VTAM interface considerations
If your IMS system requires VTAM®, the VTAM mode table must contain entries for all VTAM terminals defined to IMS.
You can use the table entry name at logon as any of the following:
- LOGMODE parameter on the VTAM VARY command
- MODE parameter on the /OPNDST command
- Parameter on the other terminal's INIT SELF command
- MODETBL parameter of the TERMINAL macro
The MODETBL parameter overrides any other entry supplied with the ACF/VTAM LOGON or SCIP exit CINIT. The MODETBL name for all parallel sessions with a given terminal is the same. Do not specify MODETBL for cross-domain resources.
The mode table entry creates the session parameters and thus controls the session established between IMS and the terminal.
Related reading: For a list of the BIND parameters for VTAM logical units, refer to IMS Version 15.3 Communications and Connections.
Define all of the following terminals:
- 3600, 3614, and SLU P as LUTYPE=0
- SLU 1 as LUTYPE=1
- SLU 2 as LUTYPE=2
- LU 6 as LUTYPE=6
A 3770P or 3790 terminal defined as SLUTYPE1 must be defined as unattended in its mode table entry. You can define a SLU 1 terminal as an exception or definite response for the secondary terminal. For terminals defined as SLUTYPEP, no options are allowed in the first 7 bytes of the BIND command.
When you specify PARSESS=NO in the VTAM APPL macro for IMS, VTAM parallel session support is not included. In this case, IMS counts as '1' within the MAXAPPL keyword of the VTAM START parameter.
When you specify PARSESS=YES in the VTAM APPL macro for IMS, VTAM parallel session support is included in the system. IMS counts as '2' within the MAXAPPL keyword of the VTAM START parameters.
Related reading: For information on IMS support for parallel sessions, see IMS Version 15.3 Communications and Connections.