Requirements specification is an important part of the software development process. Use of well developed techniques, tools, and languages during requirements specification is especially crucial for complex embedded software systems. Four langauges appropriate for the specification of software requirements for complex embedded systems (RSL, PAISLey, Statecharts, and SCR) are reviewed in detail here. In addition, other representation languages with features relevant to the embedded software systems domain are mentioned. Conclusions about the current status of embedded systems requirements specification and indications of further research are given.

Requirements specification is an important part of the software, indeed the system, development process. It is critical that this effort be started early. This work suggests an early model for software developers to incorporate a systems viewpoint in their process. This model is an attempt to formalize an approach that will include a systematic representation of essentials of the external interface for software that is embedded within a larger system. The model is useful for early analysis of the software system and environment for such things as consistency, completeness, and safety.