VTAM's representation of data structures

VTAM's representation of the data structures is the LU-mode table. One LU-mode table exists for each opened ACB of an application program capable of using the VTAM® LU 6.2 interface. It contains two kinds of information:

Defined
Information provided by system definition (on the APPL statement) or the application program (on APPCCMD CONTROL=OPRCNTL, QUALIFY=DEFINE) to define values used when negotiating a CNOS reply.
Dynamically accumulated
Information dynamically accumulated by VTAM to record data pertinent to the partner LU, or mode, or both. This information is used by VTAM when controlling the assignment of conversations to sessions and when controlling the activation and deactivation of sessions. Some of it can be displayed to the application program with APPCCMD CONTROL=OPRCNTL, QUALIFY=DISPLAY.