chapter2 computer

Chapter 2 - Internet & World Wide Web

104110 - Computer Applications Slide 1

Internet & World Wide Web

Chapter 2



What You Will Learn . . .

How the Internet worksMethods for accessing the InternetThe Internet and the World Wide WebHypertextWeb browsers and Web servers



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



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.


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:

Slide 5104110 - Computer Applications


Evolution of the Internet



•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


The Internet



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



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



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.



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



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.



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



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.



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



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.



Multimedia refers to any application that combines text with:





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.



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 .



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.



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.



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.


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.

104110 Computer ApplicationsSlide 23



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.



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.



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.



• 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.





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



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.



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



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



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



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



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.


A primary reason that people use the Web is to search for specific information.

Two types of search tools can be used:

104110 - Computer Applications

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,…


The World Wide Web




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.



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.



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.




Example of a portal



There are thirteen types of Web sites




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



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



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?



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.



E-Mail Addresses

[email protected] User’s name@name of the server that the user is on



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.



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



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.


Other Internet Services

VoIP (Voice over IP) enables users to speak to other users over the InternetAlso called Internet

telephony




Social Networking

Social networking helps people connect. Social networking sites like MySpace provide the

ability to create large communities online.



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.



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



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.



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



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.


E-Commerce



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.



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.



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.



E-Commerce

Building Your Own BusinessNeeds only a low capital

investmentRequires an ISP, a Web

site, and the ability to ship purchases



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.




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.



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

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