4.10. Network operating systems

Network Operation System (Network Operation System - NOS) is a set of operating systems of individual computers that are in contact with each other for the purpose of sharing information and dividing resources according to uniform rules (protocols). In addition, such a system is the operating system of a separate workstation, which ensures its work in the network.

Network OS contains the following tools:

1) management of local PC resources (for example, the distribution of EPs between running processes);

2) the supply of its own resources and services for general use (the server part of the OS);

3) request access to remote resources and services, as well as their use (client part of the OS);

4) network messaging (communication tools).

Any network operating system must efficiently manage resources, provide a convenient multi-window user interface, etc. Beginning in 1990s. To the network OS began to impose some standard requirements:

• ability to expand;

• portability;

• sufficient reliability;

• compatibility;

• security;

• performance.

Depending on the functions assigned to the network operating systems, they are divided into systems created specifically for peer-to-peer networks and systems for networks with a dedicated server. On server computers, you should use operating systems that are optimized for various server functions. Therefore, in networks with dedicated servers, network systems are often used, which consist of several OS variants that differ in the capabilities of server parts.

According to the scale of the networks served, network operating systems are divided into the following types:

1) the network of departments that form a small group of employees of a particular company or organization. The main task of such a system is in the process of dividing local resources;

2) campus-level networks that integrate several departmental networks within a single building or territory into a single local area network. The main function of such systems is to provide employees of some departments with access to information and network resources of other departments;

3) corporate networks (or enterprise networks), which include all local networks of an individual enterprise located in different territories. Corporate networks are global computing networks. Operating systems at this level should support a wider range of services.