A computer is an electronic device that processes data under a set of instructions. Charles Babbage developed the Difference Engine in 1822, considered the first automatic computing engine. A computer consists of both hardware and software: hardware includes physical components like the cabinet and hard drive, while software includes system software, application software, and firmware embedded in hardware. A computer can accept input, store and process data, and provide output. It performs basic operations like arithmetic, logical operations, and data storage and retrieval under the control of the central processing unit.