Abstract: According to one embodiment, a disk medium rotates in a first rotation state when access is given, and rotates in a second rotation state lower in rotation number than the first rotation state when access is not given. A controller receives, from a host device, a read command for reading first data stored in a first buffer, when the disk medium is in the second rotation state. The controller transmits the first data from the first buffer to the host device, without causing a shift into the first rotation state, and then shifts the disk medium into the first rotation state after completion of execution of the read command.

Abstract: According to one embodiment, a disk medium rotates in a first rotation state when access is given, and rotates in a second rotation state lower in rotation number than the first rotation state when access is not given. A controller receives, from a host device, a read command for reading first data stored in a first buffer, when the disk medium is in the second rotation state. The controller transmits the first data from the first buffer to the host device, without causing a shift into the first rotation state, and then shifts the disk medium into the first rotation state after completion of execution of the read command.

Abstract: 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.

Abstract: According to one embodiment, A storage device includes a magnetic disk, a head, and a control unit. The magnetic disk includes a plurality of physical sectors having a first length. A logical block having a second length shorter than the first length, and a redundant area having a length of the difference between the first length and the second length are assigned for the physical sectors. The head reads the data from the physical sector of the magnetic disk. The control unit controls to change the second length of the logical block while maintaining the first length of the physical sector in response to reception of a change request for changing the second length of the logical block from a host.

Abstract: According to one embodiment, A storage device includes a magnetic disk, a head, and a control unit. The magnetic disk includes a plurality of physical sectors having a first length. A logical block having a second length shorter than the first length, and a redundant area having a length of the difference between the first length and the second length are assigned for the physical sectors. The head reads the data from the physical sector of the magnetic disk. The control unit controls to change the second length of the logical block while maintaining the first length of the physical sector in response to reception of a change request for changing the second length of the logical block from a host.

Abstract: According to one embodiment, there is provided a disk apparatus including a disk medium, a nonvolatile memory, and a controller. In the nonvolatile memory, data to be recorded to the disk medium is written. The controller is configured to perform, according to amount of free space of the nonvolatile memory, write process of the data in the nonvolatile memory collectively, or in multiple times with dividing the write process.