You can specify two different names for an application program, one required and one optional. The required application program name is the one that you specify in the label field of the APPL definition statement. The optional application program name is the one that you specify on the optional ACBNAME operand of the APPL definition statement.

You can use wildcard characters in the name you specify in the label field and on the ACBNAME operand. Using wildcard characters enables you to define a model application program definition, which can be used as the definition for one or more VTAM® application programs. For more information about defining model application program definitions, see Model application program definitions.

If an application program name is not specified on the APPLID operand of the ACB macroinstruction, VTAM uses a name supplied by your operating system. If the name supplied by your operating system does not match a name on the APPL definition statement, the application program cannot open its access method control block (ACB) and is therefore not identified to VTAM.

If the application program is started by a job step that is a procedure invocation, the name used by the operating system is the procedure step name in the job control language (JCL) for the application program. Otherwise, it is the job step name in the JCL.