Stands for "Network Operating System" and is pronounced "N-O-S." A network operating system provides services for computers connected to a network. Examples include shared file access, shared applications, and printing capabilities. A NOS may either be a peer-to-peer (P2P) OS, which is installed on each computer, or a client-server model, where one machine is the server and others have client software installed.
Peer-to-peer network operating systems include legacy OSes such as AppleShare and Windows for Workgroups. These operating systems offered unique networking capabilities that were not available in early versions of Mac OS and Windows. They enabled computers to recognize each other and share files over a cable connecting the machines. Over time, these networking features were integrated into standard operating systems, making P2P NOSes obsolete.
Client-server network operating systems include Novell NetWare and Windows Server. These NOSes provide services from one computer to all connected machines. Novell NetWare requires specific client software to be installed on all client machines, while Windows Server works with standard Windows computers. In both cases, clients connect to the server and can access files and applications based on their access privileges. The central server manages all the connected machines and can provide updates as needed to the client systems. This makes it easy to keep all the computers on the network up-to-date.
While client-server NOSes were used for several decades, they too have faded into obsolescence. Today, desktop operating systems have advanced networking capabilities, limiting the need for network operating systems. Additionally, many organizations now use intranets to provide web-based access to all local systems. Instead of requiring specific programs to be installed on each client, users can access web applications over a local network or the Internet.
NOTE: A network operating system may also refer to a basic OS that runs on a network device, such as a router or firewall.