Product Line Methodology Overview Reference Requirements represent those aspects of a product architecture that are common across an entire product line. They are produced by one or more Domain Experts , and form a baseline to be refined for each specific application. The Reference Requirements serve as the first version of the Application Requirements.
Models describe coherent portions of the application.
They may or may not correspond to software implementation modules. Initial, generally incomplete, models are provided as part of the Reference Requirements, and are refined by Application Engineers as needed for the specific product being designed. Some models will define concepts that are referenced by other models. A DSL may be a notation invented by the Domain Experts, or may be a notation in common use within the application area. Whatever notation is used in expressing a model has fomral semantics that provide a notion of consistency and completeness.