4+1 View Model for Software Architectures (4+1 Views)
The concept for a "4+1" View Model for Software Architecture is a conceptual architecture originated in a seminal paper authored by Philippe Kruchten entitled Architectural Blueprints—The “4+1” View Model of Software Architecture published in 1995. The paper presents a model for presenting software architectures based on the use of "multiple, concurrent views". The Views describe software architecture from the Viewpoint of different stakeholders, such as users, software developers, systems engineers, and project managers. Four primary Views are described (Logical, Development, Process, Physical) and augmented with a Scenario (Use Cases) "plus 1" View. Hence, there are five software architecture Views described in total:
- Logical View: describes the Object Model of an Object-Oriented Design;
- Process View describes concurrency and synchronization aspects of the Logical View;
- Physical View: describes allocations (mappings) of software components to hardware and shows distributed processing aspects;
- Development View: describes the static organization of software in the development environment.
- Scenarios View: shows how the other four Views "work together seamlessly by the use of a small set of important scenarios—instances of more general use cases."