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Chapter 2 - Internet & World Wide Web
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Internet & World Wide Web
Chapter 2
Chapter 2 - Internet & World Wide Web
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What You Will Learn . . .
How the Internet worksMethods for accessing the InternetThe Internet and the World Wide WebHypertextWeb browsers and Web servers
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What You Will Learn . . .
Parts of a URLHow to access Web pagesWeb subject guides and search enginesUse operators to improve search resultsReliability of information on the WebMost popular Internet services
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The Internet
The Internet is a global, interconnected computerThe Internet is a global, interconnected computer network in which every computer connected to it can network in which every computer connected to it can exchange data with any other connected computer.exchange data with any other connected computer.
Cyberspace, a term used to refer to the Internet, is the unlimited span of networks using the same data exchange methods.
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Evolution of the Internet
The Internet originated as ARPANET in September 1969 and linked 4 main computers: UCLA, UCSB, Stanford, Univ .Utah
It had two main goals:
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Evolution of the Internet
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•Volunteers maintain the Internet networks.
•Private and public groups provide the equipment.
•Network service providers such as Etisalat and Du maintain the Internet backbone, the main high-speed routes for the U.A.E
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The Internet
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How the Internet Works
Interoperability is the ability to communicate with a computer even if it is a different brand or model.
Transmission Control Protocol/Internet Protocol (TCP/IP) provides methods for packaging and transmitting information.
Unix
WindowsMainframe
Internet
Macintosh
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Accessing the Internet and Web
You will need: A computer with an operating system, such as Windows, MAC
OS, or UNIX, that supports Internet protocols (TCP/IP) Communications equipment such as a modem, ISDN adapter,
or Ethernet card An Internet service provider (ISP): companies that sell Internet
account. Web browser software such as Internet Explorer or Netscape
Navigator
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Accessing the Internet The Internet can be accessed in the
following ways: Dial-up access with Point-to-Point
Protocol (PPP): Dial-up access connects users to
the Internet through a modem and a telephone line.
Home usage, because affordable . Computer directly connected to
the Internet. slow
Digital Subscriber Line (DSL) Offer high-speed access and a
permanent online connection. Service doesn’t extent more than
few KM from a telephone switching station.
Pricier than dial-up.
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Accessing the Internet Cable Access:
provides a high-speed Internet connection using a cable modem, not a phone line.
Cable TV companies are offering Internet access at speed much faster than that of dial-up access.
Temporary connection.
Satellite Access: requires a satellite dish in addition to
a phone line and modem for an Internet connection.
– Satellite for high-speed downloading
– Phone line and modem for uploading.
Fiber-optic Service (FiOS): provides extremely fast Internet
access through fiber-optic lines that run directly to users’ homes. No modems are required.
Network Access: By Companies, and Universities. Faster than Dial-up. Free
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Accessing the InternetOthers Methods:
Fixed wireless provides high-speed Internet connections using a dish-shaped antenna to communicate with a tower location via radio signals.
A Cellular radio network offers high-speed Internet connections to devices with built-in compatible technology or computers with wireless modems.
A Wi-Fi (Wireless fidelity) network uses radio signals to provide high-speed Internet connection to compatibles or properly equipped wireless computers and devices.
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The Internet and the Web: What’s the Difference?
The Internet is the physical connection of millions of networks and computers can directly access any other and exchange data.
The World Wide Web uses the Internet for its existence and is made of billions of documents.
The Web consists of hypertext embedded on Web pages that are hosted on Web sites.
No one owns or controls the Internet. But a variety of organizations are responsible for different
aspects of the networks:ICANN The Internet Corporation for Assigned Names and Numbers (ICANN) is responsible for managing and coordinating the Domain Name System (DNS) to ensure that every address is unique and that all users of the Internet can find all valid addresses.W3C The World Wide Web Consortium (W3C) develops interoperable technologies (specifications, guidelines, software, and tools) to lead the Web to its full potential
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The Web Site
What else can you find on the web? A Web site is a location that is
accessible from the Internet and makes web pages available to the public.
Web pages are individual Web documents that include text, graphics, sound, animations, or video.
A web site typically contains a home page (also called index page), which the a default page that’s displayed automatically when you access a site.
Web 2.0 refers to web sites that provide a means for users to interact.
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How all these pieces work together on the web?
Internet
World Wide Web
Hypertext Hyperlinks
Web Browser
Distributed Hypermedia System
URL
DNS
HTTP Top Level DomainServer
ProtocolSearch Engine
Upload
Download
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The Hypertext Concept
The web billions of document are created using Hypertext.
Hypertext is a method of preparing and publishing text that is ideally suited to be read with a computer.
Hypertext works by means of hyperlinks. Uses tags to specify how a Web page should display.
Hyperlinks (Links) are underlined or highlighted words that can be used to view another document or Web page.
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The Hypertext Concept
Multimedia refers to any application that combines text with:
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The Hypertext Concept
A distributed hypermedia system is a network-based content development system that uses multimedia resources.
The Web is a distributed hypermedia system or a system where the responsibility for creating content is distributed among many people.
For this reason, Dead links (Broken Links) are common on the web.
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Web Browsers and Servers
Web browsers are program that display a Web document and enable users to link to other Web pages and web 2.0 programs .
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Web Browsers and Servers The first browsers were text-only (Lynx). Lynx was initially developed in 1992 by
a team of students at the university of Kansas (Lou Montulli, Michael Grobe and Charles Rezac) as a hypertext browser used solely to distribute campus information as part of a Campus-Wide Information Service.
Mosaic (1993) – Illinois University - was the first graphical browser.
Marc Andreessen and other former students and staff of the University of Illinois, started Mosaic Communications which eventually became Netscape Communications Corporation, producing Netscape Navigator.
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Web Browsers and Servers
All have the similar features:• Navigation buttons, a program icon, address toolbar, status bar,
• Default to a home page when you start them,
• Act upon documents that are created using hypertext
• Uses plug-ins, which are software programs that allow you to derive the full benefits of a web site, such as sounds or video.
• Ability to cache or store web pages files and graphics on your computer and that you can retrieve faster next time you access them.
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Web Browsers and Servers (cont…) Problem with pages you access
from cache is that they may not be the most current version of the web page.
• Using the refresh button will help ensure that you are viewing the latest content.
Content on the web is made available by means of more than millions of Web servers.
Web servers respond to the requests of browsers. They find and send requested resources back to the browser.
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The Internet and the Web: What’s the Difference?
Every device connected to the Internet, including PCs and servers, is given a unique network identifier called an Internet Protocol (IP) address.
The identification of an Internet resource’s type and location is performed through its Web Address.
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Web addresses are an addressing system that identifies where a Web resource is located.
The uniform resource locator (URL) is the standard used to identify Web resources.
The complete URL has four parts:
URL
Web Addresses (URLs)
http://
Protocol identifies the means of access.
www.yahoo.com/
Server contains the domain name of the Web server.
help/shop/
Path identifies the
location of the document.
shop-01.html
Resource specifies the
filename of the resource.
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Web Addresses (URLs)Protocol:
The first part of a complete URL followed by a colon (:) and two forward slashes marks (//)
Ftp and other protocols can be used.Server:
Name of the web server where the web page is located.Start with www, but less common nowadays.Second part or a server name is the top-level domain name.The domain is the extension such as .com or .edu
representing the type of group or institution that the web site represents.
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Web Addresses (URLs) The domain Name System (DNS):
Enables users to type an address that includes letters (www.ajman.ac.ae) as well as numbers (172.17.10.30)
A process called domain name registration enables individuals and organizations to register a domain name with a service organization.
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Web Addresses (URLs)
• Domain name is the text version of an IP address.
• It can tell you a great deal about where a computer is located:
• For web sites in the US, top-level domain (TLD) names indicates the type of organization in which the computer is located.
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Web Addresses (URLs)
Outside the US the TLD indicates the country of where the computer hosting is: eg (Egypte,) ae (UAE), dz (Algeria), bh (Bahrain), iq
(Iraq),.lb (Lebanon), sy (Syria), ma (Morocco), sa (KSA),.ir (Iran), jo (Jordan), om (Omen), kw (Koweit), pk (Pakistan), sd Soudan, ng (Nigeria), ly(libya), Qa(Qatar), BD (Bengladesh) tr (turkey) uk (united kingdom) (ru) russia (af )afghanisthan (so) somalia (mu) mauritia .ph (philippines), .us (USA), .ca (Canada), .nl (Netherland)., .ua (Ukraine), .tu (Tunisia), .cn (China), .es (Spain), in india,ye yemen ,
In india
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Web Addresses (URLs)Path:
Specify the location of the document on the server including the names of subfolders (if any).
Resource Name:The last part of the URL.Gives the filename of the resource you’re accessing.A resource is a file, such as HTML file, a movie file, or a
graphics file. If a URL does not include a resource name, the default home
page of the web server will be retrieved.
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Browsing the Web
To access a Web page, you can do any of the following:Click a hyperlinkType a URL in the Address boxClick a button on the Links toolbarUse the Back and Forward buttonsUse a Web site’s navigation aidsUse the History listUse the Favorites or Bookmarks list
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Standard Toolbar– Contains Navigation buttons
Address Bar– Contains URL of Web page
Back & Forward Buttons– Take you to recently visited pages
Stop Button– Stops downloading
Refresh Button– Updates (refreshes) the page
Home Button– Returns to default start page
Search Button– Opens search engine program
Favorites Button– List of bookmarked Web pages
Media Button– Opens media player program
History Button– List of Web sites visited over a period of time
E-Mail Button– Opens e-mail program
Printer Button– Prints documents
Other Navigation ButtonsProgram icon– Animates when downloading
Status bar– Messages about the browser’s operation
Hyperlinks
The Web Browser’s Window
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Uploading and Downloading
Downloading – document or file is transferred from another computer to your computer
Cautions when downloading: virus are spread in data file of popular programs, such as word, excel, ..
Uploading – files transferred from your computer to another computer
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Emerging Technologies Ways to share information on the Internet
Wiki short for wiki-wiki (fast in Hawaiian) is an open-content
encyclopedia. Is a simple web page visitor can post text, or images, Businesses are interested in wikis because of their collaboration
possibilities. www.wikipedia.org
Weblog (blog) Internet journal or diary Bloggers post their thoughts and opinions. www.blogsearch.engine.com
Moblog (mobile blog) A moblog is an on-line space in which you can instantly publish
photographs, text or video that has been captured through your cellular (mobile) telephone, hence the name "moblog" (mobile-log).
Content posted from a portable phone or PDA to a Blog
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Emerging Technologies Ways to share information on the Internet
Microblog Allow users to publish short messages, usually between 100 – 200
characters fro others to read. Twitter is the most popular microblog.
Online Social Network Web site that encourages members in its online community to share
their interest, ideas, stories, photos, music, and videos with registered users.
Most popular: MySpace, Facebook. Media Sharing
A specific type of online social network that enables members to share media such as photos (Flickr, Fotki), music, videos (PixelFish, YouTube).
Podcast Used by those who wish to obtain information in an audio or video
format.
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A primary reason that people use the Web is to search for specific information.
Two types of search tools can be used:
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Finding Information on the Web
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Finding Information on the Web
Search Engines – Helpful to locate information for which you do not know an exact address or are not seeking a particular Web site.
Subject guides – Web pages are grouped under headings such as business, news,…
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The World Wide Web
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Using Search Engines
Search engines are databases that claim to index the full web to enable fast searches.To do that they use spider which are computer program that roam the World Wide Web via the Internet, visit sites and databases, and keep the databases of the Web search engines pages up-to-date.
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Using Search Engines
To use a search engine, you:• Choose a search engine (MSN,
Lycos, Alta-Vista, Yahoo, etc.).• Type in one or more words
describing your topic. The search engine checks its
database of Web pages that contain the words typed
The results are sent to your computer.
Clicking on the link takes you to the corresponding page.
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Specialized Search Engines & Portal
Full web search engines don’t index specialized information such as names, addresses, job advertisements, quotations, or newspaper articles. Specialized Search Engines do that.
Portal are gateways that provide convenient organized subject guide to Internet content.
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Finding Information on the Web
Example of a portal
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Finding Information on the Web
There are thirteen types of Web sites
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Finding Information on the Web
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Using Search Techniques
Learning a few search techniques can increase the accuracy of Web searches.
Searches using search operators will improve search performance.
Most search engines use the following search operators:• Inclusion/exclusion operators• Wild cards• Phrases• Boolean operators
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The following tables show the results of using and not using search operators.
Words Entered
Possible Results – Web pages containing
Fire station
FirestationFire station
Words Entered Possible Results – Web pages containing
+Fire+station Fire station
+Fire+station* Fire stationFire stations
+Fire-station* Fire
“Fire station” Fire station
Fire and station Fire station
Fire or stationFire stationFire station
Fire not station Fire
No Search Operators
Using Search Operators
Using Search Techniques
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Rules for Evaluating Web Pages
1. Author – Who is the author?
2. Sources – Where does the information come from?
3. Server – Who provides the server for the page?
4. Objectivity – Is the information objective or one-sided?
5. Style – Is the language objective or argumentative?
6. Purpose – What is the purpose of the page?
7. Accuracy – Is the information accurate?
8. Currency – Is the page up-to-date?
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E-Mail: Staying in Touch
E-mail is short for electronic mail. It’s the most popular of the Internet services. Messages are sent and received in a few seconds. Attachments such as photos, music files, and any
document may be sent with the message.
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E-Mail Addresses
myname@someserver.com User’s name@name of the server that the user is on
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Spam: Can It Be Stopped?
Spam – unsolicited e-mail advertisingWith Spam the recipient pays the
postage.To avoid spam:
Avoid posting your e-mail address.
Use spam protectors. Don’t reply to spam.
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Instant Messaging: E-Mailing Made Faster
Instant messaging systems let a user know when a friend or business associate is online.
It provides a means of communicating through real-time, text-based conversations.
May be susceptible to spimming—spam for instant messaging
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IRC: Text Chatting in Real Time
Internet relay chat consists of real-time, text-based conversations.
Chat groups are divided into channels that cover a specific topic.
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Other Internet Services
VoIP (Voice over IP) enables users to speak to other users over the InternetAlso called Internet
telephony
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Social Networking
Social networking helps people connect. Social networking sites like MySpace provide the
ability to create large communities online.
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Your Computer FTP Server
DOWNLOAD
UPLOAD
File Transfer Protocol (FTP)
FTP is a part of the Internet that enables client computers to transfer files.
Transferring files from an FTP site to the client is known as downloading.
Transferring files from the client to an FTP site is known as uploading.
Clients may store files on an FTP site’s server.
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Usenet - 1980 Usenet is the part of the Internet which enables
users to participate in discussions and newsgroups.
Developed at University of North Carolina at Chapel Hill and Duke University
Newsgroups are discussion devoted to a single topic.
The set of articles which can be traced to one Topic is called a thread.
Usenet newsgroups are organized into the following hierarchies (categories) and subcategories: Standard newsgroups of high-quality
discussions Alt newsgroups created by anyone Biz newsgroups devoted to commercial use
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Usenet
To use usenet you net a usenet client. Article you post will be store for long
periods in web accessibles archives. You should follow netiquette rules,
which are guidelines for good manner when using usenet (or any internet service).
If you violate netiquettes rules you will receive flames(angry, critical messages) from other newsgroup subscribers.
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Standard Newsgroup Subcategories
comp computer applications, databases, multimedia
misc activism, books, business, health
sci chemistry, archeology, math
soc human rights, world cultures
talk Euthanasia, gun control, religion
news Usenet announcements
rec sports, gardening, bicycles
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Listservs: Electronic Mail Lists - 1986
Electronic mailing lists are similar to newsgroups and forums, except that:Only subscribers can receive
and view messages.Messages posted to the
mailing list are automatically sent to everyone on the list.
is a common freeware electronic mailing list manager.
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E-Commerce
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E-Commerce
E-commerce, short for electronic Commerce, is the conducting of business through the use of networks or the Internet.
Popular uses of e-Commerce by consumers include retail, finance, travel, entertainment and health.
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E-Commerce
Three types of e-commerce are: Business-to-Business (B2B) E-Commerce refers to a
business providing supplies to other businesses via the Internet.
Consumer-to-Consumer (C2C) E-Commerce refers to the exchange of business between individuals, such as in online auction: eBay is a good example.
Business-to-Consumer (B2C) E-Commerce refers to shopping online rather than at a physical store: exple Apple web site.
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E-Commerce
The DOT-COM PhenomenonE-commerce primarily uses Web sites with a .com
suffix.The period between 1995 and 2000 is called the dot-
com boom.Many dot-coms crashed in 2000.Amazon.com is a profitable company.
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E-Commerce
Building Your Own BusinessNeeds only a low capital
investmentRequires an ISP, a Web
site, and the ability to ship purchases
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E-Commerce
Guidelines for Safe Surfing Install antivirus and antispyware utilities to avoid
malware, programs designed to damage computer systems.
Buy only from legitimate businesses.Use secure sites with https:// in address, a locked
padlock symbol, etc.Protect your identity.Protect children from unhealthy contact.
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Chapter 2 Summary
The Internet is the network of networks.The Internet is accessed by way of an ISP.World Wide Web is a global system with
billions of hypertext documents.Related information is linked using hypertext.A Web browser is a program that displays
Web pages.A URL consists of a protocol, a server, a path,
and a resource name.Search engines enable you to search huge
databases of Web documents.
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Chapter 2 Summary (continued)
You can improve search results using operators.
You should always evaluate information you receive from the Web.
Popular Internet services include:• E-mail• Instant messaging• Internet Relay Chat• File Transfer Protocol• Discussion groups• Listservs