System performance can suffer if too many jobs and/or sessions are running at the same time. Setting limits on the number of jobs and sessions that can run concurrently protects the system from inadvertent or deliberate attempts to degrade its performance. Setting limits on the number of active devices in use at any time helps control the user load, and also helps prevent access by unauthorized users.
Additional methods for controlling resources and security are provided by the Access Control Definition Facility.
