Before an application program can use VTAM® services, the application program minor node that defines the application program must be activated. An application program minor node is typically activated at VTAM startup by placing the name of the application program major node that contains the application program minor node into the VTAM configuration list.

After an application program minor node is activated, it is up to the application program to open its ACB and begin using VTAM services. The order in which the minor node is activated and the application program is started is not critical, but the minor node must be active when the application program attempts to open its ACB for VTAM.

If the operator cancels an application program, the operating system forces the application program disconnection from VTAM. For the operator to be able to cancel an application program that is active to VTAM, the operator must first associate the application program defined VTAM name with the application program job name.

The logon manager, which runs as a VTAM application, can be terminated with the MODIFY STOP command. For information about using the MODIFY STOP command, see z/OS Communications Server: SNA Operation.