Autoinstall program functions

If you are using a level of VTAM earlier than VTAM 3.3, the NETNAME and other VTAM data about the terminal are not sufficient to build a TCT entry for the terminal. This program must create a CICS identifier for the TERMINAL, and must choose a suitable model from among those passed to it by CICS.

IBM® supplies a program (DFHZATDX) that performs the basic functions, but it may not perform all the functions that you require. For example, you may have your own conventions for TERMINAL names and their relationship to NETNAMEs. (Note that TERMINAL names are up to four characters long, and NETNAMEs are up to eight characters long, so that it is often not possible to derive one from the other.)

In addition, you could code your program to perform other functions associated with terminal logon and logoff. For example:

The autoinstall control program runs in a transaction environment, rather than as a CICS exit. This means that you can read files and issue other CICS commands, to determine the TERMINAL name, or the associated PRINTER and ALTPRINTER names. The TCT entry, however, does not exist at either of the times that this program is invoked, because at logon it has not yet been created, and at logoff it has already been deleted. The program therefore runs in transaction-without-terminal mode.

You can write the autoinstall control program in the following languages: assembler, C, COBOL, or PL/I. The CICS-supplied autoinstall program is available in all these languages; the assembler version is used by default. If you decide to write your own program, you can use one of the CICS-supplied programs as a pattern. Note that for COBOL and C, you need extra program definitions in the CSD file. See the CICS® System Definition Guide for information about defining the CSD file.

You specify the name of the program you want to use in the AIEXIT system initialization parameter.

When you test your autoinstall control program, the CADL transient data destination records each installation and each deletion of TCT entries. Message DFHZC6987 is useful for indicating which model came closest to being chosen, when a null list of models is passed to the autoinstall control program.

Note: You can have only one autoinstall control program active at one time for terminals and connections. The active program is specified on the AIEXIT system initialization parameter. The DFHZATDY program described in Autoinstalling APPC connections provides the same function for terminal autoinstall as DFHZATDX, but also provides function to autoinstall APPC connections initiated by BIND requests. Therefore, if you want to autoinstall APPC connections as well as terminals, use a customized version of DFHZATDY rather than DFHZATDX.

For programming information on implementing the CICS-supplied autoinstall control program, or designing and writing your own program, see the CICS Customization Guide.