Abstract: The disclosed access control apparatus and method controls an I/O device to perform processing of access requests in a predetermined order including inputting access requests from multiple tasks to cause the I/O device to perform file processing, storing and managing information about file priorities, obtaining a file priority corresponding to an access request, managing a queue having multiple queues for which the processing priorities corresponding to the file priorities are set and causing the access request to be stored in any of the queues corresponding to the file priority, and obtaining the access requests stored in the queues in an order based on the processing priorities set for the queues and sends the access requests to the I/O device.

Abstract: An IP version storage section included in the server stores an IP version implemented in the destination terminal under the control of the server. A message receiving section receives a message from the source terminal. An IP version acquisition section acquires the IP version implemented in the destination terminal corresponding to the message from the IP version storage section. An IP version comparison section compares an IP version which is implemented in the source terminal and which is included in the message with the IP version which is implemented in the destination terminal and which is acquired by the IP version acquisition section. A comparison result sending section sends a result of the comparison by the IP version comparison section to an address converter which makes an address conversion so that IP versions of data frames exchanged between the source terminal and the destination terminal will match.

Abstract: The disclosed access control apparatus and method controls an I/O device to perform processing of access requests in a predetermined order including inputting access requests from multiple tasks to cause the I/O device to perform file processing, storing and managing information about file priorities, obtaining a file priority corresponding to an access request, managing a queue having multiple queues for which the processing priorities corresponding to the file priorities are set and causing the access request to be stored in any of the queues corresponding to the file priority, and obtaining the access requests stored in the queues in an order based on the processing priorities set for the queues and sends the access requests to the I/O device.

Abstract: A server by which time taken to establish a session can be shortened by reducing the number of messages exchanged between a destination terminal and the server and by which the manufacturing costs of terminals can be reduced. An IP version storage section included in the server stores an IP version implemented in the destination terminal under the control of the server. A message receiving section receives a message for establishing a session between a source terminal and the destination terminal from the source terminal. An IP version acquisition section acquires the IP version implemented in the destination terminal corresponding to the message from the IP version storage section. An IP version comparison section compares an IP version which is implemented in the source terminal and which is included in the message with the IP version which is implemented in the destination terminal and which is acquired by the IP version acquisition section.