DD Statement - an existing data set

This is the first of nine pages describing how the DD statement can be used to allocate various types of data set.

In this example the data set exists, having been created by a previous job or task. It is best practice that all permanent data sets, those passed from job to job, are catalogued.

The DD name, those characters between // and the first blank, is important as it is the bridge between the JCL and the program.

The DSN= and DISP= operands are described on the next page.