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 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 method of tuning a notch filter in a data storage device (DSD) including the notch filter and a shock detection system includes: adjusting pulse width modulator (PWM) frequency settings of a spindle drive signal; detecting a maximum noise level of an output signal of the shock detection system while adjusting the PWM frequency settings; and selecting a notch filter frequency corresponding to a PWM frequency setting at which the maximum noise level of the output signal of the shock detection system is detected.

A method of setting the value of an operational parameter of a well is provided. The method includes providing a measure related to the actual value of the parameter; setting a maximum limit for the measure; setting a minimum limit for the measure; setting a demanded value for the parameter; and automatically overriding the demanded value if it is such that it would result in the measure exceeding the maximum limit or being below the minimum limit to produce an actual value for the parameter with results in the measure not exceeding the maximum limit and not being below the minimum limit.

A checking unit configured to check whether or not each of the plurality of storage devices is a speed-changeable storage device capable of processing data at a plurality of rotation speeds, and a control unit configured to set a storage device among the plurality of storage devices that is checked to be the speed-changeable storage device to a first state operating at a first rotation speed that is a first threshold or less in a case where a data access to the storage device does not occur are included, whereby effective power saving can be realized in a simple manner.

A checking unit configured to check whether or not each of the plurality of storage devices is a speed-changeable storage device capable of processing data at a plurality of rotation speeds, and a control unit configured to set a storage device among the plurality of storage devices that is checked to be the speed-changeable storage device to a first state operating at a first rotation speed that is a first threshold or less in a case where a data access to the storage device does not occur are included, whereby effective power saving can be realized in a simple manner.

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.

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.

An apparatus and a computer-implemented method for generating pulses synchronized to a rising edge of a tachometer signal from rotating machinery are disclosed. For example, in one embodiment, a pulse state machine may be configured to generate a plurality of pulses, and a period state machine may be configured to determine a period for each of the plurality of pulses.

A record player includes a base, a platter, a tonearm assembly and a monitoring unit. The monitoring unit is secured on the base, and includes a light emitter, an image capturing module and a processing module. The light emitter can emit light toward the platter or an acoustical record disposed on the platter. The image capturing module can receive the light reflected by the platter or the acoustical record, and capture images of the platter or the acoustical record. The processing module can receive the images from the image capturing module, and determine a current rotating speed of the platter or the acoustical record by analyzing and comparing the images captured by the image capturing module at successive time points.