This document discusses information systems and their components. It defines an information system as a combination of hardware, software, and telecommunications networks that people use to collect, store, and distribute useful data, typically in organizational settings. It explains that information systems take raw data as input, process it, and produce information as output. The document also defines key terms like data, information, systems, and subsystems. It lists different types of information systems and provides examples. Finally, it outlines the basic components of computer-based information systems and references additional reading.