Your subsystem can use SSI function code 50 to clean up any resources for a task associated with a particular subsystem, and free any resources not normally handled by a resource manager.

Because your function routine will get control for every Early Notification of End-of-Task call, using your own subsystem might not be the most efficient way to do your own clean up for ending tasks. The preferred way to define your own resource manager is through the use of the RESMGR macro. The RESMGR service can be used to receive control for specific ending tasks, rather than having to check each ending task or address space to see if it used the subsystem. For a general description of resource managers and how they can be defined at both IPL time and dynamically, see z/OS MVS Programming: Authorized Assembler Services Guide.