問16
頻出度★☆☆
a～d の機器のうち, 組込みシステムが実装されているものを全て挙げたものはどれか。 a 飲料自動販売機 b カーナビゲーション装置 c 携帯型ゲーム機 d 携帯電話機
平成25年度 秋期 ITパスポート試験 問16
This question's explanation and your answers so far.
解説
問 16
Incorrectア
Choosing only “a, b” leaves devices out. c, a handheld game console, and d, a mobile phone, are also typical embedded-system devices that operate with a dedicated processor and control program built inside the equipment. It is a mistake to think that a device with a screen you can operate “belongs to the PC family and is therefore not embedded”: because their functions are built for a specific purpose, they too count as embedded systems.
- イ
正解 The correct answer is “イ”. An embedded system is a dedicated computer system built into the equipment itself in order to realize a specific function. Unlike a PC, which users can freely load with different software for general purposes, an embedded system has the control program (firmware) for carrying out that device’s role written in from the start. In a, a beverage vending machine, a microcontroller handles coin and bill identification, change calculation, the sold-out display, and temperature control for cooling/heating inside the cabinet. In b, a car navigation device is itself a dedicated computer that calculates the vehicle’s position from GPS and other positioning data and performs route search and guidance using map data. In c, a handheld game console uses a dedicated processor and a dedicated OS to control graphics drawing, sound, and input operations. In d, a mobile phone likewise relies on a built-in computer for radio communication control, call origination and termination processing, and control of the screen and operations. In other words, all four of a to d have an embedded system implemented in them, so “イ a, b, c, d”, which lists them all, is correct.
Incorrectウ
“a, c, d” excludes b, the car navigation device, but a car navigation unit is a dedicated computer built into the automobile for the specific functions of positioning calculation and route search, making it a prime example of an embedded system. There is no reason to exclude it.
Incorrectエ
“b, c” excludes a, the beverage vending machine, and d, the mobile phone, but a vending machine also uses a microcontroller for coin identification, stock management, and temperature control, and a mobile phone has a built-in computer for communication control. This option comes from misconceptions such as “only machine-like equipment counts as embedded” or “communication devices are out of scope”.
ここがポイント
- Embedded system = a dedicated computer system built into the inside of equipment in order to realize a specific function. Unlike a general-purpose PC, its use is limited and the control program (firmware) is written in beforehand.
- Familiar equipment such as home appliances, automobiles, vending machines, game consoles, and mobile phones—almost anything controlled by a microcontroller—qualifies as an embedded system. For “list them all” style questions, the trick is to check each item against the definition one by one and not to casually exclude a device just because it seems surprising.
用語