INFORMATION AND COMMUNICATION TECHNOLOGY

UNIT-I

What is Internet

The Internet, sometimes called simply "the Net," is a worldwide system of computer networks -- a network of networks .Today, the Internet is a public, cooperative and self-sustaining facility accessible to hundreds of millions of people worldwide. Furthermore, e-commerce, or online shopping, has become one of the largest uses of the Internet.

The Internet can be seen as having two major components: network protocols and hardware.

 

Uses of the internet

In general, the Internet can be used to communicate across large or small distances, share information from any place in the world and access information or answers to almost any question in moments.

Some specific examples of how the Internet is used include:

·         Social media and content sharing;

·         E-mail and other forms of communication, such as Internet Relay Chat (IRC), Internet telephony, instant messaging, video conferencing

·         education and self-improvement through access to online degree programs, courses and workshops and

·         searching for jobs -- both the employer and applicant use the Internet to post open positions, apply for jobs and recruit individuals found on social networking sites like LinkedIn.

Other examples include:

·         Online discussion groups and forums

·         Online dating

·         Online gaming

·         Research

·         Reading electronic newspapers and magazines

·         Online shopping, or e-commerce.

Applications of Internet

• Sending and receiving email
• Searching and browsing information archives
• Copying files between computers
• Conducting financial transactions
• Navigating (in your car, smart scooter, smart bike, or other)
• Playing interactive games
• Video and music streaming
• Chat or voice communication (direct messaging, video conferencing)

Internet Addressing:

• Every device connected to the Internet has at least one IP address.
• When devices are attached to the global Internet, they are assigned addresses that must be coordinated so as to not duplicate other addresses in use on the network.

Expressing IP Addresses

In IPv4, the dotted-quad notation for IPv4 addresses consists of four decimal numbers separated by periods. For example, 165.195.130.107. Each such number is a nonnegative integer in the range [0, 255] and represents one-quarter of the entire IP address.

                      The most common domain extensions currently available and officially approved are shown in the following list. Countries also have domain names such as .uk, .au, and .fr (United Kingdom, Australia, and France, respectively), and there is a new class of “internationalized” top-level domains that use non- English characters (ICANN, 2010). In the future, this list will expand to include many more types of organizations and industries.

The Domain Name System

Because it would be incredibly difficult for Internet users to remember strings of 12 numbers, the Domain Name System (DNS) converts domain names to IP addresses. The domain name is the English-like name that corresponds to the unique 32-bit numeric IP address for each computer connected to the Internet.

DNS servers maintain a database containing IP addresses mapped to their corresponding domain names. To access a computer on the Internet, users need only specify its domain name. DNS has a hierarchical structure .

 

 At the top of the DNS hierarchy is the root domain. The child domain of the root is called a top-level domain, and the child domain of a top-level domain is called is a secondlevel domain. Top-level domains are two- and three-character names you are familiar with from surfing the Web, for example, .com, .edu, .gov, and the various country codes such as .ca for Canada or .it for Italy. Second-level domains have two parts, designating a top-level name and a second-level name—such as buy.com, nyu.edu, or amazon.ca. A host name at the bottom of the hierarchy designates a specific computer on either the Internet or a private network.

this list will expand to include many more types of organizations and industries.

.com Commercial organizations/businesses

.edu Educational institutions

.gov U.S. government agencies

.mil U.S. military

.net Network computers

.org Nonprofit organizations and foundations

.biz Business firms

.info Information providers

URL:Definition

A Uniform Resource Locator (URL) is a set address for locating a unique resource on the internet, such as a file or an app. It is recognizable for users as the string of text which is shown in the browser address bar of every web page, or which links a user to another internet location. A URL is a type of Uniform Resource Identifier (URI).

URL Components:

 

A typical website has at least 3 parts in its URL like www.google.com but some complex URLs might also have 8 to 9 parts namely scheme, subdomain, domain name, top-level domain, port number, path, query, parameters, and fragment.

Components of a URL

1. Scheme :

 

https://

The protocol or scheme part of the URL and indicates the set of rules that will decide the transmission and exchange of data. HTTPS which stands for Hyper Text Transfer Protocol Secure tells the browser to display the page in Hyper Text (HTML) format as well as encrypt any information that the user enters in the page. Other protocols include the FTP or File Transfer Protocol which is used for transferring files between client and server, SMTP or Single Mail Transfer Protocol which is used for sending emails.

 

2. Subdomain :

https://www.

The subdomain is used to separate different sections of the website as it specifies the type of resource to be delivered to the client. Here the subdomain used ‘www’ is a general symbol for any resource on the web. Subdomains like ‘blog’ direct to a blog page, ‘audio’ indicates the resource type as audio.

 

3. Domain Name :

https://www.example.

Domain name specifies the organization or entity that the URL belongs to. Like in www.facebook.com the domain name ‘facebook’ indicates the organization that owns the site.  

 

4. Top-level Domain :

https://www.example.co.uk

The TLD (top-level domain) indicates the type of organization the website is registered to. Like the .com in www.facebook.com indicates a commercial entity. Similarly, .org indicates organization, .co.uk a commercial entity in the UK.

 

5. Port Number :

https://www.example.co.uk:443

A port number specifies the type of service that is requested by the client since servers often deliver multiple services. Some default port numbers include 80 for HTTP and 443 for HTTPS servers.

 

6. Path :

https://www.example.co.uk:443/blog/article/search

Path specifies the exact location of the web page, file, or any resource that the user wants access to. Like here the path indicates a specific article in the blog webpage.  

 

Searching the internet:

 

Go to a search engine. A search engine is a website that collects and organizes information on the internet and makes it available for searching. Search engines use algorithms to display the most relevant search results based on trends, your location, and sometimes even your web activity. Many search engines have their own mobile apps that make searching easier on your phone or tablet. Check out some of the most popular search engines:

·      Google is the most popular search engine in the world.[1] It's so popular that the word "Googling" is often used in place of "searching the web." Google also has special image and video search features that make it easy to find all sorts of media.

·      Bing is Microsoft's answer to Google, and the second most popular search engine. Many of Google's functions, like image and video searching, are also available on Bing.[2]

·      Yahoo used to be the largest search engine in the world. These days, it's powered by Bing and delivers similar results.

·      DuckDuckGo is a privacy-focused search engine that doesn't collect or store your personal information. In fact, this search engine is so privacy-focused that it doesn't even look at your location or IP address.

·      Startpage.com is another search engine focused on privacy, but it uses Google's search engine in the background instead of its own program.[3] The benefit is that you'll get Google's excellent quality results without sacrificing your personal data.

·      Swisscows is another privacy-focused search engine, but it uses its own software that gives relevant results influence by semantics.[4]

·      Yandex is one of the most popular search engines in Russia, but the English version has gained traction in other countries, including the United States.

Browser:

A web browser or Internet browser, a browser is a software program to present and explore content on the World Wide Web. These pieces of content, including pictures, videos, and web pages, are connected using hyperlinks and classified with URIs (Uniform Resource Identifiers). This page is an example of a web page that can be viewed using a browser.

Types of  Browsers

1. Google Chrome

Google Chrome is the most popular browser that people use today. The main reason for this is its speed. It’s a fast browser. It opens quickly and loads multiple tabs and pages in just one click. It’s probably the fastest browser available today.

2. Mozilla Firefox

Firefox was slower than Chrome. And this is why it stayed the second choice for many people. But that was several versions ago. The new Firefox is faster and smoother. If you don’t like Chrome because it’s a Google based product, you can switch to Firefox. 

3. Opera

Opera is another popular name in the browser industry. While it has several attractive features (such as an inbuilt adblocker), it generally stays behind the two most popular browsers. But this shouldn’t mean you shouldn’t try Opera. 

While Chrome and Firefox allow users to have a number of third party extensions, Opera has its own range of extensions that users might want to check out. Opera supports several major apps like Facebook messenger and Whatsapp. 

4. Apple Safari

Safari is a simple and clean browser with several features that make it a popular choice. It offers all the basic functionalities – the ability to open multiple tabs, easy bookmarking, fast speeds, and a plugin library. 

 

These were the common browsers that most people use. But as users become aware of the importance of their online privacy, they have started preferring private browsers that keep their data secure.

 

(Refer networking sites in notes- Twitter, Tumblr, LinkedIn, Facebook,flickr,skype,yahoo.youtube,whatsapp)

Unit-II

Working of E-mail

Email

Email is a service which allows us to send the message in electronic mode over the internet. It offers an efficient, inexpensive and real time mean of distributing information among people.

E-Mail Address

Each user of email is assigned a unique name for his email account. This name is known as E-mail address. Different users can send and receive messages according to the e-mail address.

E-mail is generally of the form username@domainname. For example, webmaster@tutorialspoint.com is an e-mail address where webmaster is username and tutorialspoint.com is domain name.

·         The username and the domain name are separated by @ (at) symbol.

·         E-mail addresses are not case sensitive.

·         Spaces are not allowed in e-mail address.

Elements of an Email Message(message Composition)

When you think of an email message, you might think of the person you’re sending it to and what you’re going to say. However, an effective email has many more elements than these few. Double check these parts before sending your next email.

1. Subject Line

What is the email about? A good subject line summarizes the email and makes it sound important enough for the reader to open. Subject lines like “Hello” or “Meeting” are vague and make it difficult to know what the email will be about.

2. Sender

The email address of the person who sent the message appears here. Most email services display the person’s name before their email address to make it easier to identify them. When you press “reply,” your email will only go to this person.

3. Recipient

If you are receiving the message, your email address probably won’t appear here. Instead, you might see wording like “to me.” Message recipients might also include email addresses in these sections:

• Carbon Copy (CC) – people who receive the email for their own information, but who are not expected to reply. When you press “reply all,” all of these addresses receive your response.
• Blind Carbon Copy (BCC) – people who receive the email but are not listed as recipients. Senders use the BCC section if they don’t want recipients to know who else has received the email. They do not receive “reply all” responses.

4. Salutation

After the subject line, your email salutation, or greeting, is the next part that the recipient will see. It should match the tone you’re trying to set in the rest of your email. Don’t skip this part unless you are emailing back and forth quickly with someone in a virtual conversation.

5. Email Body

The email body contains the message of the email. Effective emails keep their email bodies short and add more extensive information to the attachments. For formal emails, such as messages to an employer or emails to your teacher, it’s best to avoid common email abbreviations.

6. Closing

If an email message is an electronic letter, it’s polite to end it with a closing. The closing you choose should match the tone of the rest of the email. Formal closings include “Sincerely” and “Thank you,” while more friendly messages can use “Talk to you soon!” or “See you later!”

7. Signature

Friendly letters might sign off with the sender’s name. But many business email accounts have signature sections that include the sender’s position, company and even company logo. These extended signatures are helpful when reaching out to clients or employees from other companies.

8. Attachments

An email might include an attachment that provides more information. The attachment could be a document for review, a picture to share or any other file type. Most email accounts have limits on the size of attachments, so the sender might add the file to the email body itself rather than attaching it.

                                                                              

Advantages

E-mail has prooved to be powerful and reliable medium of commmunication. Here are the benefits of E-mail:

·         Reliable

·         Convenience

·         Speed

·         Inexpensive

·         Printable

·         Global

·         Generality

Reliable

Many of the mail systems notify the sender if e-mail message was undeliverable.

Convenience

There is no requirement of stationary and stamps. One does not have to go to post office. But all these things are not required for sending or receiving an mail.

Speed

E-mail is very fast. However, the speed also depends upon the underlying network.

Inexpensive

The cost of sending e-mail is very low.

Printable

It is easy to obtain a hardcopy of an e-mail. Also an electronic copy of an e-mail can also be saved for records.

Global

E-mail can be sent and received by a person sitting across the globe.

Generality

It is also possible to send graphics, programs and sounds with an e-mail.

Disadvantages

Apart from several benefits of E-mail, there also exists some disadvantages as discussed below:

·         Forgery

·         Overload

·         Misdirection

·         Junk

·         No response

Forgery

E-mail doesn’t prevent from forgery, that is, someone impersonating the sender, since sender is usually not authenticated in any way.

Overload

Convenience of E-mail may result in a flood of mail.

Misdirection

It is possible that you may send e-mail to an unintended recipient.

Junk

Junk emails are undesirable and inappropriate emails. Junk emails are sometimes referred to as spam.

No Response

It may be frustrating when the recipient does not read the e-mail and respond on a regular basis.