Types of Requirements in System Design

Requirements in system design can be broadly categorized into three types: Functional Requirements, Non-Functional Requirements, and Extended Requirements each serving a specific purpose in guiding the development process. When designing a system, understanding and defining its requirements is crucial for ensuring that the system meets its intended goals and functions effectively.

Functional Requirements

Functional requirements define the specific behaviors or functions that a system must perform. They describe what the system should do in response to various inputs and how it should behave in different situations.

• Functional requirements are typically expressed as user stories or use cases and serve as the foundation for system design and development.
• These requirements are essential for ensuring that the system meets its intended purpose and delivers the expected functionality to users.

Example of Functional Requirements

Let’s understand Functional Requirements through system design of social media platform.

• User Registration: Allow users to create new accounts by providing their name, email address, and password.
• User Profile: Enable users to update their profile information, including their profile picture, bio, and contact information.
• Friend Connections: Enable users to send and accept friend requests, and manage their list of friends.
• Post Creation: Allow users to create new posts, including text, images, and videos, and share them with friends or publicly.
• Privacy Settings: Provide users with the ability to control the privacy settings of their posts and profile.
• Messaging: Enable users to send private messages to other users and participate in group chats.
• Notifications: Notify users about new friend requests, messages, and interactions on their posts.
• Search Functionality: Allow users to search for other users, posts, and content within the platform.

Non-Functional Requirements

Non-functional requirements specify the quality attributes or constraints that the system must satisfy. They define how well the system performs certain functions rather than what functions it performs.

• Non-functional requirements include aspects such as performance, reliability, security, usability, and scalability.
• These requirements are critical for ensuring that the system meets the desired level of quality and can be effectively used in its intended environment.

Example of Non-Functional Requirements

Let’s understand Non-Functional Requirements through system design of social media platform.

• Performance: The system should be able to handle a minimum of 1000 concurrent users without experiencing significant slowdowns.
• Reliability: The system should have a uptime of at least 99.9% to ensure users can access it whenever they need.
• Security: The system should implement secure authentication mechanisms, such as HTTPS, to protect user data from unauthorized access.
• Usability: The user interface should be intuitive and easy to navigate, with clear labeling and consistent design elements.
• Scalability: The system should be able to scale horizontally to accommodate an increase in users and data volume without significant changes to the architecture.
• Availability: The system should be available 24/7, with scheduled maintenance windows communicated to users in advance.

Extended Requirements

Extended requirements encompass a broader range of considerations that may not fit neatly into the categories of functional or non-functional requirements.

• They include additional aspects of the system that are important for its overall success but may not directly relate to its functionality or quality attributes.
• Extended requirements can include regulatory compliance, legal requirements, budget constraints, and environmental considerations.

Example of Extended Requirements

Let’s understand Non-Functional Requirements through system design of social media platform.

• Regulatory Compliance: Ensure that the platform complies with all relevant laws and regulations, such as data protection laws (e.g., GDPR, CCPA) and content moderation laws (e.g., DMCA).
• Legal Requirements: Address any legal considerations specific to the platform, such as user agreements, terms of service, and intellectual property rights.
• Budget Constraints: Adhere to budget constraints for the development, maintenance, and operation of the platform, including considerations for cost-effective solutions.
• Environmental Considerations: Minimize the environmental impact of the platform, such as energy consumption and carbon footprint, through efficient design and operation.