IMS commands

The network system analyst decides whether a workstation is allowed to enter IMS commands and, if so, which commands are allowed.

IMS does not require that the controller request a specific response when sending an IMS command. DR1, DR2, and exceptions DR1 and DR2 are allowed; exception DR1 or DR2 is recommended.

IMS processes its commands and returns an IMS message when it finishes processing the command. Therefore, when a DR1 or DR2 is requested, IMS returns the DR1 or DR2, followed immediately by the message confirming command completion.

The additional line transmission required to send either the DR1 or DR2 and the command completion message can be eliminated if the controller requests exception DR1 or DR2.

If exception DR1 or DR2 is requested, the command completion message acknowledges receipt of the command and indicates that command processing is complete. If the ACK option is defined for the workstation, the VTAM® sequence number of the command does not participate in message resynchronization as it does when only DR1 or DR2 is requested. If the OPTACK option is defined, all input participates in message resynchronization.