Using Information Technology

Chapter 2The Internet & the World Wide Web

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The World of The Internet

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The Internet & the World Wide WebExploring Cyberspace

2.1 Choosing Your Internet Access Device & Physical Connection: The Quest for Broadband

2.2 Choosing Your Internet Service Provider (ISP)

2.3 Sending & Receiving E-Mail

2.4 The World Wide Web

2.5 The Online Gold Mine: More Internet Resources, Your Personal Cyberspace, E-Commerce, & the E-conomy

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2.1 Choosing Your Internet Access Device & Physical Connection

This section discusses the different technologies used to connect individuals to the internet including: 1. Access device: a personal

computer with a modem 2. Physical connection: a

telephone line

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Modem

Is a device that converts a digital signal to an analog signal and vice versa. Modem is short for modulate/demodulate

Conversion from digital to analog signals is called modulation and reverse process is called demodulation.

Modem has various types. External modem Internal modem

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Physical connection

The wired or wireless means of connecting to the Internet.

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Data Transmission Rates Data is transmitted in bits per

second. bps stands for bits per second. A bit is the

smallest unit of information used by computers. A computer with an older modem might have a speed of 28,800 bps per second.

Kbps stands for kilobits per second. This is the most frequently used measure.

Mbps stands for megabits per second We at NIIT have 1 Mbps leased line for

internet

Gbps stands for gigabits per second

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Bandwidth

- an expression of how much data can be sent through a communications channel in a given amount of time

Broadband - very high speed connection

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Download & Upload

Download - to transmit data from a remote computer to a local computer

Upload - to transmit data from a local computer to a remote computer

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Telephone (Dial-Up) Modem: Low Speed but Inexpensive & Widely Available

Modem - device that sends and receives data over telephone lines to and from computers

Most modems today have a maximum speed of 56 Kbps.

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High-Speed Phone Lines: (No dialup line)

Integrated Services Digital network (ISDN) - hardware and software that allows voice, video, and data to be communicated over traditional copper-wire telephone lines. Speeds up to 128 kbps.Digital Subscriber Line (DSL) - also uses regular phone lines but much faster than ISDN. Download speeds 1.5 – 8.4 Mbps

One for telephone wire is splitted for voice and one for data. 64kbps is required for human voice data transfer

ADSLT1 - A traditional trunk line that carries 24 normal telephone circuits and has a transmission rate of 1.5 Mbps. Good for business.

23 lines are for usage and 1 is for connectivity control 23 different phone numbers In Europe it is 29+1 and is called E1

Packet Switching

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ISDN

Type of line that could be used directly for digital transmission. End to End Digital transmissions.

ISDN adapter can move data at 128,000bps , a vast speed improvement over any modem

ISDN circuit includes two phone lines, so a user can use one line to connect to the internet and other to talk on the phone at same time.

Expensive High speed and high capacity

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High-Speed Lines

Cable : Close Competitor to DSL Speeds up to 10 Mbps

Fiber Optics: Can support speeds up to 2 Gbps

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Assignment 2 -- Due Oct 23rd Tuesday.

Study: Compare and Contrast ISDN, DSL, and Cable Internet?

Submission: What are some of the DSL options available?

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Wireless Systems: Satellite & Other Through-the-Air Connections Satellite: With a pizza-size satellite

dish on your roof, you can receive data at the rate of 400 Kbps from a communications satellite, a space station that transmits radio waves called microwaves from earth-based stations.

Other wireless connections: In urban areas, some businesses are using radio waves transmitted between towers that handle cellular phone calls, which can send data at up to 155 Mbps.

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2.2 Choosing Your Internet Service Provider (ISP)

ISP - a company that connects you through your communications line to its servers, or central computer, which connect you to the Internet via another company’s network access points

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2.3 Sending & Receiving E-MailE-Mail Software & Carriers

Buy e-mail software

Get e-mail program as part of other computer software (such as browser)

Get e-mail software as part of your ISP package

Get free e-mail services

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E-Mail Addresses

Jane_Doe@earthlink.net.uk

User name: Jane_Doe

Domain : earthlink

Top-level domain: .net

Two-letter country extension: .uk

Domain Name

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Attachments

Attachments: Files attached to an e-mail message in their own format. Individuals can attach pictures, sounds, videos, and other files to e-mail message.

Note: Many viruses ride along with e-mail as attached files. Never open an attached file from an unknown source

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Instant Messaging

Instant messaging (IM) - allows any user on a given e-mail system to send a message and have it pop up instantly on the screen of anyone else logged onto that system

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Chat Applet

A rectangular area containing a document or activity so that users can exchange messages almost instantaneously while operating other programs.

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Mailing Lists: E-Mail-Based Discussion Groups

List-serves - e-mail mailing lists of people who regularly participate in discussion groups

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Netiquette: Appropriate Online Behavior(a) Don’t waste people’s time.

(b) Don’t say anything to a person online that you wouldn’t say to his or her face.

•(c) Consult FAQs: Most online groups post FAQs--for Frequently Asked Questions--that explain expected norms of online behavior for a particular group.

(d) Avoid Flaming: Writing an online message that uses derogatory, obscene, or inappropriate language.

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Netiquette: Appropriate Online Behavior(e) Emoticons: Keyboard-produced pictorial representations of expressions.

(f) Avoid SHOUTING: Use of all-capital letters is considered the equivalent of SHOUTING.

(g) Avoid Sloppiness: Avoid spelling and grammatical errors. Try to avoid criticizing others’ sloppiness.

(h) Do not send large file attachments, unless requested. This may tie up your country cousin, who has a slow dial-up connection, when he or she badly needs to use it.

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Netiquette: Appropriate Online Behavior

(i) When replying, quote only the relevant portion. If you’re replying to just a couple of matters in a long e-mail posting, don’t send back the entire message. This forces your recipient to wade through lots of text to find the reference. Instead, edit his or her original text down to the relevant paragraph and then put in your response immediately following.

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Spam: Unwanted Junk E-Mail

Delete without opening the message

Never reply to a spam message!

Enlist the help of your ISP or use spam filters

Fight back

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2.4 The World Wide Web

The Multimedia makes the Web attractive and inviting.

The Hypertext makes the web navigable.

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Hypertext

A system in which documents scattered across many Internet sites are directly linked, so that a word, phrase or an image in one document becomes a connection to a document in a different place.

The term hypertext was coined by American computer scientist Ted Nelson in 1965 to describe textual information that could be accessed in a nonlinear way. He used the prefix hyper to describe the speed and facility with which users could jump to and from related areas of text.

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Hypertext Markup Language (HTML)

The set of special instructions (called "tags" or "markups") that are used to specify document structure, formatting, and links to other documents.

HTML is a subset of a broader language called Standard Generalized Markup Language (SGML), which is a system for encoding and formatting documents, whether for output to a computer screen or to paper.

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HTML Script <html> <head> <script language="javascript"

src="http://us.i1.yimg.com/us.yimg.com/i/mc/mc.js"> </script> <meta http-equiv="pics-label" content='(pics-1.1

"http://www.icra.org/ratingsv02.html" l gen true for "http://mail.yahoo.com" r ( nz 0 vz 0 lz 0 oz 0 ca 1))'>

<title>Yahoo! Mail - The best free web-based email!</title> </head> <body bgcolor=#ffffff onload="document.login_form.login.focus();"> <center> <script language="JavaScript"> <!-- hasMsgr = 0; /*

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The Web & How It Works

Web-- A domain on the computer

Site - a computer with a domain name

Website - the location of a web domain name in a computer somewhere on the Internet

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Web page

A Web page is a document on the World Wide Web on a Website that can include text, pictures, sound, and video.

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Designing Web Pages

Professional Web page designers can produce a page for customers, or the customers can do it on their own using a menu-driven program included with a Web browser or a Web-page design software package such as Microsoft FrontPage or Adobe PageMill.

LAB WILL FOLLOW!

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Browsers – Software for connecting with websites

In computer science, a program that enables a computer to locate, download, and display documents containing text, sound, video, graphics, animation, and photographs located on computer networks.

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URLs – Addresses for Web Pages

Uniform Resource Locator (URL) is a method of naming documents or places on the Websites.

A URL is a string of characters that identifies the type of document, the computer the document is on, the directories and subdirectories the document is in, and the name of the document.

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A URL

http://www.nps.gov/abli/index.htm

Protocol : http

Domain name: www.nps.gov

Directory name: abli

File name: index.htm

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Using Your Browser to Get Around the Web

Home page - the first page you see when you start up your browser

Getting around:

Back - takes you back to the previous page

Forward - takes you to a page you returned from

Home - takes you to your home page

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Using Your Browser to Get Around the Web

History list - list accessible from browser’s toolbar that allows you to return to a page you have recently visited

Bookmarks or favorites - your favorite URLs stored in a list to permit frequent visits without retyping the URLs

Simultaneous viewing of two pages via File menu’s “New” item

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Using Your Browser to Get Around the Web

Interactivity--hyperlinks, radio buttons, and fill-in text boxes

Radio buttons - little circles located in front of various options; selecting an option with the mouse places a dot in the corresponding circle

Radio buttons and textbox

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Web Portals: Starting Points for Finding InformationWeb portal - website that groups together in one convenient location popular features such as search tools, e-mail, electronic commerce, and discussion groups

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Web Portals: Starting Points for Finding Information

After logging on, you can:

Check the home page for general info

Use the directories to find a topic

Use keyword to search for a topic

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Search Engine

Computer software that compiles lists of documents, on the World Wide Web (WWW), and the contents of those documents. Search engines respond to a user entry, or query, by searching the lists and displaying a list of documents that match the search query. Some search engines include the opening portion of the text of Web pages in their lists, but others include only the titles or addresses (URLS) of Web pages.

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Four Types of Search Engines

Human-organized search sites

Computer-created search sites

Hybrid search sites

Metasearch sites

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Human-organized search sites

Unlike indexes created by computers, humans can judge data for relevance and categorize them in ways that are useful to you.

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Computer-created search sites

These are assembled by software "spiders" that crawl all over the Web and send back reports to be collected and organized with little human intervention. The downside is that computer-created indexes deliver you more information than you want.

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Hybrid search sites

Hybrid sites generally use humans supplemented by computer indexes. The idea is to see that nothing falls through the cracks.

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Metasearch sites

Metasearch sites send your query to several other different search tools and compile the results so as to present the broadest view.

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Tips for Smart Searching

o Start with general search tools. o Choose search terms well and watch spelling. o Use phrases with quotation marks rather than

separate words o Put unique words first in a phrase o Use Boolean operators--AND, OR, NOT, and +

and – signs--to make searching more precise o Read the Help or Search Tips section o Try an alternate general search site or a

specific search site

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Multimedia on the Web

Plug-ins Applets Text and Images Animation Video Audio

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Plug-ins

A program that adds a specific feature to a browser, allowing it to play or view certain files. Plug-ins are required by many Web sites if users want to fully experience the content. E.g in order to view a PDF file, the Adobe Reader plug in is required

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Some Common Plug-ins

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Applets

Small application programs that can be quickly downloaded and run by most browsers.

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Text and Images Most Web pages combine both text and

images.

Animation

Animation is the rapid sequencing of still images to create the appearance of motion.

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Video Video can be transmitted in two ways.

• A file, such as a movie or video clip, may have to be completely downloaded before you can view it.

• A file may be displayed as streaming video, the process of transferring data in a continuous flow so that you can begin viewing a file even before the end is sent.

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Audio Audio, such as sound or music files, may

also be transmitted in two ways:

• Downloaded completely before they can be played.

• Downloaded as streaming audio, which allows users to listen to the file while the data is still being downloaded to the computer. A popular standard for transmitting audio is RealAudio, which compresses sound so that it can be played in real time.

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Push Technology & Webcasting

Push technology - software that automatically downloads information to your computer

Webcasting - customized text, video, and audio sent to you automatically on a regular basis

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The Internet Telephone & Videophone

Internet telephony - using the Net to make phone calls, either one-to-one or for audioconferencing

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2.5 The Online Gold Mine: More Internet Resources, Your Personal Cyberspace, E-Commerce, & the E-conomy

o File Transfer Protocol (FTP)

o Telnet

o Newsgroups

o Real-Time Chat

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File Transfer Protocol (FTP) FTP is a method whereby users can connect to a

remote computer called an FTP site and transfer publicly available files to a microcomputer’s hard disk. The free files cover nearly anything that can be stored on a computer: software, games, photos, maps, art, music, books, and statistics.

In computer communications, on the Internet and other networks, a method of transferring files from one computer to another. The protocol is a set of rules that ensures a file is transmitted properly to the receiving computer. A computer that stores files that can be retrieved using FTP is called an FTP site or FTP server. FTP is part of the Transmission Control Protocol/Internet Protocol (TCP/IP), the system that enables different types of computers and networks on the Internet to communicate.

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Telnet A program or command that allows users to

connect to remote computers on the Internet using a user name and password.

Telnet, protocol, or set of procedures, that enables a user of one computer on the Internet to log on to any other computer on the Internet, provided the user has a password for the distant computer or the distant computer provides publicly available files or data. Telnet is also the name of a computer program that uses those rules to make connections between computers on the Internet. Many computers that provide large electronic databases, like library catalogs, often allow users to telnet in to search the databases. Many resources that were once available only through telnet have now become available on the easier-to-use World Wide Web.

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Newsgroups A giant electronic bulletin board on

which users conduct written discussions about a specific subject.

Real-time chat Participants have a typed discussion

("chat") while online at the same time, just like a telephone conversation except that messages are typed rather than spoken.

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Your Personal Cyberspace

Relationships--online matchmaking

Education--the rise of distance learning

Health--patient self-education

Entertainment--amusing yourself

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E-Commerce

E-tailing--retail commerce online

Auctions--linking individual buyers and sellers

Online finance--trading, banking, and e-money

Online job hunting

B2B commerce

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