To record register contents and data at specific points in JES2 processing, you can use the JES2 tracing facility. JES2 has defined a number of the 255 trace types that can be defined; new ones are occasionally added to new product releases as their need arises. Here, again, is another JES2 facility that your installation can augment. (Your installation can add installation-specific trace points if the available trace functions do not meet your requirements.)

The use of the facility is optional. Tracing is initially activated under system programmer control (by specifying initialization statements) and subsequently controlled through several operator commands. Generally, trace points are only activated as a diagnostic tool for short periods of time.

Traced data can be accessed either through a dump of unformatted trace tables or in formatted system output. (See z/OS JES2 Initialization and Tuning Guide and z/OS JES2 Diagnosis for further information regarding the initialization and use of the JES2 trace facility.)