Data is written to a magnetic recording medium of a drive using a read/write head. The read/write head has an energy source that applies a hotspot to the magnetic recording medium while recording. During the writing, a steady-state current applied to the energy source is changed by a step value. A timing error induced by the change in the steady-state current is measured based on reading back the data. A thermal gradient of the hotspot is determined based on the step value and the timing error.

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 configuration for preventing a recording error when a data recording process is performed on both lands and grooves of an optical disc is realized. An information processing device includes a data processing unit configured to control a data recording process on both lands and grooves of an optical disc. The data processing unit performs a process of detecting or matching positions at which data recording states of grooves or lands on both sides adjacent to a data recording target land or groove match when data are recorded on the lands or the grooves. The data processing unit performs, for example, a dummy data recording process or a skipping process as the process of matching the data recording states of the grooves or the lands on both sides adjacent to the data recording target land or groove.

A configuration for preventing a recording error when a data recording process is performed on both lands and grooves of an optical disc is realized. An information processing device includes a data processing unit configured to control a data recording process on both lands and grooves of an optical disc. The data processing unit performs a process of detecting or matching positions at which data recording states of grooves or lands on both sides adjacent to a data recording target land or groove match when data are recorded on the lands or the grooves. The data processing unit performs, for example, a dummy data recording process or a skipping process as the process of matching the data recording states of the grooves or the lands on both sides adjacent to the data recording target land or groove.

A disk drive thermal performance testing device includes a drive housing, an electrical connector and an adjustable power loading device. The drive housing is at least partially made of a thermally conductive material. The electrical connector is in the drive housing and provides an external connection. The adjustable power loading device is located in the drive housing, is coupled to the electrical connector, and is thermally coupled to the drive housing.

In one example, the disclosure is directed to error-correcting code techniques for managing data by a host device. In some examples, in writing the data, a host device receives parity data, data and one or more error pointers from a storage device. Each respective error pointer references a location of a respective data sector of the data that contains an error. The host device determines, based at least in part on the one or more error pointers, a first data sector of the data that contains an error. The host device recovers, based at least in part on the parity data, the data, and the one or more error pointers, the first data sector.

Implementations described and claimed herein provide a high-capacity, high-bandwidth scalable storage device. The scalable storage device includes a layer stack including at least one memory layer and at least one optical control layer positioned adjacent to the memory layer. The memory layer includes a plurality of memory cells and the optical control layer is adapted to receive optically-encoded read/write signals and to effect read and write operations to the plurality of memory cells through an electrical interface.

According to one embodiment, a magnetic disk device includes a magnetic disk, a head and a controller. The head writes data to the magnetic disk and reads data from the magnetic disk. The controller once reads the data written to a predetermined recording area according to the number of writes of data to the predetermined recording area of the magnetic disk and rewrites the read data to the predetermined recording area. The controller adjusts an additive value to the number of writes based on the presence or absence of a defect on the recording surface of the magnetic disk.

According to one embodiment, a magnetic disk device includes a disk, a head, and a controller setting a rewrite threshold value for executing a rewrite process of different tracks in a first sector group including at least one first sector continuous from a first parity sector in which error correction processing in units of tracks is executable based on the first parity sector and including the first parity sector, and a second sector group including at least one second sector continuous in which the error correction processing in units of tracks is unexecutable, and rewriting the first sector group and the second sector group with different frequencies.

According to one embodiment, a magnetic disk device includes a disk, a head, and a controller setting a rewrite threshold value for executing a rewrite process of different tracks in a first sector group including at least one first sector continuous from a first parity sector in which error correction processing in units of tracks is executable based on the first parity sector and including the first parity sector, and a second sector group including at least one second sector continuous in which the error correction processing in units of tracks is unexecutable, and rewriting the first sector group and the second sector group with different frequencies.