gtps4m1i | System Generation |
The interface between TPF and the user application programs is defined by TPF's message router support (see Message Router Support). This is true for all applications except those associated with specific 3705 EP line protocols (for example, the message switching package).
When an operator/terminal, or even another application program, is logged to an application and a message is received from that terminal or logical unit, control is passed to that application, or more precisely to a message editor program defined for that application, based on an entry in the Routing Control Application Table (RCAT). The RCAT entry defines the application as valid and active, and specifies the editor program to be entered for initial processing. The RCAT for MDBF users of the HPO feature, also specifies which subsystem and subsystem user that the application resides in. The RCAT is one of the components of the message router. It is initialized by SIP with an entry for every application the user intends to activate. Applications may be activated or deactivated via a command. Refer to Message Router Support for additional details about message router components and its generation requirements.
When the application input message editor is given control the following standard interface is presented:
If it is a SNA terminal, not logged to an application using an LNIATA rather than a resource identifier (RID), then field EBROUT contains the RID associated with the SNA logical unit (LU).
The concept of the message router interface is used not only for relating input messages from the communications network to application programs but it is also used to pass messages between one application program and another. These applications may be located within this TPF host or, with the use of ACF support, in either another TPF/ACF host, which could be within a loosely coupled complex, or any other defined host system. For MDBF users, this same technique should be used to pass messages between subsystems and subsystem users.
For a more detailed discussion of TPF's application support, refer to the following TPF documents: