HDDs including multiple heads driven by separate actuator spindles can read from or write to one or more platters simultaneously. Simultaneous active heads can be used to increase data rate or for other purposes. The multiple independently-actuated heads can access the same platter or different platters and may be moved across an associated platter surface in a number of different ways. However, multiple independently operating actuators may lead to mechanical coupling between the actuators. For example, as certain resonant frequencies, the movement of one actuator arm may cause unacceptable movement of another actuator arm within the HDD. This mechanical coupling can have detrimental effects on the HDD. The disclosed coupling observer and disable systems detect and mitigate detrimental effects of mechanical coupling between the independently operated actuators.

According to one embodiment, there is provided a disk device including a head, a disk, a first motor, and a first circuit. The disk has a recording surface. The first motor causes the head to seek along the recording surface. The first circuit can switch between a first state and a second state. The first state is a state where a current path of the first motor is electrically cut off from a first electricity storage unit. The second state is a state where the current path of the first motor is electrically connected to the first electricity storage unit.

The present disclosure generally relates to an electronic circuit and method of operating thereof to back up write cache data on DDR memory in data storage devices during an emergency power off (EPO). The method involves using a power management integrated circuit (PMIC), a combo driver and one MOSFET for regulator output. The method involves detecting a voltage value that is below a predetermined threshold value, retracting a write head away from a hard disk drive (HDD), backing up data, and then resetting the HDD after the backup is complete. The backing up and retraction may occur in parallel or in sequence. The method utilizes the spindle back-electromotive force (BEMF) power to have sufficient power to make the backup. If the power from the spindle BEMF is too low, then the retraction is suspended and a high impedance is present to lighten the load until the BEMF recovers before the power on reset. As such, the back-up data is not reset and volatized by a lack of power.

According to one embodiment, there is provided a disk device including a head, a disk, a first motor, and a first circuit. The disk has a recording surface. The first motor causes the head to seek along the recording surface. The first circuit can switch between a first state and a second state. The first state is a state where a current path of the first motor is electrically cut off from a first electricity storage unit. The second state is a state where the current path of the first motor is electrically connected to the first electricity storage unit.

The present disclosure generally relates to an electronic circuit and method of operating thereof to back up write cache data on DDR memory in data storage devices during an emergency power off (EPO). The method involves using a power management integrated circuit (PMIC), a combo driver and one MOSFET for regulator output. The method involves detecting a voltage value that is below a predetermined threshold value, retracting a write head away from a hard disk drive (HDD), backing up data, and then resetting the HDD after the backup is complete. The backing up and retraction may occur in parallel or in sequence. The method utilizes the spindle back-electromotive force (BEMF) power to have sufficient power to make the backup. If the power from the spindle BEMF is too low, then the retraction is suspended and a high impedance is present to lighten the load until the BEMF recovers before the power on reset. As such, the back-up data is not reset and volatized by a lack of power.

A back electromotive force (BEMF) of a spindle motor in a hard disk drive is rectified and exploited to drive a voice coil motor (VCM) in the hard disk drive to retract the heads of the hard disk drive to a park position. The VCM is driven in a discontinuous mode comprising an alternation of VCM on-times and VCM off-times. Rectifying the BEMF of the spindle motor is discontinued before the end of the VCM off-times, Toff with the spindle motor brought into a brake condition wherein the spindle motor is short-circuited and the spindle BEMF forces currents through the windings of the spindle motor. The spindle current is thus pre-charged and made ready to cope with a VCM current request at the next VCM on-time.

Various illustrative aspects are directed to a data storage device comprising a first spindle motor configured to rotate one or more disks in a first stack of disks, a second spindle motor configured to rotate one or more disks in a second stack of disks, and one or more processing devices configured to detect back electromotive force (BEMF) voltages generated by the first spindle motor and the second spindle motor. In other aspects the one or more processing devices can control speeds of the first spindle motor and the second spindle motor based on the detected BEMF voltages.

The half-bridges driving a multiphase motor are controlled to perform a sequence of operations to support charging a hold capacitor. First, in a brake configuration, the half-bridge transistors are controlled such that either high-side transistors or low-side transistors of the half-bridges are turned on. Second, in an active step-up configuration, the half-bridge transistors are controlled such that the high-side transistor of a first half-bridge and the low-side transistor of a second half-bridge are both turned on and the low-side transistor of the first half-bridge and the high-side transistor of the second half-bridge are both turned off. Third, in an active brake configuration, the half-bridge transistors are controlled such that the low-side transistor of the first half-bridge and the high-side transistor of the second half-bridge are both turned on and the high-side transistor of the first half-bridge and the low-side transistor of the second half-bridge stage are both turned off.

According to one embodiment, there is provided a disk device including a head, a disk, a first motor, and a first circuit. The disk has a recording surface. The first motor causes the head to seek along the recording surface. The first circuit can switch between a first state and a second state. The first state is a state where a current path of the first motor is electrically cut off from a first electricity storage unit. The second state is a state where the current path of the first motor is electrically connected to the first electricity storage unit.

In one embodiment, a computer-implemented method includes determining whether a medium in a drive is in motion, the drive being mounted in a receptacle. In response to determining that the medium is in motion, physical removal of the drive from the receptacle is prevented. In another embodiment, a computer program product for controlling removal of a drive includes a computer readable storage medium having program instructions embodied therewith. The computer readable storage medium is not a transitory signal per se. The program instructions are readable and/or executable by a computer to cause the computer to perform the foregoing method.