This standard defines concepts@ terminology@ and information required for constructing a VHDL component model to be used in a hierarchical design and simulated interoperably with other models conforming to this standard. Purpose In order to specify and simulate a complex hardware system consisting of multiple components@ it is necessary to define common modeling interfaces. conventions@ and simulation modes. Commonality assures that any new components developed for the hardware system can be simulated together. Commonalty also assures that new components will simulate with component models obtained from standard libraries or reused from previous designs. The purpose of this specification is to provide guidelines for the production of VHDL models for hardware descriptions that: ? conform to a common signal interface convention ? possess common simulation capabilities ? are reusable as library elements of other designs ? support multiple source procurement ? support technology independent reprocurement It is not the purpose of this specification to create models that promote a particular hardware design methodology.