For your program to execute on the computer and perform the work
you designed it to do, your program must be processed by your operating
system. Your operating system consists of a base control program (BCP)
with a job entry subsystem (JES2 or JES3) and DFSMSdfp installed with it.
For the operating system to process a program, programmers must
perform certain job control tasks. These tasks are performed through
the job control statements, which are listed in the first topic "Introduction
- Job Control Statements". The job control tasks and introductory
information about JCL are introduced in the second topic "Introduction
- Job Control Language (JCL)". The charts in the third topic "Job
Control Tasks" divide these tasks into detailed subtasks. The
tasks are:
- Entering jobs
- Processing jobs
- Requesting resources