a tracking pull-in circuit for reducing effect by a defect and enabling securely and promptly pulling in a tracking servo loop. To achieve the above object, the following measures are taken: In tracking pull-in operation for reducing relative moving velocity between a code read beam and a code track executed to pull the code read beam irradiated on an optical disk in a tracking servo circuit for instructing the beam to follow the code track, damping operation is forcedly inhibited in a period in which a defect is detected on the optical disk. Therefore, the wrong discrimination caused by the defect of the direction of relative movement between the code read beam and the record medium is prevented beforehand and damping operation in pulling into the tracking loop can be securely executed.

Abstract: A take-up reel sensor measures a rotation cycle of a take-up reel of a loaded tape cassette in a take-up operation. A changing rate calculating section calculates a changing rate of the rotation cycle measured by the take-up reel sensor. A type discriminating section discriminates the tape cassette as a thick hub type or a thin hub type based on the rotation cycle measured by the take-up reel sensor, while it discriminates the tape cassette as the thin hub type or a VHS-C type based on the changing rate calculated by the changing rate calculating section. A system controller conducts a high speed take-up mode suitable for the type of the tape cassette discriminated by the type discriminating section. Accordingly, the take-up mode can be controlled by employing only the rotation cycle of the take-up reel.