According to one embodiment, a data storage apparatus includes a storage media and a controller. The controller is configured to execute a first process of reading or writing user data from or to the disk storage media which includes a plurality of recording areas, in accordance with a command requested via the host interface, the command including address information that are capable of specifying a recording area; to recognize a first area in which no user data is written, in a case of executing a second process different from the first process on the plurality of recording areas, without designating address information that are capable of specifying a recording area; and to execute the second process on a second area in which user data is written excluding the first area among the plurality of recording areas.

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.

A system includes a read/write module and a caching module. The read/write module is configured to access a first portion of a recording surface of a rotating storage device. Data is stored on the first portion of the recording surface of the rotating storage device at a first density. The caching module is configured to cache data on a second portion of the recording surface of the rotating storage device at a second density. The second portion of the recording surface of the rotating storage device is separate from the first portion of the recording surface of the rotating storage device. The second density is less than the first density.

A method for writing data onto a medium on which data are stored in tracks includes encoding the data into at least one codeword, and writing a respective portion of each of the at least one codeword onto respective different tracks on the medium. The writing may include writing a respective portion of each of the at least one codeword onto respective different adjacent tracks on the medium. Another method for reading data includes positioning a plurality of read heads to read codewords that have been written across multiple tracks of a medium. Each read head in the plurality of read heads reads a different portion of the first group of the multiple tracks, and where each different portion of the multiple tracks overlaps at least one other different portion of the multiple tracks. Signals are detected from the plurality of read heads, and the detected signals are decoded.

An implementation of a system disclosed herein provides a method for managing data streams of sequential nature, wherein the method writes the sequential chunks (fragments) directly to an open band in the order these are received from the host and includes determining an end of the incoming data write request related to streaming data and in response to the determination of the end of the incoming data write request related to streaming data, copying remaining data from a current physical band mapped to logical block addresses LBAs related to the data write requests to the allocated (open) band.

Systems and techniques for writing data to a Shingled Magnetic Recording (SMR) magnetic data storage device. At least one processor may determine whether the distance between a first data track and a second data track is less than a threshold distance. If the distance is less than a threshold distance, the at least one processor may cause a write head to refrain from writing to the sector of the second data track. The at least one processor may cause data from the first data track to be copied to another storage location and write data to the sector of the second data track.

Host data to be written to a recording medium is categorized as one of sequential data or random data. The sequential data is written to a first track width on the recording medium. The random data is written to a second track width on the recording medium, the second track width being larger than the first track width.

A magnetic disk apparatus of one of the embodiments stores read position dependency information on read signal quality of a data region at a first track and measures the read signal quality at a predetermined radial position in a second data region of a second track different from the first track. A positioning error of the second data region is determined based on the read position dependency information and the read signal quality at the predetermined radial position. Data is recorded in a recording target data region in a shingled recording so as to prevent data written in the second data region from being overwritten by data in a recording target data region adjacent to the second data region by using the determined positioning error.

A configuration in which a reliable source of illegal copy content is analyzed using content in which a reproduction path can be set is realized. Content which has a segment area including a plurality of items of variation data which can be decrypted using different keys and in which a reproduction path corresponding to the selected variation data can be set is used. Each item of variation data is configured such that embedded information such as a digital watermark can be acquired from decrypted data. Each item of variation data includes a 192-byte source packet or a 6144-byte aligned unit. A reproduction device selects and reproduces one item of variation data from each segment area on the basis of a variation data identifier recorded in the variation data.

Various zone forwarding management techniques disclosed herein generally provide efficient methods of data caching, steering, mapping, and migration to reduce write amplification and command latency. In one implementation, a zone-forward storage medium management method includes receiving commands to write data sets to target LBAs included in a consecutive sequence of LBAs, selectively mapping the sequence of LBAs to a plurality of contiguous physical zones, and selectively writing the data sets to the physical zones. Various techniques may be used to migrate valid data of the plurality of physical zones to one physical zone.