What is an embedded system and how does it differ from a general-purpose computer?
The purpose and characteristics of embedded systems, with examples, and how they differ from general-purpose computer systems.
An OCR J277 1.1 answer on embedded systems: what they are, their characteristics (dedicated function, low cost, low power, small size), examples, and how they differ from general-purpose computers.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
OCR wants you to define an embedded system, give its characteristics, name realistic examples, and compare it with a general-purpose computer. The comparison is the part that earns the higher marks, so you must be able to say what is the same and what is different on both function and physical characteristics.
What an embedded system is
The embedded computer is not the whole product, it is a small part of it. A washing machine is a washing machine, not a computer, but it contains an embedded system that reads the dials and sensors and controls the motor, water valves and heater to run the chosen wash cycle.
Characteristics
Examples
How embedded systems differ from general-purpose computers
A general-purpose computer (a desktop, laptop, tablet or smartphone) is the opposite of an embedded system in the ways that matter for the exam: it runs a full operating system, lets the user install and remove a wide range of software, and is built to handle many different tasks. That flexibility costs more in size, price and power. An embedded system trades flexibility for being small, cheap, efficient and reliable at one job.
Try this
Q1. State two characteristics of a typical embedded system. [2 marks]
- Cue. Any two of: dedicated to a single task, small, low cost, low power, reliable, program fixed in ROM.
Q2. Give one example of a device that contains an embedded system. [1 mark]
- Cue. Any of: washing machine, microwave, car engine management, traffic lights, digital camera, smart thermostat.
Q3. State one difference between an embedded system and a general-purpose computer. [1 mark]
- Cue. An embedded system performs one dedicated task with fixed software, whereas a general-purpose computer can run many programs the user installs.
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20212 marksDefine the term embedded system and give one example of a device that contains one.Show worked answer →
An embedded system is a computer built into a larger device to perform a single dedicated task or a small set of fixed tasks, rather than being a general-purpose computer the user can install new programs onto.
One mark for a definition that includes "dedicated/specific function" and "built into a larger device"; one mark for a valid example such as a washing machine, microwave, dishwasher, car engine management system, traffic lights, a digital camera or a smart thermostat.
Markers reward "performs a specific/dedicated task" and "part of a larger device". Naming a desktop PC or a laptop is wrong, because those are general-purpose.
OCR 20234 marksCompare an embedded system with a general-purpose computer system, referring to their function and at least two characteristics.Show worked answer →
An embedded system performs a single dedicated function (for example controlling a washing machine), whereas a general-purpose computer can run many different programs chosen by the user (for example a laptop running a browser, a word processor and games).
Characteristics (award for valid comparison points): an embedded system is usually smaller, cheaper, lower-power and more reliable for its one job, with its program often stored in ROM and rarely changed; a general-purpose computer is larger, more expensive, uses more power, and lets the user install and remove software freely.
Markers reward making the comparison explicit ("X does ... whereas Y ...") on both function and characteristics. Listing facts about only one of the two systems limits the marks.
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Sources & how we know this
- OCR GCSE (9-1) Computer Science (J277) specification — OCR (2020)