Characteristics of Embedded Systems

Selecting a different washing programme does not turn it into a general-purpose computer. Each programme still serves the washing machine’s purpose.

By contrast, a general-purpose computer, such as a laptop, can run many different types of software. The same laptop might be used to write an essay, browse the web or play a game. An embedded system is not normally designed for its user to install programs for unrelated tasks.

Hardware matched to the task

Embedded systems typically have only the processing power and storage capacity needed to perform their particular job. They do not need the resources required to run a wide range of general-purpose applications.

This helps explain several typical characteristics:

• Small physical size: the computer must fit inside the larger device, and its relatively simple hardware can make it compact.
• Low power consumption: it typically uses less electrical power than a general-purpose computer.
• Low manufacturing cost: modest processor and storage requirements help keep costs down. Producing large numbers of the same system also helps reduce the cost per unit.

These characteristics are connected: hardware chosen for a limited task can make a system smaller, cheaper and less power-hungry.

Reliable operation and simple controls

Embedded systems are designed to perform their dedicated function reliably, often repeating the same operations whenever the device is used.

Their user interface is usually limited to what the device needs. A washing machine might have buttons to select a programme, a display showing progress and a sound indicating that the wash has finished. It does not need the flexible interface of a laptop. Some embedded systems have no direct user interface at all.

Typical features, not absolute rules

Small size, low power use and low cost are typical characteristics, not conditions that every embedded system must satisfy. The defining distinction is its role: it is built into a larger device and dedicated to that device’s particular function.