Because every system that uses JES2 to manage its work input and output is unique, so too are the requirements that each system has for JES2. To meet these varying requirements, most JES2 functions can be customized by changing and using the JES2 initialization data set that is provided with the product, in the HASIPARM member of the SYS1.SHASSAMP data set. Although this data set will not run as shipped without some installation additions, it is a valuable model that can save hours of system programmer input time.

With a set of approximately 70 initialization statements, you can control all JES2 functions. The JES2 initialization data set provides all the specifications that are required to define output devices (printers and punches), job classes, the JES2 spool environment, the checkpoint data sets, the trace facility, and virtually every other JES2 facility and function.

Each initialization statement groups initialization parameters that define a function. The use of most JES2 initialization statements is optional; you only need to define them to implement or customize a particular function. Furthermore, many of the parameters provide default specifications that allow your system to perform basic JES2 processing with no explicit definition on your part. JES2 requires only a minimal set of initialization statements (or parameters) that you define when first installing JES2.