Using an application program to determine whether programmed symbol buffers are loaded

The buffers might have been loaded with the desired programmed symbols by a previous user of the device, and this knowledge can save resending the entire programmed symbol data stream. A handwritten log at the device is one method of maintaining the current status of the programmed symbol buffers for subsequent users.

Another method is a user-written application program that attempts to use the desired programmed symbols. If the desired programmed symbols are already loaded, the output from the application program is successfully displayed at the device. If the programmed symbols are not loaded, the output message is returned to the IMS message queue, the terminal is made inoperable, and a message is sent to the master terminal operator (MTO). The MTO should have a procedure to correct this condition. For example, the MTO could do one of the following:

Reassign the LTERM, assign an LTERM that has the correct PS load message, restart the terminal, and then reassign the first LTERM back to the terminal.
If the terminal does not have PS capability, reassign the LTERM to one that does.
If the terminal does not have PS capability, dequeue the rejected message.

Exception: For an SLU 2 terminal, the output rejected was not a response mode reply. In this case, the MTO receives the error message and can try to enter a transaction that would cause the buffers to be loaded.