This document discusses fundamentals of computer information systems. It defines key terms like data, information, and data processing. It describes the basic components and functions of an information processing system including input, processing, storage, and output of data. The three major components of a computer system are hardware, software, and peopleware. It also discusses the basic units of computer hardware like the CPU, memory, input/output devices, and storage devices. It provides an overview of operating systems, applications software, files, and directories.