A method for a server to access a shingled magnetic recording (SMR) disk includes: receiving, by the server, a data operation request, where the data operation request includes address information of target data; determining, according to the address information, a target storage zone in the SMR disk and that corresponds to the target data; determining that there is write pointer information of the target storage zone in a cache, and obtaining the write pointer information from the cache, where the write pointer information is address information of latest stored data in the target storage zone; generating a data operation instruction according to the write pointer information and the address information of the target data, where the data operation instruction is used to perform an operation on the target data; and sending the data operation instruction to the SMR disk.

According to one embodiment, a magnetic disk device includes a magnetic disk, a first magnetic head, a second magnetic head, a buffer memory, and a control circuit. The magnetic disk includes a plurality of first storage regions. The control circuit controls the first magnetic head to read first data from a second storage region of the first storage regions to the buffer memory. The control circuit controls the second magnetic head to write second data to a third storage region concurrently with the reading of the first data. The third region is of the first storage regions, different from the second storage region. The second data corresponds to the first data stored in the buffer memory.

The present disclosure describes aspects of constant-density writing for magnetic storage media. In some aspects, a constant-density writer delays transitions between bits within write data to enable constant-density writing. The write data has an initial bit period based on a constant clock signal, which is generated based on the rotation of a media disk. The constant-density writer modifies the write data to generate phase-delayed write data, which has a bit period that is greater than or equal to the initial bit period. To realize this bit period, the constant-density writer changes write phases of bit transitions within the write data. The constant-density writer can also insert stretch bits, filter single-bit transitions, and mitigate glitches within the phase-delayed write data.

Systems and methods for servo zone transition optimization are described. In one embodiment, the storage system device includes a disk drive and a controller. In some embodiments, the controller may be configured to assess at least one operation of a read/write head of the disk drive; and format, based at least in part on the assessing of the read/write head, a disk surface of the disk drive with a first servo zone, a second servo zone, and an overlap region extending between a start point of the second servo zone and an end point of the first servo zone. In some cases, the overlap region starts towards a disk inner diameter (ID) and ends towards a disk outer diameter (OD).

According to one embodiment, a magnetic disk device includes a disk including two first servo sectors and at least a second servo sector, a head, and a controller, wherein the first servo sector includes burst data and a first data pattern written before the circumferential direction of the burst data, the second servo sector includes the burst data, the first data pattern, and a second data pattern written after the circumferential direction of the burst data, a first frequency of the first data pattern is different from a second frequency of the second data pattern, and a first length of the first data pattern is different from a second length of the second data pattern.

According to one embodiment, a recording density setting method includes performing first process and performing second process. The first process including recording and reading data on and from a disk medium of a magnetic disk device, and acquiring first information for setting the read data to satisfy a certain quality criterion. The first information represents a first shape of a first plurality of unit regions. Each of the a first plurality of unit regions is a recording region of a unit capacity. The second process includes acquiring second information representing a second shape of the first plurality of unit regions, and setting a recording density on the basis of the second information. The second shape is formed by adding margin regions having the same area to the first plurality of unit regions of the first shape.

In a disk drive, when an off-track error occurs during a sequential disk access operation that spans multiple contiguous data tracks, efficient recovery is performed. In an embodiment, the disk access operation (e.g., reading from or writing to a disk) is attempted for all sectors of the sequential disk access operation. The disk access operation is then attempted again for sectors associated with any off-track errors that occurred during the disk access operation. In another embodiment, when an off-track error occurs during a sequential write operation in a shingled magnetic recording drive, the data originally targeted to be written to a first portion is written to a second portion of the data track that follows the first portion. Since no additional revolutions of the disk are needed for data associated with the sequential write operation to be written to the disk.

A method comprising: determining, by a tape library, respective tape densities supported by each of a plurality of tape drives and respective tape densities indicated for each of a plurality of tape cartridges; receiving, by the tape library, a command to load a given one of the tape cartridges into a given one of the tape drives; determining, by the tape library, that the indicated tape density for the given tape cartridge matches a tape density supported by the given tape drive; and in response to the determination that the tape densities match, configuring, by the tape library, the given tape drive to initialize the given tape cartridge to the tape density indicated for the given tape cartridge.

According to one embodiment, a magnetic disk device includes a disk, a head including a main magnetic pole having a first end and a second end opposite to the first end in a radial direction of the disk, a write shield facing the main magnetic pole with a gap, and an assist element provided in the gap and at a position where a first distance between the first end and the assist element and a second distance between the second end and the assist element are different from each other, and a controller which controls a voltage applied to the assist element according to a shingled write direction in which a second track is overwritten on a first track.

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.