The terminal control table user areas

A terminal control table user area (TCTUA) is an optional storage area associated with a terminal control table terminal entry (TCTTE). TCTUAs are available for application program use. You specify the storage key for TCTUAs globally for a CICS® region by using the TCTUAKEY system initialization parameter.

By default, CICS obtains user-key storage for all TCTUAs. Review the use of TCTUAs in your CICS regions, and only specify CICS key for TCTUAs when you are sure that this is justified. If you specify CICS-key storage for TCTUAs, no user-key applications can write to any TCT user areas.

For SNA LUs, you specify that you want a TCTUA by means of the USERAREALEN attribute on the TYPETERM resource definition. The USERAREALEN attribute determines the TCTUA sizes for all terminals that reference the TYPETERM resource definition.

For sequential terminals, definitions are added to the terminal control table (TCT), and sizes are defined by means of the TCTUAL parameter on the DFHTCT TYPE=TERMINAL and TYPE=LINE entries. For information about the TCTUAL parameter, see Terminal control table (TCT).