A Network Operating System (NOS) is software that manages network resources and allows multiple computers to communicate and share data. It provides essential services such as file sharing, printer access, and user management across a network. Examples of NOS include Windows Server, Linux, and Novell NetWare. NOS enables users to connect to a network, access shared resources, and manage security settings. It supports various protocols, ensuring that different devices can communicate effectively. By centralizing control, a NOS simplifies network administration and enhances collaboration among users within an organization.