Response mode for transactions

When the response mode is in effect, IMS does not accept input from the line, terminal, or user until IMS has sent an output response to the previous input. Response mode can be defined for either full function or Fast Path.

Response mode describes a connection between IMS and a communication line, terminal, or user that occurs for certain types of terminals or users under conditions specified during system definition.

You can specify communication lines, terminals, or users as:

Always operating in response mode
Never operating in response mode
Operating in response mode only if the transaction code being processed specifies it

Any transaction can be defined as a response-mode transaction. When IMS receives an input transaction that requires response mode, IMS makes the terminal unusable (locks the keyboard) until IMS processes the transaction and sends the response.

While in response mode, if the user enters a single transaction for which the application program generates no response, IMS automatically sends message DFS2082 as the response to the transaction. This message removes the terminal from response mode and unlocks the keyboard, if necessary.

While in response mode, if the user enters multiple transactions for which the application program generates no response, the keyboard remains locked and the terminal is unusable. The terminal remains in response mode even if the user attempts to unlock the keyboard (by, for example, pressing the RESET key on a 3270 terminal); any subsequent input is rejected. The first output from an application program whose input originated from this terminal satisfies the response.

User IDs defined with ETO user descriptors remain in response mode after abnormal session termination or autosignoff. In this situation, the end user should contact the MTO (using a means other than the terminal or user ID). If the terminal is non-operational, the MTO can enter an /RSTART command to restore terminal operation.

Attention: If you restart IMS while users are in response mode, what happens to transactions depends on whether they have reached a sync point:

If the transaction is complete (it has reached a sync point), and the end user is waiting for a response, the user does not receive the normal response because IMS restart resets response mode. After the restart completes, the user might reenter the transaction, which could adversely affect data integrity.
If the transaction is incomplete (it has not reached a sync point), IMS discards the transaction.

You should develop operating procedures to cover this situation for all end users who could be affected.

To reset static nodes and ETO dynamic users that are hung in Fast Path input response mode, issue the /STOP and /START commands in sequence with the appropriate parameter. For static nodes, issue the commands /STOP NODE and /START NODE. For ETO dynamic users, issue the commands /STOP USER and /START USER.