Multiple tasks, each with its own ACB

In a VTAM® application program consisting of more than one task, each task can open its own ACB (see Figure 1). In such a structure, the macroinstructions (OPEN and CLOSE) that open and close a particular ACB must be issued in the same task.

Figure 1. Multiple tasks, each with its own ACB
The diagram shows an example of multiple tasks, each of which has its own ACB. Task 1 opens and closes ACB1 and requests communication using ACB1. Task 2 opens and closes ACB2 and requests communication using ACB2. Task 3 opens and closes ACB3 and requests communication using ACB3.