embedded system (ES)
Embedded systems(ES) are computer systems that are embedded in devices, systems and machines and process special applications. Such embedded systems can be found in aerospace, automation, automotive, telecommunication, consumer and household appliances such as cell phones, CD players, clocks, video recorders, washing machines, microwave ovensetc. Due to the wide variety of applications and requirements, a general characterization of embedded systems is extremely complex.
In contrast to personalcomputers, embedded systems are not equipped with the usual peripherals such as mouse, keyboard or hard disks, but use special peripherals; functional keys, rotary switches and displays of the corresponding devices. The spectrum of output units ranges from a simple blinking lamp to LCD displays and large displays. Input options offer a similar variety.
Direct embedding of computer systems in devices and plants
An embedded system has precisely defined tasks; in terms of software and hardware, it forms a functional unit that performs only these defined tasks. In accordance with the requirements, ES systems should require minimal hardware and software effort in many applications; they should make do with reduced operating systems, use as few components as possible, and have a processor that fulfills the tasks set but is not designed for other tasks. They should also use field programmable gate arrays(FPGAs) and special application specific integrated circuits (ASICs) to increase performance and security. This is all from a cost and reliability perspective but also to keep power consumption as low as possible. Furthermore, real-time capability plays a decisive role.
Embedded systems often do not use an operating system or they work with special embedded versions of standard operating systems, such as Embedded Windows CE or Windows XP, Embedded Linux but also with special operating systems like OSEK, OS-9 and others.
The application software, executed as embedded software, is characterized by fixed functions and supports only the corresponding application.