According to one embodiment, a magnetic disk device includes a magnetic disk section and a control section. The magnetic disk section includes a magnetic disk, a magnetic head, and a preamplifier. The control section included a processing section configured to cause the preamplifier to execute processing of generating the recording current used by a write head to write data to the magnetic disk, and processing of receiving an output reproduced from the magnetic disk by a read head, and configured to control the magnetic disk section. In the preamplifier, processing of reading data from the magnetic disk is executed by the read head in parallel with processing of writing data transferred from the control section to the magnetic disk by means of the write head.

According to one embodiment, a magnetic disk device includes a magnetic disk section and a control section. The magnetic disk section includes a magnetic disk, a magnetic head, and a preamplifier. The control section included a processing section configured to cause the preamplifier to execute processing of generating the recording current used by a write head to write data to the magnetic disk, and processing of receiving an output reproduced from the magnetic disk by a read head, and configured to control the magnetic disk section. In the preamplifier, processing of reading data from the magnetic disk is executed by the read head in parallel with processing of writing data transferred from the control section to the magnetic disk by means of the write head.

According to one embodiment, a magnetic disk device includes a disk, a head including a main magnetic pole having a first end and a second end opposite to the first end in a radial direction of the disk, a write shield facing the main magnetic pole with a gap, and an assist element provided in the gap and at a position where a first distance between the first end and the assist element and a second distance between the second end and the assist element are different from each other, and a controller which controls a voltage applied to the assist element according to a shingled write direction in which a second track is overwritten on a first track.

A magnetic disk device includes a magnetic disk that includes a plurality of zones divided in a radial direction, a plurality of tracks in each of the zones, and a plurality of sectors in each of the tracks divided in a circumferential direction, a magnetic head configured to read and write data to and from the magnetic disk, and a control unit configured to determine a setting value of a recording current to be applied to the magnetic head when writing to each of a plurality of sections of a first sector, based on error rates in data read from a second sector that is in the same zone as the first sector and to which a write was performed while changing setting values of recording currents applied to the magnetic head while writing to each of a plurality of sections of the second sector.

A computer program product, according to one embodiment, includes a computer readable storage medium having program instructions embodied therewith, wherein the computer readable storage medium is not a transitory signal per se, the program instructions executable by a processing circuit to cause the processing circuit to perform a method that includes reading data from a magnetic data storage medium. The processing circuit uses a tracking threshold module to detect and track positive peak amplitudes and negative peak amplitudes of a readback waveform during the data reading. Asymmetry compensation is performed on the data based on input from the tracking threshold module. The asymmetry compensation does not rely on an input except from the tracking threshold module in order to perform the asymmetry compensation.

According to an embodiment, there is provided a disk device including a disk, a head, a preamplifier and a controller. The head writes information to the disk according to a write current. The preamplifier causes the write current to flow through the head. The controller is capable of causing the preamplifier to perform current zero control for maintaining an amplitude of the write current at zero, and is capable of changing a time for maintaining the amplitude of the write current at zero according to a pattern of write data.

An apparatus may include a circuit configured to generate, by an analog to digital converter (ADC), one or more ADC samples based on an input signal. The circuit may be further configured to generate a first estimated signal using a first channel pulse response estimation with a gain constraint based on the one or more ADC samples and generate a second estimated signal using a second channel pulse response estimation with a phase constraint based on the one or more ADC samples.

Disclosed are a two-stage audio gain circuit based on analog-to-digital conversion and an audio terminal. The two-stage audio gain circuit includes a PGA configured to receive an analog audio signal and perform programmable gain amplification processing on the received analog audio signal; an ADC configured to convert the analog audio signal after the programmable gain amplification processing into a digital audio signal and output the digital audio signal; a first AGC gain unit configured to perform a first AGC processing on the digital audio signal and output a first gain adjustment value to the PGA, for the PGA to perform gain adjustment on the received analog audio signal; and a second AGC gain unit configured to perform a second AGC processing on the digital audio signal and output a second gain adjustment value to the PGA, for the PGA to perform gain adjustment on the received analog audio signal.

Methods, apparatuses and systems for detecting defective sectors on a recording medium. A defective sector detector apparatus comprises an error-corrected ECC symbol number calculator and a defective sector determination unit. The error-corrected ECC symbol number calculator is configured to count a total number of error correcting code (ECC) symbols that are error-corrected in data read from data sectors on a track of a recording medium of the storage device. The defective sector determination unit is configured to receive the total number of ECC symbols that are error-corrected for a data sector from the error-corrected ECC symbol number calculator and determine whether the total number of ECC symbols that are error-corrected exceeds a threshold value. If it is determined that the total number of ECC symbols that are error-corrected exceeds the threshold value, the defective sector determination unit outputs information indicating the data sector to be a defective sector.

A data storage device is disclosed comprising a head actuated over an energy assisted magnetic media comprising a plurality of data tracks, wherein each data track comprises a plurality of data sectors. A write operation to a first data sector is executed by applying a first current to a write coil of the head while the head is over a second data sector preceding the first data sector, wherein the first current comprises a first amplitude. A second current is applied to the write coil while the head is over the first data sector, wherein the second current comprises a second amplitude lower than the first amplitude.