Abstract: According to one embodiment, a magnetic disk device incudes a first magnetic disk, a first actuator that reads/writes data from/to the first magnetic disk, a first controller that controls the first actuator, a second magnetic disk, a second actuator that reads/writes data from/to the second magnetic disk, a second controller that controls the second actuator, wherein the first controller executes read/write processing, and the second controller stores trace data of the read/write processing when the first controller executes the read/write processing.

Abstract: According to one embodiment, a magnetic disk device incudes a first magnetic disk, a first actuator that reads/writes data from/to the first magnetic disk, a first controller that controls the first actuator, a second magnetic disk, a second actuator that reads/writes data from/to the second magnetic disk, a second controller that controls the second actuator, wherein the first controller executes read/write processing, and the second controller stores trace data of the read/write processing when the first controller executes the read/write processing.

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 disk storage device includes: a controller configured to write data pieces stored in a buffer memory to a disk medium by a physical sector size which is an integer multiple of a unit logical block, wherein the controller is configured to detect at least one of the write data pieces stored in the buffer memory, the at least one of the write data pieces being to be written to a portion of a physical sector of the disk medium, configured to store the at least one of the write data pieces to the non-volatile memory, configured to store the rest of the write data pieces to the disk medium, and configured to write, upon non-detection of a command for a predetermined time period, the at least one of the write data pieces to the disk medium by the physical sector size through read-modify-write processing.

Abstract: A control unit in a disk apparatus stores a command in a queue. When the execution of the command stored in the queue is not completed within a predetermined time, the control unit stores an LBA corresponding to a command which is executed within the predetermined time and during execution of which the disk retry is generated more than a predetermined number of times, as a monitoring object LBA in a monitoring object LBA management table. Further, when an LBA corresponding to an execution object command corresponds to the monitoring object LBA stored in the monitoring object LBA management table, the control unit rearranges the command in the position at the end of the queue.