A data storage device has a closed loop extended park mode during spin down operation. A data storage device comprises a spindle motor configured to rotate one or more disks, and one or more processing devices. The one or more processing devices are configured to determine a value of current that is discharged from the spindle motor over time during a spin down of the spindle motor, and control a braking duty cycle for braking the spindle motor during the spin down such that the value of current discharged from the spindle motor over time does not exceed a selected current limit.

A data storage rack may only have a subset of the HDDs therein operating in an active mode where read/write operations may be performed. Other HDDs may operate in an idle mode, which is a power-saving state that permits the HDDs to quickly change-over to the active mode, when needed. In storage racks containing numerous HDDs, a majority of the HDDs may be operated at idle mode for a majority of the time. Where a large number of HDDs are operated at idle mode, a fixed common idle speed shared by the numerous HDDs can cause unwanted excitation, vibration, and resonance. This can yield increased wear on rack components, decreased performance from the HDDs therein, and increased noise. Variable HDD idle spindle speeds mitigate the foregoing, which is caused by an idle spindle speed previously common to many, if not all HDDs within the data storage rack.

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.

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.

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.

A motor driver device includes: a driver driving a motor by a driving method, wherein the driving method includes: a first driving method performing driving control of the motor based on zero cross timing of back electromotive force generated in a coil of a predetermined phase; and a second driving method performing driving control of the motor such that a first differential phase between zero cross timing of driving current flowing through the coil of the predetermined phase and zero cross timing of driving voltage applied to the coil of the predetermined phase coincides with predetermined first target phase, and wherein, even when the motor is being driven by the first driving method, the first differential phase is sequentially detected and, when transition from the first driving method to the second driving method occurs, the first differential phase detected immediately before the transition is set to the first target phase.

According to one embodiment, there is provided a disk device including a first connector, a second connector and a controller. The first connector is connectable to a host. The first connector includes a first pin that is electrically connectable to a light emitting device in the host. The second connector is connectable to the host. The second connector includes a second pin that is receivable with data from the host. The controller is communicable with predetermined information with the host via the first pin.

A data storage device has a closed loop extended park mode during spin down operation. A data storage device comprises a spindle motor configured to rotate one or more disks, and one or more processing devices. The one or more processing devices are configured to determine a value of current that is discharged from the spindle motor over time during a spin down of the spindle motor, and control a braking duty cycle for braking the spindle motor during the spin down such that the value of current discharged from the spindle motor over time does not exceed a selected current limit.

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.