Priority levels

Each job can have one of the following priority levels:
Highest priority user jobs.
High priority user jobs.
Normal priority user jobs.
Low priority user jobs such as background loads and jobs that should not affect other activity.
Note: There are two additional priorities, but these are used exclusively by internal processes and are not visible to and cannot be set by users:
System critical
This priority is ranked higher than critical.
System background
This priority is ranked lower than low.