The document provides definitions and descriptions of common computer system hardware components related to input and output. It defines input as anything inserted into a system to activate or modify a process, such as data from input devices. It then describes common input devices like mice, joysticks, webcams, and USB ports. It also defines output as anything exiting a system to activate or modify a process, and describes common output devices like printers, monitors, and keyboards that display or record the results of processed data.