CHAPTER Network Operating System Concepts

Chapter Objectives Provide an overview of network operating systems and its functions Explain the concept of resources Outline the operating system components –Client OS, server OS, Domain etc. Introduce the concept of sharing data and devices

Chapter Modules Network Operating System Overview Resources in a Network Operating System Components of a Network Data and Device Sharing

© N. Ganesan, All rights reserved. MODULE Network Operating System Overview and Basic Functions

Module Objectives Operating system definition Operating system: past and present Resources and users Managing resources Managing users Managing the network

Operating System Defined Application Software Hardware Operating Systems

Network Operating System: Past and Present Past –Linked computers operating under different operating systems –Example: LAN Manager Present –Operating systems by themselves –Example: Windows NT Server

Network Operating Systems Controls and manages network operations with respect to: –Resources –Users

Resources and Users Install Coordinate Control Manage Provide reliability and security Ensure continuity

Networking: Linking Users and Resources Resource User Security Privilege Effective Sharing

Managing Resources Install and ensure availability Enable secure access at different levels –Read, write etc. –Password protection Monitor performance

Managing Users Enroll users Provide secure privileges at different levels –Administrator –Account manager –Printer serve operator etc. Monitor usage

Managing the Network Backup features Fault tolerance Performance monitoring Trouble-shooting etc.

END OF MODULE

© N. Ganesan, All rights reserved. MODULE Resources in a Network

Module Objectives The concept of resources in a network Resources and objects Resource examples Resource identification Real world resource example

The Concept of Resources in Networking PrinterModem CD-ROM Tower Disk Storage Server Subdirectory

Resources and Objects Any sharable object is a resource in the network –Logical and physical entities are not distinguished from one another Terms used for the resource –Share (Microsoft NT) –Object (A developing general term)

Resource (Share) Examples Physical Examples –Disk drives themselves, Printers etc. Logical Examples –Subdirectories, Files etc.

Resource Identification By a given name By a drive letter, if desired and if applicable By a name that conforms to the Uniform Naming Convention (UNC)

Real Word Resource ID Examples Click to View

END OF MODULE

© N. Ganesan, All rights reserved. MODULE Operating System Components in a Network

Module Objectives Operating system components in a network Server side operating system –Multitasking, preemptive etc. Client side operating system A typical client-server OS implementation Components of a named domain A demonstration of a domain constituents

Major Components of the Network Operating System Server-side operating system Client-side operating system

Server and Client Operating Systems Client Server Windows NT Server Windows 95/98

Server-side Operating System Generally known as the Network Operating System –Windows NT Server Coordinates and manages network access to the resources Coordinates the functions of all computers and devices in the network Provides security for access to network resources

Multi-Tasking in NOS All NOSs are multitasking operating systems Types of multitasking –Preemptive –Non Preemptive

Preemptive Operating system can take control of the CPU overriding a task in execution A desired characteristic from a networking point of view All recent NOSs are preemptive operating systems

Non-preemptive NOSs Corporation from task is required –For relinquishing possession of CPU to the operating system Not desirable form a networking point of view Found in old NOSs

Client Operating system for the client –Windows 95/98 Manages local client In a client-server environment –Provides access to the services at the server In a peer-to-peer environment –Manages local sharing of resources by other peers as well

A Typical Client-Server OS Implementation NT Domain Controller Client File Server Domain

Components of a Named Domain Named IDs –Domain –Server –Client –Shared devices Domain is a collection of servers, clients and shared devices Multiple domains can be linked to form large networks

A Real Example of a Domain Click to View

END OF MODULE

© N. Ganesan, All rights reserved. MODULE Data and Device Sharing

Module Objectives Data sharing mechanism in a network Data sharing –Physical and logical sharing –The concept of soft resources Device sharing –Physical and logical sharing –The concept of hard resources Redirection of sharing request at the client

Data Sharing in a Network B: C: Shared Director F: Client Server Physical Presence Logical Presence

Logical Data Sharing Notes A shared directory at the server is shared at the client as a: –local logical drive such as drive f: –local logical directory/subdirectory with a name

Logical Data Sharing Example Click to View

Device Sharing in a Network Physical Local Printer Sever Shared Printer Logical Shared Printer Client Physical Presence Logical Presence LPT1 LPT2

Logical Device Sharing Notes Devices are shared by installing the device at the client as a network shareable device Example: –Local printer Attached to port Lpt1 –Network printer Attached to port Lpt2

Logical Device Sharing Example Click to View

Redirection: The Essence of Sharing at the Client Server Client Redirector Request for Reource Local Network

Notes on Redirector Redirector may be considered as a shell in the client operating systems Purpose –Filter local and network request for resources

END OF MODULE END OF CHAPTER