ubsystem) Software that provides batch communications for IBM's MVS operating system. JES accepts data from remote batch terminals, executes them on a priority basis and transmits the results back to the terminals.
JES2 and JES3 are the major JES subsystems. The primary difference is the control of multiple processors. JES3 provides central control over all processors, whereas JES2 controls only one. In VM, the JES counterpart is RSCS. See JCL