Requisitos Não Funcionais (NFRs) são aspectos críticos de design de sistema that define how a system performs under various conditions, rather than what the system does. These requirements encompass a wide range of attributes, including usability, reliability, performance, security, and compliance with standards. Unlike functional requirements, which specify the specific functions or features of a system, NFRs focus on the quality and constraints of those functions.
Por exemplo, um requisito funcional pode state that a user must be able to log in to a system, while a corresponding NFR could specify that the login process must occur within two seconds and must not exceed three failed attempts for security reasons. Other common NFRs include:
- Desempenho: Quão rapidamente um sistema responde às entradas do usuário ou processa dados.
- Escalabilidade: The ability to handle growth in users or data volume without performance degradation.
- Segurança: Measures and protocols para proteger os dados e manter a privacidade do usuário.
- Usabilidade: Quão fácil e intuitivo o sistema é para os usuários.
- Confiabilidade: The system’s ability to operate consistently over time sem falhas.
Compreender e especificar os NFRs é essencial durante o desenvolvimento de software lifecycle, as they can significantly impact user satisfaction and system success. They also play a crucial role in testing and validation processes, ensuring that a system not only meets its functional requirements but also provides a satisfactory user experience and complies with necessary standards and regulations.