Question

Suggest how an engineer responsible for drawing up a system requirements specification might keep track of the relationships between functional and non-functional requirements.

Short answer

Use a traceability matrix to track the relationships, employing requirement management tools for documentation and regular updates.

Step-by-step solution

Understand the Types of Requirements

Before tracking the relationships between functional and non-functional requirements, it's important to clearly understand what each type of requirement is. Functional requirements describe what the system should do and include specifications of behavior and functionality. Non-functional requirements pertain to how the system performs certain functions, such as performance, usability, reliability, etc.

Categorize Requirements

Organize all gathered requirements into two categories: functional and non-functional. Use a checklist or a table to ensure that each requirement is correctly categorized. For example, if a requirement specifies a feature the system must perform (like user authentication), classify it as functional. If it specifies constraints on how the system performs (like response time under load), classify it as non-functional.

Use a Traceability Matrix

Create a traceability matrix to map and keep track of the relationships between functional and non-functional requirements. This matrix displays how each functional requirement is impacted by non-functional requirements, highlighting potential conflicts or dependencies. Label columns with functional requirements and rows with non-functional requirements.

Employ Requirement Management Tools

Utilize requirement management tools that help maintain these relationships digitally. Software such as IBM DOORS or JIRA can automatically track and visualize connections between requirements, providing an easy interface for managing complexities and documenting interactions.

Regular Reviews and Updates

Conduct regular reviews to update and validate the traceability matrix. Understanding that requirements can change over time, it's essential to keep the matrix up-to-date to reflect the current system scope and requirements accurately. Use team review sessions to discuss findings and incorporate changes.

Key concepts

Functional Requirements

In software and systems engineering, functional requirements are crucial. They represent the specific behaviors or functions of the system - essentially what the system should do. These can include tasks like processing orders, managing databases, or handling user interactions. Functional requirements are usually gathered during the early stages of development through stakeholder interviews and need assessments. They form the blueprint for developers, guiding them on building features and functionalities that align with user needs and business goals.

Functional requirements are typically described using simple and clear statements. They can often be expressed in use cases or user stories, which highlight user interactions with the system. This ensures that all necessary operations are included. These requirements must be measurable and testable. Thus, a successful software project clearly outlines its functional requirements early on to avoid any discrepancies during development.

Non-Functional Requirements

While functional requirements focus on what the system does, non-functional requirements define how the system performs. They form critical constraints on the performance and quality of the system's functions. Non-functional requirements include aspects like:

• Performance – how fast a function executes.
• Scalability – the system's ability to handle growth.
• Security – measures taken to protect data and access.
• Usability – ease of use and learnability of the system.
• Reliability – capability of the system to deliver consistent results.

These attributes significantly affect user satisfaction and system success. Unlike functional requirements, they are often tested under various scenarios to ensure compliance with specified standards.

Non-functional requirements can sometimes be more challenging to measure, as they often involve subjective factors. However, they are equally important. A system with exceptional functional capabilities may fail if it doesn't meet key non-functional requirements like usability or reliability. Thus, these requirements must be carefully documented and continuously validated to align with stakeholder expectations.

Traceability Matrix

A traceability matrix is a valuable tool used to track the relationships and dependencies between functional and non-functional requirements. It is essentially a document (often in table format) that maps each item to something that influences or is influenced by it, ensuring that all requirements are accounted for throughout the project lifecycle.

To create a traceability matrix, list all functional requirements and all non-functional ones. The matrix helps to identify how functional requirements are met or affected by non-functional requirements. Centering efforts on this document can proactively surface potential conflicts or dependency issues between the various requirements, allowing for their resolution before they become significant problems.

A comprehensive traceability matrix can streamline the testing process by directly linking requirements to test cases. This ensures coverage and helps teams verify that all objectives are met. Additionally, it is a critical component in maintaining project scope and requirement changes, providing a centralized point of reference for stakeholders and developers alike.

Requirement Management Tools

Managing system requirements, especially in complex projects, can be a daunting task. This is where requirement management tools come into play. These tools help automate and streamline the process of capturing, organizing, and tracking requirements throughout a project's lifecycle.

Tools like IBM DOORS or JIRA offer powerful capabilities such as:

• Collaboration features for team input and review.
• Version control to manage requirement changes over time.
• Visualization of requirement relationships and dependency management.
• Traceability features to track requirements from conception to deployment.

Using these tools, engineers can efficiently handle large volumes of requirements, maintain consistency, and ensure that the final deliverable meets all outlined specifications.

By providing a single platform for requirements management, these tools help mitigate the risk of project drift and help satisfy stakeholder expectations with greater precision. They also aid in documenting interactions and changes, offering a clear audit trail which is beneficial for assessments and revisions.