Abstract: A method of protecting information written to a recording medium includes magnetizing the recording medium to form a first magnetic pattern corresponding to information to be stored, and magnetizing the recording medium to form a protective magnetic pattern having a phase difference of 180° from the first magnetic pattern at a position adjacent to where the first magnetic pattern is formed, with adjacent bits of the first magnetic pattern opposite and the protective magnetic pattern opposite to each other.

Abstract: An apparatus can include a disk drive controller that includes at least one repeatable run out (RRO) compensator corresponding to a RRO component, the disk driver controller configured to change a head assembly position, and to disable the at least one RRO compensator in response to the head assembly position changing from one predetermined area of a disk to at least one other predetermined area of the disk

Abstract: A decoder includes a first decoder configured to iteratively decode input data, accumulate iteratively decoded data in bit units, compare an accumulated value obtained for each bit of the iteratively decoded data with a plurality of reference values, and output decision data and indicator data according to a comparison result. The decoder includes a second decoder configured to perform error correction on a symbol including the decision data according to the indicator data.

Abstract: A method to compensate repeatable run out of a hard disk drive apparatus includes receiving a write or read command to write or read data with respect to a disk having an inner diameter (ID) area, a middle diameter (MD) area, and an outer diameter (OD) area which are preset, determining a present position of a magnetic head and a position where the magnetic head writes or read data, stopping an operation of at least one of RRO compensators for RRO components of particular frequencies when the present position of the magnetic head is the ID area and the position where the magnetic head writes or reads the data is the MD area or OD area of the disk, and performing data writing or reading by performing seeking and settling of the magnetic head.

Abstract: Provided are systems and methods to communicate data transfer of data between a disk device and an external storage device. A host can generate a control command to communicate with an external storage device, and a disk device to receive the control command from a host to identify and communicate with an external storage device when connected to the external storage device and to configure the external storage device by assigning an ID code to each storage area of the external storage device.

Abstract: A ferroelectric hard disk device is provided and includes: a ferroelectric media having a bottom electrode and a ferroelectric layer disposed on the bottom electrode; and a head formed above the ferroelectric media, the head being operative to write and reproduce information on the ferroelectric layer.