問49
頻出度★★☆
新システムに求められる運用時間を24時間, 365日と決定した。この決定を行う開発工程はどれか。
平成24年度 春期 ITパスポート試験 問49
ストラテジ系システム企画 › 要件定義
This question's explanation and your answers so far.
解説
問 49
Incorrectア
Software acceptance is the final process in which the client inspects the completed system, confirms that it works as required, and takes delivery of it. It is the side that checks whether the 24 hours a day, 365 days a year operating time decided in requirements definition has been met; it is not the process that newly decides the operating time itself.
Incorrectイ
Testing is the process of verifying that the deliverables that were designed and implemented behave as specified. Availability and performance tests may be run, but the pass/fail criteria (the target of 24 hours a day, 365 days a year) have already been fixed in requirements definition; the testing process is not what determines the required level.
Incorrectウ
Programming is the process of actually writing code based on the design documents — the stage that realizes how to build it. What is required has already been fixed by this point, and business requirements such as operating time are not decided here.
- エ
正解 The correct answer is エ, Requirements definition. Running 24 hours a day, 365 days a year is a requirement about the availability and operating time the system must provide; it is not a function itself but a non-functional requirement that sets quality and operational conditions. Development generally proceeds in the order requirements definition → system design → programming → testing → software acceptance, and the stage that decides what the users and the business ask of the system is the most upstream one, requirements definition. Fixing the operating time here allows the later design work to study how to achieve it — redundant configurations, backup methods, time slots for maintenance work — and allows testing and acceptance to verify whether the system really runs 24 hours a day, 365 days a year. The process in which this decision is made is therefore requirements definition.
ここがポイント
- How roles are divided among development processes: requirements definition is the most upstream stage, deciding what is required; design and programming answer how to build it; testing and acceptance confirm that what was required has actually been achieved. Judge which process a decision belongs to by asking which of these questions it answers.
- Operating time, availability rate, response time, security, maintainability and the like are non-functional requirements concerning quality and constraints rather than function. Just like functional requirements, they must be made clear by the user side at the requirements definition (business requirements definition) stage.
用語