The console name and other MVS™ data about the console are not sufficient to build a terminal control table terminal entry (TCTTE) for the console. The autoinstall control program must create a CICS® terminal identifier (termid) for the console, and choose a suitable model from the list of models passed by CICS in the communications area.
IBM® supplies two assembler versions of an autoinstall control program (DFHZATDX and DFHZATDY in SDFHLOAD) that perform the basic functions, but it these may not perform all the functions that you require. For example, you may have your own conventions for terminal names and their relationship to console names. Terminal names are up to four characters long, and console names are up to eight characters long, hence it is often not possible to derive one from the other.
The autoinstall control program runs in a transaction environment as a user-replaceable program, rather than as a CICS exit. This means that you can read files, and issue other CICS commands, to help you determine the terminal name. The TCTTE entry for the console, however, does not exist at either of the times that the program is invoked, because (1) for the install function it has not yet been created, and (2) for the delete function it has already been deleted. The program therefore runs in transaction-without-terminal mode.
You can write an autoinstall control program in the following languages: assembler language, C, COBOL, or PL/I. The CICS-supplied autoinstall program source is available in all four languages. The assembler version, which is used by default, is also shipped in executable form in SDFHLOAD. If you decide to write your own program, you can use one of the IBM-supplied programs as a pattern.
You specify the name of your autoinstall control program on the AIEXIT system initialization parameter. CICS supports only one autoinstall control program at a time, and therefore your program must handle console and terminal autoinstall requests if support for both is required.
When you test your autoinstall control program, you will find that CICS writes install and delete messages to the transient data destination, CADL, each time CICS installs and deletes a TCT entry. If there are no autoinstall models installed for consoles, CICS does not call the autoinstall control program, and fails the autoinstall request.
For information on implementing the CICS-supplied autoinstall control program, or designing and writing your own program, see the CICS Customization Guide.