- These define system properties and constraints e.g. reliability, response time and storage requirements. Constraints are I/O device capability, system representations, etc.
i.e. Deactivate or delete record after 24 hrs
- Process requirements may also be specified mandating a particular programming language or development method.
- Non-functional requirements may be more critical than functional requirements. If these are not met, the system may be useless.
Types of Nonfunctional requirement
Product requirement: Examples
The MHC-PMS shall be available to all clinics during normal working hours (Mon–Fri, 0830–17.30). Downtime within normal working hours shall not exceed five seconds in any one day.
Organizational requirement: Examples
Users of the MHC-PMS system shall authenticate themselves using their health authority identity card.
External requirement: Examples
The system shall implement patient privacy.
Non-functional requirements implementation
- Non-functional requirements may affect the overall architecture of a system rather than the individual components.
- For example, to ensure that performance requirements are met, you may have to organize the system to minimize communications between components.