5.1 Overview
A Network Operating System (NOS) is an operating system designed to enable multiple computers to communicate, share resources, and access services over a network while maintaining their individual system identities.
Unlike distributed operating systems, where multiple systems appear as one unified machine, a network operating system treats each computer as a separate entity connected through a communication network.
The primary objectives of a Network Operating System are:
Resource sharing
Communication between systems
Centralized management
Network security
Remote access support
Network operating systems are widely used in:
Enterprise networks
Office environments
Server-client architectures
Educational institutions
Data centers
Examples include:
Windows Server
Linux-based servers
UNIX network systems
Basic Concept of a Network Operating System
In a network operating system:
Each computer runs its own operating system
Systems communicate through network protocols
Users explicitly access remote resources
Examples:
Accessing shared folders
Connecting to network printers
Using remote servers
Unlike distributed systems:
Users are aware of multiple machines in the network
5.2 Working Mechanism
A network operating system enables communication and resource sharing among independent systems connected through a network.
Step 1: Independent Operating Systems
Each computer runs:
Its own local operating system
Its own processes
Its own memory management
Systems operate independently.
Step 2: Network Connectivity
Computers connect using:
LAN
WAN
Ethernet
Wi-Fi
Communication occurs through networking hardware such as:
Routers
Switches
Network Interface Cards (NICs)
Step 3: Communication Through Protocols
Systems communicate using standard network protocols such as:
TCP/IP
HTTP
FTP
SMB
DNS
Protocols define:
Data transmission rules
Addressing methods
Communication procedures
Step 4: Resource Sharing
Resources such as:
Files
Printers
Storage
Applications
can be shared across the network.
Users access these resources explicitly.
Example:
Accessing a shared folder using a network path
Step 5: Authentication and Permissions
The operating system verifies:
User identity
Access rights
Security permissions
before allowing access to network resources.
Client-Server Architecture
Most network operating systems follow:
Client-Server Architecture
Server
Provides:
Services
Shared resources
Authentication
Data storage
Client
Requests services from servers.
Examples:
File server
Print server
Database server
5.3 Characteristics
Independent Systems
Each node maintains:
Its own operating system
Its own processing environment
No Single System Image
Unlike distributed systems:
Systems do not appear as one unified machine
Users know:
Which resource belongs to which computer
Resource Sharing
The NOS enables sharing of:
Files
Printers
Applications
Internet access
Centralized or Distributed Management
Network administration may be:
Centralized through servers
Distributed among systems
Communication Support
The NOS supports:
Data transfer
Remote login
Network communication
Security Mechanisms
Network operating systems implement:
User authentication
Access control
Permission management
5.4 Advantages
Easy to Set Up and Manage
Network operating systems are relatively easier to configure compared to distributed systems.
Flexible Resource Sharing
Users can access shared resources from different systems across the network.
Scalability
New systems can be added easily to the network infrastructure.
Centralized Administration
Administrators can manage:
Users
Permissions
Security policies
Shared resources
from centralized servers.
Backup and Recovery Support
Centralized storage simplifies:
Data backup
Disaster recovery
Remote Access
Users can access resources remotely through the network.
5.5 Disadvantages
Lower Transparency
Users remain aware of:
Different systems
Remote resource locations
Unlike distributed systems:
There is no single-system illusion
Network Dependency
If the network fails:
Resource access becomes unavailable
Security Risks
Network communication introduces risks such as:
Unauthorized access
Malware attacks
Data interception
Server Dependency
In client-server systems:
Server failure may disrupt services for many clients
Maintenance Cost
Large network infrastructures require:
Dedicated administrators
Maintenance
Hardware investment
5.6 Resource Sharing in NOS
One of the main purposes of a network operating system is:
Resource Sharing
File Sharing
Users can:
Upload
Download
Modify shared files
Printer Sharing
Multiple systems can use:
Common network printers
Application Sharing
Applications installed on servers may be accessed remotely.
5.7 Security in Network Operating Systems
Security is critical because resources are shared across networks.
Common Security Mechanisms
User authentication
Password protection
Access control lists
Firewalls
Encryption
Importance
These mechanisms help:
Protect sensitive data
Prevent unauthorized access
5.8 Examples of Network Operating Systems
Windows Server
Provides:
Active Directory
File sharing
Domain management
Centralized administration
Widely used in enterprise environments.
Linux-Based Network Servers
Linux systems support:
Web servers
File servers
Database servers
Network services
Examples:
Ubuntu Server
Red Hat Enterprise Linux
CentOS
UNIX Systems
UNIX operating systems have long supported networking and multi-user communication.
5.9 Difference Between Network OS and Distributed OS
| Feature | Network OS | Distributed OS |
|---|---|---|
| System Identity | Separate systems | Single unified system |
| Transparency | Low | High |
| User Awareness | Users know remote systems | Hidden distribution |
| Complexity | Lower | Higher |
| Resource Access | Explicit | Transparent |
5.10 Real-World Analogy
Imagine an office building with multiple departments.
Each department:
Works independently
Has its own employees
Uses its own computers
However:
Departments share printers
Access common servers
Communicate through the office network
Similarly:
Network operating systems connect independent computers while allowing resource sharing.