What is a Network Operating System?

Unlike operating systems, including Windows designed for single users on a single computer network operating systems (NOS) command to coordinate the activities of multiple computers on a network. The network operating system acts as a director to keep running the network.
The two main types of network operating systems are:
• Peer to Peer
• Client / Server
Nearly all modern networks are a combination of both. The networks design can be used independently of the servers and workstations that it will be considered to share.
peer to peer
Peer-to-peer network operating systems users to share resources and files on their computers and to access available to shared resources on other computers. However, they do not have a file server or a centralized management source (see fig. 1). In a peer-to-peer network, all computers are considered equal; they all use the same capabilities of the resources on the network. Peer-to-peer networks are designed primarily for small to midsize local area networks. Almost all modern desktop operating systems such as Mac OSX, Linux and Windows, can function as peer-to-peer network operating systems.

Fig. 1. Peer-to-peer network
Benefits of a peer-to-peer network:
• Reduce initial costs – No need for a dedicated server.
• Setup – An operating system (like Windows XP) already in place may only need to be configured for peer-to-peer operations.
Disadvantages of a peer-to-peer network:
• Decentralized – No central repository for files and applications.
• Security – does not provide security in a client / server network.
Client / Server
Client / server network operating systems as possible to centralize the network functions and applications on one or more dedicated file servers (see Fig. 2). The file servers become the heart of the system, providing access to resources and providing security. Individual workstations (clients) have access to the information available on the file server resources. The network operating system provides the mechanism to integrate all components of the network and allows multiple users to simultaneously share the same resources regardless of physical location. UNIX / Linux and Microsoft Windows family of servers are examples of client / server network operating systems.

Fig. 2. Client / server network
Advantages of a client / server network:
• Central – Resources and data security are controlled through the server.
• Scalability – Any or all elements can be replaced individually as needs increase.
• Flexibility – New technology can be easily integrated into the system.
• Interoperability – All components (client / network / server) work together.
• Accessibility – Server can be accessed remotely and across multiple platforms.
Disadvantages of a client / server network:
• Expense – Requires initial investment in dedicated server.
• Maintenance – Large networks will need a team in order to ensure efficient operation.
• Dependence – goes down with server, will cease operations on the network.
Network Operating System Software
The following links include some of the more popular peer-to-peer and client / server network operating systems.
• Macintosh OS X
• Microsoft Windows Server
• UNIX / Linux