What is Pseudo Conversation?
In batch system, the system is in continuous wait status to perform the tasks given by the user even during the idle time. But in CICS region, the system sends or displays something to terminal (SEND) and if the same requires user's action, then the system terminates (RETURN) the connection for the task.
When the user enters the data, the system automatically establishes the connection back for the task to receive the data (RECEIVE). This technique is called as Pseudo Conversation which is effectively saves the CPU utilization. In the system point of view, it effectively utilizes the CPU time by terminating and reinitiating the task processing.
Pseudo Conversation = Terminating & Reinitiating
CICS application program communicates with the user by using pseudo conversation. Let us discuss with this a simple example -
Assume an application program has defined with a transaction, map to receive and sends data to the terminal. User enters the transaction in the terminal. System receives the transaction, gets the corresponding application program from the tables and started executing.
System executes SEND MAP to send the map to terminal and terminates the process because system doesn't know when the user enters the data (may be after 1 min or 2 mins etc). At this point of time, system RETURNs the control to CICS to perform another task.
Once the users enter the data or there is an interaction, the system establishes the connection back to the task and completes the remaining process. Once the task completed, it returns the control to CICS region.
Commands used in pseudo conversation -
The below are the list of commands majorly used in pseudo conversation.
|SEND||Sends the data to the screen. It also terminates the control from the program (make the control returns to the CICS after sending).Sending data is of three types -|
|RETURN||Used to establish the connection back. (Reinitiates the program).|
|RECEIVE||Receives the data entered on the screen by the user.|