Categories of NFRs • Product-oriented Approach

• Functional requirements describe what the system should do – things that can be captured in use cases – things that can be analyzed by drawing sequence diagrams, statecharts, etc. – Functional requirements will probably trace to individual chunks of a program • Non-functional requirements are global constraints on a software system – e.g. development costs, operational costs, performance, reliability, maintainability, portability, robustness etc. – Often known as the “ilities” – Usually cannot be implemented in a single module of a progra