User sense field (USENSE)

IMS uses the user sense field to pass on the number (converted to binary) of the appropriate error message.

For example, an invalid transaction code generates the message:

DFS064  DESTINATION CANNOT BE FOUND OR CREATED

If IMS receives an invalid transaction code, it returns an exception DR1 or DR2 response with X'0040' in the user sense field.

In the XRF complex, the alternate system sends SSENSE=X'0826', USENSE X'0F15', and a DFS3861I SYSTEM TAKEOVER OCCURRED message if an input transaction is lost across the XRF session takeover. You must then retransmit the last input record.

IMS binds each session with unconditional bracket termination. When IMS sends an exception DR1 or DR2 to input, it must remain in a send state (regardless of the current bracket state), and the workstation must go to a receive state. Both IMS and the workstation must go to a between-brackets state if the input message in error specified end-bracket. IMS then places the workstation between-brackets and into a contention state by sending the entire IMS error message as a single chain with the appropriate bracket indicators.

An IMS error message can have multiple segments, with a maximum message length of 32,000 bytes. However, all current IMS error messages that are sent to the workstation are single-segment and less than 132 bytes. These messages adhere to the FM header and transmission rules for all output messages.

The generation of the user sense data is dependent on the standard IMS error message format. The session can be terminated if any user Output edit routine modifies this format.