PCMEF is an architecture style presented in the book Practical Software Engineering by Maciaszek and Liong. The layers are: P: Presentation C: Controller M: Mediator E: Entity F: Foundation. It is some kind of enchancement compared with MVC - architecture. I recommend it to interactice, data and communicating - oriented purposes. I have programmed it using Visual Prolog. Foundation in my applications is the data model (domains) for the application. PCMEF is like a simulated computer: Presentation is the display, Controller the user interface and event handling, Mediator the internal logic and data highway. Entity is the database or external interfaces and F defines the knowledge. This is a really nice small architecture. Does any other have experiance of it?