Which of the following are external qualities of a software product ?
2016
Which of the following are external qualities of a software product ?
- A.
Maintainability, reusability, portability, efficiency, correctness.
- B.
Correctness, reliability, robustness, efficiency, usability.
- C.
Portability, interoperability, maintainability, reusability.
- D.
Robustness, efficiency, reliability, maintainability, reusability.
Attempted by 249 students.
Show answer & explanation
Correct answer: B
Answer: Correctness, reliability, robustness, efficiency, and usability are external qualities of a software product.
Why these are external qualities:
Correctness: The software produces the expected and specified results; this is observable by users and testers.
Reliability: The system performs consistently and correctly over time under defined conditions; users experience dependable behaviour.
Robustness: The software can handle invalid input, unexpected situations, or stress without failing; this is seen during usage and testing.
Efficiency: How well the system uses resources (time, memory, bandwidth); this affects user-perceived performance.
Usability: How easy and pleasant the system is for users to learn and operate; directly observable by users.
Why the other attributes are not external qualities:
Attributes such as maintainability, reusability, portability, and interoperability are internal qualities. They refer to the software's structure, design, or ease of change and integration, which are primarily of concern to developers and maintainers rather than end users.
Quick classification rule: External qualities describe observable system behaviour and user experience; internal qualities describe code/design characteristics that affect development and maintenance.