問11
頻出度★☆☆
電化製品などに組込みシステムを採用する利点として, 適切なものはどれか。
平成23年度 秋期 ITパスポート試験 問11
This question's explanation and your answers so far.
解説
問 11
Incorrectア
Incorrect. An embedded system is also a computer that runs programs, so there is no guarantee that it will not be infected by a virus or malware. In recent years the number of embedded devices connected to networks (IoT devices) has increased, and there are real cases of routers, multifunction printers, surveillance cameras, and the like being infected and used as stepping stones for attacks. Having a software structure different from a PC is not a reason to claim there is no infection risk; embedded devices also need security measures such as firmware updates and changing authentication credentials.
Incorrectイ
Incorrect. The fact is the opposite: an embedded system is subject to hardware constraints even more strongly than PC software is. The CPU performance, memory size, and storage capacity that can be installed are small, and the design must be carried out under conditions such as power consumption and heat, product cost, and real-time behavior (always responding within a fixed time). Not being subject to hardware constraints is not an advantage of an embedded system.
- ウ
正解 An embedded system is a computer system built into equipment such as an electrical appliance or an automobile for the purpose of controlling that equipment. Rather than fixing the processing into electronic circuits (hardware), it is implemented as firmware (software) running on a microcomputer, so the operating specifications of the equipment are determined by software. Therefore, when a product is improved, functions can be added or specifications changed within a certain range allowed by the performance and the inputs/outputs of the existing hardware, simply by replacing the program written into ROM, without remaking the hardware (boards and components). This property, which leads to shorter development time, lower cost, and easier deployment of product variations, is a representative advantage of adopting an embedded system, so ウ is the correct answer.
Incorrectエ
Incorrect. Fail-safe (a design principle of making a system operate toward the safe side even when a failure occurs) is not an environment that is automatically provided just by adopting an embedded system. The designer must consider and implement safety mechanisms for each individual system according to the use and the hazard of the equipment. On the contrary, embedded systems often control equipment that directly affects human life and facilities, so fail-safe and fault-tolerant design is strongly required to be built in on a per-system basis.
ここがポイント
- Embedded system = a dedicated computer built in to control a specific piece of equipment. Because its functions are realized by firmware (software), a certain range of functions can be added or improved by rewriting only the software without changing the hardware, and this is the advantage of adopting it.
- Also grasp the weak points of embedded systems. Hardware constraints on CPU, memory, power consumption, cost, and real-time behavior are severe; network connection also brings a risk of virus infection; and safety design such as fail-safe must be built in individually for each system.
用語