The need for software systems engineering

One of the ‘big-picture problems’ I came across while consulting on software engineering in the automotive world was the relationship between systems engineering and software engineering. Traditionally, automotive systems engineering has focused on system attributes such as power, weight, performance and cost, to name but a few. Software has been treated as a separable component of the system by systems engineers.

The OEM for whom I consulted had adopted the RFLP systems engineering paradigm: Requirements, Functional Architecture, Logical Architecture and Physical Architecture. The principles of RFLP are that use cases and requirements are collected together to determine functional requirements. These are used to produce an architecture for each (set of) function(s). Parallel functional architectures are then integrated into a logical architecture that composes related functional architecture elements together into related logical units that reflect the conceptual architecture of the intended product. However, the logical architecture should remain implementation independent. Physical architecture includes the technology domains that will contribute to the realization of the end product, eg mechanics, hardware, fluid dynamics, and so on. As such, RFLP isn’t substantially different from other systems engineering paradigms, such as CAFCR.