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.

An emulation mitigation module is configured to mitigate emulation of legacy write requests on advanced disk devices using cached data stored in a cache memory of a storage system. A legacy write request may comprise write data blocks formatted in a legacy sector size while an advanced disk device may be formatted in an advanced sector size. The emulation mitigation module may execute a first method for modifying write requests using cached data, a second method for enforcing a minimum requested data size sent to the advanced disk device, and/or a third method for conditionally retrieving data from the advanced disk device and storing to cache. In some embodiments, the second and/or third method may be used with the first method to increase the effectiveness of the first method. The emulation mitigation module may improve performance and/or data integrity for of processing legacy write requests.

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.

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.

A derivation device is a device that derives a reading path by a reading element in a case where plural pieces of data to be read are read from a recording medium, and includes a first derivation unit that derives a value representing a recording density of the data for each of plural areas in which the plural pieces of the data to be read are recorded, and a second derivation unit that derives a path for sequentially reading the data as the reading path for an area in which the value representing the recording density is equal to or larger than a predetermined threshold value and derives the reading path according to a predetermined path determination method for an area in which the value representing the recording density is less than the threshold value.

The magnetic tape has a timing base servo pattern on the magnetic layer, wherein the centerline average surface roughness Ra on the surface of the magnetic layer is less than or equal to 1.8 nm, the magnetic layer contains a fatty acid ester, the full width at half maximum of spacing distribution measured by optical interferometry on the surface of the magnetic layer before and after vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 7.0 nm, the difference of spacing measured by optical interferometry on the surface of the magnetic layer after and before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 8.0 nm.

A method according to one aspect of the present disclosure includes the steps of: acquiring a play list including identification information indicating each of a plurality of elementary streams; selecting an elementary stream indicated by predetermined identification information from the acquired play list; acquiring a difference file including data that is not included in the selected elementary stream; and converting the selected elementary stream into an MP4 file format by combining data included in the difference file and data included in the selected elementary stream based on a manifest file corresponding to the selected elementary stream, the manifest file being necessary for the conversion of a file format based on a predetermined rule.

A command to write data to a virtual location is received at a disk storage system. The virtual location is mapped to a tape storage system. A record is generated including the data, the virtual location, and a sequence value. The sequence value indicates relative sequence when compared to other sequence values. The record is written to a record location on a tape cartridge loaded in a tape drive. Record metadata on the disk storage system is modified to indicate that the first record location contains the first record. The data on the record can be read from the tape cartridge.

An information recording method of recording information is provided in an information recording medium having a plurality of recording layers including a first recording layer and a second recording layer located to be closer to a surface than the first recording layer, each of the plurality of recording layers includes a user data area for recording user data, a spare area for alternatively recording data of failed recording into the user data area, and a management information area for recording management information. The first recording layer is used as a recording object layer at start of recording. When any one of the user data area, the spare area, and the management information area of the first recording layer runs short of a free space, then the recording object layer of the user data area, the spare area, and the management information area is switched over to the second recording layer.

According to one embodiment, a magnetic disk device includes a magnetic recording medium, a head including a recording magnetic pole, a spin torque oscillator provided near the recording magnetic pole, and a coil which excites the recording magnetic pole, a first current supply which supplies the coil with a first current corresponding to write data, a detector which detects a first signal corresponding to the write data, and outputs a second signal in accordance with the first signal, and a second power supply which varies, in accordance with the second signal, a second current supplied to the spin torque oscillator.