Varying the resources installed by the setup program

Checking startup type

Your setup program can determine how the CICS system started by issuing an EXEC CICS INQUIRE SYSTEM STARTUP command. It could use this to install different sets of FEPI resources for warm and cold starts.

Recording the status of resources

If you install all your FEPI resources at CICS startup, and then alter their accessibility, consider writing a non-terminal transaction that runs frequently and uses the FEPI INQUIRE commands to determine the status of each FEPI resource. Write these to a recoverable temporary storage file. (You could, for example, use an XSZARQ global user exit program to log changes to FEPI resources.) At restart time, your setup program can read the file to determine the required access settings.

Using timed actions

You could take advantage of CICS automatic transaction initiation (ATI) at specified times to control FEPI resources. If you want to terminate FEPI access to another system at a specific time each day, schedule a transaction to run at the required time. When this transaction runs it can either make the required FEPI resources unavailable for access, or discard them. Because FEPI resources remain available for use by current tasks in this circumstance, this has no effect on existing FEPI users.

You could use timed initiation in a similar way to make FEPI resources available.

Using event handlers

Another way of controlling FEPI resources is to use the begin-session and end-session event handlers. (See Other functions.)

These handlers are invoked when a conversation starts and ends. Although they are primarily designed to handle signon and signoff to the back-end systems, you can take advantage of the fact that all FEPI functions are available to them. So you can use them to control access to back-end systems by either installing or discarding FEPI resources.

For example, suppose you want to ensure that no FEPI application is waiting for a connection to a back-end system. In the handlers, issue FEPI INQUIRE POOL commands, and look at the WAITCONVNUM option, which returns the number of FEPI applications waiting for a connection. If this option exceeds a certain trigger value, issue FEPI commands to increase the number of connections (that is, add nodes, define new pools, and so on).

This technique can be extended to provide tuning of FEPI access to back-end systems.