The purpose of this paper is to communicate an understanding of that cluster of concepts within computer science collectively referred to as an operating system. The approach taken to this sojourn is somewhat akin to that of evolutionary theory as utilized in the biological sciences. To elaborate, the evolutionary approach to the study of a conceptual unit involves the exploration of its historical and ontological development, and its functions. To relate this to the concepts of systems technology involves the exploration of the appearance and subsequent changes of those ideas which are the framework and body of the collective operating system, in a historical sense. To provide breadth to this exploration the determination of the ontology of a single system allows more specific treatment of environmental factors, as well as crystalizing the perspective to form molecules of definitive dimension within the larger element. The understanding of function completes each concept by relating its inner elements to its environment. Thus, it may be seen that an evolutionary approach provides an encompassing view of a conceptual unit.