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, a magnetic disk device includes a control device and a regulator device. The control device and the regulator device are connected to each other through a first interface and a second interface. The control device transmits a required voltage value to the regulator device through the first interface and transmits a correction value based on the required voltage value and an output voltage output from the regulator device to the regulator device. The regulator device outputs a voltage to the control device on the basis of the received required voltage value and corrects a value of the voltage to be output to the control device on the basis of the received correction value.

A method for writing data in a disk drive having actuators each controlling arms extending over disk surfaces, including: receiving a write command from a host; receiving from the host data; dividing the data into data blocks; determining: a first surface from the disk surfaces where data is written by a first head of an arm controlled by a first actuator of the actuators; and a second surface from the disk surfaces where data is written by a second head of an arm controlled by a second actuator of the actuators; determining storage blocks of each of the first and the second surface; and writing first data blocks of the divided data blocks to the determined storage blocks of the first surface using the first head while writing second data blocks of the divided data blocks to the determined storage blocks of the second surface using the second head.

According to one embodiment, a magnetic disk device includes a control device and a regulator device. The control device and the regulator device are connected to each other through a first interface and a second interface. The control device transmits a required voltage value to the regulator device through the first interface and transmits a correction value based on the required voltage value and an output voltage output from the regulator device to the regulator device. The regulator device outputs a voltage to the control device on the basis of the received required voltage value and corrects a value of the voltage to be output to the control device on the basis of the received correction value.

An approach to a reduced-head hard disk drive (HDD) involves an actuator subsystem that includes a ball screw cam assembly wherein the number of starts of a multi-start screw equals the number of balls riding in a corresponding start. A stepper motor may be disposed within the screw, to drive rotation of the screw, which drives translation of an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack. The actuator subsystem may further include a cam locking mechanism for coupling and decoupling the actuator arm with a coil support structure and corresponding voice coil, so that the cam mechanism is able to move under the control of a voice coil motor when input/output operations are performed and is able to move the actuator arm assembly during translation operations.

An approach to a reduced-head hard disk drive (HDD) involves an actuator subsystem that includes a ball screw cam assembly wherein the number of starts of a multi-start screw equals the number of balls riding in a corresponding start. A stepper motor may be disposed within the screw, to drive rotation of the screw, which drives translation of an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack. The actuator subsystem may further include a cam locking mechanism for coupling and decoupling the actuator arm with a coil support structure and corresponding voice coil, so that the cam mechanism is able to move under the control of a voice coil motor when input/output operations are performed and is able to move the actuator arm assembly during translation operations.

A method for writing data in a disk drive having actuators each controlling arms extending over disk surfaces, including: receiving a write command from a host; receiving from the host data; dividing the data into data blocks; determining: a first surface from the disk surfaces where data is written by a first head of an arm controlled by a first actuator of the actuators; and a second surface from the disk surfaces where data is written by a second head of an arm controlled by a second actuator of the actuators; determining storage blocks of each of the first and the second surface; and writing first data blocks of the divided data blocks to the determined storage blocks of the first surface using the first head while writing second data blocks of the divided data blocks to the determined storage blocks of the second surface using the second head.

Disclosed herein is a motor driver circuit including a first output terminal to be connected to a first end of a to-be-driven motor via a sense resistor, a second output terminal to be connected to a second end of the motor, an error detector that generates an error signal, an A/D converter that obtains a digital signal, a compensator that generates a voltage command value, a D/A converter that converts the voltage command value to an analog control signal, a pulse width modulator that generates a first pulse and a second pulse, and an output stage that generates a first driving voltage and a second driving voltage. During a first mode, the compensator uses the error signal obtained by the A/D converter at a negative edge timing of the first pulse, for the error signal at a positive edge timing of the second pulse.

Embodiments provide a method of operating a voice coil motor via a transconductance loop. The method includes detecting an actual value of a supply voltage of the transconductance loop. An offset compensation signal of the transconductance loop is produced as a function of the detected actual value of the supply voltage based on a relationship between offset values and the supply voltage of the transconductance loop. The offset compensation signal is applied to a loop control signal of the transconductance loop. A drive current is applied to the voice coil motor. The drive current is related to a target drive current that is based on the loop control signal.

Rotational latency is reduced in a standard conventional form factor HDD system by replacing, for example, the prior art rotary arm actuator of a conventional HDD, with one or more belts and pulleys and one or more read/write heads mounted on, or otherwise associated with the belts. Multiple scaled iterations facilitate energy savings and power optimized systems, without compromise to data access performance.