ABSTRACT
The decision regarding whether to evolve, transition, or transform an architecture should depend on how we should improve the architecture and system designs to support the comprehensive solution. At times, the needed improvements will automatically dictate an evolutionary, transitional, or transformational path. Other times, performance, cost, schedule, and risk trade-offs are required to determine the best-fit architectural path. Just as understanding the current operational state is essential to improving the process, understanding the current architectural state is critical to improving the architecture. Appendix C.3.1 on Configuration Management explains how to document an IT architecture through the 4 + 1 view [1]. The physical and logical views include all the hardware and software in the architecture, the facility and network infrastructures, the network and security boundaries, and end-user devices. The process view links all the architectural components from the perspective of operations and the development view provides insight on the construction of the components. Finally, the use case scenarios connect the architecture with the system process and user workflows. Architectural constraints include industry-accepted products/technologies, communication/interface standards, common data formats, compatible database base schemas, and interdependent security controls. The 4 + 1 view approach for developing architectural/engineering artifacts is effective for all software-intensive systems. In modern times, this includes many physical systems with software modules. For other physical systems, traditional engineering designs remain valid.
