A computer consists of at least one processing element, typically a or cpu, and some form of memory. The processing element carries out arithmetic and logical operations, and a sequencing and control unit can change the order of operations in response to stored information. Peripheral devices allow information to be retrieved from an external source, and the result of operations saved and retrieved.
In world War II,Mecanical analog computer were used for specialized military applications. During this time the first electronic digital computers were developed. Originally they were the size of a large room, consuming as much power as several hundred modern personal computer.
Modern computers based on integrated circuit are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into mobile, and mobile computer can be powered by small battries. Personal computers in their various forms are icons of the information age and are what most people think of as “computers.” However, the embeded computer found in many devices from the most numerous.