Abstract: A magnetic disk device according to an embodiment includes a disk including a plurality of tracks, a head configured to write and read data to and from the disk, and a controller configured to control an off-track of the head, which occurs when data is written to one track included in the plurality of tracks, within an allowable range of an amount of the off-track, which is set based on a count value of at least another track other than the one track.

Abstract: A magnetic disk device according to an embodiment includes a disk including a plurality of tracks, a head configured to write and read data to and from the disk, and a controller configured to control an off-track of the head, which occurs when data is written to one track included in the plurality of tracks, within an allowable range of an amount of the off-track, which is set based on a count value of at least another track other than the one track.

Abstract: According to one embodiment, a storage device is provided which includes a control unit configured to, in case that first data coincides with third data out of second data of a second size greater than the first size stored on a storage medium, do not write fourth data obtained by replacing the third data included in the second data with the first data onto the storage medium.

Abstract: According to one embodiment, a storage device includes a plurality of writable non-volatile memory devices, a buffer memory, a memory controller, and a spare non-volatile memory device. The buffer memory temporarily stores write data from a host. The memory controller writes the write data in the buffer memory to the non-volatile memory devices in a distributed manner. The memory controller writes write data in the buffer memory not having been written to the non-volatile memory devices to the spare non-volatile memory device when detecting a power down, and writes the write data having been written to the spare non-volatile memory device to the buffer memory when the power is restored.

Abstract: In a control method for a storage system including a plurality of storage devices connected via a network, when starting operation, a first storage device on the network determines whether data of a control program for controlling the first storage device is broken. When the data of the control program is broken, the first storage device transmits a signal indicating that the data of the control program is broken to the network. Upon receipt of the signal, a second storage device on the network determines whether it stores the same control program as that stored in the first storage device. When storing the same control program, the second storage device transmits the control program to the first storage device. The first storage device rewrites the broken control program with the control program received from the second storage device.