Embedded software is very important economically because, almost each electronic device now includes software. There are many more embedded software systems than other types of software system. If you look around your house, there have one or two laptops or personal computers.
But you probably have 20 or 30 embedded systems, such as systems in phones, cookers, microwaves, etc.
Embedded systems generally run continuously and do not terminate. They start when the hardware is switched on and must execute until the hardware is switched off. Embedded systems can be thought of as reactive systems; that is, they must react to events in their environment at the speed of that environment (Berry, 1989; Lee, 2002).