User talk:Sujeeba

Non-Functional Requirements

The SE definition for a non-functional requirement specifies how the system should behave:

"A non-functional requirement is a statement of how a system must behave; it is a constraint upon the systems behavior."

Non-functional requirements specify all the remaining requirements not covered by the functional requirements. They specify criteria that judge the operation of a system, rather than specific behaviors, for example:

"Display of the patient's vital signs must respond to a change in the patient's status within 2 seconds."

Typical non-functional requirements are:

•	Performance - Response Time, Throughput, Utilization, Static Volumetric •	Scalability •	Capacity •	Availability •	Reliability •	Recoverability •	Maintainability •	Serviceability •	Security •	Regulatory •	Manageability •	Environmental •	Data Integrity •	Usability •	Interoperability Non-functional requirements specify the system’s ‘quality characteristics’ or ‘quality attributes’. Potentially many different stakeholders have an interest in getting the non-functional requirements right. This is because for many large systems the people buying the system are completely different from those who are going to use it (customers and users).