Question

Identify and briefly describe four types of requirements that may be defined for a computerbased system.

Short answer

Functional, non-functional, user, and system requirements are key types of requirements for computer-based systems.

Step-by-step solution

Functional Requirements

Functional requirements are specific features or functions that a system must perform. They describe what the system should do, including tasks like managing data, processing transactions, and offering certain user commands or feedback. For example, a functional requirement for a banking application could be the ability to process deposits and withdrawals.

Non-Functional Requirements

Non-functional requirements describe how the system performs a function rather than the specific behaviors or features of the system. These include qualities such as performance, security, usability, and reliability. For example, a non-functional requirement might specify that a response from the system should not take longer than 2 seconds.

User Requirements

User requirements are the needs and expectations of the end-users who will interact with the system. These are usually written in a narrative form or as user stories, emphasizing ease of use, and ensuring that the system meets user goals. An example is a requirement stating that users want an intuitive interface that allows them to easily navigate the system.

System Requirements

System requirements encapsulate all the high-level requirements and specifications that the complete system must satisfy. These include both functional and non-functional requirements but also address hardware and software interfaces, network capabilities, and constraints related to operations. An example would be a detailed specification of the operating systems and hardware that the system must support.

Key concepts

Functional Requirements

Functional requirements are critical in defining what a system is designed to do. They focus on the specific activities and operations that software must perform.
These requirements are directly related to the functions the system needs to deliver. Examples include the ability for users to log in, process payments, or manage diverse data sets. Each functional requirement should be clear and detailed to ensure correct implementation.
To illustrate, a functional requirement for an e-commerce application might specify that it should enable users to create and manage shopping carts or check out using various payment methods. Another example is the requirement for an educational app to allow users to download learning materials and track their progress.
Functional needs are essential for guiding developers in coding and testing phases, as they describe exactly what outcomes the system should achieve.

Non-Functional Requirements

Non-functional requirements describe the qualities and constraints of a system, focusing on how well the functions are delivered rather than what is delivered. These requirements help to enhance the user experience and system performance without defining specific functionality.
They typically include specifications for speed, security, reliability, scalability, and usability. For example, a non-functional requirement might state that the system should support at least 10,000 concurrent users while maintaining quick response times. Another might address data security, mandating all user data be encrypted end-to-end to prevent unauthorized access.
Because non-functional requirements are qualitative in nature, they often include benchmarks or measurements to define satisfactory performance levels, such as system uptime must be 99.99%. Meeting these requirements is crucial for user satisfaction and overall system integrity.

User Requirements

User requirements focus on what users need from a system, encompassing their goals, experiences, and expectations. These requirements ensure that the developed system aligns with the user's needs and enhances their interaction.
They are often articulated as user stories or scenarios that describe what users want to achieve. Key traits of user requirements include user-friendliness, intuitiveness, and accessibility. An example could be an interface designed to allow users to quickly navigate through various sections with ease.
For instance, a social media application may have user requirements that highlight the necessity for a feature allowing users to share content seamlessly across platforms.
By prioritizing user requirements, developers can ensure they build a product that is not only functional but also engaging and easy to use, increasing the likelihood of user satisfaction and adoption.

System Requirements

System requirements are comprehensive specifications that detail the characteristics of the entire system and its components, encompassing both hardware and software needs.
These requirements merge both functional and non-functional aspects with technical constraints and configurations, ensuring that every part of the system interacts seamlessly.
Included in system requirements are details such as supported operating systems, minimum hardware specifications, network connectivity, and integration points with other systems or software. For example, a requirement might state that the system must run on Windows and Linux platforms, support multilingual interfaces, and integrate with a specific database management system.
By clearly defining system requirements, developers can ensure that the system meets not only the immediate functional needs but also fits within the technological framework, facilitating future expansion and compatibility.