Method and apparatus for enhancing write current switching efficiencies during data write operations in a data storage device. In some embodiments, write data are described in the form a sequence of symbols of nT length where T is a channel clock rate and n is an integer over a selected range. Bi-directional write currents are applied to a write element to record the sequence of symbols to a storage medium. The write currents are switched between a first rail current and a second rail current for alternating symbols. The write currents are further transitioned to an intermediate current value for at least one channel clock period immediately preceding a next occurrence of a symbol boundary between an adjacent pair of symbols in the sequence.

According to one embodiment, servo patterns different in servo pattern frequency are recorded in zones divided in a radial direction on a magnetic disc, and the servo patterns in the adjacent zones overlap each other in a predetermined area from a zone servo boundary between the zones, and a determination boundary where it is determined to execute a crossing process is set within the overlapping area of the servo patterns upstream from the zone servo boundary, based on position information on a seek destination and the present position of the magnetic head.

Apparatus and method for magnetic recording media. A rotatable magnetic recording disc has an outermost annular sidewall that extends at nominally 97 millimeters, mm for a 3 inch form factor data storage device or at nominally 67 mm for a 2 inch form factor data storage device. The rotatable magnetic recording disc further has a disc shaped substrate of metal or glass, and a magnetic recording layer supported by the disc shaped substrate and configured to magnetically record data along concentric tracks.

A storage device includes a storage controller configured to operate a heat-assisted magnetic recording head to write data to a band of consecutive data tracks in a consecutive track order while selectively alternating a power level of the heat source when writing to some data tracks of the band.

A method includes storing a data group in a first zone of a plurality of radial zones of a data storage disc. Each different one of the plurality of zones has a different throughput level. The method further includes obtaining information related to an access frequency of the data group stored in the first zone of the plurality of zones. Based on the information related to the access frequency of the data group and the different throughput levels of the different zones, a determination is made as to whether to migrate the data group from the first zone of the plurality of zones to a second zone of the plurality of zones.

An optical disk includes a disk management information area in which predetermined information is recorded in advance, and a recording system area in which information for identifying a recording system of the optical disk recorded in a predetermined position within a non-data area included in a recordable area is recorded. A method for accessing the optical disk is decided based on disk management information and the information for identifying a recording system.

Methods, systems, and apparatuses are described for provisioning storage devices. An example method includes determining a write status of an adjacent track that is adjacent to a target track of a shingled magnetic recording (SMR) disk drive. The method may further include determining an offset for a write head based on the write status of the adjacent track and positioning the write head according to the offset.

Identifying recording disk defects in a data storage device such as a hard disk drive (HDD), for which disk defects are not previously identified, includes responsive to a first user data write request to a particular storage area of a disk medium, writing the user data to the particular storage area, reading the written user data from the particular storage area, and verifying the integrity of the user data read from the particular storage area. Upon passing, a second user data write request to the same particular storage area can be fulfilled without again reading and verifying. Upon failing, the particular storage area is marked as defective and the user data is written to a different storage area. This procedure can be repeated in response to each initial user write request to each storage area of each disk medium, foregoing the need for disk surface scanning during manufacturing.

There is provided a magnetic disk device including a magnetic disk, and circuitry configured to receive a control command for instructing to write data in the magnetic disk or to rear the data from the magnetic disk, perform a data access process of writing the data in the magnetic disk or reading the data from the magnetic disk according to the received control command, specify a data amount of object data of the data access process, calculate a cumulative value of the data amount of the object data from a start of an operation, and perform notification when the cumulative value is equal to or larger than a predetermined threshold.

Data can be encoded in physical medium and represented by shapes having many various physical attributes. In various examples, data points are encoded and represented by the physical shape, color, size, and/or structure of objects. In one embodiment, holes in memory surface substrates represent data. Various attributes of such holes, including depth, profile size, profile shape, and/or angle can represent data.