In computer security, a Discretionary Access Control (DAC) gives a user complete control over all the programs it “owns” and executes and determines the permissions other users have to those those files and programs.
A “non-discretionary access control” system relies on a set of rules or roles to provide access (e.g. a time-controlled access 9am-5pm). It is non-discretionary because it cannot be influenced by someone’s discretion, judgement or preference.