Requirements specification is the process of writing down the user and system requirements in a requirements document. Ideally, the user and system requirements should be clear, unambiguous, easy to understand, complete, and consistent. The user requirements for a system should describe the functional and nonfunctional requirements so that they are understandable by system users who don’t have detailed technical knowledge. should specify only the external behaviour Ideally, they of the system. The requirements document should not include details of the system architecture or design. Consequently, if you are writing user requirements, you should not use software jargon, stru ctured notations, or formal notations. You should write user requirements in natural language, with simple tables, forms, and intuitive diagrams. System requirements are expanded versions of the user requirements that are used by software engineers as the starting point for the system design. They add detail and explain how the user requirements should be provided by the system. They may be used as part of the contract for the implementation of the system and should therefore be a complete and detailed spec ification of the whole system. Ideally, the system requirements should simply describe the external behaviour of the system and its operational constraints. They should not be concerned with how the system should be designed or implemented. User requiremen ts are almost always written in natural language supplemented by appropriate diagrams and tables in the requirements document. System requirements may also be written in natural language but other notations based on forms, graphical system models, or mathe matical system models can also be used.
