According to one embodiment, a magnetic disk device includes a disk, a head including a read head that reads data from the disk, a write head that writes data to the disk, and an assist element that generates energy to enhance write performance by the write head, and a controller that selects and performs a first recording mode and a second recording mode different from the first recording mode, and selects and performs one of the first recording mode and the second recording mode according to an assist effect of the assist element.

An apparatus includes: a media; a heat assisted magnetic recording (HAMR) head over the media; and control circuitry, coupled to the HAMR head, the control circuitry being configured to: receive a write command to write the media; apply a dynamic flying height (DFH) control before asserting a write gate of the HAMR head; assert the write gate to the HAMR head; and enable a flying height compensation mechanism to maintain a constant value of a flying height of the HAMR head over the media during a next assertion of the write gate.

According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a magnetic head, and a processor. The magnetic head includes a first reproducing element portion and a second reproducing element portion. The processor is configured to acquire a first signal and a second signal, and to output an output signal according to either one of the first signal and the second signal. The first signal is obtained by reproducing information recorded on a first recording region by the first reproducing element portion. The second signal is obtained by reproducing the information recorded on the first recording region by the second reproducing element portion.

According to one embodiment, a magnetic disk device includes a disk, a head including a read head that reads data from the disk, a write head that writes data to the disk, and an assist element that generates energy to enhance write performance by the write head, and a controller that selects and performs a first recording mode and a second recording mode different from the first recording mode, and selects and performs one of the first recording mode and the second recording mode according to an assist effect of the assist element.

According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a magnetic head, and a processor. The magnetic head includes a first reproducing element portion and a second reproducing element portion. The processor is configured to acquire a first signal and a second signal, and to output an output signal according to either one of the first signal and the second signal. The first signal is obtained by reproducing information recorded on a first recording region by the first reproducing element portion. The second signal is obtained by reproducing the information recorded on the first recording region by the second reproducing element portion.

According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a magnetic head, and a processor. The magnetic head includes a first reproducing element portion and a second reproducing element portion. The processor is configured to acquire a first signal and a second signal, and to output an output signal according to either one of the first signal and the second signal. The first signal is obtained by reproducing information recorded on a first recording region by the first reproducing element portion. The second signal is obtained by reproducing the information recorded on the first recording region by the second reproducing element portion.

A hard disk drive write drive method and integrated circuit that provide a configurable overshoot current based on the length of the pattern in the write current signal that is being written to the hard disk by the write driver. The hard disk write driver adds a first overshoot current to all patterns in the write current signal and adds an additional second overshoot current to patterns in the write current signal shorter than a first duration. The hard disk drive write driver utilizes an H-bridge circuit configured to add the first overshoot current and the additional second overshoot current to the write current signal. The H-bridge circuit is comprised of four switching elements that are configured to generate a first overshoot current for all pattern transitions of the write current signal and generate a second overshoot current for pattern transitions shorter than the first duration.