An apparatus for two-dimensional magnetic recording includes an array reader comprising a number of read sensors configured to read data from at least one track on a storage medium, a number of two-dimensional equalizer circuits each comprising inputs for receiving signals derived from each of the read sensors, each comprising an equalized output, and a number of iterative inter-track interference cancellation circuits, each operable to cancel inter-track interference in a different one of the equalized outputs from the two-dimensional equalizer circuits.

An apparatus for two-dimensional magnetic recording includes an array reader comprising a number of read sensors configured to read data from at least one track on a storage medium, a number of two-dimensional equalizer circuits each comprising inputs for receiving signals derived from each of the read sensors, each comprising an equalized output, and a number of iterative inter-track interference cancellation circuits, each operable to cancel inter-track interference in a different one of the equalized outputs from the two-dimensional equalizer circuits.

According to one embodiment, a magnetic disk device in includes a disk including a recording surface, a head configured to write and read data to and from the disk, and a controller configured to correct a threshold value causing data written in a track in at least one recording area of recording areas radially sectioned on the recording surface of the disk to be rewritten according to an index value indicative of signal quality of the data in the track and variable with the number of times of executed writing into the track.

A control mechanism may control the height and/or position of a read/write head configured to interact with a rotating information storage surface. A computation unit may compute a detected topography from gap measurements using a dynamic filter including a model of read/write head dynamics. A sensor may detect gap measurements of a side read/write track while the read/write head is interacting with a current read/write track. A memory may store the detected topography. The control mechanism may adjust the height of the read/write head based on the detected and/or stored topography. The control mechanism may be a reactionless control mechanism configured to apply a counterforce to offset movements of the read/write head and/or a slider.

During field operation of a heat-assisted magnetic recording data storage device, a laser adjustment procedure is performed. The laser adjustment procedure involves writing on a recording medium at least three tracks. If a bit error rate of a middle tracks has increased, the laser current is swept while recording test tracks to determine a new laser current that results in a minimum bit error rate. The new laser current is used for subsequent write operations.

During field operation of a heat-assisted magnetic recording data storage device, a laser adjustment procedure is performed. The laser adjustment procedure involves writing on a recording medium at least three tracks. If a bit error rate of a middle tracks has increased, the laser current is swept while recording test tracks to determine a new laser current that results in a minimum bit error rate. The new laser current is used for subsequent write operations.

A magnetic recording and reproducing device includes a magnetic recording medium having a lubricant on a surface of the magnetic recording medium, a heat-assisted magnetic recording head configured to perform magnetic recording on the magnetic recording medium, a humidity sensor, and a write procedure control circuit configured to control a write procedure of the heat-assisted magnetic recording head in accordance with a measurement result of the humidity sensor.

A laser power applied to a recording head is changed for a plurality of iterations. Each iteration involves, via the recording head at each laser power, writing multiple adjacent tracks to a heat-assisted recording medium and determining a bit error rate for at least one of the adjacent tracks at each laser power. A first laser power is found that achieves a minimum bit error rate of the iterations. An operational value of laser power that is smaller than the first laser power is used during operational recording to reduce adjacent track interference.

Described are systems, devices and methods for regulating speculative reading in a hard disk drive that has a read reliability budget. Regulating speculative reading under a read reliability budget involves selecting an amount of read look ahead (RLA) in response to determining whether or not a read rate exceeds the read reliability budget. When the read rate is lower than the read reliability budget, a full RLA amount can be used, thus ensuring high performance. When the read rate exceeds the read reliability budget, the RLA amount can be adjusted down while maintaining performance at acceptable levels. Adjustments to RLA may be made at periodic intervals, and in response to whether the workload is more sequential or more random.

Described are hard disk drives (HDDs) operable for archival applications and utilizing the same mechanical and electrical design of conventional HDDs. The capacity of a conventional HDD may be extended by up to 25% to 40% or more by employing multiple write and/or read spins before declaring success in write and read processes. The multiple write and/or read spins are designed to address the lower reliability that would otherwise result from high density packing of the data, at the cost of reducing performance. The result is an HDD with lower performance at higher capacity without sacrificing reliability and without altering conventional HDD mechanical or electrical design.