In contrast to the standard scheduler, the system/emergency job scheduler is a constituent part of the $SYSJS job stream, which is coupled with the operating system.
It executes in the TPR state and manages only jobs that are assigned to the system class $SYSJC. Its scheduling strategy, which is based on the LIFO (Last In First Out) principle, cannot be changed, i.e. the START parameter is ignored.
This is an advantage above all when errors occur when the job management system is started and when errors are displayed when the $TSOS.SJMSFILE or
$TSOS.SJMSFILE.WORK file is opened or accessed.
It is thus always possible to reconstruct the files after an error and start the corresponding jobs.
The following commands can also be used to process the $SYSJC system class and the $SYSJS system job scheduler.
HOLD-JOB-STREAM HOLD-JOB-CLASS RESUME-JOB-STREAM RESUME-JOB-CLASS SHOW-JOB-STREAM SHOW-JOB-CLASS
The $SYSJS and $SYSJC definitions are constant and not addressable by the JMU routine.
The system job scheduler permits jobs to be started under the TSOS user ID at any time during the session and independently of the standard job scheduler. Unless systems support has defined further job classes for the users, the $SYSJC system job class is the standard job class for all users, which means that all user jobs are then processed by the $SYSJS system job scheduler.