Introduction to JES2

This introduction answers the following questions:

• What is a JES?
• Why is JES required in an MVS™ system?
• What is the relationship between JES and the system users?
• Is there really any difference between JES2 and JES3?
• What are some of JES2's key functions?

An initial consideration when installing MVS is whether to select the JES2 or the JES3 component. This introduction provides some background if you are new to MVS, followed by a more detailed discussion of JES2. If you require further insight into the functional differences between JES2 and JES3, or are deciding which to install, you should also read z/OS JES3 Introductionz/OS JES3 Introduction which provides a similar overview of JES3.