According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, an electric power supply section, a control section, and an address storage section. The control section reads data from the magnetic disk by means of the read head on the basis of the address stored in the address storage section at predetermined timing, and writes the read data to the magnetic disk by means of the write head without suppressing the magnetic field range.

A noncontact communication medium includes a processor, and a memory incorporated in or connected to the processor, and performs noncontact communication with an external communication device. The memory has a storage block where information regarding an attribute of the noncontact communication medium is stored and that includes a plurality of storage fields. The plurality of storage fields include a specification-independent storage field where information independent of a specification of a magnetic tape cartridge, in which the noncontact communication medium is mounted, is stored. The processor is configured to write accompanying information regarding the magnetic tape cartridge in the specification-independent storage field in response to an instruction given from the external communication device to the noncontact communication medium by the noncontact communication.

A noncontact communication medium includes a processor, and a memory incorporated in or connected to the processor, and performs noncontact communication with an external communication device. The memory has a storage block where information regarding an attribute of the noncontact communication medium is stored and that includes a plurality of storage fields. The plurality of storage fields include a specification-independent storage field where information independent of a specification of a magnetic tape cartridge, in which the noncontact communication medium is mounted, is stored. The processor is configured to write accompanying information regarding the magnetic tape cartridge in the specification-independent storage field in response to an instruction given from the external communication device to the noncontact communication medium by the noncontact communication.

According to one embodiment, a magnetic disk device incudes a first magnetic disk, a first actuator that reads/writes data from/to the first magnetic disk, a first controller that controls the first actuator, a second magnetic disk, a second actuator that reads/writes data from/to the second magnetic disk, a second controller that controls the second actuator, wherein the first controller executes read/write processing, and the second controller stores trace data of the read/write processing when the first controller executes the read/write processing.

According to one embodiment, a magnetic disk device incudes a first magnetic disk, a first actuator that reads/writes data from/to the first magnetic disk, a first controller that controls the first actuator, a second magnetic disk, a second actuator that reads/writes data from/to the second magnetic disk, a second controller that controls the second actuator, wherein the first controller executes read/write processing, and the second controller stores trace data of the read/write processing when the first controller executes the read/write processing.

In a card reader, an interfering magnetic field generation mechanism 11 includes a core part 14a, a core part 14b, and a core part 15a, each of which is formed of soft magnetic material in a straight line, a coil 16 that is wound around the core part 14a, a coil 17 that is connected to the coil 16 in series and is wound around the core part 14b, a coil 18 that is wound around the core part 15a, a first drive circuit that supplies alternating current to the coils 16 and 17, and a second drive circuit that supplies alternating current to the coil 18. The core part 15a is disposed between the core part 14a and the core part 14b. The core part 15a is formed independently of the core parts 14a and 14b, and is separated from the core parts 14a and 14b.

Systems and methods are disclosed for synchronous writing of a grain patterned medium. The systems and methods can be implemented within a data storage device having a grain patterned medium. Further, a calibration process to determine a count of bits between servo wedges can be implemented in manufacturing, within the data storage device, or both. In some examples, the data storage device, during operation, can utilize the count of bits to perform synchronous writing, determine write errors, or both. Further, the servo wedge of the grain patterned medium may be patterned with a same or similar grain pattern as the data area that follows the servo wedge. Such a data storage device can implement a single clock for reading a servo wedge and writing a data area.

According to one embodiment, a magnetic recording device includes a magnetic head and a controller. The magnetic head includes a first magnetic pole, a magnetic element including a first magnetic layer, and a coil. The controller is electrically connected to the magnetic element and the coil. The controller is configured to supply a recording current to the coil and supply an element current to the magnetic element. The recording current includes a first period of a first polarity, a second period of a second polarity, a third period that shifts from the first to second period, and a fourth period that shifts from the second to first period. The element current includes DC and AC components. The AC component in the first period is the same as the AC component in the second period, the AC component in the third period, and the AC component in the fourth period.

A media library (10) for evaluating a health of a head (256) of a media drive (26) includes a library control system (30) that is configured to control oversight functionality of the media library (10). The library control system (30) receives media drive information generated during at least one of a read procedure and a write procedure being performed by the media drive (26) and analyzes the media drive information to determine the health of the head (256) of the media drive (26). The media drive information includes drive performance metrics generated by the media drive (26) during a read verify procedure performed by the media drive (26) upon request of the library control system (30) of the media library (10).

The technology disclosed herein provides a method including determining an acceptable parameter rate for a dual reader storage device having dual readers, identifying one of the dual readers as the preferable reader, comparing an actual parameter rate of the storage device to the acceptable parameter rate of the storage device, and in response to determining that the actual parameter rate is below the acceptable parameter rate, operating the storage device using only the preferable reader. In one implementation, the parameter rate is bit-error rate (BER) of the dual readers.