Abstract: A control unit is configured to determine a first parameter from a back EMF signal, and to determine at least one second parameter from the back EMF signal corresponding to the first parameter. The control unit verifies, based on the first parameter, at least one condition containing the at least one second parameter, and detects stall or step-loss in the stepper motor based on the verification. The control unit uses a pattern detection by identifying characteristic features of peaks of the back EMF signal, which are order, magnitude and polarity. These characteristic features are independent of RPM, backlash, load and do not require complex calculations and are very robust even at lower RPMs.

Abstract: In a data storage system, the available space of a magnetic storage device is divided into multiple sequential write regions for storing sequentially written data, where the regions are each separated from adjacent sequential write regions by a guard space. Object data, such as key-value pairs, are written sequentially to a particular sequential write region, in blocks of data that correspond to the contents of a nonvolatile buffer being flushed to the magnetic storage device. When a key-value pair stored in the magnetic storage device is subsequently updated, the original key-value pair is not overwritten. Instead, the new version of the key-value pair is included in the next block of data to be written to the magnetic storage device, and a mapping table tracks the location of the newest version of each key-value pair stored in the magnetic storage device.

Abstract: In a disk drive, when an off-track error occurs during a sequential disk access operation that spans multiple contiguous data tracks, efficient recovery is performed. In an embodiment, the disk access operation (e.g., reading from or writing to a disk) is attempted for all sectors of the sequential disk access operation. The disk access operation is then attempted again for sectors associated with any off-track errors that occurred during the disk access operation. In another embodiment, when an off-track error occurs during a sequential write operation in a shingled magnetic recording drive, the data originally targeted to be written to a first portion is written to a second portion of the data track that follows the first portion. Since no additional revolutions of the disk are needed for data associated with the sequential write operation to be written to the disk.

Abstract: There is provided a method for controlling a stepping motor by employing a micro-step mode at deceleration or acceleration of the stepping motor, which moves an optical pickup head in a full step mode or a half step mode, to minimize lens vibration of the optical pickup head. The method includes setting an initial step of the stepping motor, applying a micro-step mode to the stepping motor at the set initial step to move the optical pickup head, and after the initial step, applying a full step mode or a half step mode to the stepping motor to accelerate the optical pickup head by a desired speed. Also, the method includes setting a late step of the stepping motor, applying a full step mode or a half step mode to the stepping motor to decelerate the optical pickup head by a desired speed, and applying a micro-step mode to the stepping motor at the set late step to move the optical pickup head.

Abstract: Stable recording and reproduction of data onto and from a recording medium that requires precise tracking is provided by using a simple head tracking mechanism. In a hard disk drive (200), a piece of sector data to be written or read is pre-associated with a sector number of a sector where the piece of sector data is to be written or read. A seek control unit (260) corrects first-order run-out relative to a revolution axis of a DTM magnetic disk (100) and permits second-and-higher order run-out relative to the revolution axis, and moves a read/write head (122, 124) gradually in one radial direction of the DTM magnetic disk at a shift pitch smaller than the track pitch for each revolution in accordance with the sector numbers of the sectors where pieces of sector data are to be written or read, within a range of tracks containing the sector numbers of the sectors where the pieces of sector data are to be written or read.

Abstract: A method for referencing a polyphase stepper motor by monitoring the current step response in at least one driven phase is presented. The coil current step response is compared to past step responses in order to determine when an increase in or maximum load is present. A combination of step to step variance, step response variance from mean current magnitude, and average current magnitude variance, as well as other measures can be combined to create an algorithm output. The output is compared to a pre-determined threshold and if the value is greater than the threshold, the motor is commanded to halt its position, which remains magnetically synchronous. This position is then used as a reference point to zero, or to home the motor.

Abstract: A floppy disk apparatus improves power efficiency and quietness by commencing rotation of a stepping motor in a smooth fashion. The floppy disk apparatus includes an interface control circuit that outputs, in accordance with an instruction from a host apparatus, a first step pulse signal, step pulse period signals that indicate the period of the first step pulse signal and that are output before the first step pulse signal and a direction signal, and a floppy disk control circuit that generates a second step pulse signal delayed by a predetermined time from the first step pulse signal in accordance with the step pulse period signal, that generates a first signal that toggles in synchronization with the first step pulse signal and a second signal that toggles in synchronization with the second step pulse signal, and that outputs the first and second signals as control signals in accordance with the direction signal.

Abstract: In a flexible disk drive for driving a flexible disk inserted in the flexible disk drive, when a power supply is turned on and when the flexible disk is not inserted in the flexible disk drive, a seek operation is inhibited and a track 00 signal is supplied to a host system just as if the flexible disk drive were operating normally.

Abstract: A motor driving device is provided with a motor and a motor driver circuit for controlling the motor. The motor driver circuit limits the current supplied to the motor to a current below a predetermined limit value.

Abstract: A control IC is mounted on a circuit board and is used for driving both a one-inch stepper motor and a half-inch stepper motor. The control IC includes at least a number of pads required for driving the half-inch stepper motor. When the control IC drives the one-inch stepper motor or the half-inch stepper motor, the saturation voltage, the arrangement of the pads having the same functions for driving the one-inch stepper motor and the half-inch stepper motor, and the read/write constants for reading and writing from/into a floppy disk are set to be equal for both the one-inch stepper motor and the half-inch stepper motor.

Abstract: A seek pattern formation circuit includes a seek pattern generation circuit for generating a seek pattern formed of a predetermined pulse train every time a step pulse is applied and a seek pattern shaping circuit for shaping the seek pattern and supplying the shaped seek pattern to a stepping motor driver. When the period for which the step pulse is supplied is shorter than the period for which the seek pattern is generated, and when at least one of pulses included in the seek pattern is very narrow, the seek pattern shaping circuit selectively eliminates the narrow pulse. As a result, narrow pulses which may induce noise are not supplied to the stepping motor driver, and hence a malfunction in the stepping motor driver does not occur.

Abstract: A disk drive includes a disk from and to which information can be read and written; a disk driving motor for spinning the disk; a read/write head disposed in the vicinity of the disk; a head transfer mechanism for transferring the read/write head in the radial direction of the disk; and a controller for controlling the overall disk drive. The disk drive is connected to a host control unit through a Universal Serial Bus interface. When a step signal for driving the head transfer mechanism is output at a point at which the disk driving motor is activated, the controller immediately deactivates the disk driving motor and only actuates the head transfer mechanism to move step by step.

Abstract: In a disk device, in a state where no access to the disk is permitted, instead of permitting the head to be driven stepwise whenever step pulses are fed in, the head is inhibited from being driven stepwise until a predetermined period of time elapses after the disk starts being rotated. This helps reduce electric power consumption in such a state. Moreover, when the head has been retracted to its initial position because of an error in the stepwise driving thereof, instead of waiting for step pulses to be fed in from the host and thereby losing much time before the head is moved back to the track at which it was located before the error, the position of the head before the error is stored so that the head can be, by self recovery, moved back to the position before the error without waiting for an instruction from outside the disk device.

Abstract: In a stepping motor control method using an encoder, a timer means is provided, and an excessive advance of a phase during low rotation is restricted to attain a high speed without compromising stability during low rotation by driving the motor in such a manner that a pre-reversal state is recovered a predetermined time after a voltage reversal and a post-reversal state is recovered after one cycle of an angle detecting means. A device is provided which controls a speed by a pulse generator generating pulses at predetermined intervals, which detects a sudden drop in speed from a predetermined time elapsed from the last pulse, and which detects, when a speed is to be recovered, an abnormal drop in motor rotation independent of the motor rotation speed by changing a threshold value of an elapsed time according to an actual speed, a speed command value and an acceleration command value.

Abstract: In an FDD control apparatus for controlling a floppy disk drive for driving a floppy disk loaded in the floppy disk drive, an FDD control part including a floppy disk controller (FDC) is disposed in an FDD side in lieu of a host side (a SET side). The host side (SET side) is loaded with a USB connector connected to the FDD control part. The FDD control part includes a flash ROM for storing a program for adjusting a step timing of a stepping motor.

Abstract: In an FDD control apparatus for controlling a floppy disk drive for driving a floppy disk loaded in the floppy disk drive, an FDD control part including a floppy disk controller (FDC) is disposed in an FDD side in lieu of a host side (a SET side). The host side (SET side) is loaded with a USB connector connected to the FDD control part. The FDD control part includes a flash ROM for storing a program for adjusting a step timing of a stepping motor.

Abstract: A disk drive includes a disk from and to which information can be read and written; a disk driving motor for spinning the disk; a read/write head disposed in the vicinity of the disk; a head transfer mechanism for transferring the read/write head in the radial direction of the disk; and a controller for controlling the overall disk drive. The disk drive is connected to a host control unit through a Universal Serial Bus interface. When a step signal for driving the head transfer mechanism is output at a point at which the disk driving motor is activated, the controller immediately deactivates the disk driving motor and only actuates the head transfer mechanism to move step by step.

Abstract: A control IC is mounted on a circuit board and is used for driving both a one-inch stepper motor and a half-inch stepper motor. The control IC includes at least a number of pads required for driving the half-inch stepper motor. When the control IC drives the one-inch stepper motor or the half-inch stepper motor, the saturation voltage, the arrangement of the pads having the same functions for driving the one-inch stepper motor and the half-inch stepper motor, and the read/write constants for reading and writing from/into a floppy disk are set to be equal for both the one-inch stepper motor and the half-inch stepper motor.

Abstract: A seek pattern formation circuit includes a seek pattern generation circuit for generating a seek pattern formed of a predetermined pulse train every time a step pulse is applied and a seek pattern shaping circuit for shaping the seek pattern and supplying the shaped seek pattern to a stepping motor driver. When the period for which the step pulse is supplied is shorter than the period for which the seek pattern is generated, and when at least one of pulses included in the seek pattern is very narrow, the seek pattern shaping circuit selectively eliminates the narrow pulse. As a result, narrow pulses which may induce noise are not supplied to the stepping motor driver, and hence a malfunction in the stepping motor driver does not occur.

Abstract: In an FDD control apparatus for controlling a floppy disk drive for driving a floppy disk loaded in the floppy disk drive, an FDD control part including a floppy disk controller (FDC) is disposed in an FDD side in lieu of a host side (a SET side). The host side (SET side) is loaded with a USB connector connected to the FDD control part. The FDD control part includes a flash ROM for storing a program for adjusting a step timing of a stepping motor.

Abstract: A conventional motor driving device needs to have, as a stage preceding a motor driver circuit, a regulator circuit as a means of maintaining the current flowing through a high-efficiency motor with high accuracy. This leads to a higher cost, and also to a larger area on the circuit board used. By contrast, according to the present invention, a motor driving device is provided with a motor and a motor driver circuit for controlling the motor, and the motor driver circuit has a function of limiting the current supplied to the motor below a predetermined limit value.

Abstract: A disk drive with steering magnets that reduce the magnetic flux leakage from the actuator magnets of a linear actuator is disclosed. The steering magnets reduce flux leakage in the area of the magnetic disk where magnetic information is read and record, thereby enabling disk drive size to be reduces. The steering magnets are arranged along the sides of the outer return path. Like poles of the steering magnets face inward toward like poles of the actuator magnets.

Abstract: Disclosed is a calibration method for an acceleration sensor in a storage device for calibrating and a storage device, an enclosure for calibrating the acceleration sensor for compensating a vibration of an enclosure in a state of its being mounted in a storage drive. The calibration method and mode comprises a step of exciting a actuator of the drive by flowing a drive current having a predetermined current value, a step of calculating the acceleration of the enclosure of the drive from the predetermined current value and a mechanical transfer function of the storage device, a step of detecting a measured value of the acceleration sensor, and a step of calculating a sensitivity of the acceleration sensor from the calculated acceleration and from the detected measured value. The acceleration sensor is calibrated in the state of its being mounted in the disk drive, and hence the sensitivity can be precisely calibrated.

Abstract: A servo control system for a voice coil motor including a servo controller using position feedback to provide an acceleration current to the voice coil motor and voice coil brake providing a deceleration current based upon velocity feedback from the voice coil motor. In one embodiment, the velocity of the voice coil motor is derived from current feedback. A method for braking an actuator driven by a voice coil motor including the steps or receiving and processing current feedback from the voice coil motor and supplying a deceleration current to the voice coil motor derived from the current feedback from the voice coil motor.

Abstract: In a disk device, in a state where no access to the disk is permitted, instead of permitting the head to be driven stepwise whenever step pulses are fed in, the head is inhibited from being driven stepwise until a predetermined period of time elapses after the disk starts being rotated. This helps reduce electric power consumption in such a state. Moreover, when the head has been retracted to its initial position because of an error in the stepwise driving thereof, instead of waiting for step pulses to be fed in from the host and thereby losing much time before the head is moved back to the track at which it was located before the error, the position of the head before the error is stored so that the head can be, by self recovery, moved back to the position before the error without waiting for an instruction from outside the disk device.