SESSION ESTABLISHMENT TERMINATING SYSTEM

PURPOSE:To encode an application program without minding a main station or a sub-station, and also to simplify a procedure for the establishment of a session and its termination, by adopting a contention system for terminating the establishment of the session. CONSTITUTION:A host computer 1 is provided with application programs 2, 3, a virtual communication access system 4 and an inter-application program communication mechanism 5. Also, a session acquisition macro-instruction can be issued from both the application programs, unless a session is established. Also, a session release macro-instruction can be issued from both the application programs, if the session is established. Furthermore, in order to realize a contention system, a contention flag is provided newly so that session establishment/ termination processings can be executed successively. In such a way, the application program which has issued the macro-instruction first can burn on this flag.