When a get resource message arrives from an exterior, a resource allocation part 102 reserves a resource. In case of data reading or data writing, a declared value management part 111 checks parameters and a slot allocation part 103 allocates the resource, thereby constructing an efficient file system guaranteeing delay quality in relation to data reading. As the result, it is possible to provide a file system providing pictures in a quick response time for requests from users and supporting users requiring various regeneration speeds. <IMAGE>
