Software Requirements Engineering

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Questions and Answers

What defines functional requirements in software development?

They outline non-functional attributes such as usability and reliability.

They detail the features and functions the system must provide. (correct)

They specify the monetary costs associated with the project.

They describe how well the system performs under load.

Which of the following best describes non-functional requirements?

They define how a system performs and behaves rather than what it does. (correct)

They are requirements that are not related to user experience.

They can be considered as part of the system's functional requirements.

They are measurable characteristics of a system's functionality.

What is one of the potential risks mentioned in managing software requirements?

Misunderstanding the business context of the software. (correct)

Overly specific functional requirements.

Too many technical specifications.

Clarity in communication with customers.

What does the 'moving target problem' refer to in software development?

Changes in requirements during the development process. Signup and view all the answers

Why is requirement elicitation considered a difficult stage?

Customers often have vague ideas of what they need. Signup and view all the answers

What is meant by 'requirement iterations' in software development?

An iterative process of elicitation, specification, and validation. Signup and view all the answers

How can changes in requirements affect software projects?

They can uncover new risks or opportunities. Signup and view all the answers

What role does communication play during the requirement elicitation process?

Continuous communication with customers is crucial. Signup and view all the answers

What do functional requirements primarily describe?

Intended behaviors of a system Signup and view all the answers

Why are non-functional requirements essential for a software system?

They specify quality attributes that ensure usability. Signup and view all the answers

Which of the following is a characteristic of functional requirements?

They can be tested at different levels of testing. Signup and view all the answers

What is one potential issue with imprecise non-functional requirements?

They may be difficult to verify. Signup and view all the answers

How do functional requirements relate to the interactions between a system and its environment?

They detail the interactions and specific inputs. Signup and view all the answers

Which of the following statements correctly describes the purpose of non-functional requirements?

They are quantifiable measures of product performance. Signup and view all the answers

In a Patient Management System, what does a functional requirement entail regarding appointment lists?

Searching through the appointment lists of clinics. Signup and view all the answers

What is a key distinction between functional and non-functional requirements?

Functional requirements indicate what actions a system must perform. Signup and view all the answers

Which aspect does usability primarily relate to in the context of non-functional requirements?

System's ease of use for individuals Signup and view all the answers

What characteristic distinguishes functional requirements from non-functional requirements?

Functional requirements describe system functionality, while non-functional requirements describe system properties. Signup and view all the answers

Why is it important to quantify non-functional requirements?

To avoid subjective descriptions and facilitate measurement Signup and view all the answers

At what stage of system testing are non-functional requirements typically assessed?

At the final system testing stage Signup and view all the answers

Which type of constraints does the term 'design constraints' refer to?

Technical limitations imposed by the development environment Signup and view all the answers

What is a critical factor in measuring non-functional requirements?

The operating conditions under which requirements must be satisfied Signup and view all the answers

When quantifying a non-functional requirement regarding ease of use, what must be specified?

The maximum number of training hours required Signup and view all the answers

Which of the following is considered a non-functional requirement?

The system shall process transactions in less than 2 seconds Signup and view all the answers

What does the term 'Mean time to failure (MTTF)' refer to in software reliability testing?

Average time between failures of a system Signup and view all the answers

Which of the following is NOT a measure of software reliability testing?

Average response time for user input Signup and view all the answers

What is meant by 'down time' in the context of reliability testing?

The duration of operational failures within a year Signup and view all the answers

In security testing, which ability is primarily tested?

Resistance to unauthorized access Signup and view all the answers

Which metric reflects the success of security testing?

Successful penetrations per year Signup and view all the answers

What is a critical reliability factor indicated by the precision of calculations metric?

Acceptable margin of error in calculations Signup and view all the answers

Which of the following is a key aspect of security testing in hostile environments?

Continuity of service during denial of service attacks Signup and view all the answers

What does 'attack surface exposure' measure in security testing metrics?

Potential entry points for attackers Signup and view all the answers

What is the primary goal of vulnerability testing?

To identify and mitigate security weaknesses Signup and view all the answers

Which of the following is not a method of vulnerability testing?

Load balancing testing Signup and view all the answers

What does throughput measure in performance testing?

Amount of transactions processed in a given time Signup and view all the answers

Which performance testing metric indicates the maximum time to respond to a transaction request?

Response Signup and view all the answers

What is the purpose of stress testing?

To check system performance under extreme conditions Signup and view all the answers

Which of the following requirements illustrates an example of performance testing?

System shall process 100 payment transactions per second Signup and view all the answers

What is the purpose of fuzz testing?

To provide malformed inputs and test system behavior Signup and view all the answers

Which statement is an example of a performance metric?

CPU usage shall be less than 50% Signup and view all the answers

Study Notes

Evolving Requirements

Requirements can change during development due to changing business priorities, evolving customer understanding, or new risks or opportunities
This is known as the “Moving Target Problem”
Requirement engineering is an iterative process of elicitation, specification, and validation, to accommodate changing requirements

Functional and Non-functional Requirements

Functional requirements specify “what” the software must do, from the user's perspective, describing the intended behaviors of a system
Non-functional requirements (NFR) specify the “quality attributes” of the software, defining constraints or performance requirements
NFR are important to ensure the system's usability and effectiveness, but imprecise NFR can be difficult to verify

Examples of Functional Requirements

Functions the software must perform
How the system should react to particular inputs
What inputs the system should accept
What outputs the system should produce
What data the system should store
What computations the system performs

Examples of Non-functional Requirements

Quality Attributes: Reliability, Robustness, Security, Usability, Performance
Design Constraints: Platform constraints, Response times

Measures of Non-functional Requirements

NFR describe emergent properties of the system that must be measured and satisfied
NFR are typically not checked in unit tests or static analysis, but require system-level testing with prototypes or the final system
NFR quantification needs measurable metrics, avoid subjective terms, and require understanding of trade-offs between different requirements

Reliability Testing

Measures of reliability include probability of no failure in a specified time, probability of failure on demand, mean time to failure (MTTF), and downtime

Security Testing

Security testing focuses on resisting unauthorized usage, continuing to provide service to legitimate users under attack, and resisting denial of service (DoS) attacks

Performance Testing

Performance testing focuses on requirements related to throughput, response time, memory utilization, I/O rates, latency, etc.
Statistical testing based on an operational profile is often used, with probabilities and confidence levels

Performance Testing Metrics

Throughput: amount of transactions processed in a given time
Response time: average or maximum time to respond to a request
Threshold: system behavior within required limits
Stress: system behavior under extreme conditions

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Description

Explore the intricacies of software requirements engineering, focusing on both functional and non-functional aspects. Learn about the iterative process of elicitation, specification, and validation to adapt to changing business needs. Delve into real-world examples to understand the significance of precise requirements.