ICT

Key Unit Competency

By the end of this unit, you should be able to understand the rationale of a computer network and use the Internet efficiently and effectively.

Learning Objectives
Knowledge and understanding

By the end of this unit, you should be able to:

(i) Explain network and computer network terms.

(ii) Explain the role, advantages and disadvantages of a computer network.

(iii) Identify the common types of computer networks according to geographical areas.

(iv) Define the Internet and World Wide Web (www).

(v) Identify a webpage, web site, web browser, URL, and ISP.

(vi) Explain the importance of using the Internet in daily life.

(vii) Identify different methods used to connect to the Internet.

(viii) Explain the different types of search engines.

(ix) Identify and decipher search results on information from the Internet.

(x) Define and identify the advantages and disadvantages of using email.

Skills

By the end of this unit, you should be able to:

(i) Describe a computer network, the characteristics of a network, the role, and the advantages and disadvantages of a computer network. (ii) Classify a computer network according to geographical areas. (iii) Research Internet terms: Internet, World Wide Web (www), webpage, web site, web browser, URL, and ISP.

(iv) Apply different methods to connect to the Internet.

(v) Explore different search engines to perform searches on the Internet.

(vi) Apply and decipher search results using techniques to filter information from the Internet.

(vii) Create and manage an email account.

                                                                            165

Attitudes and values

By the end of this unit, you should be able to:

(i) Appreciate the importance and power of a computer network and the Internet on daily life.

(ii) Enjoy improved communication and research by using the Internet efficiently.

Keywords in the Chapter

Computer Network Concepts

Definition of Network

A network is generally described as a system or group of interconnected objects or people.

Definition of Computer Network

A computer network is a set of interconnected computing nodes which communicate with one another through a transmission medium using a set of rules. The nodes share resources and services. A computer network must have sharable resources, transmission medium and set of rules (protocols).
Node

                                                                        166

Characteristics of a Computer Network

The following are some characteristics of a computer network:

(i) Security: A network must provide protection data from unauthorised access, manipulation and implement policies for recovery from data loss.

(ii) Reliability: A computer network should work consistently to perform according to its requirement.

(iii) Transmission capacity: It must have two or more computing nodes connected using a transmission medium.

Role of a Computer Network

A computer network can be used to do the following:

(i) Store data centrally for ease of access and backup

. (ii) Communicate with other network users

. (iii) Share resources.

Advantages of a Computer Network

(i) Resource sharing: A computer network allows sharing of resources such as printers among the users in a network thus eliminating the need to have individual printers for each computer. This reduces the cost of purchasing and maintaining the resources.

(ii) Speed: A computer network provides a very fast means of sharing and transferring files thus saving time while maintaining file integrity.

(iii) Communication: A computer network provides the hardware necessary for exchanging information between the users in the network, for example, use of e-mail.

(iv) Work group computing: Many users in different geographical locations can work on a document or a project at the same time using workgroup software and hardware, thus saving time and traveling expenses.

(v) Security: A computer network allows administrators to manage critical data by regularly backing up and implementing security measures to control access to critical information.

(vi) Increased storage capacity: Many computers in a network provide a lot of memory that can be shared among the computers to increase the overall storage capacity.

(vii) Entertainment: A computer network supports multi-player computer games and entertainment.

                                                                                    167

Disadvantages of a computer network

(i) Expensive to install and maintain: High costs are involved in installing and maintaining the network, for example, the cost of cables, file servers, software and technical support services among others.

(ii) Failure of the server and other hardware: The whole network breaks down if the server fails and in some configurations, one broken cable or a malfunction of a node may terminate the functioning of the entire network.

(iii) Insecurity of information: Shared information in a network is exposed to hacking, cracking and eavesdropping among others.

(iv) Spread of computer viruses: Viruses can easily spread to other computers within a computer network.

Classification of computer network according to geographical areas

Types of Networks

There are four main types of computer networks classified according to geographical areas. They are Personal Area Network (PAN), Local Area Network (LAN), Metropolitan Area Network (MAN) and Wide Area Network (WAN).

Personal Area Network (PAN)

It is also known as Wireless Personal Area Network (WPAN). It is the smallest network used for data transmission among devices within the environment of an individual user. These devices may include Bluetooth-enabled devices or infra-red enabled devices such as a wireless printer, a telephone,  a TV remote control, a wireless computer keyboard and a mouse among others.

• Bluetooth: This is a wireless protocol that connects electronic devices over a short distance of upto about 10 meters creating a PAN with a high level of security.

• Infra-red: This is a wireless electromagnetic energy technology with a wavelength longer than those of red visible light. It is use in conveying data from one device to another.

                                                                                                  168

(a) Local Area Network (LAN

This is a network that covers a small geographical area for example, an office, a building, an institution, or an organization.

(b) Metropolitan Area Network (MAN)

A metropolitan area network covers a city or town. It can be made up of many LANs and can provide Internet connectivity in a Metropolitan region.

                                                                                   169

Differences between LAN and WAN

                                                                         170

Assignment 8.1
1. Define the following terms:

 (a) Network 

(b) Computer Network

2. State three characteristics of a computer network

3. Explain two advantages of a computer network.

4. State two disadvantages of a computer network.

5. Classify computer networks according to geographical area.

Learning Activity 8A

Find out the type of network in your school and the neighbouring institutions.

Internet Concepts

Definition of the Internet

Internet stands for International Network. It is a worldwide network of computers connecting millions of computer networks via communication media such as telephone lines, wireless connections, and fiber optic.

Definition of Terms

• World Wide Web (WWW): It is commonly referred to as the Web. WWW refers to a large virtual space in the Internet where information pages called web pages are installed. The web pages can be accessed using a web browser.

• Webpage: This is Hypertext and hypermedia documents containing information about an individual or organization.

• Website: A collection of related web pages stored as a single file in a web server.

• Web browser: It is commonly referred to as a browser. These are programs used for displaying and viewing web pages on the World Wide Web (WWW), for example, Mosaic, Netscape Navigator, Internet Explorer, Mozilla Firefox, Opera and Google Chrome among others

. • URL: It is an abbreviation for Uniform Resource Locator. A website address is commonly known as URL. It is a unique address of each web page in a websites which identifies the location of a specific web page on the Internet.

• The URL consists of three parts namely; protocol, server name and resource ID.

                                                                        171

• An example of URL is http://www.techrwanda.com

• ISP: This is the abbreviation for Internet Service Provider (ISP) is a licensed organization or company that provides access to the Internet usually at a fee. Examples of ISPs include Rwandatel, Tigo, ISPA, and MTN Rwanda among others.

Assignment 8.2

1. Define the term Internet as used in computer.

2. Write the following abbreviations in full:
 (a) ISP

(b) WWW  (c) URL

3. Differentiate between a web page and website as used in the Internet.

4. Briefly explain the term web browser.

Learning Activity 8B Explore the Internet.

Find out the URL of:

(i) Your school

(ii) The Rwanda Education Board

(iii) other institutions of your choice

History of the Internet

Development of the Internet

The root of today’s Internet came from visionary people in the 1960’s for the purpose of information and research sharing. In 1962 packet switching was developed and it formed the basis of Internet connection. The Advanced Research Projects Agency (ARPANET) which was a branch of the department of defense was the first known fully operational packet-switching network.

                                                                      172

In 1969, ARPANET began working on an experiment to determine whether computers at different universities could communicate with each other without a central system.

The corporation Bolt Baranet and Newman developed Interface Message Processor (IMP), the basis of the new communications system. IMPs were small machines which were dedicated to forming the network between computers. They used a technology which split large sections of data into small parts called packets, each labelled with its destination address, and later re-assembled at the destination computer. In 1970, Vinton Cerf and others, published a proposal for protocols and later ARPANET began operating Network Control Protocol (NCP) to enable computers to communicate. In 1974, Vinton Cerf together with Bob Kahn presented their protocol for packet network interconnection, which became the basis of the modern Internet. In 1978, TCP was split into two protocols TCP/IP (Internet Protocol). In 1982, TCP/IP was established as the protocol for ARPANET and by January 1983, all of the ARPANET was switched over from NCP to TCP/IP.

By the end of the 1980’s, a young British Scientist, Tim Berners-Lee assigned a common system of written addresses and hypertext links to all information. Hypertext is the organization of information units into connections that a user can make. In 1990, Lee started working on a hypertext graphical user interface browser and editor. By 1991 the first World Wide Web (WWW) files were made available on the net for downloading using File Transfer Protocol (FTP).

The mid 1990’s saw the introduction of search engines and by late 1990’s Independent Internet Service Providers (ISPs) such as Sprint and AT&T had so many subscribers.  In 1993, the world started waking up to the WWW and at least 200 known HTTP

                                                                                        173

servers were connected. In 1994, Netscape Communications was born and Microsoft created a Web browser for Windows 95. Later in 1998 Google search engine was born changing how users engaged with the Internet.

Today the Internet is everywhere, enabling people to communicate and share interests in many ways more faster using sites such as Facebook, Twitter, Linked-In, YouTube, blogs, wikis, and many more.

Internet Uses in Daily life

Internet can be used in the following ways in daily life;

(a) Communication: Through electronic mails (e-mails), social sites, chat rooms and newsgroups, Rwandese can easily exchange information within and outside the country.

(b) Research: People use the Internet to get information on various topics. For example, university students in Rwanda can use the internet to research on topics of study.

(c) Business: Customers can buy and sell goods and services through the Internet. They can pay for the goods and services through Electronic Funds Transfer (EFT), cheques and credit cards among others. In Rwanda, people are able to buy goods from other countries in the comfort of their homes.

(d) Education: The Internet is used in various ways such as distant education or online education, Internet or Web-based training. It can also be used to take up short term courses with the course materials available online, attend virtual classes, learn and take examinations.

(e) Medicine: Medical practitioners are using the Internet to update themselves on specific areas of interest and even take refresher courses to enhance their medical knowledge for better services. This has enhanced delivery of services in Rwanda hospitals.

(f) Internet banking: Bank customers access their accounts and carry out transactions through the Internet. Rwanda people are able to tranfer money online from one account to another without necessarily having to physically visit their respective banks.

(g) Entertainment: Internet provides various forms of entertainment, for example, one can play games, watch online movies, upload and download entertainment materials such as music.

                                                                           174

Methods /Ways of connecting to the Internet

Connecting to the Internet can be done using the following ways:

(i) Dial up

It involves connecting a computer to an Internet Service Provider (ISP) by use of a modem and telephone line such as a Subscriber Identity/ Identification Module (SIM) card, only when accessing the Internet.  The connection is terminated once the user logs out from the Internet. Dial-up Internet connection is mostly used in rural or remote areas where broadband Internet access is not available. However, dial up Internet is potentially approaching extinction because of the advancements in wireless technology.

(ii) Broadband

This is a high capacity transmission technique that uses a wide range of frequencies to enable a large number of messages to be communicated simultaneously. Some examples of broadband are Wi-Fi , 4G and satellite among others.

(iii) Wi-Fi

Wi-fi stands for Wireless Fidelity. This is a wireless networking technology that uses radio waves to provide high-speed Internet and networking connections. Examples of Wi-Fi enabled devices includes laptops, cell phones, tablets, iPads, and  peripheral devices such as the mouse, printers and keyboards among others. They communicate with a single computer which is fitted with a Wi-Fi adapter.

Getting online

Web browser

These are programs used for displaying and viewing web pages on the World Wide Web (WWW), for example, Mosaic, Netscape Navigator, Internet Explorer, Mozilla Firefox, Opera Mini and Google Chrome among others.

                                                                                 175

Basic parts of a web browser

The following are basic parts of a browser window:

(a) Menu bar – It consist of a list of menus to choose from, for example, File, Edit, View, Tools, and Help.

(b) Control buttons – These buttons are found on the far right-side of the title bar of the search engine and include the following:

• Minimize: It removes a web page window from a view to an icon on the taskbar.

• Restore Down: It reduces the size of a web page window.

• Maximize: It enlarges the web page window and fills up the screen.

• Close: It exits the active window.

(c) Address bar:  This is where an address (or name) is typed so as  to go to a given web site page.  An example of a web site address is www.techrwanda.com.

(d) Search Text box: This is where keywords are typed to describe the information that one wants to find. (e) Search button: It is the command button clicked in order to initiate the search.

(f) Search Query: It is the information typed by the user to help the search engine decipher the required information.

                                                                                    176

Web Address

A website address is commonly known as Uniform Resource Locator (URL). It is a unique address of each web page in a websites which identifies the location of a specific web page on the Internet.

The URL consists of three parts namely; protocol, server name and resource ID. An example of URL is http://www.techrwanda.com

Assignment 8.3
1. Give a brief description of the Internet history.

2. Explain the application of the Internet in the following areas:

(a) Communication 

(b) Research

(c) Education

3. Explain two ways in which one can get connected to the Internet.

4. Explain three basic parts of a web browser.

5. State the three main parts of a website address.

Learning Activity 8C

Explore the Internet connection in your school.  Identify the method of connection.

(i) Find out the web address of your school

(ii) Write the domain of your school.

Search Engines

Search Engines are programs that help a user to look for and identify items that corresponds to keywords or phrases specified from the World Wide Web. Examples include; Yahoo, Google, Bing and Ask.com among others.

Advantages of search engines

• They provide precise results.

• They have indexes representing important parts of the Internet which offer a wide range of information resources.

• They enable users to describe the information being searched.

• They enable users to locate and access information in different websites.

• They reduce the time taken to locate desired information.

• They provide a wealth of information for professional and personal use.

Disadvantages of search engines

• Tiresome and complex to search if the keyword typed is ambiguous. Many users get discouraged and frustrated because of the many links they have to search

                                                                                         177

before getting the correct information.

• A lot of irrelevant information gets displayed after typing a keyword.

• A lot of distractions from advertisements that keep on popping up.

•  A link to sites containing viruses could be displayed as a search result.

List of search engines

The following are some examples of search engines.

a) Google  (b) Google scholar (c) Yahoo! (d) Bing   (e) Ask.com  (f) Wikipedia (g) WiseGeek.com

Deciphering search results

Deciphering is the conversion of text written in code form into natural language. A search engine results page displays a lot of different information. In fact, one may not be aware of all the different types that appear. From vertical search engine results to related new stories, to suggested spellings, the results page offers all sorts of ways for one to dig dipper into a subject.

                                                                        178

Procedure for deciphering search results

(i) Type your search query in the Search Box.

(ii) Click on the Search Button. The result is displayed with the following sections:

Search Box: The box where you type your search query. In this case it is “Use of ICT in Rwanda.”

Search Verticals: Links to the vertical search engines, the specialized ones that narrow your search into a specific type of result, such as news or images. Clicking one of these links takes you to a results page with only news or only images.

Page Count: The number of Web pages the search engine finds that match your search query in some way.

Time the Search took: How long the search engine took to retrieve your results.

Related Searches: Other topics that contain your query or other searches the search engine thinks might be relevant.

Images: Picture files that match your query. This comes from Images vertical engine. Clicking the link would take you to the vertical search results.

News Results: Any news results pertaining to your query or containing a keyword. These come from the vertical news engine. Clicking the link would take you to the news page.

                                                                            179

Sponsored Links: These are paid advertisements (ads). Note how some of them relate to a specific geographical location near you. This is thanks to the local vertical search engine.

Organic Results: The listing results from a general search of Google’s index, with algorithms applied to determine relevance. Pagination: Links to the additional pages of results.

Disambiguation:  The “Did you mean . . . ?” suggestions that usually display after a misspelled search query or search queries that turned up very few results. It is the search engine’s way of trying to guess what you actually wanted. When the search query is spelt correctly, no disambiguation appears. You can test this feature for yourself by typing a mispelt query in Google.

(iii) Click on one of the options within the sections to access the web page.

Assignment 8.4

1. Define the term search engine.

2. State two advantages of using a search engine.

3. Outline two disadvantages of search engines.

4. List three examples of search engines.

Learning Activity 8D

Search for information on the following topics and do brief write-ups:

(i) The harmful effects of drug and substance abuse

(ii) The importance of conserving the environment

(iii) The dangers of engaging in premarital sex

(iv) The importance of maintaining peace in a country

Electronic Mail (E-Mail)

E-Mail refers to a system of exchanging messages electronically over a computer network. The user must have an e-mail address in order to use e-mailing services.

E-mail address

The following is a sample format of an e-mail address:

username@hostcomputer.domainname

Explanation

• username: It identifies the owner of the e-mail address.

• @ (“at” sign): Separates the username from the rest of the address parts.

                                                                   180

• hostcomputer: The name of the remote server on which the e-mail account is hosted. For example gmail, yahoo, and hotmail among others.

• .(dot): Separates the domain from the other part of the e-mail address.

• domain name: It identifies the type of institution offering the services. This has been discussed earlier in this book.

• For example, nkwanga@gmail.com, nkwanga is the username, gmail is the host computer and .com is the domain name for a commercial organization.

Advantages of E-Mail

(i) It allows sending of one mail to many recipients at the same time.

(ii) It is cheaper compared to traditional mails.

(iii) It is convenient since it allows sending and receiving mails from anywhere in the world.

(iv) E-mails can be saved for future retrieval.

(v) It is easier to reply and forward mails.

(vi) Allows sending and receiving of any form of information.

Disadvantages of E-Mails

(i) Requires some computer literacy to use.

(ii) E-mails are not accessible to everyone due to Internet connectivity problems.

(iii) Expensive to set up. (iv) Allows spread of viruses such as hoax.

Creating an e-mail account

Follow steps:

(i) Open the e-mail application software. Then select Check Mail option. The Sign in dialog box is displayed.

(ii) Click Sign Up and follow the procedure provided in the application.

Note: When creating a password for the account ensure that the password is strong enough. A strong password should have a minimum of 8 characters and should be a mixture of both letters, numbers and if possible symbols.

• Passwords are case sensitive.

• Always use a combination of characters that you can easily remember.

• Avoid using characters that can be guessed.

• Passwords are always encrypted for security purposes.

                                                                        181

For example: To create a mail account in Gmail, the steps are as follows:

(i) Open Gmail application software.

(ii) Click Create an account link in the Sign in dialog box. This will open the sign up page.

(iii) Type the required information on the sign up page.

  A sample of the page is shown in Figure 8.12.

(iv) Finish by clicking on the check box “ I agree to the Google’s Terms of Service and Privacy Policy”.

(v) Click Next Step button.

Sending and Reading messages

Before sending and reading a message, the user must open their account. The procedure of opening an account is referred to as Signing in.

Sign In

To sign in to an existing account do the following:

(i) Open the web browser software installed in the computer.

(ii) Open the e-mail application program to display the sign in window.

A sample is shown in figure 8.13.

(iii) Type the e-mail address under User Name box and password under the Password box.

(iv) Click Sign in button to open the e-mail.

                                                                   182

Receiving a message

Upon signing in, the user’s inbox is automatically opened. The messages are displayed in three columns showing the name of the sender, the subject and the Date/Time when the mail was sent. To read a message, click on the Subject. Once the message is read the user can decide to select one of the following options available on the message window: Reply, Reply to All, Forward, Move and Delete among others.

• Reply: This option is selected if the user desires to respond to the read mail.

•Reply to All: This option is selected if the user desires to respond to all the addresses listed in the CC, BCC and To box. Both CC and BCC forward a copy of the message to everyone listed as a recipient. The difference between CC or Carbon Copy and BCC (Blind Carbon Copy) is that, with the latter, the recipients do not get to know each other.

• Forward: This option is selected if the user desires to send the same message to other e-mail addresses.

• Delete: This option is selected if the user desires to erase the mail. Note that deleting the message only sends it to the Trash folder. The user can retrieve the message from this folder if so desired.

• Move: This option is selected if the user wishes to remove the message from the Inbox folder and transfer it to another folder.

Sending messages

The user can either compose a new message or send one that already exists in their inbox. Composing is the process of creating a new mail.

                                                                  183

To compose a message do the following:

• Click on the Compose button in the e-mail account window. A dialog box appears.

• Click at To text box and type the e-mail address of the recipient.   Note:  To send the same message to a number of people the following options can be used. X Cc (Carbon Copy): When this option is used, the list of all the recipients appears in each recipient’s mail.   X Bcc (Blind Carbon Copy): When this option is used, the list of all the recipients is hidden from the other recipients of the mail.

• Click at Subject text box to type the title that describes what the e-mail is about.

• Type the message in the body section.  Note: E-mail text can be formatted the same way as in a Microsoft Word document using the formatting bar.

• Click Send button once the message is completed.

• To permanently delete the message, empty the trash folder.