Functional and non-functional requirements are crucial components of system specifications, especially in software development and system engineering. These requirements help in guiding the development of a system. Here’s a breakdown:
Functional requirements describe the specific behavior or functions of a system. They specify what the system should do. Essentially, they define the system’s functionality.
Examples of functional requirements include:
- User Authentication: Users must be able to log in and log out of the system.
- Search Functionality: Users should be able to search for products using keywords.
- Data Management: The system should allow administrators to add, modify, or delete user accounts.
- Reporting: The software should be able to generate monthly sales reports.
- Integration: The application should be able to integrate with third-party email services.
Non-functional requirements, on the other hand, describe how the system works. They specify the criteria that can be used to judge the operation of a system, rather than specific behaviors. These requirements are often referred to as the “quality attributes” or “quality goals” of a system.
Examples of non-functional requirements include:
- Performance: A page should load within 2 seconds under normal network conditions.
- Reliability: The system should have an uptime of 99.99%.
- Usability: All features of the application should be accessible within three clicks from the main screen.
- Security: Data transfers must be encrypted. Unauthorized users should not have access to private data.
- Scalability: The system should handle an increase in users and data volume without performance degradation.
- Maintainability: The codebase should be modular and well-documented, enabling easy changes and updates.
- Portability: The application should work on both Windows and MacOS.
- Accessibility: The website should be usable for people with disabilities, adhering to WCAG guidelines.
- Backup and Recovery: There should be daily backups of data, and the system should allow for recovery within 2 hours in case of system failure.
In essence, while functional requirements define what a system is supposed to do, non-functional requirements define how the system should do it. Both types of requirements are vital to develop a comprehensive and effective system that meets user needs and expectations.