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As well as general purpose computers, there are other types of computer system. The most common of these are known as embedded systems.

An embedded system is a small computer that forms part of a larger system, device or machine. Its purpose is to control the device and to allow a user to interact with it. They tend to have one or a limited number of tasks that they can perform.

Examples of embedded systems include:

• central heating systems
• engine management systems in vehicles
• domestic appliances, such as dishwashers, TVs and digital phones
• digital watches
• electronic calculators
• GPS systems
• fitness trackers

Embedded devices are not usually programmable by a user - the programming is normally done beforehand by the manufacturer and stored in read only memory (ROM). However, it is often possible to upgrade the software on an embedded device. For example, fitness trackers are embedded systems but the software can often be upgraded by connecting the device to a PC and installing the new software.

Embedded systems can have advantages over general purpose computers.

• Their limited number of functions means they are cheaper to design and build.
• They tend to require less power. Some devices run from batteries.
• They do not need much processing power. They can be built using cheaper, less powerful processors.