問20
頻出度★☆☆
クラウドコンピューティング環境では, インターネット上にあるアプリケーションやサーバなどの情報資源を, 物理的な存在場所を意識することなく利用することが可能である。次のサービスのうち, このクラウドコンピューティング環境で提供されるサービスとして, 最も適切なものはどれか。
平成27年度 春期 ITパスポート試験 問20
ストラテジ系システム戦略 › ソリューションビジネス
This question's explanation and your answers so far.
解説
問 20
- ア
正解 The correct answer is ア“SaaS”. SaaS (Software as a Service) is a service model in which a provider delivers application software over the Internet, so users do not own servers or software themselves and use only the functions they need from a browser or similar client. Users do not have to be aware of which data center or which machine the application or server actually runs on, which matches exactly the stem's description of cloud computing: “using information resources on the Internet without being aware of their physical location”. Cloud service models are classified by how much is provided: SaaS (up to the application), PaaS (up to the application execution platform), and IaaS (only infrastructure such as servers and storage). Among the choices, only SaaS belongs to this XaaS family.
Incorrectイ
Escrow is a mechanism in which, instead of the parties to a transaction exchanging things directly, a trusted third party temporarily holds money or software source code and hands it over once the agreed conditions are met (third-party deposit). It is used for payment settlement in online shopping, for source code deposit when software development is outsourced, and so on. It is a safeguard for transactions, not a cloud service that lets users use information resources over the Internet.
Incorrectウ
Systems integration (SI) is a service that builds an information system by taking on the whole job in response to a customer's requirements: planning, design, development, deployment, and operation. It is ultimately a contract-based service that creates an individual system, not a delivery model in which existing information resources are shared and used over a network, so it is not appropriate as a description of a service provided in a cloud computing environment.
Incorrectエ
Housing is a model in which users install and operate servers and other equipment they have prepared themselves by renting rack space, power, and lines inside a provider's data center (colocation). The owner of the equipment is the user, and the user must be clearly aware of the physical location, namely which facility and which rack the equipment sits in, so it is the exact opposite of the stem's condition of “using it without being aware of the physical location”. Note also that the model in which you rent servers prepared by the provider is called hosting, which should be remembered as distinct from housing.
ここがポイント
- Cloud computing is a model in which you use information resources such as servers and applications over the Internet, only as much as you need, without being aware of where they are physically installed. The representative service models, in order of how much is provided, are SaaS (up to the application) > PaaS (up to the execution platform) > IaaS (hardware infrastructure only).
- Telling confusingly similar services apart: housing = placing your own equipment in the provider's facility; hosting = renting the provider's servers; SI = taking on system construction as a whole; escrow = third-party deposit. Anything that requires you to be aware of a physical location or specific equipment is not cloud.
用語