This document defines a computer and its components. It states that a computer is an electronic device that operates under instructions stored in its memory and takes input, processes it, and provides output. The main components are the CPU, memory, and input/output devices. It describes the input-process-output cycle and characteristics of computers like speed, reliability, and accuracy. The document also classifies computers by size and function, describing microcomputers, mini computers, mainframes, and supercomputers. It outlines the different generations of computers and their components over time. Finally, it discusses common input devices, output devices, storage media, and other internal computer components.