Architectures are a hierarchical description of the
design of a system and in many cases how it will be developed, evolved, and
operated-- "the structure not only of the system, but of its functions, the
environment within which it will live, and the process by which it will be built
and operated."13 Architectures provide the underlying blueprint for the more detailed design and implementation decisions about components of a system. When well-defined architectures exist, engineers can design individual components and builders can implement them with a high degree of confidence that the end result will work as expected and meet user needs. Successful architectures are driven by more than technical consideration--they have as their fundamental goal the support of the requirements of users throughout an organization and are often represented in multiple dimensions, e.g., functional views, physical views, and operational views. When done well, architectures have enormous influence on the success of the overall endeavor. Some examples of commercial information systems architectures that have had such impact are the Ethernet local area network, the IBM S/390, and Digital's VMS.
Within an organization, development of architectures goes hand in hand with business process reengineering. In the military context, such business process reengineering would translate to an examination of how doctrine and procedures might evolve to exploit new capabilities offered by C4I systems (see also section 4.1.4). The mere automation of existing processes results not only in less-than-optimal gains, but also in "islands" of functionality (determined by the preexisting business processes) that exchange information only with great difficulty. Because reengineering requires an understanding of information flows that cut across old organizational boundaries, it lays the intellectual groundwork for an architecture that will support those flows.