This document provides an overview of computer systems and their components. It discusses that a computer system consists of four major hardware components: input devices, output devices, a processor, and storage devices. It also requires software and a user. The document describes these components in further detail. It explains input devices feed data to the processor, the processor processes the data, storage devices store processed and unprocessed data, and output devices display the processed data. It also discusses computer hardware, software, data representation and measurement, and various input devices.