Question

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

Short answer

Functional, Non-functional, Technical, and User requirements.

Step-by-step solution

Functional Requirements

Functional requirements specify what the system should do. They describe the functions the software must execute, such as calculations, data manipulation, user interface, and data processing capabilities. Functional requirements are often documented in user stories or system use cases.

Non-Functional Requirements

Non-functional requirements define the quality attributes, system performance, or constraints that the system must comply with. These can include performance metrics like speed and response time, security details, usability standards, capacity, reliability, and scalability.

Technical Requirements

Technical requirements are the technical issues that need to be considered to successfully implement the system. These often involve technology constraints, implementation details, interfaces, and integration with other systems. They set the groundwork for the development and testing environments.

User Requirements

User requirements explore what the end-users need from the system in terms of functionality, delivery, and performance. These can be captured through user stories or scenarios and are often written in natural language to describe what the user can achieve with the system.

Key concepts

Functional Requirements

Functional requirements are the backbone of any system design. They define what actions and tasks the system should be able to perform. Imagine you are using a calculator application; the functional requirements would be the ability to add, subtract, multiply, and divide numbers. These requirements focus on "what" the software needs to accomplish, such as processing data or providing user interfaces. For developers, functional requirements are translated into user stories or system use cases, which highlight how the user interacts with the system in practical scenarios.
The importance of these requirements lies in their ability to define the core operations that the system must execute effectively. Without a clear understanding of functional requirements, developers may struggle to provide a system that meets the needs of its users.

Non-Functional Requirements

Non-functional requirements don't dictate what the system should do; rather, they describe how the system performs certain functions. These include aspects like performance, security, usability, and reliability. For instance, a non-functional requirement for an online banking system might be that transactions are processed in under two seconds. Such requirements focus on the system's quality and efficiency. They are crucial in ensuring that the system runs smoothly and offers a satisfactory user experience.
When developing a system, non-functional requirements help in establishing benchmarks for operations, ensuring that the system is not only functional but also efficient and user-friendly. Addressing these requirements can often involve setting thresholds for response times or ensuring data security measures are robust.

Technical Requirements

Technical requirements provide the blueprint for the technological infrastructure needed to implement the system. They encompass the technological environment, software, and hardware specifications necessary to create and maintain the system. For example, if a software system needs to work on multiple operating systems like Windows and macOS, these explicit details would be outlined in the technical requirements.
This category helps developers understand the boundaries and dependencies related to technology, ensuring compatibility and proper integration with other systems. Technical requirements are vital during the planning stage to make sure the selected technologies fit the project's scope and objectives.

User Requirements

User requirements focus on what the end-user expects from the system. These are crucial as they directly influence user satisfaction. To capture user requirements, developers often utilize user stories or scenarios, which describe functions or features from the user's perspective. For instance, a user requirement for a smartphone app might be the ability for users to track their fitness activities.
These requirements are generally written in simple, clear language to ensure everyone involved has a solid understanding of the user's expectations. Meeting user requirements is essential because a system that aligns well with users' needs is more likely to be adopted and acclaimed.