Abstract: A data storage device is disclosed comprising a storage medium, an input configured to receive a supply voltage from a voltage source, and control circuitry powered by the supply voltage. The control circuitry is configured to adjust a load of the data storage device, detect a load voltage at the adjusted load, detect a load current at the adjusted load, process the detected load voltage and the detected load current to detect a current limit of the voltage source, and configure the data storage device in response to the detected current limit of the voltage source.

Abstract: According to one embodiment, a magnetic disk device includes an actuator assembly including an actuator block including a rotatable bearing unit, a plurality of heads movably supported by the actuator assembly, a first sensor provided to the actuator block, and a second sensor provided at a position different from the first sensor.

Abstract: A method, computer program product, and computing system for defining user data that needs to be available to a user application. The user data is stored within a data array. It is determined whether the user data is available to the user application. If the user data is not available to the user application, notice concerning the unavailability of the user data is provided.

Abstract: A magnetic disk device includes a magnetic disk, a magnetic head, a voice coil motor which drives movement of the magnetic head relative to the magnetic disk, a drive circuit which drives the voice coil motor, a memory in which a seek time for a seek operation is stored in association with a seek distance of the magnetic head, and a controller. The controller changes the seek time stored in the memory in association with the seek distance based on a temperature and a power supply voltage of the drive circuit.

Abstract: A wireless power transmission antenna is disposed at a wireless charging mat. Another second wireless power transmission antenna is disposed at another location at the wireless charging mat. A temperature sensor is disposed at a location between the antennas. The temperature sensor is responsive to heat propagated from both of the antennas. A controller regulates charging power at each antenna based on information provided by the temperature sensor.

Abstract: Provided is a rotary-electric-machine temperature estimation system for a vehicle. The temperature estimation system includes a rotary electric machine, a cooler, a temperature sensor, and a controller. The rotary electric machine is fixed to a vehicle body of the vehicle and provided in the vehicle. The rotary electric machine includes a stator coil. The cooler has an injection outlet for injecting refrigerant, and cools off the stator coil by the refrigerant thus injected from the injection outlet. The temperature sensor measures a temperature of the stator coil. The controller estimates an actual temperature of the stator coil by use of the measured temperature and a preset temperature correction value. The controller changes the temperature correction value according to a change in a posture of the vehicle body.

Abstract: A method for enhancing read performance in an ARMR system includes: obtaining CTS information for a plurality of readers in a multi-reader head of the ARMR system, the CTS information defining a relationship between skew angle and CTS between respective combinations of subsets of the readers; determining, as a function of the CTS information, a subset of the readers which provides enhanced read performance among the readers for each of a plurality of skew angles; assigning a weight value to each of a plurality of read signals generated by a corresponding one of the readers for each of the skew angles, the weight value being indicative of a performance of the corresponding one of the readers relative to one another; and decoding information read from at least one target track of a magnetic storage medium being read as a function of the read signals and corresponding weight values.

Abstract: A disk drive has a servo control system that implements just-in-time (JIT) seeks with low power consumption for all long seeks. The servo controller receives a seek command to move the transducer to a target data track and sector, calculates rotational latency from the seek command, and limits the transducer velocity for seeks longer than a predetermined seek length. The servo controller then generates a JIT gain from the calculated rotational latency, modifies the transducer acceleration and deceleration using the JIT gain, and modifies the transducer velocity limit using the JIT gain. Positive current is applied to the actuator to move the transducer with the JIT gain-modified acceleration until the transducer reaches the modified velocity limit. The servo controller determines when to initiate deceleration of the transducer, and applies negative current to the actuator to move the transducer with the JIT gain-modified deceleration until the transducer reaches the target track.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks, wherein at least two of the tracks comprise a thermal asperity. Prior to seeking the head from a first track to a second track, for each of at least two of the thermal asperities a minimum seek delay and a maximum seek delay that will cause the head to miss the thermal asperity are computed, and an allowed seek delay range that will cause the head to miss the thermal asperity is computed. When the undelayed seek will cause the head to hit at least one thermal asperity, the seek is delayed by a seek delay determined based on the minimum seek delays, the maximum seek delays, and the allowed seek delay ranges.

Abstract: A data storage device is disclosed comprising a disk comprising a plurality of tracks, and an actuator configured to actuate a head over the disk. While seeking the head from a first track toward a second track, a velocity of the head over the disk is measured, and a deceleration distance and a deceleration time is generated based on the measured velocity. A coast velocity is generated based on the measured velocity, the deceleration distance, and the deceleration time, and a control signal applied to the actuator is adjusted based on the measured velocity and the coast velocity.

Abstract: A disk drive is disclosed comprising a microactuator configured to actuate a head over a disk, and control circuitry comprising a first digital accumulator responsive to a first register. The first digital accumulator generates at least one of a velocity command and a position command for the microactuator, and the control circuitry configures the first register in order to limit at least one of a velocity and an acceleration of the microactuator.

Abstract: An apparatus includes: a media motor; a media mounted on the media motor; a head, over the media, the motion of the head controlled by a head actuation motor; a motor driver, coupled to the media motor, configured to adjust a media speed; and control circuitry configured to: coast the media motor in preparation for accelerating the head, and activate the head actuation motor including accelerating the head in a first direction for repositioning the head over the media.

Abstract: A disk drive is disclosed comprising a disk comprising tracks defined by servo sectors, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk in response to the servo sectors. The head is loaded over the disk during a load operation, and a radial velocity of the head is determined during the load operation. A target track is generated based on the determined radial velocity of the head, and the servo control system seeks the head to the target track.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, wherein each track comprises a plurality of servo sectors. When entering an idle mode, the head is floated over the disk, and when exiting the idle mode, a radial velocity of the head is measured, a seek distance is determined in response to the radial velocity, and a seek operation seeks the head the seek distance to a first track.

Abstract: A disk drive is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The VCM is controlled to seek the head over the disk during a first seek, and a back electromotive force (BEMF) voltage generated by the VCM during the first seek is measured. Feed-forward compensation is generated based on the measured BEMF voltage, and the VCM is controlled to seek the head over the disk during a second seek using the feed-forward compensation while writing servo data to the disk.

Abstract: A data storage device is disclosed comprising a disk comprising a plurality of tracks, a head, and an actuator configured to actuate the head over the disk. An adjusted seek time is determined to seek the head from a first track to a second track, and an adjusted coast velocity and an adjusted coast time of the seek is determined based on the adjusted seek time and a power consumption of the seek when a driving current applied to the actuator is substantially constant during at least one of an acceleration time and a deceleration time of the seek.

Abstract: A disk drive is disclosed comprising a disk comprising tracks defined by servo sectors, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk in response to the servo sectors. The head is loaded over the disk during a load operation, and a radial velocity of the head is determined during the load operation. A target track is generated based on the determined radial velocity of the head, and the servo control system seeks the head to the target track.

Abstract: A disk drive is disclosed comprising a first head actuated over a first disk surface comprising servo information, a second head actuated over a second disk surface, and a voice coil motor (VCM) operable to actuate the first and second heads radially over the respective disk surfaces. The first disk surface and the second disk surface are rotated, and the servo information is read from the first disk surface using the first head to generate a read signal. The read signal is processed to generate a control signal applied to the VCM to move the second head radially over the second disk surface while applying an erase signal to the second head in order to erase at least part of the second disk surface.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, and control circuitry operable to seek the head to a target track and settle the head on the target track during a settle time, adapt a settle parameter over an adapting delay of the settle time, wherein the settle parameter is used to settle the head on the target track, and decrease the adapting delay based on a speed that the settle parameter adapts.

Abstract: A method or apparatus for changing a performance level of a disk drive from an initial performance level to a target performance level, wherein the disk drive includes a profile table. The method including determining an initial performance level, determining a target performance level, determining constant offset values that cause the performance level of the disk drive to match the target performance level, and programming a constant offset table of the profile table with the constant offset values.

Abstract: The present disclosure includes systems and techniques relating to control of storage device, such as disk drives. A described technique includes controlling a motor to actuate a head within a storage device, the motor being associated with first and second states of electric current, where a duration of the first state is longer than a duration of the second state. Controlling the motor can include using both a first mode and a second mode to control current to the motor. The technique further includes detecting an instance of the first state, and initiating, when the instance of the first state is detected, a switch from the first mode to the second mode to control the motor. The switch can be based on a condition of operation with respect to the storage device. A start-up time of the second mode is shorter than the duration of the first state.

Abstract: The disclosure is related to an apparatus and methods of suppressing seek repeatable runout. In a particular embodiment, a servo loop is disclosed. The servo loop includes a seek signal generation component that generates a seek trajectory acceleration signal. The servo loop also includes a STRRO suppression component that is coupled to the seek signal generation component. The STRRO suppression component injects STRRO suppression signals into the seek trajectory acceleration signal and outputs an STRRO suppressed seek trajectory acceleration signal.

Abstract: The present invention is a method of maximizing drive performance under any power constraint. In one embodiment, the method includes actively adjusting a seek power draw based on a comparison of real-time calculations of average seek power to a target power threshold.

Abstract: A servo control method in a seek retry condition includes determining whether the seek retry condition is generated, and terminating a servo control process that is currently performed and decelerating a voice coil motor such that a speed of the voice coil motor is minimized using a back electromotive force when the seek retry condition is generated.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, and control circuitry operable to seek the head to a target track and settle the head on the target track during a settle time, adapt a settle parameter used to settle the head on the target track, access the target track after an access delay, and decrease the access delay based on a speed that the settle parameter adapts.

Abstract: According to one embodiment, a disk storage device includes: a disk on which a servo pattern is recorded; a head; a driver; a signal generator; a demodulator; and a controller. Position signals for detecting an offset position from a center of a track are recorded in a recording area of a servo pattern. The signal generator generates a first timing signal indicating a timing for reading the position signals. When the controller performs a seek operation for moving the head to a target track, the signal generator generates a second timing signal. The period of the second timing signal for reading each of the position signals is made shorter than that of the first timing signal. A center time of the period of the second timing signal is shifted closer to a demodulation center time corresponding to a center of the recording area than that of the first timing signal.

Abstract: A method is disclosed of operating a disk drive, the disk drive comprising a disk having a plurality of tracks, a head, and a closed loop servo system comprising a seek servo loop and a settle servo loop for actuating the head over the disk. The seek servo loop is used to seek the head toward a target track. When the head approaches the target track, the settle servo loop is used to settle the head on the target track in response to a reference signal generated in response to a system inversion of the settle servo loop.

Abstract: Methods, systems, and apparatus, including computer program products, are described for calibrating voice coil motors. In one aspect, a method is provided that includes seeking toward an outer diameter of a machine readable medium from a target servo track to a blank portion of the machine readable medium. A radial velocity of an actuator is determined after accelerating the actuator to a target radial velocity. The radial velocity is compared to the target radial velocity, and a current, that is used to controllably modify the radial velocity of the actuator if the radial velocity is different from the target radial velocity, is calibrated.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, and control circuitry operable to seek the head to a target track and settle the head on the target track during a settle time, adapt a settle parameter used to settle the head on the target track, access the target track after an access delay, and decrease the access delay based on a speed that the settle parameter adapts.

Abstract: The present disclosure includes systems and techniques relating to control of recording devices, such as disk drives. A described technique includes controlling a motor to actuate a head about a surface of a rotating recording medium, the motor being associated with first and second states of electric current, where a duration of the first state is longer than a duration of the second state; detecting an instance of the first state; and initiating, when the instance of the first state is detected, a switch from a first mode to a second mode to control the motor. The switch can be based on a condition of operation with respect to the rotating recording medium.

Abstract: A ramp-unloading seek control device includes a voice coil motor, a detector, an instruction-current detector, a head-speed computing unit, and an identification structure. The identification structure estimates an error between a true resistance value and an estimated resistance value of the voice coil motor. The identification structure can minimize an estimated error defined as a difference between an estimated value ?(k) of the head speed and the head speed y(k), and employs {circumflex over (b)}1 to calibrate the estimated error. {circumflex over (b)}1 is determined by minimizing the estimated error. ?(k) and y(k) are defined by the equation (A): ?(k)=?â1y(k?1)+{circumflex over (b)}0u(k?1)+{circumflex over (b)}1u(k?2)??(A). y(k?1) denotes a head speed computed by the head-speed computing unit at the last sampling time. k denotes the present sampling time. u(k?1) and u(k?2) denote instruction currents at the last sampling time and the last but one sampling time, respectively.

Abstract: A move-sled-home device is used in an optical disc drive. The move-sled-home device includes a processing unit, a motor actuator, a sled, a sled motor, and a current-detecting unit. The processing unit outputs a control signal. The motor actuator generates a driving voltage according to the control signal. The sled motor generates a driving current according to the driving voltage to move the sled. The current-detecting unit is used for receiving and converting the driving current into an indicating signal, and issuing the indicating signal to the processing unit. During a move-sled-home action, the processing unit realizes a magnitude of the driving current according to the indicating signal, thereby determining whether the move-sled-home action is finished.

Abstract: The present disclosure includes systems and techniques relating to control of recording devices, such as disk drives. Systems and techniques can include controlling a motor to actuate a head about a surface of a rotating recording medium, switching from a first mode to a second mode to control the motor based on a condition of operation with respect to the rotating recording medium, and synchronizing the switch from the first mode to the second mode based on a state of electric current associated with the motor.

Abstract: A computer implemented method is disclosed, for energy-saving operation of a storage device with a read/write head. The method includes monitoring workload of the storage device, calculating current mean workload and adjusting seek speed of the read/write head of the storage device to one of a plurality seek speeds depending on the calculated current mean workload. The step of adjusting the seek speed of the read/write head includes adjusting the seek speed of the read/write head to be a first seek speed if the calculated current mean workload is below a first threshold, adjusting the seek speed of the read/write head to be a second seek speed if the calculated current mean workload is between the first threshold and a second threshold, and adjusting the seek speed of the read/write head to be the first seek speed if the calculated current mean workload is greater than the second threshold. A computer program product and a data processing system are also disclosed.

Abstract: An information storing device and an information processing device having a memory for registering a plurality of working modes at recording/reproduction and a switching circuit for selecting one of the plurality of working modes, which select the optimum working mode automatically or by an instruction of an operator according to power supply capacity of a device of higher rank to effect recording/reproduction.

Abstract: Methods, systems, and apparatus, including computer program products, are described for calibrating voice coil motors. In one aspect, a method is provided that includes seeking toward an outer diameter of a machine readable medium from a target servo track to a blank portion of the machine readable medium. A radial velocity of an actuator is determined after accelerating the actuator to a target radial velocity. The radial velocity is compared to the target radial velocity, and a current, that is used to controllably modify the radial velocity of the actuator if the radial velocity is different from the target radial velocity, is calibrated.

Abstract: A hard disk drive with a circuit that can perform a seek routine by providing a seek current to a voice coil motor. The voice coil motor is coupled to a head that is coupled to a disk. The seek current provides a predetermined number of harmonics. The number of harmonics is a function of a seek length of the seek routine. By way of example, the seek current may include only a first harmonic for seek lengths less than 20,000 tracks, or only the first and second harmonics for seeks less than 40,000 tracks. The harmonics can be determined by plotting PES settle versus seek length for a hard disk drive.

Abstract: A method of tuning a seek operation of a disk drive is disclosed, the disk drive comprising a disk, an actuator arm, a head coupled to a distal end of the actuator arm, a voice coil motor (VCM) for rotating the actuator arm about a pivot, and a closed loop servo system for generating a VCM control signal applied to the VCM. A function h is applied to the closed loop servo system and a corresponding output g of the closed loop servo system is measured. A reference signal is generated in response to a summation of a plurality of the function h, wherein each of the plurality of the function h is shifted by an offset and scaled by a coefficient, and the coefficients are generated in response to the measured output g.

Abstract: A method of calibrating a parameter to measure the back electromotive force (BEMF) of a voice coil motor (VCM), and a method and apparatus to use the calibrating method to perform unloading control. The calibration method includes: reading servo data and measuring a BEMF value while seeking two predetermined points on a disk, and storing the servo data and the BEMF value, generating an actual velocity curve of a head using the stored servo data, and an estimated velocity curve of the head using the stored BEMF value and adjusting a parameter related to a BEMF measurement to align the actual velocity curve of the head with the estimated velocity curve of the head.

Abstract: Apparatus and method for compensating for positional indicia misplacements in the positioning of a control object, such as with servo seam misplacements on a data storage device storage medium. An actual position for the control object is determined in relation to a corrected commanded position of the control object and a corrected position error of the control object. The corrected commanded position is determined in relation to a gain error and an actual commanded position, and the corrected position error determined in relation to the gain error and an actual position error. Preferably, an actual position error of the control object is next determined in relation to the actual position, and the control object is moved to reduce the actual position error. The positional indicia preferably comprise AB and CD seams of ABCD servo dibit patterns on a recording surface.

Abstract: Provided is an apparatus for adjusting static attitude of a thin film magnetic head attached to a flexure of a head arm assembly. The apparatus has an adjusting unit for bending the flexure, a laser emitter unit for irradiating a laser beam to a bent area of the flexure a measuring unit for measuring a static attitude angle of the thin film magnetic head, and a computer system including a CPU and a memory unit in which adjustment conditions corresponding to static attitude angles of the thin film magnetic head are previously ranked and memorized. The CPU is configured to retrieve from the memory unit a particular adjustment condition corresponding to a measured angle supplied from the measuring unit and supply the retrieved adjustment condition to the adjusting unit, enabling the adjusting unit to bend the flexure based on the retrieved adjustment condition supplied from the computer system.

Abstract: a seek procedure for a hard disk drive which provides a significant reduction in acoustic noise as well as high performance fast seek times is described. The seek procedure lowers the peak acceleration for short seeks and imparts a smooth transition from a sine seek to an exponential arrival at the target track. The seek procedure provides an error free feedforward signal derived from a single sine table. The procedure which contains a time domain sinusoid acceleration feedforward combined with a phase-plane trajectory controlled velocity which, near seek completion. The procedure is constructed so that the acceleration begins at zero and, in the fashion of a sine, increases to a maximum, decreases to a minimum and then increases again until a computed switchpoint is reached. The switchpoint is determined in-situ, to provide a smooth and continuous velocity transition from sinusoid to exponential. The velocity trajectory is computed from a look-up table.

Abstract: A feedback controller performs a feedback control based on an error between a target position and an actual position of a head. A model controller obtains a control command, a model position to be output as a command for the target position to the feedback controller, and a model velocity for the head to follow a target velocity, by using a preset control equation model, and obtains the control command and the model position with the target position as an input, based on a differential value of the target velocity corresponding to a remaining distance from the model position to the target position.

Abstract: Embodiments in accordance with the present invention provide a magnetic disk drive with reduced noise during seek operation without causing any delay in control response. According to one embodiment of the present invention, a control circuit of a magnetic disk drive controls the drive power supplied to a voice coil motor during a seek operation adapted to move a magnetic head over a target track formed on a magnetic disk so as to bring the travel speed of the magnetic head close to a predetermined target speed. The control circuit determines a provisional current according to the difference between the predetermined target speed and an actual travel speed in an acceleration zone adapted to accelerate the magnetic head to the predetermined target speed. If the provisional current exceeds a limit specified in relation to an elapsed time from the start of acceleration, the control circuit sets the limit as the current of the drive power supplied to the voice coil motor to control the motor.

Abstract: A seek control device controls the seek of a plant to prevent the position shift due to an error between a model for generating seek current and a model of the plant. When the seek trajectory is provided by seek trajectory generation for controlling the seek of a plant, the frequency characteristic of a feed back loop is changed according to the seek time and the gain of the position shift component due to the shift of the actual plant and the model of the plant is increased, so as to suppress the position shift by the feed back loop. Dispersion of the seek time can be decreased, and an overrun or underrun can be prevented.

Abstract: Provided are a method, apparatus, and storage medium for controlling a track seek servo in a disk drive. Thus, a transducer is moved to a target track using a transformed Proximate-Time Optimal Servo (PTOS) velocity trajectory in which an acceleration duration is symmetrical to a deceleration duration in a track seek mode.

Abstract: Controlling seeking of a transducer includes accelerating the transducer to a seek velocity, generating a linearized switching curve defining a position and velocity of the transducer at which deceleration should begin, and controlling the velocity of the transducer in response to the current position and seek velocity of the transducer relative to the linearized switching curve. The linearized switching curve has a slope and an offset that are determined in response to the seek velocity and a current position of the transducer relative to a nonlinear switching curve.

Abstract: In a position control device based on a current observer control for performing two degree of freedom control, calculation accuracy is improved using a fixed point processor. For a target position trajectory and position error, which are inputs of a two degree of freedom control system using an observer, relative values of which reference is the reference trajectory are used, so that the state variable of the observer can hold a relative distance from the reference position. Compared with the case of holding an absolute distance, a range where the value changes is smaller, and the number of effective digits of a decimal point can be increased, and calculation accuracy can be improved even if a fixed point method is used. As a consequence, control current becomes smooth and the generation of resonance and noise can be prevented in an acceleration period, and the generation of residual vibration can be prevented in a constant velocity period and deceleration period, and seek time can be decreased.

Abstract: A system comprises a positioning module that positions an actuator arm to read spirals that are prewritten. A frequency measuring module measures a first frequency of sync marks of said spirals. An estimation module calculates a second frequency of said sync marks when said actuator arm moves at a predetermined actuator velocity. A control module calculates an actuator velocity at which said spirals are prewritten based on said first frequency, said second frequency, and said predetermined actuator velocity.

Abstract: In an embodiment of the present invention, a Hard Disk Controller Microprocessing Unit (HDC/MPU) supplies, prior to the unloading process, different currents to a VCM, with an actuator positioned in place and kept at a standstill. The HDC/MPU determines a correction factor from VCM speeds vmeas, each of which is detected at each of VCM currents Ivcm. If the determined correction factor falls outside a reference limit, the HDC/MPU determines a new circuit parameter for a VCM speed detection circuit. Further, the HDC/MPU calculates a new correction factor appropriate to the circuit parameter. The HDC/MPU and the VCM speed detection circuit control the speed of the VCM in the unloading process using the new circuit parameter and the new correction factor.