A dual disk spindle motor hard disk drive includes a first portion having a first spindle motor and a first disk media stack mounted thereon and housed in a first enclosure, and a second portion having a coaxial second spindle motor and a second disk media stack mounted thereon and housed in a second enclosure, where the second portion further includes both the first actuator and head sliders corresponding to the first disk stack as well as the second actuator and head sliders corresponding to the second disk stack. The first and second portions are coupled together such that the open sides of the enclosures mate, referred to herein as a clamshell configuration, and each separate spindle motor is configured to operate independently of the other. With independent control of multiple spindle motors, various control functions may be utilized to address power consumption and temperature control.

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 an embodiment, a magnetic disk device includes a magnetic disk, a spindle motor that rotates the magnetic disk, a motor driver, and a controller. The motor driver supplies a motor current to the spindle motor and measures a counter electromotive voltage of the spindle motor every time the spindle motor makes one rotation. After the rotation of the magnetic disk starts, the controller adjusts a motor position where the counter electromotive voltage is measured to a set first position.

The spindle motor includes; a shaft including a shaft portion and a flange portion, the shaft portion having a columnar shape extending in an axial direction, the shaft portion including a shaft end portion, the flange portion being provided at the shaft end portion and receiving a load in the axial direction; and a bearing sleeve rotatably supporting the shaft, the bearing sleeve having a tubular shape including a sleeve end portion having a large-diameter recess part formed in the axial direction. The shaft is a member formed of a copper alloy containing from 0.5 mass percent to 1.5 mass percent of silicon and from 0.5 mass percent to 3.0 mass percent of manganese, and the member includes the shaft portion and the flange portion integrated with one another.

According to an embodiment, a magnetic disk device includes a magnetic disk, a spindle motor that rotates the magnetic disk, a motor driver, and a controller. The motor driver supplies a motor current to the spindle motor and measures a counter electromotive voltage of the spindle motor every time the spindle motor makes one rotation. After the rotation of the magnetic disk starts, the controller adjusts a motor position where the counter electromotive voltage is measured to a set first position.

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.

An apparatus and associated method that contemplate a data storage disc and a motor supporting the disc in rotation. Control circuitry operates to spin up the disc drive by accelerating the motor to a steady state speed by: beginning the spin up by energizing the motor with a primary power; comparing an amount of auxiliary power that is available from a battery to a predefined threshold; and before the motor is accelerated to the steady state speed and if the threshold comparison is favorable, then boosting the primary power by discharging the battery for a predetermined boost interval.

An ohmic-inductive electrical load, such as an electric motor, for example, for a hard-disk drive, is driven by supplying thereto a load current via a switching power stage supplied with a source current delivered by a supply source. The driving action may include sensing the load current; estimating the source current starting from the load current sensed; generating a feedback signal that assumes different values as a function of the result of the comparison between the source current estimated and a source-current threshold value; and driving the switching power stage via the feedback signal, increasing or decreasing, respectively, as a function of the different values assumed by the feedback signal, the load current, thereby controlling the source current.

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.

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.