Network Operating System

Lo1.1 TYPES OPERATING SYSTEMS

The tremendous development of the computer and communications industry over the last few years has made most computers connect to a network today. Practically, it is not enough to analyse the operation of a self-contained computer, but we need to consider an approach from the perspective of the computer network to which it is connected.

The definition unanimously accepted by all (even if there are several definitions for the term computer network) is that a computer network is a collection of two or more computers connected to each other. The immediate benefit of connecting to a network is obvious: users can share files and peripherals (printers, modems, backup drives, CD-ROM drives, etc.). If networks from multiple locations are interconnected with the services offered by Internet service providers (telephone lines, cable, antennas), users can use highly popular applications such as e-mail, chat, video chat, video conference with other users connected to the network and located anywhere in the world.

The immediate benefit of connecting to a network is obvious: users can share files and peripherals (printers, modems, CD-ROM drives, etc.). If networks in multiple locations are interconnected with the services of Internet service providers (telephone lines, cable, antennas), users can use today's most popular applications such as e-mail, chat, video chat, video conference with other network-connected users located anywhere in the world.

-Components of a computer-

A computer network typically includes the following components:

-The server is the basic computer, considered host with which helps manage the entire network, also concentrating most of the resources;

-Workstations are heterogeneous computing equipment connected to the server and between them, with the ability to transmit and receive information

-Physical supports provide physical transmission of electrical, radio or optical signals between network nodes;

-Adaptation equipment ensures compatibility between network workstations and physical carriers;

-Communications control equipment, provides protection of network information while optimizing information flows between network components;

-The operating system is the application or group of applications installed on the Server, ensuring the coordination of the basic computer functions and the accounting of the applications installed on the workstations.

Classification

FROM GEOGRAPHICAL POSITION

Local Area Networks (LANs) that implement an enterprise or enterprise's computer system, operating at short distances of tens or hundreds of meters;

- Metropolitan Area Networks (MAN), which interconnects subsidiaries or work points of the same entity;

-Wide Area Networks (WAN), which interconnect national or international computer centres.

AFTER TOPOLOGY

One of the first notions presented when talking about a computer network is the notion of topology, which in fact means the structure of the network. Topology can be both physical and logical. A physical topology is the way in which network components are stacked in space, while the logical topology refers to how to access the networked devices.

1 Physical topologies

The most common physical topologies are:

- Topology of bus (bus)

This topology uses only one main connection cable and the devices on the network are all connected to this connection (bus)

Topology of bus and ring

- Ring topology -

Unlike a regular operating system (SO), network operating systems (NOS) provide network features, network services, multiuser capability, multitasking, security, resource sharing, and centralized network management.

A network operating system has the following features:

- Allows access for multiple users

- Executing multi-user applications

- It's robust and redundant

- Offers increased security when compared to desktop operating systems

NOS must have a robust kernel to avoid errors and interruptions. It is especially important that the NOS kernel can handle multiple processes, thus preventing other parts of the system from being blocked.

NOS uses file systems to store information quickly and securely.

The most common NOSs are Windows and Linux; operating systems that offer customers and users the ability to make a clear comparison and choice. The Windows system was first marketed as a desktop operating system with a user-friendly graphical user interface (GUI), later evolving as a network operating system. Linux was originally designed as a network operating system, distributed free of charge (under the GNU / GPL license), using a command line interface (CLI) to manage. Later, when he became more familiar, he began to migrate to desktop systems, accompanied by a friendly graphical user interface (GUI). We mention that there are distributions or versions of commercial Linux, but great majority is distributed free of charge, including source code (http://carment.ase.ro/rc/sem/nos.html, 2017)