Requirements Engineering for Software vs. Systems in General

Are there fundamental technical differences between requirements engineering for software vs. systems in general? It seems as though even functional requirements can mean something more general for a system including mechanical parts than for software alone. Quality requirements on safety deal with humans and their relationship with some real artifacts in their environment, so they cannot be dealt with by software alone. However, reliability of underlying software will be important in this context. While the internal structure of software will not normally be specified in its requirements, structure of a more general system may well be. These are just examples of what should be discussed. With regard to intelligent enterprises, there exist defined methodologies for enterprise modeling. Much as any other complex system, an enterprise may be better understood through modeling. Once an enterprise is better understood, it may be easier to make it intelligent. Whatever technical system is to be developed in an enterprise, it needs to fit into. By connecting enterprise modeling and requirements engineering, the likelihood of such a fit is increased. For software development, such connections have been worked out and are part of defined methodologies, some of them based on objectoriented modeling. Are they applicable to the development of general systems? Keywords-requirements engineering; software; systems; enterprises