Starting the CQS

In an IMS shared-queues environment, IMS starts the CQS subsystem during IMS startup or restart if the CQS subsystem is not already running. You can use the z/OS® START command to start the CQS subsystem if you want to ensure CQS is running before you start IMS.

After CQS is running, the IMS online subsystem identifies itself to the CQS subsystem during IMS initialization or restart.

If you register CQS with the z/OS Automatic Restart Manager, you do not have to restart CQS after a CQS failure. Because CQS and IMS are separate subsystems, you do not have to restart CQS after an IMS failure.

You can start CQS in one of three ways:

  • As a z/OS task, using the z/OS START command
  • As a z/OS batch job
  • As a client task — Some clients (such as IMS) automatically start CQS, when appropriate
    Example: If IMS is the client, define the CQS name in the DFSSQxxx or the DFSDFxxx member in the IMS PROCLIB data set and specify the CQS name on the SHAREDQ parameter of the IMS procedure. IMS does not start CQS if the CQS is needed only to manage a resource structure.

A CQS that supports only a resource structure must be started manually because IMS does not start this CQS.