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The Internet: A Resource for All of Us Chapter 8 Objectives Briefly describe the history of the Internet Explain what is needed to get on the Internet Describe generally what an Internet service provider does Describe the rudimentary functions of a browser

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The internet a resource for all of us l.jpg

The Internet:A Resource for All of Us

Chapter 8


Objectives l.jpg
Objectives

  • Briefly describe the history of the Internet

  • Explain what is needed to get on the Internet

  • Describe generally what an Internet service provider does

  • Describe the rudimentary functions of a browser

  • Describe how to search the Internet

  • List and describe the non-Web parts of the Internet

  • Explain some of the ongoing problems associated with the Internet


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Contents

  • History of the Internet

  • URL

  • Getting Started

  • Internet Service Provider

  • Browser

  • Browser Support

  • Moving Between Sites

  • Searching the Internet

  • Other Uses of the Internet

  • Internet Issues


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History of the Internet

  • Government and Universities over 30 years

  • Who’s connected today?

    • Individuals

    • Educational institutions

    • Government

    • Research

    • Medical

    • Businesses

    • Everyone!


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ARPANetAdvanced Research Projects Agency Network

  • 1969 – US Department of Defense and Rand Corporation

  • Origins

    • Cold War – fear that a bomb could demolish computing capabilities

    • Several computers, geographically dispersed, networked together

    • Plan – if one computer was disabled, others could carry on using alternative communication routes


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ARPANetTransmitting the Message

  • Messages divided into packets

  • TCP/IP protocol

    • TCP – does the packeting and reassembling of the message

    • IP – handles the addressing


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ARPANetExpands Beyond the Military

  • Research computers from universities

  • Defense contractors

  • Needed technical expertise to work on Internet


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Tim Berners-Lee

  • 1990

  • Perceived a spider’s web of computers with links from computer to computer

  • CERN site

    • Dr. Berners-Lee’s physics laboratory

    • Birthplace of the World Wide Web

  • Easy movement due to links

    • Hypertext

    • Hyper-region


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Marc Andreessen

  • 1993

  • Created browser software

  • Mosaic – first browser

  • Provided attractive images and a graphical interface permitting users to click on pictures as well as text


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ARPANet to Internet

  • TCP/IP software is public domain

  • Network became more valuable as it embraced other networks

  • ARPANet disappears


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Internet Explosion

  • Mid 1990s

  • Estimate over 333 million users worldwide

  • Part of our daily lives

  • Four factors

    • TCP/IP standard

    • Ability to link from site to site

    • Ease of use of browser

    • Growth of PC and LANs that can connect


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URLUniform Resource Locator

  • Unique address of a web page or file on the Internet

  • Case-sensitive

http://domain-name.top-level-domain/last-section


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httphypertext transfer protocol

  • Protocol – rules

  • Communication using links

http://domain-name.top-level-domain/last-section


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Domain name

  • Address of the ISP

  • Domain names are registered

  • Ongoing fee is paid for each domain name

http://domain-name.top-level-domain/last-section


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Top-level Domain

Represent the purpose of the organization of entity

.com

.gov

.edu

.org

.net

May be a two-letter country code


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Last section

Directories and file names that specify a particular web page

http://domain-name.top-level-domain/last-section


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Getting Started

  • Computer with a modem or NIC

  • Internet service provider (ISP)

  • Browser

  • Related software


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Internet Service Provider

  • Vehicle to access the Internet

  • Provides

    • Server computer

    • Software to connect


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Online service

  • ISP

  • Members-only services and information

  • Simple interface with clickable topics

  • Parent controls


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Wireless Internet Access

  • Supports mobile handheld devices

    • Text pagers

    • PDAs

    • Pocket computers

    • Web-enabled cellular phones

  • Applications

    • E-mail

    • Checking weather

    • Making airline reservations


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Wireless Internet Access

  • Need

    • Account with wireless access provider

    • Cellular modem card or adapter

  • Wireless Application Protocol (WAP)

    • Convert web pages into format for mobile devices

    • Resized for limited display area

    • Fewer graphics transmitted

  • Slow download speeds


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Browser

Netscape Communicator

Microsoft Internet Explorer


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Browser

  • Used to explore the Internet

  • Dials the ISP

  • Display web pages


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BrowserParts of the screen


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BrowserFunctions and Features

  • Browser display window

    • Displays contents of web page from each Internet site visited

    • Screen limits how much of the site you can view at a time. The page can be scrolled using the scroll bar to see its entire contents

  • Status line – progress of data being transferred and other messages


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BrowserFunctions and Features

  • Welcome banner on title bar

  • Browser logo – animation indicates you are in the process of moving to a new site

  • Hot list

    • Bookmark

    • Favorites

    • Store your favorite URLs

  • Browser control panel – menus and buttons


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BrowserMenus and Buttons

  • Pull-down menu

  • Buttons

    • Convenient shortcuts for commonly used functions

    • Click button rather than locate command from pull-down menu


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Browser SupportFrames

  • Divides page into rectangular sections

  • Each section displays web pages independently

  • Several small pages on one screen

    • Can be scrolled independently

    • Can be replaced with other pages independently


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Plug-ins

  • Software that increases the functionality of a browser

    • Audio-video

    • Image viewing

  • Download from web sites

  • Install

  • Example

    • Adobe Acrobat Reader

    • Shockwave


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Programming

Java

  • Write software that is machine independent

  • Programming language

    • Dancing icons

    • Sound clips

    • Flashing messages

    • Banners that scroll

  • Applets – Permits dynamic web pages

    • Display animations

    • Receive input

    • Perform calculations


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Programming

ActiveX Controls

Capabilities similar to Java

Browser must be enabled to support applets / ActiveX Controls

Security issues


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Moving Between Sites

  • Clickable categories in the browser

    • Sports

    • Weather

    • News

    • Technology

    • Comic strips

  • Enter the URL in the address text box and press <Enter>


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Processing RequestsURL

  • User enters a URL

  • User computer sends request to the ISP server

  • ISP server sends request across networks of TCP/IP computers

  • Destination site is reached

  • Content is transmitted back to your computer (process in reverse)


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Searching the Internet

Search engine

  • User specifies a search request

  • Browser links to Search Engine

  • Request returns matching pages based upon the Search Engine’s database

  • Results presented


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Processing RequestsSearch Engine Database

  • Search Engine builds database

    • Searchable terms

    • Related web sites

  • Spider, robot, bot

    • Follows links across the web

    • Automatically indexes pages to a database

      • One word

      • All words

  • Pages may be submitted by the owner


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Processing RequestsSearch Engine Database

  • Request same search using different engines yields different results

  • Databases built independently

    • Size

    • Content

    • Search methodology

  • Metasearch – atomically puts the same request to several search engines


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Processing RequestsDirectory vs. Search Engine

  • Directory

    • Human involvement

    • Sites organized by content category

    • May concentrate on specific content areas

    • Subjective decisions regarding inclusion and importance

  • Search Engine

    • Spider, robot, or bot automatically builds database

    • Index on a few keywords

    • Index on all words on web page


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Processing RequestsSearch Engine Limitations

  • Index only a fraction of the Web

  • Approximately 20% to 33% of sites

  • More web pages added daily

  • Solution

    • Same request to several search engines

    • Metasearch


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Directories

Yahoo!

NetGuide

Metasearch Sites

MetaCrawler

Dogpile

Search Engines

AltaVista

Excite

Google

HotBot

Infoseek

Lycos

Northern Light

Search Tools


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Refine the Search

  • Add words

  • Enclose words in “quotes”

  • Use Boolean logic

  • Examples

    • “World Trade Center”

    • Jordan AND NOT Michael


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Other Uses of the Internet

  • Newsgroups

  • FTP

  • Telnet

  • E-mail

  • Internet Relay Chat (IRC)


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Newsgroups / Usenet

  • Large bulletin board divided by category

  • Posting and reading of messages that focus on specific topics

  • Over 20,000 newsgroups

  • Functions

    • Conversation

    • File download

  • Newsreader software required (included with most browsers)


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Newsgroup Operations

  • Lurking

  • Posting material

    • Inappropriate material

      • Flame

      • Flame war

    • Moderated newsgroup


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FTPFile Transfer Protocol

  • Download files to your local computer

  • Upload files to another computer

  • Requirements to download file

    • Permission to download from a site

    • File is available for copying

  • Anonymous FTP – do not need to identify yourself to the remote computer


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Public Archives

Sounds

Free files provided by educational institution or the government

Images

Graphics

Programs

Text


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Telnet

  • Use your PC as a terminal providing remote access to another computer

  • Permits

    • Log on to a host

    • Use as if you are sitting at a local terminal

  • Need account on the host system

  • Telnet software required (provided with most browsers)


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e-mail

  • Send/receive written messages

  • Most used feature of the Internet

  • Mail server – Collects and stores e-mail

  • Mailbox – Assigned to each user

  • E-mail address

    • User name

    • @

    • Domain of the mail server


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Retrieve

Create

Send

Store

Print

Delete

Address book

Attach files

Filters

e-mailClient Software Functions


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IRCInternet Relay Chat


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Not Quite Perfect Yet

  • Unregulated

  • Useless web sites

  • Misinformation and misstatements on web sites

  • Concern over government censorship


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Not Quite Perfect YetSocial Issues

  • Behavior problems

    • Who is out there?

    • What are they doing?

  • Netiquette

    • Suggestions for appropriate behavior

    • Example: TYPING IN CAPS is shouting


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