1. A method for sending/receiving data in a storage system, the storage system comprising: a first storage device; and a second storage device, the first storage device comprising: a port, a port control unit to control the port, a storing device to store a data, a control unit; and a memory, wherein the method comprises the step of: generating a target task including a plurality of processes to execute a first process which receives data from the second storage device based on a demand received by the first storage device from the second storage device; generating an initiator task including a plurality of processes to execute a second process which transfers data from the first storage device to the second storage device based on a demand by the control unit; and controlling the port so as to execute in a timesharing manner the plurality of the processes included in the first process and the second process by changing executions of the generated plurality of processes included in the target task and the plurality of the processes included in the initiator task.