1. Introduction

1. Introduction
	Chapter 6. Network Operating Systems

Introduction
Definition:
Distributed computer systems contain software programs and data resources dispersed across different computers. To operate as a system, there should be certain system-wide standards for interoperability.
This set of standards composes a Network Operating System.
Characteristics:
- It does not depend upon a particular Operational System.
- It is used in low coupled parallel machines, like the computers in a local network.
- It establishes the interoperability rules between applications, but not the implementation of such applications.
Collection of services
A Network Operating System is composed by a collection of well established services. They usually were created independently and bundled together to form a system.
NOS services are targeted to a specific network. For the Internet there are:
- DNS - Domain Name Server.
- NFS - Network File System.
- RSH - Remote Shell.
- RLOGIN - Remote login.
- FTP - File Transfer Protocol.
There can be other services, but those are common ones.
Is there a real NOS?
You can not find a NOS in a box from a vendor. Usually the services of a NOS are sold as applications or bundled with the machine OS. Why?
Maybe just Operational System isn't the best paradigm to describe network services, as it is machine rather network centred.


Chapter 6. Network Operating Systems		2. DNS - Domain Name Server