The IMS adapter

The WebSphere MQ adapters enable different application environments to send and receive messages through a message queuing network. The IMS adapter is the interface between IMS application programs and a WebSphere MQ subsystem. It makes it possible for IMS application programs to use the MQI.

The IMS adapter receives and interprets requests for access to WebSphere MQ using the External Subsystem Attach Facility (ESAF) provided by IMS. This facility is described in the IMS Customization Guide. Usually, IMS connects to WebSphere MQ automatically without operator intervention.

The IMS adapter provides access to WebSphere MQ resources for programs running in the following modes or states:

• Task (TCB) mode

• Problem state

• Non-cross-memory mode

• Non-access register mode

The adapter provides a connection thread from an application task control block (TCB) to WebSphere MQ.

The adapter supports a two-phase commit protocol for changes made to resources owned by WebSphere MQ with IMS acting as the syncpoint coordinator.

The adapter also provides a trigger monitor transaction (CSQQTRMN). This is described in The IMS trigger monitor.

We can use WebSphere MQ with the IMS Extended Recovery Facility (XRF) to aid recovery from a IMS error. For more information about XRF, see the IMS Administration Guide: System manual.