FURPS
FURPS (Functionality, usability, reliability, performance, supportability) is a model for classifying software quality attributes (functional and non-functional requirements): == Model == Functionality - capability (size and generality of feature set), reusability (compatibility, interoperability, portability), security (safety and exploitability) Usability (UX) - human factors, aesthetics, consistency, documentation, responsiveness Reliability - availability (failure frequency (robustness/durability/resilience), failure extent and time-length (recoverability/survivability)), predictability (stability), accuracy (frequency/severity of error) Performance - speed, efficiency, resource consumption (power, ram, cache, etc.), throughput, capacity, scalability Supportability (serviceability, maintainability, sustainability, repair speed) - testability, flexibility (modifiability, configurability, adaptability, extensibility, modularity), installability, localizability The model, developed at Hewlett-Packard was first publicly elaborated by Grady and Caswell. FURPS+ is now widely used in the software industry.