It is a special purpose computer system designed to perform a specific task or work. The special computer system is usually less powerful than general-purpose systems, although some exceptions do exist where embedded systems are very powerful and complicated. Usually a low power consumption CPU with a limited amount of memory is used in embedded systems. Many embedded systems use very small operating systems; most of these provide very limited operating system capabilities. Since embedded systems are used for special purpose tasks, there is usually no need to add new applications to the system once it is built. Therefore programs and operating systems are usually loaded only once into read-only memory. The read-only memory is available in many forms these days and includes some type of ROM, flash chips and flash cards. In case an upgrade is required, a new ROM chip replaces the old one.
If you look at your surroundings, you will find tiny computers everywhere. They are present even in places where you rarely notice them. Some of the most common embedded systems used in everyday life are:
- Microwave ovens
- TV, VCR, DVD players
- Cars (Antilock brakes, engine control, sun roof, climate control, automatic transmission and so on)
- Personal digital assistants
Complicated and more sophisticated embedded systems include routers and switches where high performance CPUs are used.