Architectural patterns may reflect the organization of a system from different viewpoints. The patterns here reflect common control ways of organizing the control in a system.
Centralized control, where there is a component in charge which calls on services from other components in the system. The reflects the method/procedure/subroutine calls in programming languages.
Event-based control where the system responds to asynchronous events from the system's environment.
Event-based control is the norm in real-time systems and in many interactive systems with inputs from keyboards, mice, etc.