This chapter is only a background to your learning of JCL.

This material will not be required later in the book, nor will you use it directly in writing JCL. However, it is extremely important that you understand the "surroundings" of a job in the computer so that everything you will learn here will make sense and fall into its right place.

First, what is JCL, Job Control Language?

It is not an ordinary computer language like you may have learned up to now e.g., COBOL, Pascal, C, or even Assembler. You do not use it to write a program.

It is a language that the programmer uses to communicate with the Operating System of the computer to let it know what resources and special conditions are needed to run programs. 

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