Edward J. Barkmeyer Jr., Evan K. Wallace: This document is a part of the definition of a reference architecture for the integration of manufacturing software applications in the areas of fabrication and assembly of discrete electro- mechanical parts. This document captures, at a high level of abstraction, the engineering and operations functions involved in producing discrete products, and the general nature of information flows among them. The function elements provide a frame of reference for product- and facility- specific functions in a production systems, and thus for specifications for manufacturing software/hardware systems components. Assigning these narrower functions to components begets a systems architecture, for which the information flows described in this document identify the necessary interactions among the components. The information flow elements also provide a frame of reference for specifying the information involved in those interactions and in the corresponding component interfaces. In short, these models are part of a framework for specifying production systems architectures, and the related architectures for the software systems that support production systems engineering.