問46
頻出度★★★
ソフトウェアの品質特性を, 機能性, 使用性, 信頼性, 移植性などに分類した場合, 機能性に該当するものはどれか。
平成25年度 春期 ITパスポート試験 問46
マネジメント系システム開発技術 › システム開発技術
This question's explanation and your answers so far.
解説
問 46
Incorrectア
“When a failure occurs, data can be recovered to the state it was in before the failure” describes recoverability, a sub-characteristic of reliability. Reliability looks at whether a level of performance can be maintained under stated conditions for a stated period, and it consists of maturity (how unlikely failures are), fault tolerance (whether the software keeps working when a failure occurs), and recoverability (whether it can be restored after a failure). This is a different category from functionality, which asks whether the functions themselves match the specification.
- イ
正解 The correct answer is イ. Functionality means whether the software actually has the functions that were required, and whether those functions work correctly as stated in the specification. In JIS X 0129 (ISO/IEC 9126), the sub-characteristics of functionality are suitability (whether the necessary functions are provided), accuracy (whether the results are correct), interoperability, and security. Choice イ, “Operations can be performed as specified in the specification document, and appropriate execution results are obtained,” describes that the operations required by the specification can actually be carried out (suitability) and that their results are appropriate (accuracy), which corresponds directly to the definition of functionality. The other choices are about how easily the software recovers from a failure (reliability), how easy it is to use and learn (usability), and how easily it can be moved to another environment (portability). These all evaluate “how it runs” on the assumption that the functions are already there, so they do not belong to functionality.
Incorrectウ
“It can also run in other OS environments” describes adaptability, a sub-characteristic of portability. Portability looks at whether software can be moved from one environment, such as a particular hardware platform, OS, or network, to another, and it consists of adaptability, installability, and replaceability. This is about the range of environments in which the software runs, not about functionality, which asks whether the functions work correctly as specified.
Incorrectエ
“The time required for users to become proficient is short” describes learnability, a sub-characteristic of usability. Usability looks at how easy the software is for users to understand and use, and it consists of understandability, learnability, and operability. Among the categories listed in the question, this belongs to usability, which is distinct from functionality, which asks whether the required functions are provided.
ここがポイント
- JIS X 0129 (ISO/IEC 9126) defines six software quality characteristics — functionality, reliability, usability, efficiency, maintainability, and portability. Only functionality asks whether the required functions are provided and work correctly as specified; the rest assume the functions are already there and ask how the software runs or how it can be handled. The heart of this question is telling which characteristic each choice is a paraphrase of.
- Matching by sub-characteristic keywords is quicker. Functionality = suitability, accuracy, interoperability, security (as specified / correct results); reliability = maturity, fault tolerance, recoverability (failure, recovery); usability = understandability, learnability, operability (easy to understand, easy to learn); portability = adaptability, installability, replaceability (can be moved to another environment).
用語