An architecture expresses a fundamental structural organization schema for software systems. It provides a set of predefined subsystems, specifies their responsibilities, and includes rules and guidelines for organizing the relationships between them.

★ Object-Oriented/Abstract Data Style

★ Layered Hierarchies

★ Blackboard architecture

★ involving shared access to data with loosely coupled agents

★ Client/Server

★ Three tier Client/Server architectures

★ Peer-to-Peer Architecture