As a technical professional in the world of mainframe computing, you will need to know JCL, the language that tells z/OS® which resources will be needed to process a batch job or to start a system task. You also will need to use SDSF to check the output of jobs and tasks submitted to the system.

Job control language (JCL) is used to tell the system what program to execute, followed by a description of program inputs and outputs. Basic JCL contains three types of statements: JOB, EXEC, and DD. A job can contain several EXEC statements (steps) and each step might have several DD statements. JCL provides a wide range of parameters and controls, but you will find that you use only a subset most of the time.

System users are expected to write simple JCL, but they normally use JCL procedures for more complex jobs. A cataloged procedure is written once and can then be used by many users. z/OS supplies many JCL procedures, and locally written ones can be added easily. To supply the parameters (usually DD statements) needed for a specific job, a user must understand how to override or extend statements in a JCL procedure.

After submitting a job, it is common to use System Display and Search Facility (SDSF), which is a utility that allows you to monitor, control, and view the output of jobs in the system.