COM111 Lecture Schedule 8

COM111 Lecture Schedule 8

Introduction to Internet, Internet Applications, Internet Tools, Web Browser and Email client

Internet

Internet is a worldwide system of computer networks, that is a network of networks, which allows the participants to share information.

Evolution of Internet

The foundation of internet was laid in 1969 by the Department of Defense of United States of America. Computer network was created function in the event of a disaster, such as a nuclear war. Even if a part of the network was damaged or destroyed, the rest of the system would continue to work. That network was known as ARPANET (Advanced Research Project Agency Network), which linked US scientific and academic researchers.

Basic Internet terms

WWW

World Wide Web is a collection of linked documents or pages, stored on millions of computers and distributed across the world. In hypertext system, the documents are connected to other related documents on the internet through links. The web uses a specific Internet protocol called HTTP to support hypertext documents.

Web page

The hypertext documents on the WWW are known as Web pages. A web page is written in a language called HTML(Hyper Text Markup Language) which enables to embed hypertext links in the documents. Using these hyperlinks the user can jump from one web page to another.

Website
           A website is a set related Webpage, published by an organization or an individual. Web site contains a home page along with other additional web pages. Web site is accessed by its own address known as URL (Uniform Resource Locator). All the web site on the internet constitutes the WWW.

Homepage
          Home page (also called index page) is the starting point or doorway to the web: it refers to the web page that identifies a web site and contains hyperlinks to other web pages in the website.

Browser

Browser is special software that enables users to read/view Web Pages and jump from one web page to another. It is the software to find, retrieve, view and send information over the internet. The most popular browsers are Microsoft Internet Explorer and Netscape Navigator.

Browsers are of two types

Graphical Browsers: Allow retrieval of text, images, audio, and video. Navigation is accomplished by pointing and clicking with a mouse on highlighted words and graphics. Netscape Navigator, Internet Explorer, and Mozilla are graphical browsers.

Text Browsers: Provide access to the web in text-only mode. Navigation is accomplished by highlighting emphasized words on the screen with the arrow up and down keys, and then pressing the Enter Key to follow the link. Lynx is an example of a text-based browser.

            Each Web page has a unique address, called a URL (uniform resource locator), which identifies its location on the Internet. Usually, the format of an URL consists of four parts: protocol, name of the web server (or domain name), path, and filename. Here is an example, http://www.xyz.com/tutor/start/main.htm. The structure of this URL is:

v  Protocol: http

v  Web server name/domain name: www.xyz.com

v  Path: tutor/start/

v  File Name: Main.htm

The first part of the address, the part before the colon, is the protocol. Most of the time http (hypertext transfer protocol) is used for accessing a Web page. Apart from http, there are other protocols such as ftp (file transfer protocol), news (news server), and telnet (for accessing remote computers). After the protocol, comes the domain name. The protocol and the domain name are separated by colons and slashes.

      A domain name is a unique name that identifies a particular Web site and represents the name of the server where the Web pages reside. They are the human-readable addresses and hence are easier to remember. Domain names have two or more parts separated by dots. The letters occurring after the dot (.) identify the domain type. A domain type represents the type of organization or countries to which the Web server (sometimes called host computer) belongs.

Domain Types

Some of the domains that are typical on the Internet are:

Com    Commercial and for-profit organizations

Edu     Colleges and universities (education providers)

Gov     Federal government agencies

Mil       US military sites

Net      Internet infrastructure and service providers

Org      Miscellaneous and non-profit organizations

Hypertext

            The hypertext is a system that provides a simple and consistent way to organize large data (that includes text, images, pictures videos, etc.) available on the Internet. In hypertext systems, the documents contain links to other related documents on the Internet. These links are called hyperlinks, hotlink, or simply links. A hyperlink is used to jump to another part of the same page or to load a different Web page. Usually hypertext links appear in a different color (typically in blue and underlined) from the rest of the text. When the cursor is moved over a text link or over a graphic link, it will change from an arrow to a hand. The hypertext words often provide a hint about the connected page.

jInternet Service Provider (ISP)

            An ISP is an organization that connects its subscribers’ computer using modem to the Internet. The connections can be provided by telephone lines, cable lines, or wireless connections. In order to use the Internet connection, the user has to first log on to the host computer using the username and password provided by the ISP. Some of the well-known ISPs are America Online (AOL), Microsoft Network (MSN), Yahoo!, etc.

Web server

            A server is a computer equipped with server software, which provides a specific kind of services to client software running on other computers. It can refer to a particular piece of software, for example, a Web server, or to a machine on which the server software is running. A Web Server receives request from the clients, processes this request, and sends the result back to the client.

Download and Upload

            Download refers to the act of transmitting data from a remote computer on the Internet or other network to one’s own computer. When the user downloads a file, he/she is actually copying a particular file from the remote computer and placing it on his/her hard drive. Downloading allows a user to save file for later use, thereby reducing the time spent online and the corresponding charges.

            Upload is just the opposite of download. Upload refers to the act of transmitting data from local computer to any other computer on the Internet or network. For example, a software company may upload a demonstration of its new software onto the Web so that users can then download the software.

Online and Offline

            The term online is commonly referred to the state of being connected to the networked computer system or Internet. For example, if you are browsing the WWW, your computer said to be online. Being online also refers to any peripheral device (like printer) that is connected to the system and ready to use.

            Offline is just the opposite of online; it refers to the state of not being connected to the remote computer, or internet. A printer or other peripheral that is not ready to use is also considered offline. 

Internet Applications

            Internet has grown from a small network to biggest network of computers. Due to this colossal growth, the Internet has become the biggest domain of information. Internet user has access to a wide variety of services such as e-mail, file transfer, vast information resources, interest group membership, interactive collaboration, multimedia displays, real-time broadcasting, shopping opportunities, and much more.

Electronic Mail (E-mail)

            Electronic mail, or e-mail, is a fast, easy, and inexpensive way to communicate with other Internet users around the world. It is one of the basic and earliest services of the Internet and the most used application on the Internet too. E-mail overcomes most of the problems and delays of getting a physical document from one person to another. Rather, it has the dual advantage of not only being faster but cheaper to use as well.

File Transfer Protocol (FTP)

            The FTP is a set of rules that enables a user to transfer files from one system to another. It was the first service developed for the Internet so that government and educational institutions could easily exchange files. It allows the user to get access to the files stored in the directory of a remote computer that is connected to the Internet. Using FTP, one can upload and download files from the remote computer (known as FTP servers), if he/she has access permission on the remote machine. Though files can be transferred using e-mail, this is not a good choice if the file size is large or when there are many files. FTP sites can consist of hundreds to thousands of files with information on books, music, software, games, images, sounds, multimedia, course ware, etc. FTP can be done using the command prompt, browsers, and various GUI-based FTP software such as CuteFTP and WS_FTP.

Telnet

            The word “telnet” is derived from telecommunications and network and is a protocol that allows a user to log on to a remote computer. Telnet is also known as remote login, which means connecting one machine to another in such a way that a person may interact with another machine as if it is being used locally. It means that someone in New Delhi could connect to a computer in the New York City Public Library and search the card catalogue the same way as someone located at a terminal in the library. Once connected, the user’s computer emulates the remote computer. When the user types in commands, they are executed on the remote computer.

Internet Relay Chat (RC)

            IRC or Internet Relay Chat is a service on the Internet that allows people to communicate in real time and carry on conversations via the computer with one or more people. It provides the user with the facility to engage in simultaneous (synchronous) online “conversations” with other users from anywhere in the world. Unlike other forms of group communication on the Internet, chat is an instant communication. However, both parties must be connected to the Internet and that too at the same time, running the right software and actively participating in order to chat            Generally, the user runs a program (called “client”) to connect to an IRC server. The server relays information to and from other servers on the same net. Popular IRC client applications are mIRC.

Chatting and Instant Messaging

            Chat programs allow users on the Internet to communicate with each other by typing in real time. They are sometimes included as a feature of a Web site, where users can log into chat rooms to exchange comments and information about the topics addressed on the site.

            A variation of chat is instant messaging where a user on the Web can contact another user currently logged in and type a conversation. To avail this Internet service, the user must have software called instant messenger installed on the system. Instant messaging is just as if making a text-only telephone call over the Internet, that is, the user is “talking” to the other person (possibly more) instantly. There are various products out there for instant messaging such as MSN Messenger and Yahoo Messenger.

Internet Telephony

            Internet telephony is the use of the internet rather than the traditional telephone company infrastructure, to exchange spoken or other telephonic information. It consists of hardware and software that enable people to use the Internet as a transmission medium for telephone calls. There are many Internet telephony applications available. Some applications such as CoolTalk and NetMeeting come bundled with popular Web browsers.

Video Conferencing

            Video conferencing uses the same technology as IRC, but also provides sound and video pictures. It enables direct face-to-face communication across networks. A video conferencing system has two or more parties in different locations, which have the ability to communicate using a combination of video, audio, and data. A video conference can be person to person (referred to as “point-to-point”) or can involve more than two people (referred to as “multipoint”), and the video conferencing terminals are often referred to as “endpoints”.

            The following five elements are common to all video conferencing endpoints:

v  Web Camera: It captures live images to send across the network.

v  Visual Display: It displays the images of the people taking part in the video conference.

v  Audio System: It includes both microphones to capture audio from the endpoint and loudspeakers to play back the audio received from other endpoints across the network connection.

v  Compression: Videos are very bandwidth intensive and they take a long time to load. Therefore, video systems include technologies, often referred to as codecs, to compress and decompress video and audio data, allowing transmission across a network connection in near-real time.

v  User Interface and Control System: The user interface allows the users to control interactions, for example, placing calls, storing and locating numbers, and adjusting environment settings such as volume. The control system handles the underlying communication that takes place between endpoints.

Commerce through the Internet

            E-commerce refers to buying and selling goods and services online. It integrates communication, data management, and security capabilities, which allow organizations to exchange information about the sales of goods and services. Essentially, it is the end-to-end digital exchange of information needed to conduct business including electronic data interchange (EDI) and electronic funds transfer (EFT). EDI is the computer-to-computer exchange of routine business transactions including payments, information exchange, and purchase order requests. EFT is a technology that allows the transfer of funds from the bank account of one person or organization to that of another.

            Developments in software mean that an increased number of facilities are becoming available all the time. Some of the well-known e-commerce sites are http://www.amazon.com and http://www.ebay.com.

            The increased use of mobile devices such as PDAs (personal digital assistants) and mobile phones has opened a new horizon of proliferation in the electronic market and has coined a new term “mobile commerce”. Mobile commerce or M-commerce refers to transactions through a mobile phone network and data connection that result in the transfer of value (monetary or otherwise) in exchange for goods and services. Mobile commerce has evolved as a new and simpler concept to operate financial transaction through mobile phones and it includes services such as banking, payment, and ticketing. M-commerce users may view and interact with information that appears through SMS (short message service), WAP(wireless application protocol), or a standard HTML browser on a PDA, web-enabled mobile phone or laptop computer connected to a mobile phone on a wireless network.

Newsgroups (Usenet)

            Newsgroups are international discussion groups that focus on a particular topic and helps in gathering information about that topic. The topics discussed here cover all the fields such as politics, computers, technology, and many more. The information or articles that make up the “news” are written by people interested in a specific topic.

Newsgroups provide a source of information and a medium through which users can ask questions from the Internet community. They provide a forum for users to discuss topics of mutual interest. It is normal to post the rules, restrictions, and subject matter for the newsgroup in a message called frequently asked questions (FAQ). To simplify the selection of suitable newsgroup, they are divided into subject classifications known as top-level categories.

Newsgroups Prefixes and Forums

Prefixes	Forums
Biz	Business
Comp	Computers and software
News	News and topical subjects
Rec	Recreation and entertainment
Sci	Science
Soc	Social issues and socializing
Talk	Debate and discussion
Misc	Anything else

Mailing Lists (Listserver)

            The internet is home to a large community of individuals who carry out active discussions, organized around topic-oriented forums that are distributed via e-mail. This method of Internet communication is known as mailing list and it enables people with similar interests from all over the world to communicate and share information with each other. The mailing list groups are administered by a software program known as listserver. There are varieties of programs available such as Listserv and Majordomo. A listserver watches for incoming mail on a certain mailbox continuously and forwards any message to a list of other addresses. Such a mailing list can bring people together with a common interest.

Web Browsers

Web Browsers are software installed on your PC. To access the Web, web browser, such as Netscape Navigator, Microsoft Internet Explorer or Mozilla Firefox. On the Web, when you navigate through pages of information, this is commonly known as web browsing or web surfing.

There are four leading web browsers − Explorer, Firefox, Netscape, and Safari, but there are many others browsers available. While developing a site, we should try to make it compatible to as many browsers as possible. Especially sites should be compatible to major browsers like Explorer, Firefox, Chrome, Netscape, Opera, and Safari.

Internet Explorer

Internet Explorer (IE) is a product from software giant Microsoft. This is the most commonly used browser in the universe. This was introduced in 1995 along with Windows 95 launch and it has passed Netscape popularity in 1998.

Google Chrome

This web browser is developed by Google and its beta version was first released on September 2, 2008 for Microsoft Windows. Today, chrome is known to be one of the most popular web browser with its global share of more than 50%.

Mozilla Firefox

Firefox is a new browser derived from Mozilla. It was released in 2004 and has grown to be the second most popular browser on the Internet.

Safari

Safari is a web browser developed by Apple Inc. and included in Mac OS X. It was first released as a public beta in January 2003. Safari has very good support for latest technologies like XHTML, CSS2 etc.

 

Opera

Opera is smaller and faster than most other browsers, yet it is full- featured. Fast, user-friendly, with keyboard interface, multiple windows, zoom functions, and more.

  The Internet Explorer Toolbar

 

The main toolbar is composed of eleven different buttons. Each of these buttons has a different function and purpose in Internet Explorer.

1.      The Back Button :  This button will take you back to whatever document you were previously viewing. Pressing it immediately takes you back one document. If you have browsed many pages, or are well into a multi-page document, pressing it repeatedly will continue to back you up one page at a time. Once you reach your starting location, it will be greyed-out and unavailable.

2. The Forward Button :  This button will take you forward to the next document if you have previously browsed multiple documents and had then backed-up to the page you are currently viewing. Pressing it repeatedly will continue to move you forward one page at a time. You can move forward until you reach the last page that you had browsed, at which time the forward button will be greyed-out.
3. The Stop Button :  The stop button stops ANY current operations by Internet Explorer. It will stop any type of file from loading. It can also be used to stop animations from continuing once a page is loaded. If you press it before a page has finished loading, the page will display everything it had finished loading before the stop button was pressed. If a document is completely loaded and there are no animations, movies, or other files still running, the stop button will have no immediate function.
4. The Refresh Button:  This button will reload the current document that you are viewing. It is useful if the page updates very frequently so that you can view these changes as soon as they are available. If you are loading a document and the transfer was interrupted, you can reload the full document again by clicking here.
5. The Home Button:  This button will return you to the page you have selected as the default start-up page for Internet Explorer. It will not take you back to the beginning of your web browsing, it will just return you to your home location from where you are. If you press back after reaching your home page, you will go back to the page you left after you hit the Home button.
6. The Search Button:  This button will take you to the page you have selected as the default Web search page for Internet Explorer. If you have not selected a page it will take you to Microsoft's default search page.
7. The Favorites Button:  This button will open up the Favorites menu. You can choose a favorite that you wish to go to from the list, add a favorite to the list, or organize your favorites from this menu.
8. The Print Button:  The print button will bring up a Print dialog box. In the box you can decide if you would like to print the contents of the page you are viewing, how many pages you will print, and also how many copies you will print.
9. The Font Button :  Pressing this button causes Internet Explorer to cycle through the available font sizes. This button is useful if the text is too small to read, or too large to fit comfortably in the window.
10. The Mail Button:  This button will open into a drop down menu from which you can select to read or send E-Mail. You can also open up your newsgroups from this menu.
11. The Edit Button:  This button will ONLY be on your toolbar if you have a Windows system Web editor (such as Microsoft Frontpage or Microsoft Word) installed on your computer. If you press this button, it will launch that editor and open the document you are currently viewing in it.

 Email

E-mail is an electronic version of sending a letter. You can send e-mail from your computer at any time of the day to any address around the world and your electronic letter will arrive at its destination seconds after you send it... even if the receiver lives on the other side of the world.

The receiver has to "pick-up" their mail - usually this means dialing their local Internet Service Provider to check their mail box before they will receive your e-mail. Today many people use broadband Internet connections that are "always on", and often work with computers daily, meaning they receive their e-mail more regularly.

E-mail is one of the most popular applications on the Net. It is a cheap and effective way to keep in touch with friends and family. To send a letter in Australia costs 50 cents (excluding the cost of paper for the envelope and letter), whereas, providing you have a computer, e-mail costs virtually nothing.

To use e-mail, you need software called a "mail client". Often people use "Outlook Express" or "Eudora Pro" for Windows machines or "Claris Emailer" for Macintosh computers.

The mail client simply allows you to:

·         compose e-mail to send to your ISP to be forwarded to your addressee,

·         to receive e-mail,

·         to read and file mail that has been sent and received,

·         to manage e-mail addresses of your contacts.

Your E-mail Address

Your e-mail address is usually your user name, followed by an @ sign, followed by the domain name of the Internet Service Provider (ISP) through which you are connecting to the Internet.

If your name is "Mary Smith" and your user name is "msmith", and you are connecting through the ISP Ozemail, your e-mail address will be "msmith@ozemail.com.au".

Like a URL on the web, the "ozemail.com.au" is the domain name of the server you will dial to send and receive your e-mail. The "ozemail" is the name of the service provider, the "com" means "company" or "commercial", the "au" denotes "Australia" (if you left the "au" off the end then the e-mail message might be delivered to a mail server in America if there happen to be a "ozemail.com" domain name server there).

Information from your ISP

You will need 5 things before your e-mail software will be able to locate your ISP's mail servers and send and receive mail:

1.      an Internet connection (dial up or broadband, it doesn't matter which type).

2.      the name of your POP (Post Office Protocol) server. The POP server is your inbound mail server - it receives your e-mail. This is often the domain name preceded with the word "mail". e.g. mail.ozemail.com.au

3.      the address of the SMTP (Simple Mail Transfer Protocol) server. A SMTP server sends your e-mail. This is often the domain name preceded with the word "mail" or "smtp". e.g. mail.ozemail.com.au

4.      Your user name. "msmith" in the example above

5.      your password

Search Engines:             

            The internet access to a wealth of information on countless topics contributed by people throughout the world. However, the Internet is not a library in which all its available items are identified and can be retrieved by a single catalogue. In fact, no one knows how many individual files (could be in billions) reside on the Internet. Hence, to conduct a search on the Internet, a special search tool known as search engines is used. Search engine searches a database of Internet files collected by a computer program called a wanderer, crawler, or spider. It allows the user to enter keywords relating to particular topics and retrieve information about the Internet sites containing those keywords. Some of the well-known search engines are www.google.com, www.hotbot.com, www.lycos.com and www.altavista.com. As such, a search engine consists of four components:

1. Spider: Program that traverses the Web from link to link, identifying and reading pages.

2. Indexing Software: Program that analysis web pages that are download by spiders.

3.Database: Warehouse of the web pages downloaded and processed.

4. Search Engine Mechanism: Software that enables users to query the index and that usually returns results in term relevancy ranked order

Refining the Search

            The user can refine the search by adding one or more words or symbols to the search topic.

v  AND: It is used to search for two or more terms on the same page. Type the word AND between the terms (for example, poverty AND crime) or put a plus sign right before the second term (example:poverty+crime).

v  OR: It is used to search for either of two (or more) terms on the same page. Type the word OR between the terms (for example, college OR university).

v  NOT: It is used to search for pages that include the first term but not the second. Type the words NOT between the terms (for example, cats NOT dogs) or put a minus sign right before the second term (for example, cats-dogs).

v  “”: Double quotes are used to search for an exact phrase. For example, “desktop wallpapers”.

v  (): Parentheses are used to group parts of the search phrase. For example, type desktop AND (themes OR wallpapers). This returns pages with the words desktop and themes or both the words themes and wallpapers.

v  *:Asterisk is used to search for various forms of a word For example, prior* returns pages with the words prior, prioritize, priority, and so on.

Instant Messaging

            Instant messaging is a web-based service to exchange messages in real time between two or more people over the Internet. It is a combination of e-mail and chat room. For sending instant messages, users create a list of users with whom they wish to communicate. The messages sent through this service take less time and the delivery of messages is instantaneous. However, to send and receive instant messages, Internet connection along with instant messaging software (known as instant messengers), such as Yahoo Messenger or MSN Messenger, is required. Instant messenger is one of the most popular Internet tools, which allows the users to communicate over the Internet through voice, live pictures, or text. It is free and faster than e-mail because instant messages can be sent to friends whether they are online or offline. It allows the users to carry multiple conversations at a time.

Features of Messenger

            The features of messenger that make it a favorite among Internet users include:

v  Chatting: With a messenger, one can chat using a webcam or microphone and send textual messages. In addition, users can find and meet people instantly.

v  Audible: Audible are faces used to say something or express the attitude of the user in the form of greetings, games, and fun. These audible are used for sending verbal animations directly from the instant messaging application.

v  Emoticons/Smileys: The emoticons or smileys are used to express the feelings in the form of little symbols and smiling faces.

v  Games: When connected online, users can play multi-player games such as chess, checkers, and many more. Users can even see how they stack up against their friends by comparing their scores.

v  Address Book: Messengers also provide address books so that users can easily find and manage their friend’s contact details.