When you determine where and when you want specific JCL to run, you will consider using batch jobs or started tasks. Batch jobs are scheduled by a job entry subsystem (JES2 or JES3) and are scheduled to run based on the resources they require and their availability, or based on controls that you place on the batch system. Controlling where and when a batch job runs is more complex than using a started task.

A started task is a set of JCL that is run immediately as the result of a START command. Started tasks are generally used for critical applications. An advantage offered by started tasks are control over where and when the JCL is run. For example, you could have the JCL started at each IPL of the system.

For more information about system symbols and JCL symbols, see Using symbols in started task JCL.