In accordance with an embodiment, a circuit is configured to vary an intensity of a drive current of a resistive heater element based on the digital control signal. The circuit includes and output circuit configured to control a respective slew rate and an electric energy dissipated in the resistive heater element independently of a resistance value of the resistive heater element.

A magnetic disk device of an embodiment includes: a head structure including at least one reproducing head and main magnetic pole gap installation portion behind a flying slider and including at least two thermal actuators; and a control unit that can independently control the thermal actuators and that sets spacing of the reproducing head and the main magnetic pole gap installation portion with respect to a recording medium by setting a rotational speed at the time of contact, which rotational speed is a rotational speed of the recording medium, to be lower than a normal rotational speed when the reproducing head and the main magnetic pole gap installation portion are brought into contact with the recording medium.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including an assist part to assist recording of data into the magnetic disk, a controller configured to control the recording of data by the magnetic head based on a recording condition, and a memory configured to record a first threshold value used to define that an assist element included in the assist part is in a deterioration condition. Furthermore, the controller detects the condition of the assist element, determines whether or not the recording condition is changed based on the detected condition and the first threshold value stored in the memory, and changes the recording condition based on the result of the determination.

The present disclosure generally relates to a magnetic media drive employing a magnetic recording head. The magnetic recording head comprises a first write head and a second write head each coupled to a first pad and a second pad of a slider pad and an electrical circuit coupled to the first and second pads. The first write head is a wide writing write head, and the second write head a narrow writing write head. The electrical circuit comprises a first sub-circuit and a second sub-circuit connected in parallel. The first sub-circuit comprises a capacitor and a connection to a first thermal fly height control (TFC) of the first write head. The second sub-circuit comprises an inductor and a connection to a second TFC of the second write head. The electrical circuit is further connected to a third TFC of a read head, the second write head comprising the read head.

Example systems, data storage devices, and methods to provide long-term spacing compensation for heat assisted magnetic recording are described. The data storage device includes a storage medium with data tracks and a head that can be positioned for reading and writing those tracks. The head includes a laser for heat assisted magnetic recording and a fly height actuator. Based on the operation of the laser, both a short-term fly height compensation parameter and a long-term fly height compensation parameter are determined based on different temperature state models. The operating power of the fly height actuator is determined, at least in part, based on the short-term and long-term height compensation parameters.

According to an embodiment, a circuit includes a biasing and a low-frequency recovery circuit. The biasing circuit includes a voltage digital to analog converter (V-DAC), a differential difference amplifier coupled to the V-DAC, a common-mode feedback (CMFB) amplifier coupled to the differential difference amplifier, and a first pair of transistors arranged as a high-impedance structure and coupled to the differential difference amplifier and the CMFB amplifier. The low-frequency recovery circuit includes a current digital to analog converter (C-DAC), a second pair of transistors arranged as a high-impedance structure and coupled to the first pair of transistors, a pair of resistors having a resistance value equal to half a resistance of the resistive sensor, the pair of resistors arranged between the second pair of transistors and coupled to the C-DAC, and a gain circuit coupled to shared nodes between the second pair of transistors and the pair of resistors.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a heater a control section. When making the magnetic head carry out the seek operation from the first position to the second position, the control section starts application of a first voltage to the heater while the seek operation is carried out and, after application of the first voltage, makes the voltage to be applied to the heater a second voltage greater than the first voltage before the magnetic head is positioned to the second position and write of data is started by the magnetic head.

A storage device includes a controller that determines a degree of data degradation for a data track targeted by a pending read command and sets a head/media clearance parameter for execution of the read command based on the determined degree of data degradation for the data track, the head/media clearance parameter providing for a greater head-media separation when the determined level of degradation is lower than when the determined level of degradation is higher.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including a read head, a write head, a heater and the magnetic head, and a sensor and the control section. The control section when applying electric power to the heater, the control section predicts, on the basis of a relationship between a value of the electric power to be applied to the heater and an output value of a spectrum at a pulse frequency of a DC output of the sensor in a state where pulsed electric power is applied to the heater, the output value of the spectrum, and detects contact between the magnetic head and the magnetic disk before the predicted output value of the spectrum becomes less than or equal to a threshold.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including a read head, a write head, a heater and the magnetic head, and a sensor and the control section. The control section when applying electric power to the heater, the control section predicts, on the basis of a relationship between a value of the electric power to be applied to the heater and an output value of a spectrum at a pulse frequency of a DC output of the sensor in a state where pulsed electric power is applied to the heater, the output value of the spectrum, and detects contact between the magnetic head and the magnetic disk before the predicted output value of the spectrum becomes less than or equal to a threshold.