Presentation Abstraction Control
Presentation Abstraction Control (PAC) is an Architectural Pattern similar to Model view controller. It consists of a hierarchy of agents, each of with is made from a triad of presentation, abstraction and control parts. The control agent acts as a mediator, through which the presentation and abstraction agents communicate. Because of the insulation of presentation and abstraction from each other, it is possible to multi-thread these two agents to give the end user very short program execution times. This differs from the Model view controller where these concepts are not insulated from each other, and some coupling exists.
Relation to Hierarchical Model View Controller
One variation of the PAC is known as Hierarchical Model View Controller (HMVC). The main difference being that PAC insulates what are essentially the model and view components. The HMVC has much of the traditional structure of the Model view controller, which allows communication between the model and view directly.
