Internet explorer

Internet explorer is a default web browser for Windows operating system installed computers or tablets. To open internet explorer go to start button  select all programs  select internet explorer (or) double click the internet explorer icon on the desktop, then the internet explorer window will appear. The internet explorer window is:

The parts of the internet explorer are: title bar, menu bar, tool bar, address bar, web page area and status bar.

 The title bar displays the name of the webpage or website you have opened.

 The menu bar contains menus like file, edit, view favorites, tools, and help, each menu contains its own options.

 Tool bar contains short cut buttons to menu options, which speedup your work.

 In the address bar you have to type the address of the website, and then press enter key. The website will open and the contents of the web site or web page are displayed at web page area.

 The status bar displays the status about the internet explorer.

Back button: Your web browser keeps a stack of the web pages that you have visited in that window. Let's say your home page is google.com and from there you visit a few other websites: youtube.com, yahoo.com, and cnn.com. Upon visiting the last one, the list looks like this:

google.com -> youtube.com -> yahoo.com -> cnn.com

                                                                                    ^

                                                                                    |

                                                                         current page

When you press the Back button, the browser takes you back to the previous page in

the list, like this:

google.com -> youtube.com -> yahoo.com -> cnn.com

                                                              ^

                                                              |

                                                    current page

Forward Button: when you press the forward button, the browser takes you forward to the current page in the list, like this

google.com -> youtube.com -> yahoo.com -> cnn.com

                                                                 ^

                                                                 |

                                                        current page

google.com -> youtube.com -> yahoo.com -> cnn.com

                              ^

                              |

                     current page

Stop Button: If you want to stop loading the current web page then press stop button.

Refresh Button: the web page you have typed at address bar is not fully displayed at web page area or the links are not properly working, etc. in these cases you have to press refresh button to reload the webpage.

Home Button: the internet explorer lets you set one web page as your home page, this page will automatically opened when the internet explorer window is opened. If you want to open your home page at any time then press home button.

Entering a website address:

The area which is dedicated to enter the website address in the internet explorer is address bar. Put cursor at the address bar then type the address of the website you want to open.

                          www.facebook.com

For example if you want to open Facebook website then type www.facebook.com in the address bar and then press the enter button the Facebook page will displayed at web page area in the browser

Searching the internet:

By using the search engines, searching the information on the internet is easy. Search engine is an approach to organize the information and locating the information on the web, which is a computer program.

Popular search engines are: www.google.com, www.ask.com, www.alltheweb.com, etc. for example you want to search about the applications of internet on the internet. Then you have followed these steps:

 Enter the website of the search engine at the address bar for example www.google.com

 After Google page opened then type “applications of internet” at the search box and then press enter button on the keyboard.

 The Google will search about “applications of internet” in its server and displays some results.

 Open the results one by one; in any one of them you got the relevant information.

Introduction to Social networking:

Social networking on social media websites involves the use of the internet to connect users with their friends, family and associates. Social media websites are not necessarily about meeting new people online, although this does happen. Instead, they are primarily about connecting with friends, family and associates you already have in real life.

The most well-known social media sites are Facebook, Twitter, Instagram and LinkedIn. These sites allow you to share photos, videos and information, organise events, chat, and play online games. Concepts in the social media are:

• Your Profile Page: When you sign up to a social media site you need to provide your email address to verify your identity. This will automatically create your profile page. Depending on the social media site you're using, a profile page usually allows you to post a picture and a few general details about you and your interests. Your friends will be able to see your profile page and the information that you share. They will also be able to leave comments or share information with you on your profile page.

• Privacy: Social media sites have a variety of privacy settings you can adjust. This means you can control who sees your profile page and other information you share on the site. Some people do not mind having their personal information available for anyone to view online. However, we strongly recommend that you don't publish your home address and be mindful of posting other personal information about yourself (including your birthday), or others especially if you don't have their permission.

• Friends: The whole point of joining social media websites is to be in touch with your friends and family. "Friends" in the context of social media, and Facebook in particular, has a specific meaning. For example, for you to interact online with a friend, family member or associate either one of you must first send a "friend request" to the other and then have that request accepted. Once accepted, the technology recognises you as "friends" and you can interact with each other online, so you can view the other person's profile page, see their pictures, and send them messages.

* Twitter: is an online social networking service that enables users to send and read short 140-character messages called "tweets". Registered users can read and post tweets, but those who are unregistered can only read them. Users access Twitter through the website

interface, SMS or mobile device app

Twitter was created in March 2006 by Jack Dorsey, Evan Williams, Biz Stone, and Noah Glass and launched in July 2006. The service rapidly gained worldwide popularity; it was one of the ten most-visited websites and has been described as "the SMS of the Internet". As of March 2016, Twitter has more than 310 million monthly active users.

*Tumblr:Tumblr is a micro-blogging and social networking website founded by David Karp in 2007, and owned by Yahoo! since 2013. The service allows users to post multimedia and other content to a short-form blog. Users can follow other users' blogs. Bloggers can also make their blogs private.

Linkedin: LinkedIn is a business-oriented social networking service. Founded on December

14, 2002, and launched on May 5, 2003, it is mainly used for professional networking. As of

2015, most of the site's revenue came from selling access to information about its users to

recruiters and sales professionals. As of March 2016, LinkedIn has more than 433 million users, out of which more than 106 million are active.

Facebook: Facebook is an online social networking service based in Menlo Park, United States. The Facebook website was launched on February 4, 2004 by Mark Zuckerberg, along with fellow Harvard College students and roommates, The founders had initially limited the website's membership to Harvard students; however, later they expanded it to higher education institutions in the Boston area,

Users can create a user profile, add other users as "friends", exchange messages, post status updates and photos, share videos, use various applications (apps), and receive notifications when others update their profiles. Additionally, users may join common-interest user groups organized by workplace, school, or other topics, and categorize their friends into lists such as "People from Work" or "Close Friends". In groups, editors can pin posts to top.

Flickr: Flickr is an image hosting and video hosting website and web services suite that was created by Ludicorp in 2004 and acquired by Yahoo in 2005. In addition to being a popular website for users to share and embed personal photographs, and effectively an online community, the service is widely used by photo researchers and by bloggers to host images that they embed in blogs and social media.

Skype: Skype is an application that provides video chat and voice call services. Users may exchange such digital documents as images, text, video and any others, and may transmit both text and video messages. Skype allows the creation of video conference calls. Skype is available for Microsoft Windows, Macintosh, or Linux, as well as Android, Blackberry, and both Apple and Windows smart phones and tablets. Skype Credit or a subscription is required to call a landline or a mobile phone number. At the end of 2010, there were over 660 million worldwide users, with over 300 million estimated active each month as of August 2015.

Yelp: Yelp is an American multinational corporation headquartered in SanFrancisco, California.  It  develops,  hosts  and  markets  Yelp.com  and  the  Yelp mobile  app,  which

publish crowd-sourced reviews  about  local  businesses,  as  well  as  the  online  reservatio service SeatMe and online  food-delivery  service Eat24.  The  company

also  trains small businesses in how to respond to reviews, hosts social events for reviewers, and provides data about businesses, including health inspection scores.

Vimeo: Vimeo is  a video-sharing website in  which  users  can  upload, share and view videos. It  was the first video  sharing site  to  support high-definition  video. Vimeo was founded in November 2004 by Jake Lodwick and Zach Klein.

Yahoo!: Yahoo is   an American multinational technology   company headquartered in Sunnyvale, California.  It is  globally  known  for  its Web  portal, search  engine Yahoo!

 Search, and related services, including Yahoo! Directory, Yahoo! Mail, Yahoo! News, Yahoo!

Finance, Yahoo! Groups, Yahoo! Answers, advertising, online mapping, video

sharing, fantasy sports and its social media website. It is one of the most popular sites in the United States.

Yahoo was founded by Jerry Yang and David Filo in January 1994 and was incorporated

on March 2, 1995. Marissa Mayer, a former Google executive, serves as CEO and President

of the company.by Google Inc. The service, Google's fourth foray into social networking, experienced strong growth in its initial years, although usage statistics have varied, depending on how the service is defined. Three Google executives have overseen the product, which has undergone substantial changes leading to a redesign in November 2015.

YouTube: YouTube is a global video-sharing website headquartered in San Bruno, California, United States. The service was created by three former PayPal employees in February 2005. In November 2006, it was bought by Google for US$1.65 billion. YouTube now operates as one of Google's subsidiaries. The site allows users to upload, view, rate, share, and comment on videos, and it makes use of WebM, H.264 / MPEG-4 AVC, and Adobe Flash Video technology to display a wide variety of user-generated and corporate media video. Available content includes video clips, TV clips, music videos, movie trailers, and other content such as video blogging, short original videos, and educational videos.

Whatsapp:WhatsApp Messenger is a proprietary cross-platform, encrypted, instant messaging client  for smartphones. It  uses the Internet  to  send text messages,  documents, images,  video,  user  location  and  audio  messages  to  other  users  using  standard cellular mobile.  As  of  February  2016,  WhatsApp  had  a  user  base  of  one billion, making  it  the most popular messaging application.WhatsApp Inc.,  based in Mountain View,  California,  United States,  was  acquired by Facebook Inc. on February 19, 2014, for approximately US$19.3 billion.

Computer Viruses and its types & Browser

Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation. A virus might corrupt or delete data on your computer, use your e-mail program to spread itself to other computers, or even erase everything on your hard disk. Most Common Types of Viruses and Other Malicious Programs

• Resident Viruses: This type of virus is a permanent which dwells in the RAM memory. From there it can overcome and interrupt all of the operations executed by the system: corrupting files and programs that are opened, closed, copied, renamed etc

• Multipartite Viruses: Multipartite viruses are distributed through infected media and usually hide in the memory. Gradually, the virus moves to the boot sector of the hard drive and infects executable files on the hard drive and later across the computer system.

• Direct Action Viruses: The main purpose of this virus is to replicate and take action when it is executed. When a specific condition is met, the virus will go into action and infect files in the directory or folder that it is in and in directories.

• Overwrite Viruses: Virus of this kind is characterized by the fact that it deletes the information contained in the files that it infects, rendering them partially or totally useless once they have been infected.

• Boot Virus: This type of virus affects the boot sector of a floppy or hard disk. This is a crucial part of a disk, in which information on the disk itself is stored together with a program that makes it possible to boot (start) the computer from the disk.

A browser is a software application used to locate, retrieve and display content on the World Wide Web, including Web pages, images, video and other files.

Types of Browsers:

Web Browsers are software installed on your PC. To access the Web, you need a web browser, such as Netscape Navigator, Microsoft Internet Explorer or Mozilla Firefox.

• 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.

• 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 browsers 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, and more.

Internet and its services:

Internet: The internet is a global network that connects billions of computers all over the world. It is a network of networks. The internet links different organizations, academic institutions, government offices, and home users to share information among large group of users.

Internet services: Today the internet become a part of not only the big organizations, universities, and offices, but has become the need of home users all over the world. The internet services are:

E-Mail: Electronic mail or e-mail is a means of transmission of messages electronically over communication networks. E-mail is one of the most widely used services on the internet. Anyone who has e-mail account can send an e-mail to any other person who also has an e-mail account. Gmail.com, yahoomal.com, rediffmail.com, hotmail.com, etc. are provides the e-mail facility to the users.

File transfer protocol: File transfer protocol is one of the oldest applications of the internet, which is basically used for transferring files from one computer to another computer, such as from a user’s personal computer to a web server. It is the preferred method of exchanging files because it is faster and reliable.

Chatting: Chatting is a very popular service of the internet that allows two or more online users come together to talk using an instant messenger. Chatting helps users to stay connected with concerned people in business or family who live many miles away.

Electronic news paper: An online news paper is a newspaper on the internet, which is either published separately or as an online version of a printed periodical.

World Wide Web: the technical definition of the World Wide Web or simply web can be given as “all resources and users on the internet that are using the hypertext transfer protocol” on the web, all the documents are formatted in a special markup language is called HTML.

Online shopping: Online shopping refers to buying goods or services from merchants who sell on the internet.

Search engine: The World Wide Web stores enormous amount of information on an amazing variety of topics in hundreds of millions of pages.

Internet addressing:

Each computer and router on the internet must have a name so that it can be uniquely identified. An Internet addressing or Internet protocol address or IP address consists of 32 bits, or four bytes. IP addresses as four natural numbers from 0-255. It is common to express IP addresses as four natural numbers separated by dots. The network interface card NIC of every computer that wants to send or receive messages on the internet must have at least one address. This is similar to the need for you to have a unique address receive mail. On the internet, this address is called IP address. IP address is often expressed in the dotted decimal format, such as: 192.168.1.1

Internet applications:

• Search engine: It can be used to search anything and everything. Most popular search engines are Google and yahoo.

• Shopping: Shopping has become easier with the advent of internet. You can buy or sell online.

• Communication: This is a major role of the internet. It helps people to communicate either with the use of social networking websites or through e mails. Even chatting is a major use of the internet.

• Job search: Nowadays, many people search for their jobs online as it is quicker and there is a larger variety of job vacancies present.

• Studying: Now right from kinder garden children are exposed to internet and computers. They find many useful things to learn on the internet.

Data Communications - Types of Networks

“Data communication means sharing the information. This sharing can be local or remote or with in a building. Local communication usually occurs in face to face, while remote communication takes place over distance.”

Data communication is the exchange of data between the two devices via some of transmission medium. Data communication devices must be the part of the communication system made up of combination of hardware and software.

Components of data communication: The following are the five major components of data communication system.

Message: the information which is to be communicated.

Sender: it can be computer, workstation, telephone, etc.

Receiver: it can be computer, workstation, telephone, etc.

Medium: it is physical path by which the message travels from sender to receiver.

Protocol: it is the set of rules that govern the data communication.

Signals used in communication: different types of signals used in communication are analog and digital.

Analog signal: Analog refers to continues set of specific points of data and all possible points between. Analog signals can have any value in a range.

Digital signal: digital signal is discrete. It can have only limited number of defined value often as simple as 1 and 0. It is as a light being switched off and on. Digital signals can have only a limited number of values.

Types of Networking: there are three types of network. They are: Local area network (LAN), wide area network (WAN), Metropolitan area network (MAN).

Local area Network (LAN): when two or more computers are connected in a small are i.e. within a diameter of not more than a few kilometers then such network is known as local area network. It is made for an organization and most of the times it is within a single building. The data rate in LAN is in the form of Mbps. The characteristics of LAN are:

 it covers an area of less than 5 kilometers

 it provides high speed data communication

 They have low error rates.

 They use simple data communication protocols.

Wide area network (WAN): a wide area network is connection of two or more computers which are geographically dispersed. It has longer distance communications than LAN. It uses public networks like telephone network or microwave relays for communication facilities. A cost is involved with such networks so high mostly it is used by government agencies.

The characteristics of WAN are:

 It inter connects computers at different sites.

 it can connect two or more LAN’s too

 It operates nationwide or worldwide.

 Links are slow as compared to LAN’s i.e. 1200 kbps

Metropolitan area Network (MAN): it resides between LAN and WAN. It interconnects computer within a city. It uses dual queue dual bus protocol. The implementation for MAN provides transfer rates from 34 mbps which is not very slow as compared to LAN. They use broad band cables as transmission media. They also use fibre optical cable as transmission media.

Difference Between LAN MAN WAN

Networking concepts

Definition of Network: Two or more computers connected logically with the help of data communication devices and transmission media referred to as computer network.

Network Components: The important components used in the computer network are:

Media: It is the medium through which the data travels. The various alternatives for

Transmission media are: twisted pair cable, coaxial cable, fibre optics, etc.

Processor: Processor is the hardware which helps to transfer the data from source to

Destination. Different processors used in the data communication are: modem, router, bridge, etc.

Software: To transfer the data from source to destination we require software,

examples are: networking operating system software, internet explorer, etc.

Topology: It is the way which data travels, the various topologies available are: star, ring, bus, mesh, tree, etc.

Advantages: Advantages of computer network is:

Sharing: network lets you share the information with other computers on the network

Sharing resource: this means that you can setup certain computer resources like a disk drive or a printer that all of the computers on the network can access them.

Backup: all data is stored on the server, backing up the critical data is a simple process.

Disadvantage:

Crash: if the server crashes, then whole of the system will be disturbed.

Data integrity: As all the data is shared it is possible unauthorized person can access the data if the network security is poor or weakly implemented.

No privacy: network may also means loss of privacy. Especially your boss, with the right network privileges may be in the position to read your private email.