An apparatus may include a preamplifier configured to implement multiple operational modes and configured to be connected to a magnetic read/write head, wherein the magnetic read/write head includes a read sensor to read data from a disk and a write element to write data to the disk. The preamplifier may further include an input configured to receive a test mode control signal to activate a mode monitoring mode of one or more test modes of a test mode circuit of the preamplifier, the test mode circuit configured to determine an indicator of the current operational mode of the preamplifier, and an output to provide the determined indicator of the current operational mode of the preamplifier.

An apparatus comprises a slider having a media-facing surface and that is configured for heat-assisted magnetic recording. The slider comprises a write pole, a heatsink layer, and a diffusing metal. The write pole includes two or more sides extending into the slider and a pole tip at the media-facing surface. The heatsink layer is proximate at least part of the two or more sides of the write pole, and a first portion of the heatsink layer is proximate the pole tip. The diffusing metal is disposed proximate the write pole.

According to one embodiment, a magnetic disk device includes a disk, a head configured to write data to the disk, and an integrated circuit configured to acquire a detection signal indicative of a first pattern of a first frequency of write data, change a first current of a second pattern of a write current corresponding to the first pattern on the basis of the detection signal, detect a third pattern of a second frequency which is greater than the first frequency from the write data, change a second current of a fourth pattern of the write current corresponding to the third pattern, and output the write current with the changed first current and the changed second current to the head.

An apparatus comprises a slider configured for writing data to and reading data from a magnetic recording medium and for heat-assisted magnetic recording. The slider comprises a heater configured to receive an AC signal and to cause oscillation in a spacing between the slider and the medium, and a contact sensor situated on the slider and configured to produce a DC response signal. A detector is coupled to the slider and configured to measure an amplitude of a spike in the DC response signal, calculate a ratio between the spike amplitude and an amplitude of the DC response signal, and detect contact between the slider and the medium in response to the ratio exceeding a predetermined threshold.

A storage system includes a magnetic write head, a magnetic storage medium, a write data circuit having a write data output and a magnet length signal output, and a preamplifier that receives the write data and a magnet length signal from the write data circuit, and sets at least one write current characteristic through the magnetic write head based at least in part on the magnet length signal. The write data circuit processes write data to be recorded on the magnetic storage medium by the magnetic write head. The magnet length signal output communicates magnet lengths in the write data.

A storage system includes a magnetic storage medium, a magnetic write head, a channel circuit and a preamplifier. The channel circuit includes a write data input, a differentiated edge emphasis signal generator, a write data output and a differentiated edge emphasis signal output. The preamplifier includes a write data input configured to receive write data from the channel circuit write data output, an edge emphasis signal input configured to receive a differentiated edge emphasis signal from the channel circuit differentiated edge emphasis signal output, and a write current edge emphasis controller configured to generate a write current to the magnetic write head based at least in part on the write data and on the differentiated edge emphasis signal.

A storage system includes a magnetic write head, a magnetic storage medium, a channel circuit comprising a write data output, wherein the channel circuit is operable to process write data to be recorded on the magnetic storage medium by the magnetic write head, and a preamplifier operable to receive the write data from the channel circuit, wherein the preamplifier comprises a number of register pages configured to store pattern dependent write current characteristics for a variety of magnet lengths, and wherein the preamplifier is operable to retrieve the write current characteristics based on magnet lengths and to record data bits on the magnetic storage medium using the write current characteristics.

For each head in a collection of heat-assisted magnetic recording read/write heads, a reader width and a writer width is measured. A predicted life is determined for each head based on the respective reader width and writer width. In a first set of drives having relatively fewer heads per drive, a first subset of the heads having a higher value of the predicted life are used. In a second set of drives having relatively more heads per drive, a second subset of the heads having a lower value of the predicted life are used.

A storage system includes a magnetic write head, a magnetic storage medium, a channel circuit comprising a write data output, wherein the channel circuit is operable to process write data to be recorded on the magnetic storage medium by the magnetic write head, and a preamplifier operable to receive the write data from the channel circuit, wherein the preamplifier comprises a number of register pages configured to store pattern dependent write current characteristics for a variety of magnet lengths, and wherein the preamplifier is operable to retrieve the write current characteristics based on magnet lengths and to record data bits on the magnetic storage medium using the write current characteristics.

A storage system includes a magnetic storage medium, a magnetic write head, a channel circuit and a preamplifier. The channel circuit includes a write data input, a differentiated edge emphasis signal generator, a write data output and a differentiated edge emphasis signal output. The preamplifier includes a write data input configured to receive write data from the channel circuit write data output, an edge emphasis signal input configured to receive a differentiated edge emphasis signal from the channel circuit differentiated edge emphasis signal output, and a write current edge emphasis controller configured to generate a write current to the magnetic write head based at least in part on the write data and on the differentiated edge emphasis signal.