Transcript Introduction - Eastern Illinois University

School of Business
Eastern Illinois University
Local Area Networks:
Software
(Week 8, Thursday 3/1/2007)
© Abdou Illia, Spring 2007
Learning Objectives
2

Identify main functions of operating systems

Describe basic features of common Network
operating systems

Explain main features of Network Operating Systems:
 Remote Access
service
 Directory service
 Software Disk Fault-tolerance
 Clustering
 Network Load Balancing
Software and Support Systems
• Workstation Operating System on workstations
• Network Operating System on servers
- Workstation Operating System
- Client application programs
- Network Operating System
-Utility programs
- Application programs:
- Word processor
- Spreadsheets
- Accounting
3
User
Operating Systems
4
Application program
Interfaces
Operating system

Program initially loaded
into computer memory

Manages hardware & software resources:
–
Hardware
Disks, memory, processors, application programs, etc.

Key function: Ensure that each application gets
necessary resources

Suppose that a Web browser and a word processor
are executed at the same time. Which resources
the two applications might need to access to ?
Operating Systems

A special program for managing hardware and
software resources that ensure each application
program gets necessary resources
5
Common OS functions: Multitasking

6
Multi-tasking (multiple prog./tasks running at the same time)
–
–
OS allocates small amount of the time to each prog./task
Jumps quickly from one prog./task to another.
Common OS functions: Virtual Memory,
Security

Virtual memory management:
–
–

Handling:
–
–

OS feature that allows loading
programs even if RAM is limited
Needs enough HD space
Input operations from attached devices (e.g. disks)
Output operations to attached devices (e.g. disks, printers)
Providing resource security
–
E.g. Directory & files security to provide protection from
unscrupulous users
7
Network Operating Systems (NOS)

OS designed for Servers use (also called SOS)
Same functions as Workstation OS
+
- Ability to manage users and other resources common to the LAN
- Providing key network services

Common resources managed by NOS
–
–
–
–
–
Server(s)
Printer(s)
Network interconnection(s)
Users
Group policies to be applied to users and computers
8
Network Operating Systems (NOS)
9
Summary Questions
Your organization has 12 employees, each with his
or her own stand-alone PC running Windows 98.
Each computer has a 10 Mbps NIC that could work
with coaxial cable or twisted pair (see next slide)
a) List all the additional hardware and software you
would have to buy to install a 100BaseTX LAN. Be
very sure that you list all the things the organization
will have to buy. The organization wishes to use
electronic mail, word processing, file sharing, and
print sharing with four existing printers fed with
parallel ports.
b) How many ports should the hub or switch have?
Explain.
10
11
Dual-transmission NIC
RJ45 connector
BNC “Thinnet” connector
Ethernet standards
12
Remote Access Service
Remote
Access Client
Software
Remote Access Server
Remote Access Server
13
14
Remote Access Service

User dials into a remote access server

Server authenticates the user (user must prove identity)

If authenticated, user may use network resources

Client PC needs RAS client software
RAS
Internal
Server
LAN
RAS
Client
Software
Dial-Up
Telephone
Line
Dial-In
Client
Directory Service

Needed in large networks with dozens or hundreds of servers

Directory database contains info about all network resources

Usually provides: Single login and Resource lookup.
Directory
Database
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16
Disk Fault-tolerance

Disk Fault-tolerance could be achieved through
–
Hardware RAID (Redundant Array of Independent Disks)
–
Software RAID
File
Data spread across these disks
Last disk contains
ECC* data for
disks 1-4
Clustering
17

Technique for providing uninterrupted service (even in case of
hardware/software failure)

Combining two or more servers into one virtual server

Services installed on external storage

Users connect to the virtual server (167.10.11.5 in illustration)

One of the clustered servers provides the service at a time
Win 98 Workstation
Mac client
Win 2000 Pro Workstation
Windows client
Virtual server
167.10.11.5
SharedFolder
- Web service
- Email service
Hub
Hub
External Disk
Server
Server
Load Balancing
18

Load balancing = Distributing the load among multiple servers

No External disk containing services to be provided

Multiple independent servers configured to participate in the load balancing

Same service with the same content on each server

Users connect to the virtual server (167.10.11.5 in illustration)

Users’ requests are redirected to one server at a time so that the load is distributed among all the servers
Virtual server
167.10.11.5
Webservice
Webservice
Server
Server
Webservice
Server
Hub
Webservice
Server
Webservice
Server
Current Network Operating Systems

19
Novell NetWare SOS
–
Once dominant, but market share has shrunk
–
Excellent file service
–
Excellent directory service called NetWare Directory
Services (NDS), now eDirectory.
NetWare strong directory service is convincing
many medium firms to continue using NetWare.
Version
Comment
NetWare 286
Released in 1986, Uses IPX/SPX
NetWare 3.x – 4.x
Included clustering, NDS
NetWare 5.x – 6.x
Switch to TCP/IP, Apache webserver
Novell Open Enpterprise Server Released in 2005, Linux platform
Current Network Operating Systems

Microsoft Windows Server Operating Systems
–
Microsoft Windows NT Server
–
Microsoft Windows Server 2000:
 Windows 2000 Server
 Windows 2000 Advanced Server
 Windows 2000 DataCenter Server
–
Microsoft Windows Server 2003
 Windows Server 2003 Standard Edition
 Windows Server 2003 Enterprise Edition
 Windows Server 2003 DataCenter Edition
 Windows Server 2003 Compute Cluster Edition
20
Current Network Operating Systems

Microsoft Windows Server Operating Systems
–
Easy to install, learn, and use because resembles
desktop Windows
–
Is dominant for small business and small department
servers
–
Windows Server OS has serious reliability problems:
–
–
Tend to crash more frequently than other OS
Windows 2003 Server versions promise to improve
reliability, but:
–
A path called Windows Server 2003 R2 released in 2005
21
Current Network Operating Systems

UNIX
–
Extremely reliable (speed, stability)
–
UNIX server OS dominate the enterprise server market
–
Many versions of UNIX exist
 UNIX: Must with the Single UNIX Specification
 Free UNIX-Like versions initiated by GNU project
 Different management utilities
22
Current Network Operating Systems

23
LINUX
–
–
–
Version of UNIX (Free UNIX-Like)
Runs on Intel PCs; low cost
Available free
 But
–
–
usually pay around $50 to $150 for packaged
version
Reliable like other UNIX versions
Open Source: Many people are developing tools to add
to the LINUX core
Current Network Operating Systems

24
Mac Server OS
–
"Classic" Mac OS (1984-2001)
 User-friendly,
–
completely graphical operating system
Mac OS X Workstation and Server (2001-present)
 based
on the BSD* implementation of UNIX
Mac OS X versions
Mac OS X v10.0 “Cheetah”
Mac OS X v10.3 “Panther”
Mac OS X v10.4 “Tiger”
Mac OS X v10.5 “Leopard”
Date Released
March 2001
October 2003
April 2005
Upcoming in 2007
* Berkeley Software Distribution or Berkeley UNIX
Summary Questions
1.
In remote access service, what kind of software does the
remote PC need? What is needed on the LAN side?
2.
What kind of services are provided by Directory
servers? What is disk fault-tolerance? What is the
difference between Clustering and Network Load
Balancing?
3.
What is the difference between a Workstation Operating
System and a Network Operating System?
4.
Name two Workstation Operating System and two NOS.
5.
Name one important strength of Novell NetWare NOS
that is convincing many firm to continue using it.
6.
What is virtual memory?
25