IMS System Services provide the following services to both IMS DB and IMS TM:

• Provide data integrity
• Restart and recover IMS after failures
• Provide security, by controlling access to and modification of IMS resources
• Manage the application programs, by dispatching work, loading application programs, and providing locking services
• Provide diagnostic and performance information
• Provide facilities for operating IMS
• Provide interfaces to other z/OS subsystems that communicate with IMS applications

The IMS System Services are by:

• Issuing IMS commands
• Running IMS-supplied utility programs
• Running IMS-supplied or user-written exit routines
• Defining the services you want as part of the system definition process