A computer is a machine that manipulates data according to a list of instructions. Modern computers are based on tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space. Simple computers may be made small enough to fit into a wristwatch and be powered from a watch battery. Personal computers, in various forms, are icons of the Information Age and are what most people think of as 'a computer'; however, the most common form of computer in use today is the embedded computer. Embedded computers are small, simple devices that are used to control other devices, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and children's toys. The ability to store and execute lists of instructions called programs makes computers extremely versatile and distinguishes them from calculators. Computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks given enough time and storage capacity.