ABSTRACT
This chapter focuses on the important topic of nonfunctional (operational) requirements (NFRs). It aims to capture and implement these requirements in designing and developing a software solution. The operational (nonfunctional) requirements cannot be modeled with, say, a use case or an activity diagram. In addition to the operational requirements of the software developed, some additional constraints impact the NFRs. The nonfunctional parameters are stated as requirements in the early stages of software development. NFRs of the system are not isolated, independent requirements, even though they are presented here as such. Owing to the guess work involved in NFRs, it is also a good idea to pair these requirements with corresponding assumptions. Business stakeholders and domain experts participate in workshops, usually organized by business analysts, to discover these otherwise unfamiliar and unclear requirements. Performance requirements specify the speed or the response time required of a software solution.
