This document defines and describes the main internal and external components of a basic computer system. It explains that the mouse is used to control the graphical user interface, the keyboard is used for text input similarly to typewriters, and the printer enables printing documents stored electronically on paper. It also outlines the functions of the central processing unit (CPU), monitor for output, hard disk for storage, graphics card for processing visuals, motherboard for connecting components, and other peripherals like scanners, cameras, speakers, cabinet and power supply.