Patent ID: 7110831

Claim:
A communication control method of exchanging data between an initiator and a target, comprising: a transmitting step of transmitting a read command and/or a write command from the initiator to the target so as not to exceed the total number of commands which can be held in the target, each command corresponding to a designation indicating to which one of a plurality of queues provided in the target the command corresponds; and a performing step of, in the target, a read operation to read data from a designated location in a memory area of the initiator or a write operation to write data into a designated location in the memory area of the initiator in accordance with the read or write command, wherein the initiator allocates the number of commands for each of the plurality of queues so that the initiator can transmit from at least one command up to the number of commands allocated for each queue in said transmitting step, the total number of commands allocated for each queue being smaller than the total number of commands which can be held in the target, and if the total number of commands that are not allocated for each queue among the total number of commands which can be held in the target is greater than the total number of commands held by the target in excess of the number of commands allocated for each queue, the initiator can transmit, in said transmitting step, a further command in excess of the number of commands allocated for each queue.