Network Operating System (NOS)
Unlike microcomputer operating systems, which are designed for interacting with one computer and its applications, the network operating systems (NOSs) control and coordinate the activities between multiple computers on the network. These activities include electronic communication and sharing of information and resources.
These are some of the more popular network operating systems:
AppleShare
Microsoft Windows Server
Novell Netware
Every network has a strategy, or way of coordinating the sharing of information and resources. The most common network strategies are:
Terminal
Peer-to-Peer
Client/Server
Terminal Network System
In a terminal network system, processing power is centralized in one large computer, usually a mainframe. The nodes connected to this host computer are terminals with little or no processing capabilities.
Advantages of a Terminal Network System:
- Centralized location and control of technical personnel, software, and data.
Disadvantages of a Terminal Network System:
- Lack of control and flexibility for the end user.
- Terminal systems do not use the processing power available with microcomputers.
Though the terminal strategy was once very popular, most new sytems do not use it.
Peer-to-Peer Network System
Peer-to-Peer network operating systems allow users to share resources and files located on their computers and to access shared resources found on other computers. These operating systems do not have a file server or a centralized management source. All computers are considered equal, they all have the same abilities to use the resources available on the network. The nodes can act as both servers and clients.
Peer-to-Peer networks are designed primarily for small to medium local area networks. This setup usually work well with no more than 10-15 nodes. As the number of nodes increases, however, the performance of the network declines. A typical configuration for a Peer-to-Peer system is the bus network.
Commonly used Peer-to-Peer network operating systems are Novell's Netware Lite, Microsoft's Windows NT, Windows for Workgroups, Windows XP Home, Apple's Macintosh Peer-to-Peer LANs, and AppleShare.
Advantages of a Peer-to-Peer Network System:
- Less initial expense of network setup - no need for a dedicated server.
- Easy setup - no need for an additional operating system, the operating system is already installed and only need to be reconfigured for networking.
Disadvantages of a Peer-to-Peer Network System:
- Decentralized, no central repository for files and applications.
- Lack of powerful management software to effectively monitor a large network's activities.
- Security - Does not provide the security available on a client/server network.
Client/Server Network System
Client/Server network operating systems allow the network to centralize functions and applications in one or more dedicated file servers. This powerful computer coordinates and supplies services to all other nodes on the network. The file servers become the center of the system, providing access to resources and security on the network. Individual workstations (clients) use the resources such as databases, application software, and hardware available on the file servers.
The network operating system provides the mechanism to integrate all the components of the network and allow multiple users to simultaneously share the same resources regardless of their physical location.
Commonly used Client/Server network operating systems are Novell's Netware, Microsoft's Windows NT, Windows 2000 or 2003, Windows XP Pro, IBM's LAN Server.
Advantages of a Client/Server Network System:
- Centralized - Resources and data security are controlled through the server.
- Scalability - Any or all elements can be replaced individually as needed.
- Flexibility - New technology can be easily integrated into the system.
- Interoperability - All components work together.
- Efficiency - Ability to handle very large networks efficiently.
- Accessibility - Server can be accessed remotely and across multiple platforms.
Disadvantages of a Client/Server Network System:
- Expense - Requires an initial investment into a dedicated server.
- Maintenance - Large networks will require a staff to ensure efficient operation.
- Dependence - When server goes down, all opperations across the network will discontinue.
