Network Operating Systems :Tasks and Examples

Instructor: Dr. Najla Al-Nabhan2014

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Lecture Outline NOS Examples:

Last Lecture (Windows 95, and windows for workgroups)

This Lecture: Windows NT Server Novell NetWare UNIX/LINUX MAC OS AppleShare

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Windows NT Server Windows NT Server was first introduced in the

mid-90s and is capable of managing workgroups just like Windows for Workgroups/95.

Windows NT Server has all of the advantages mentioned for the other Windows operating systems, plus, it contains several other features making it more robust.

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Windows NT Server Features:1.It is a client/server NOS that uses routable

protocols, making it a true Internetworking Operating System enabling network administrators to connect LANs to WANs.

2.Windows NT Server also provides services for OS/2 and Novell NetWare clients

3.It is able to run on various microprocessors such as Intel Pentium, DEC Alpha, RISC, MIPS, and PowerPC based systems.

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Windows NT Server Features:4.The security on Windows NT allows a network

administrator to not only provide passwords for resources but also to individuals or groups.

5.This operating system does require the use of a more powerful server computer whose sole function is to act as administrator of the NOS program.

6.Having a server where all access data is stored makes managing Windows NT Server Operating Systems efficient.

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Security in Windows NT Server Windows NT Server has more than one level of

security beyond access/no access. This NOS offers: no access. access that restricts the user to read only

capabilities. access that allows read and write usage. access that allows you to change access

permissions for network users. Each user who wishes to access services on the

network must have a password and a user account set up within the domain.

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Security in Windows NT Server Domain: A domain is a security model where the

database of user accounts is stored on one or more computers known as domain controllers.

Important for the centralize control of the network.

The network administrator creates, deletes, and manages these accounts and passwords using the User Manager for Domains program that comes with Windows NT Server.

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Security in Windows NT Server For security reasons, companies often have two servers

capable of authenticating passwords: one that acts as the Primary Domain Controller (PDC) and the other as the Backup Domain Controller (BDC).

PDC: The PDC is a computer on the network that maintains a

database of users and security policies for the domain. This database contains the names of users and the resources they may access. User access may be defined for individual files or for entire directories.

Note that although the PDC is often a server computer, this is not necessary. Network services can be implemented on one computer and the PDC functions on another

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Security in Windows NT Server BDC (Backup Domain model) :

A BDC maintains a copy of the PDC database. This backup database prevents network disruption in the event of failure of the PDC.

If a failure occurs, the backup domain controller can be easily switched to the PDC.

With Windows NT Server networks can connect to other domains.

There are four basic domain models:

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Windows NT Domain Models Single Domain Model— In the single domain

model, there is only one defined set of security and user accounts. This means that all management functions are centralized.

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Windows NT Domain Models Master Domain Model— In this model, there

is one master domain server that has the defined set of security and user account data of all other domain servers. However, each of these has only the specific security data for one domain. A user on one domain cannot get permissions not found on her/his domain server. This improves on the single domain model since it allows segmentation of networks, which increases security measures, yet still allows centralized management of network user accounts and accessibility.

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Windows NT Domain Models · Multiple Master Domain Model—The

Multiple Master Domain Model has several master domain servers, each with their own specific domains. In this model, network management becomes somewhat decentralized and network administrators cannot maintain the entire network from one central domain server.

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Windows NT Domain Models Multiple Trust Domain Model— This model

is really a peer-to-peer relationship among domain servers, therefore it becomes decentralized and security is essentially the same as with Windows for Workgroups and Windows 95.

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Novell NetWare Operating Systems Novell NetWare Operating Systems, also a

client/server based NOS, is not domain based but binary based.

It has evolved over time from NetWare 2.X, now obsolete, which was designed for small workgroup environments to NetWare 5.X that is aimed at global enterprise network environments.

NetWare is optimized for managing, sharing, translating, and synchronizing information throughout the network-computing environment

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Features of Novell NetWare Novell NetWare 4.X features NetWare Directory

Services (NDS), which allows a user to logon from anywhere on the network and access the same resources regardless of where the user logs on.

This product has become Novell’s migration strategy for the future.

Novell NetWare does not actually provide a computer operating system for client workstations; it supplies an operating system for a dedicated server computer, and networking support to existing client workstation operating systems.

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UNIX/LINUX UNIX is the oldest network operating system

still being widely used today. It can be used on either peer-to-peer or

client/server networks. LINUX is basically a free version of UNIX,

which is developed cooperatively by a community of expert programmers.

Various computer manufacturers have released proprietary versions of UNIX which run on their particular hardware platforms.

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UNIX/LINUX Because of differences in processor hardware and

variations from UNIX standards, each company’s operating system has its own “flavor”.

End user applications for UNIX must be individually compiled for each different hardware platform and operating system variant.

The networking components in UNIX have been under development for many years, and are based on the collaborative efforts of many developers.

Consequently, UNIX networking is extremely reliable.

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UNIX/LINUX Because of UNIX security, many companies use

UNIX to provide their primary networking services and interface to the Internet.

In spite of the rise in popularity of Web and Internet services deployed on Windows NT, for security and reliability UNIX is a popular choice in commercial and university environments.

Networking under UNIX is based on the TCP/IP protocol, which has only been integrated into the Microsoft Windows NOSs in recent years. The early work, which established the Internet, was

based on UNIX platforms. Most of the TCP/IP services used in UNIX are also commonly used on.

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UNIX vs. Microsoft Windows OS Microsoft Windows operating systems, with

a few exceptions:1- Network File System (NFS)—

NFS provides hard disk sharing over TCP/IP networks.

It is the primary file and directory sharing protocol used in UNIX.

NSF clients are available for Microsoft Windows operating systems, but are generally used for interoperation with UNIX hosts.

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UNIX vs. Microsoft Windows OS 2- Remote login services (RLOGIN and

TELNET)—UNIX has always been a truly multi-user multi-session operating system.

Multitasking of applications and processes is extremely robust; much more so than under Windows NT.

In addition many users can run private sessions simultaneously under UNIX, by logging in to a host using a character-based terminal or emulated terminal over a serial or network connection.

RLOGIN and TELNET protocols support logging in over network connections.

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UNIX vs. Microsoft Windows OS Graphical user interface windowing system (X

Windows)— X-Windows is a completely distributed graphical user

interface system. Using X-Windows, a user can execute an application on one

computer, and let that application interact with a user on a different computer, using a network connection.

X Windows allows computers to share their video displays, keyboards and pointing devices with applications running on other computers.

There is no requirement that the application execution and display hosts even have the same type of hardware or run the same operating system, as long as the client application and the display server support the X Windows protocol.

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UNIX vs. Microsoft Windows OS Graphical user interface windowing system (X

Windows)— Windows NT has recently included support for graphical

session-based terminal servers that offer some similar functionality to X Windows, but with much less flexibility.

In addition, X Windows server software is available for Microsoft Windows operating systems, allowing applications running on UNIX hosts to be displayed on computers running Microsoft Windows operating systems.

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MAC OS AppleShare AppleShare provides network services for the

Mac OS operating systems. AppleShare supports file and printer sharing

over several types of physical networks by using one of the AppleTalk transport protocols: LocalTalk, EtherTalk, TokenTalk or FDDITalk.

As the Internet has grown in popularity, TCP/IP software has been developed for the Apple MacIntosh computers, along with the standard TCP/IP client applications like Web Browsers and FTP file transfer clients.

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MAC OS AppleShare AppleShare’s peer-to-peer networking is

used in small or moderately sized workgroup settings, but has not been adopted widely in large-scale corporate LAN environments.

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Check Your Understanding What are the advantages and disadvantages of

Windows for Workgroups/95? What are some of the features added to Windows

NT Server that are not supplied for Windows for Workgroups/95?

What are some differences between NetWare and Windows NT Server?

How has the popularity of the Internet affected network support in Mac OS and the Microsoft Windows operating systems?

Which family of operating systems has traditionally supported TCP/IP and internetworking?

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Midterm next lecture

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