An embedded system is defined by wikipedia here. Embedded systems existed before the term was created, but lately one stumbles over it more and more frequently. It's usually devices, which have a built in microcontroller or microprocessor, but that's usually not obvious. A good example is a car, where roughly hundred micros could be inside performing various things from moving the wipers to controlling the engine. This exiting field is very broad ranging from four bit micro systems to full blown PCs, which might do some dedicated work and run "XP Embedded". Here we will try to show up what's inside those little black boxes called embedded systems.