Patent ID: 7272852

Claim:
A reserve/release control method for a target device accessed by a first host computer, the method comprising steps of: managing an access permission ID for identifying access permission to a local device of the target device; transmitting the access permission ID to the first host computer when permitting an access permission request received from the first host computer; judging whether to grant access in response to an access request from a first device by using the access permission ID which was added to the access request, and which was transmitted in response to the access permission request from the first host computer, wherein the target device and the first device are storage devices accessed from a plurality of host computers, and the target device manages a plurality of access permission IDs, wherein the target device gives different access permission IDs to each of a plurality of access permission requests from the plurality of host computers and transmits the access permission IDs to the host computers; updating the access permission ID in the target device; updating the access permission ID held for the local device when a request for invalidating the access permission ID is received from the first host computer for which the access permission request has been permitted; issuing, by the first host computer, an access permission request to the target device prior to issuing of the access request to the target device by the first device; and acquiring by the target device the access permission ID which was added to the access request when the target device determines whether to permit the access request from the first device.