embedded system

Any electronic system that uses a CPU chip, but that is not a general-purpose workstation, desktop or laptop computer. Such systems generally use microprocessors, or they may use custom-designed chips or both. They are used in automobiles, planes, trains, space vehicles, machine tools, cameras, consumer electronics, office appliances, cellphones, PDAs and other handhelds as well as robots and toys. The uses are endless, and billions of microprocessors are shipped every year for a myriad of applications.

Although versions of Linux and other commercial and proprietary operating systems control embedded systems, low-cost consumer products can use CPUs that cost less than a dollar. Such systems may have very limited storage, in which case the OS and application may be combined into one program.

Programs Are in Firmware
In embedded systems, the software typically resides in firmware, such as a flash memory or ROM chip, in contrast to a general-purpose computer that loads its programs into RAM each time. Sometimes, single board and rack mounted general-purpose computers are called "embedded computers" if used to control a single printer, drill press or other such device. See embedded market, smart car, Windows XP Embedded, Embedded Linux and embedded language.

Embedded Systems

These are the systems in a 1998 Volvo S80, all of which were linked via two networks and controlled by a central module. Thirty years earlier, the Volkswagen 1600 used a microprocessor to control its fuel injection, making it the first embedded system in the auto industry. Today, a car's electronics cost more than the steel used to build it, and high-end cars can have more than 100 CPUs.

Embedded in a Shoe!

The microprocessor embedded in this adidas running shoe calculates the pressure between the runner's foot and the ground five million times per second and continuously changes the cushioning to match an adjustable comfort level. The computer controls a motor that lengthens and shortens a cable attached to a plastic cushioning element. (Image courtesy of adidas-Salomon AG.)

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(computer)

embedded system - Hardware and software which forms a component of some larger system and which is expected to function without human intervention. A typical embedded system consists of a single-board microcomputer with software in ROM, which starts running some special purpose application program as soon as it is turned on and will not stop until it is turned off (if ever). An embedded system may include some kind of operating system but often it will be simple enough to be written as a single program. It will not usually have any of the normal peripherals such as a keyboard, monitor, serial connections, mass storage, etc. or any kind of user interface software unless these are required by the overall system of which it is a part. Often it must provide real-time response. Usenet newsgroup: news:comp.arch.embedded.