Abstract: A method of evaluating a dual stage actuator (DSA) servo loop in a disk drive is disclosed. The disk drive comprises a dual stage actuator (DSA) servo loop operable to actuate a head over a disk surface. A first sinusoidal signal A1 is added to a VCM control signal B1 generated by a VCM servo loop. A response of the VCM control signal B1 to the first sinusoidal signal A1 is measured, and a closed loop response of the VCM servo loop is computed in response to A1 and B1. A second sinusoidal signal A2 is added to a microactuator control signal B2 generated by a microactuator servo loop. A response of the microactuator control signal B2 to the second sinusoidal signal A2 is measured, and a closed loop response of the microactuator servo loop is computed in response to A2 and B2.

Abstract: A disk drive is disclosed comprising a disk having a plurality of servo tracks defined by servo sectors, and a head actuated over the disk. The disk drive further comprises control circuitry comprising a servo control system operable to position the head over the disk. A disturbance is induced in the servo control system, and while positioning the head over the disk, a data track is accessed. The disturbance induced in the servo control system causes the data track to be non-circular relative to a rotation axis of the disk such that the non-circular data track crosses multiple of the servo tracks over a revolution of the disk.

Abstract: The disclosure is related to monitoring a portable electronic device to detect an occurrence of a power event. A command can be sent to a data storage device to initiate a maintenance procedure on the data storage device. In a particular embodiment, a method includes monitoring a portable electronic device to detect an occurrence of a power event. The method also includes selectively sending a command to a data storage device to initiate a maintenance procedure on the data storage device when the occurrence of the power event is detected.

Abstract: A disk drive is disclosed comprising a disk, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk. A plurality of disturbance signals is generated in response to a vibration. A plurality of correlations is generated in response to each disturbance signal and an error signal of the servo control system. At least one of the disturbance signals is selected in response to the correlations. A feed-forward compensation value is generated in response to the selected disturbance signal, and the feed-forward compensation value is applied to the servo control system to compensate for the vibration.

Abstract: Disclosed are an automatic three-phase unbalanced load compensation experimental device and its control method. The experimental device comprises an automatic compensation device, a load simulation part, and detection, display and control parts. The automatic compensation device comprises power capacitors and intelligent grouping compound switches; the detection, display and control part comprises current transformers, molded case circuit breakers, a three-phase digital display ammeter, a three-phase electric power monitoring instrument, a protocol conversion module, 485 buses, Ethernet cables and an upper computer; the load simulation part comprises phase A, B and C loads which are in star connection and are same in component and circuit connection, an analog output module and a relay output module. Power monitoring instrument and digital ammeter are connected to the grid by circuit breaker and current transformer.

Abstract: An aspect of the present disclosure relates to implementing a data protection mode based on system vibration modes in a data supported system. An exemplary system vibration mode is associated with an operating mode of the data supported system. The data protection mode operates to limit, or prevent, errors caused by the vibration. In one exemplary embodiment, a method is provided for operating a data supported system. The method includes receiving an indication that a vibration associated with an operating mode of the system will occur and, in response, implementing a data protection mode in the system.

Abstract: Apparatus and related methods are described for adjusting servo gain. In an exemplary apparatus, a circuit determines a bias force error that occurs between an estimated bias force and an actual bias force on an actuator during movement by a servo motor. The circuit adjusts a servo gain in response to the bias force error, and regulates movement of the actuator by the servo motor in response to the servo gain.

Abstract: An aspect of the present disclosure relates to implementing a data protection mode based on system vibration modes in a data supported system. An exemplary system vibration mode is associated with an operating mode of the data supported system. The data protection mode operates to limit, or prevent, errors caused by the vibration. In one exemplary embodiment, a method is provided for operating a data supported system. The method includes receiving an indication that a vibration associated with an operating mode of the system will occur and, in response, implementing a data protection mode in the system.

Abstract: The disclosure is related to monitoring a portable electronic device to detect an occurrence of a power event. A command can be sent to a data storage device to initiate a maintenance procedure on the data storage device. In a particular embodiment, a method includes monitoring a portable electronic device to detect an occurrence of a power event. The method also includes selectively sending a command to a data storage device to initiate a maintenance procedure on the data storage device when the occurrence of the power event is detected.

Abstract: Apparatus and related methods are described for adjusting servo gain. In an exemplary apparatus, a circuit determines a bias force error that occurs between an estimated bias force and an actual bias force on an actuator during movement by a servo motor. The circuit adjusts a servo gain in response to the bias force error, and regulates movement of the actuator by the servo motor in response to the servo gain.