Patent ID: 8880832

Claim:
A controller which can be connected to a host system and a plurality of storage devices, the controller comprising: a status table in which an operating status of the plurality of storage devices and a write destination for data are set; a monitor configured to monitor the operating status of the plurality of storage devices and to set the operating status of the storage devices in the status table; a buffer memory capable of holding data; a timer configured to count to a previously set time in accordance with an instruction to start counting and to send a deadline notification when the previously set time has elapsed; a command responding unit configured such that, upon receiving a write command from the host system, the command responding unit instructs the timer to start counting, sets the write destination for data in the status table, outputs a control signal that gives an instruction to write data to the storage device of the write destination, holds in the buffer memory, write data sent from the host system within a certain period of time after the write command, and returns a write completion response corresponding to the write command to the host system when receiving the deadline notification from the timer; and a data processor configured such that, upon receiving the control signal that gives an instruction to write data from the command responding unit, the data processor refers to the status table to choose a storage device of the write destination and writes data read from the buffer memory to the chosen storage device.