Approved by Curriculum Development Centre 151 Oasis Radiant Computer Science, Book 8 ● Do not use computer for illegal work to harm individuals and society. ● Do not use others' intellectual property without getting permission from them. ● Always use the computer system for positive thinking, development and creative work. ● Do not use computer system to steal. ● Never hack the computer system and stop spreading computer viruses to harm the computer system. ● Do not use the computer system to bear false witness. ● Do not access others' resources without getting permission to access. ● Use the computer system to respect social norms, values, harmony and culture. ● Provide equal access to the computer system and do not discriminate according to gender, culture, caste, etc. Cyber Law in Nepal Nepal is a developing county. Like other sectors, Information and Communication Technology (ICT) sector is also in a developing stage. So the business sector, government sector and public sector are using ICT as a major tool to support all types of business process. So it is very essential to legalise the digital activities like online work to make it useful and standard. Nepal has formulated some cyber laws to support and legalise the online trading activities, government activities, tax payment and electronic payment using some electronic cards. It has a strong provision of punishment against the illegal work in such activities. According to the level of cyber crime, criminals will be punished. It prevents hacking, faking digital signature, privacy issues, damage of programme source code, etc. The cyber law is popular as electronic transaction act 2061 BS (2004). It addresses the following aspects to control cyber crime and other indiscipline in the field in Nepal. These are listed as below:
Oasis Radiant Computer Science, Book 8 152 Approved by Curriculum Development Centre ● It explains the provisions to punish hackers who download, copy and manipulate data without getting permission of the owner and who introduce virus in to the system and disrupt a computer or networked environment. ● It provides a detailed provision for controlling and verifying the authorities to use digital data. ● It provides legal provision to give online banking, electronic fund transfer (EFT), etc. ● It gives legal provision to use the digital signature which is very essential to identify and verify the documents. ● It has a provision of appeal to judicial body to hear the cyber related issues. ● It helps in electronic data transaction, electronic filing of documents, use of public and private key for security management, etc. Key Points ● All the legal and regulatory aspects of internet and internet-based work are called cyber law. ● Cyber law deals with digital signature, telecommunication law, cyber crime law and electronic transaction act, etc. ● Digital signature is similar to the ordinary signature that is used to authenticate the users. ● Intellectual property rights deal with the copyright, patent right and trademark. ● The process to get unauthorised access to the computer system by cracking the software is called hacking. ● Ethics is the morality of individuals, society and political society. ● IT policy 2000 is the first policy related to information technology. ● Ethical issues of computer deal with the issues of what to do and what not to do with computer system. ● Cyber law in Nepal explains the use of digital signature, electronic fund transfer and other electronic transactions. ● Cyber law of Nepal was enacted in 2062 B.S.
Approved by Curriculum Development Centre 153 Oasis Radiant Computer Science, Book 8 ● The process to change the user language message into machine code form and again into message is encryption and decryption. ● Cyber crime is a criminal activity involving the information technology infrastructure. 1. Answer the following questions. a. What is cyber law? b. Write the importance of cyber law. c. What is cyber crime? d. Describe digital signature. e. Write the use of digital signature. f. What is ethics? g. Write the use of computer ethics. h. What is hacking? i. What are intellectual property rights? j. Explain some ethical issues in computing. k. Discuss some aspects of cyber law in Nepal. 2. Write short notes on: a. Data protection and privacy law b. Electronic transaction act c. Cyber crime law d. Ethical issues e. Digital signature 3. Differentiate between a. Cyber law and ethical issues b. Digital signature and ordinary signature c. Electronic transaction act and telecommunication law d. Hacking and data security e. Ethics on computing and cyber laws Exercise
Oasis Radiant Computer Science, Book 8 154 Approved by Curriculum Development Centre 4. Fill in the blanks. a. Digital signature is similar to ____________ signature but processed digitally. b. Cyber law was formulated in Nepal in ____________ B.S. c. A criminal activity related to electronic infrastructure is ____________ crime. d. The process to change user language data into cipher text is called ____________. e. Copyright is related to ____________. 5. State True or False. a. Copyright act was formulated in 1992 B.S. b. The law that provides a legal framework to facilitate and safeguard electronic transaction in the electronic medium is called electronic transaction act. c. Intellectual property rights deals with copyrights, trademark and patent right. d. We should not use computer system for illegal work. e. Cyber law provides a detailed provision for controlling cyber related work. 6. Project Work a. Prepare a list of cyber crimes in Nepal. b. Explain about the cyber law in Nepal. c. What is ethics? Explain some ethical issues in computing.
Approved by Curriculum Development Centre 155 Oasis Radiant Computer Science, Book 8 Information and Communication Technology 11 Chapter 8 The concept of ICT 8 Uses of ICT 8 Components of ICT
Oasis Radiant Computer Science, Book 8 156 Approved by Curriculum Development Centre Information Technology Information Technology - IT refers to the computing technology, such as networking, hardware, software, the internet, or the people that work with these technologies. Many companies now have IT departments for managing the computers, networks, and other technical areas of their businesses. IT jobs include computer programming, network administration, computer engineering, Web development, technical support, and many other related occupations. Communication Technology Communication Technologies – CT designs, supports and maintains the communication systems, network and telephony infrastructure. It is used for communication between individuals or groups. Communication technology facilitates communication between individuals or groups who are not physically present at the same location. Systems such as telephones, telex, fax, radio, television, and video are included, as well as more recent computer-based technologies, including electronic data interchange and e-mail. Concept of ICT ICT stands for Information and Communication Technology that defines both IT (Information Technology) and CT (Communication Technology). It can be defined as the set of technological tools and resources used to communicate, and to create, disseminate, store, and manage information. These technologies include computers, the internet, broadcasting technologies (radio and television), and telephony. In recent years, there is a common interest in how computers and the internet can be used to improve the efficiency and effectiveness of education at all levels and in both formal and non-formal forms. But ICTs are more than just these technologies. Older technologies such as the telephone, radio and television are going to be replaced by computer and internet applications. For instance, radio and television were used for open and distance learning but now a days Information and Communication 11 Technology Chapter
Approved by Curriculum Development Centre 157 Oasis Radiant Computer Science, Book 8 we are using internet=based online learning. The use of computers and the internet is still growing in developing countries due to limited infrastructure, high cost and the skills of user. ICT (Information and Communication Technology - or technologies) is an umbrella term that includes any communication device or application, encompassing radio, television, cellular phones, computer and network hardware and software, satellite systems and so on, as well as the various services and applications associated with them, such as videoconferencing and distance learning. Impact of ICT on the Society There are many good points to the social impact of ICT. • ICT has brought the world together through social networking sites. • ICT has made researching information easier, as information can be found by looking over the internet. This helps people who haven’t got a local library near where they live. • Through social networking people can speak to family and friends from across the globe. This helps people who can’t travel to visit family or friends. • ICT has created many jobs for people to apply for, ICT skills are now required for almost every job and with internet access widely available, people are able to communicate and work away from an office which has made working from home a more popular choice. • Fast and flexible access to airline booking system from internet • Large supermarket stock control are done by ICT, which is difficult to do physically. • Easy means of banking. • Large amount of cash can be carried using credit or debit card and cash can be withdrawn using ATM. • Computer-aided designs are used in designing for engineering. • Faster production of products. • Weather can be forecast.
Oasis Radiant Computer Science, Book 8 158 Approved by Curriculum Development Centre • Robots perform complex industrial or manufacturing physical tasks. • Wider range of entertainment. Disadvantages • Children and teenagers spend most of their free time using computers, which affects their social development. • ICT can also affect people’s personal health, as they aren’t getting enough exercise. They are spending most of their free time indoors on computers instead of going outside. • Small local businesses are being affected by the effects of ICT as people would rather shop. • Many older people are feeling pressured and overwhelmed with learning how to use new technology and with many services such as banking, bill paying and shopping rapidly becoming internet based, some older people are struggling accessing these services. • ICT has caused many legal impacts. Many media forms such as Movies and Music have become easily available across the internet, which has led to copyright material to become easy to steal. • There are also ethical impacts of ICT. With personal information being stored on computers, personal privacy has become an issue. Almost all aspects of our lives is recorded on computers, this includes our medical records, what we buy in supermarkets, who we call and text on mobile phones and what we search for on the internet using search engines. • It may create unemployment because many factories now have fully automated production lines. Instead of using people to build things, computer-controlled robots are used. Applications of ICT ICT has become an integral part of our society. Applications of ICT in different sectors like e-Government, e-Commerce, e-Education, e-Health and e-Environment are becoming very easy tools to support our daily life and to deliver a wide range of basic services in remote and rural areas. ICT applications makeour life easier and help reduce poverty and improve health and environmental conditions in developing countries. We can list some major applications of ICT as below:
Approved by Curriculum Development Centre 159 Oasis Radiant Computer Science, Book 8 E-Government Electronic government is the modern concept and procedure to manage good governance. Use of ICT for good governance is e-Governance. E-Government focuses on the adoption of ICTs to deliver government services through the internet and other emerging digital technologies. E-Health Use of ICT to support health related activities is the concept of electronic health. It is a cost-effective and secure use of information and communications technologies to support the health and health-related fields, including health-care services, health surveillance, health literature, and health education, knowledge and research.
Oasis Radiant Computer Science, Book 8 160 Approved by Curriculum Development Centre E-Environment Information and communication technologies (ICTs) are being rapidly used around the world. Although ICTs require energy resources, they also offer opportunities to monitor, learn about and protect the environment, reduce carbon emissions, and mitigate climate change. It can be used to support different environment preservation activities. In communication ICT itself the communication technology so it has wide range of communication applications to support our daily life. Use of email, internet, social networking etc. are making the world small. The concept of ICT has become popular due to the popular uses of ICT in the communication sector. To support the disabled Information and communication technologies are widely used to improve the quality of life of people who have a disability or a special need. For example the internet can help those who find it difficult to leave their home to shop and to communicate with friends and relatives. In education ICT is used in schools for administration purposes and to deliver courses to students. Computer Assisted Learning (or CAL) is the term used for using computers to deliver learning materials to students. Computer Based Training (or CBT) is the name given to teaching programmes
Approved by Curriculum Development Centre 161 Oasis Radiant Computer Science, Book 8 that are delivered mainly through a computer system. Interactive white board systems allow a teacher to share their learning resources with a class and access the internet. In entertainment Information and communication technologies are used to provide a wide range of entertainment applications. User can play the game, download the songs from internet, watch online TV and can share the entertainment materials using social networking like YouTube and Facebook, etc. Large numbers of online movies are available freely on internet. In shopping and business ICT is highly used in the commerce and business fields. Users can visit different types of websites and select the items according to their requirements. This concept is called electronic commerce. E-Commerce helps us to do the online shopping to settle the electronic business. It also helps us for online payment and processing to support the e-commerce activities. Key Points ● All the legal and regulatory aspects of internet and internet-based work are called cyber law. ● Cyber law deals with digital signature, telecommunication law, cyber crime law and electronic transaction act, etc. ● Digital signature is similar to the ordinary signature that is used to authenticate the users. ● Intellectual property rights deal with the copyright, patent right and trademark. ● The process to get unauthorised access to the computer system by cracking the software is called hacking.
Oasis Radiant Computer Science, Book 8 162 Approved by Curriculum Development Centre ● Ethics is the morality of individuals, society and political society. ● IT policy 2000 is the first policy related to information technology. ● Ethical issues of computer deal with the issues of what to do and what not to do with computer system. ● Cyber law in Nepal explains the use of digital signature, electronic fund transfer and other electronic transactions. ● Cyber law of Nepal was enacted in 2062 B.S. ● The process to change the user language message into machine code form and again into message is encryption and decryption. ● Cyber crime is a criminal activity involving the information technology infrastructure. 1. Answer the following questions. a. What is cyber law? b. Write the importance of cyber law. c. What is cyber crime? d. Describe digital signature. e. Write the use of digital signature. f. What is ethics? g. Write the use of computer ethics. h. What is hacking? i. What are intellectual property rights? j. Explain some ethical issues in computing. k. Discuss some aspects of cyber law in Nepal. 2. Write short notes on: a. Data protection and privacy law b. Electronic transaction act c. Cyber crime law d. Ethical issues e. Digital signature Exercise
Approved by Curriculum Development Centre 163 Oasis Radiant Computer Science, Book 8 3. Differentiate between a. Cyber law and ethical issues b. Digital signature and ordinary signature c. Electronic transaction act and telecommunication law d. Hacking and data security e. Ethics on computing and cyber laws 4. Fill in the blanks. a. Digital signature is similar to ____________ signature but process digitally. b. Cyber law was formulated in Nepal in ____________ B.S. c. A criminal activity related to electronic infrastructure is ____________ crime. d. The process to change user language data into cipher text is called ____________. e. Copyright is related to ____________. 5. State True or False. a. Copyright act was formulated in 1992 B.S. b. The law that provides a legal framework to facilitate and safeguard electronic transaction in the electronic medium is called electronic transaction act. c. Intellectual property rights deal with copyrights, trademark and patent right. d. We should not use computer system for illegal work. e. Cyber law provides a detailed provision for controlling cyber related work. 6. Project Work a. Prepare a list of cyber crimes in Nepal. b. Explain about the cyber law in Nepal. c. What is ethics? Explain some ethical issues in computing.
Oasis Radiant Computer Science, Book 8 164 Approved by Curriculum Development Centre Computer Viruses and Security Measures 12 Chapter 8 The concept of virus 8 Types of viruses 8 Methods to protect computers from virus 8 Anti-virus software and its uses
Approved by Curriculum Development Centre 165 Oasis Radiant Computer Science, Book 8 Computer Virus Small micro programmes that are designed to replicate and attach to application programmes and perform some destructive actions to the computer system are called computer virus. Such micro programmes are linked into commonly used programmes. When such programmes are used the system will automatically attach the virus and infect the booting process, executes files, and other application programmes. In most of the cases such viruses are attached with the external disk and programmes like pen drive, memory card and programmes downloaded from the internet. Virus will be inactive until you execute infected programmes and start the computer using virus infected disk. Once a virus is active, it loads into our computer's memory and may save itself to our hard disk. Sometimes it copies itself and is attached with the applications and system files on disks that we use. Some viruses are programmed to damage the data from our computer by corrupting programmes, deleting files and making the system unusual for working. Virus has the ability to infect different portions of the computer hardware and software system. Types of Viruses There are various types of viruses but most common types of viruses are: ● Boot Sector Virus ● File Infector Virus ● Macro Virus ● Self-modifying Virus ● Multipartite Virus ● Script Virus Computer Viruses and Security 12 Measures Chapter
Oasis Radiant Computer Science, Book 8 166 Approved by Curriculum Development Centre Boot Sector Virus This virus overwrites the boot sector of our bootable disk like Hard Disk and infect them to interrupt the booting process. The boot sector holds the system files and the information required to boot the computer. This virus effectively disables our system to boot. Examples of these viruses are AntiExe, and Unashamed virus. File Infector Virus Viruses which are attached to the executable and system files to infect them and cause the irregular functioning are called file infector viruses. For example, .com and .exe files. This virus spreads when the programme is executed, loaded itself into memory and attached itself to other programmes on our system. It usually spreads to other computers when infected programmes are shared. Examples of these viruses are Jerusalem and Cascade viruses. Macro Virus Virus that usually comes as a part of the document or spreadsheet, often in email is called Macro Virus. Microsoft provides a version of Visual BASIC in its Office product, to allow users to write some customised module. These modules are called macros. Many of the current macro viruses are written in this language and attached to Word documents like a "Macro Virus". The Melissa and I LOVE YOU viruses are examples of macro viruses. Self-modifying Virus Virus which was designed to avoid detection by antivirus software by changing itself internally is called self-modifying virus. There are two types of self-modifying viruses: 1. Metamorphic virus: A metamorphic virus rewrites itself completely each time it infects a new executable. An example of a metamorphic virus is Win95. Zmist.A. 2. Polymorphic virus: The polymorphic virus is one of the more complex computer threats. During the process of infection, it creates slightly modified, fully functional copies of itself. Multipartite Virus A multipartite virus is a hybrid of a Boot Sector and Programme viruses. It infects program files and when the infected programme is active it will affect the boot
Approved by Curriculum Development Centre 167 Oasis Radiant Computer Science, Book 8 record. So the next time you start up your computer it'll infect your local drive and other programmes on your computer. Script Virus Script viruses (sometimes called macro viruses) generally travel embedded in email and office automation documents, although they can be found in web pages as well. Signs (Symptoms) of a Virus Infection Some signs that may indicate that your computer is infected with viruses are given below. These are the major symptoms which frequently indicate on the computer system. ● The computer is slower than in normal time operation. ● Computer programmes take longer to load than normal operation. ● Computer stops responding or freezes frequently. ● Applications on the computer do not work correctly. ● Computer crashes and restarts every few minutes. ● Disks or disk drives are inaccessible. ● The computer does not run as usual. ● Error messages appear rapidly. ● Printing items is difficult. ● It distorts menus and dialogue boxes. ● Antivirus programmes get disabled. ● Antivirus programmes will not start, and it will be difficult to install new. ● Programmes disappear from the computer. ● Strange sounds play from the speakers unexpectedly.
Oasis Radiant Computer Science, Book 8 168 Approved by Curriculum Development Centre How to Protect Computers from Viruses Software which is used to prevent, detect, and remove malicious effects and other computer viruses is called Anti-Virus Software. Antivirus software systems detect and search the malicious patterns and viruses in executable code. It is possible for a user to be infected with new viruses that have no sign or symptoms or existence. To counter this problem of zero threats, antivirus systems can be used to detect and remove these viruses when you don't even know that they are there. Be cautious about what disks and files you accept from other people. Here are some precautions and detection methods for viruses. ● If your system has old antivirus and cannot detect a virus, update antivirus from the web site and install updated antivirus, then run the antivirus. The software may not be able to delete the virus, but it may be able to identify it. ● Don't reuse disks that have been in other computers, don't download files from insecure sites, and don't open e-mail attachments from unknown senders. Scan the email attachments, disks first and then only use them. ● Run virus scan software to make sure the virus was removed properly. ● Download and install any software patches or other programmes that will help you eliminate the virus. Or follow any instructions you find on deleting the virus manually. ● Some tools used to give security from the virus infection are: Antivirus, scandisk, use of firewall, etc. ● Use only the branded genuine software and stop software piracy. Antivirus Software Antivirus software is the system that scans, detects and removes the viruses from the disk or email attachment. So many companies have developed such software to detect and remove the viruses. Now a days, we have some standard antivirus software available in the market. These are: Some popular Antivirus Software are: ● Kaspersky Anti-Virus ● The Shield Deluxe Antivirus & Antispyware
Approved by Curriculum Development Centre 169 Oasis Radiant Computer Science, Book 8 ● Avira antivirus ● Web root Antivirus with Antispyware 6.0 ● McAfee Virus Scan Plus ● Bit Defender Antivirus ● ESET NOD 32 ● CA Anti-Virus Plus ● Norton Antivirus 2 ● AVG Antivirus Key Points ● Micro programmes that are designed to replace and attach to other program, and perform undesirable and malicious actions are called viruses. ● Viruses have the ability to infect different portions of the computer system. ● Viruses are entered from external sources and easily hide in healthy software. ● There are different types of viruses like macro virus, boot sector virus, file infector virus, stealth virus, polymorphic virus, etc. ● A program designed to detect and remove viruses from the infected programmes or files in the computer system is called antivirus software. ● A virus that infects the executable (.EXE) and .COM files is called file infector virus. ● Polymorphic virus uses the encryption technique to hide from antivirus. ● Boot sector virus infects the bootable system files that causes the failure of booting. ● There are different symptoms of virus infection. Major symptoms are files are erased, reduced speed of computer, a strange message or strange patterns on screen. ● Major process to remove the viruses is: use of antivirus software, use of external disk after virus scan and never download virus infected software from internet. ● A computer virus that infects executable program files having an extension of exe, and .com files is script virus. ● Popular antivirus are: Avira, Eset, Mcafee, Norton, etc. ● Viruses spread from networking system, attached files on email, infected
Oasis Radiant Computer Science, Book 8 170 Approved by Curriculum Development Centre Exercise boot disk and use of pirated software. ● Firewall is a system that filters the message from global network to local user and from local user to global network. ● Process to convert message into cipher text and again cipher to message is called cryptography. 1. Answer the following questions. a. What is computer virus? b. Describe different types of computer viruses. c. What is boot sector virus? d. Explain about macro virus. e. Define file infector virus. f. Write some symptoms of a virus-affected computer. g. Explain the ways to spread viruses on computer system. h. What is antivirus? List some antivirus software. i. Explain different methods to protect the computer from viruses. j. Define: Worms and logic bomb. 2. Write short notes on: a. Threats to computer system b. Boot sector virus c. Symptoms of virus infection d. Antivirus e. Process to spread virus 3. Differentiate between: a. Virus and antivirus b. Macro virus and boot sector virus c. File infector virus and stealth virus d. Worms and logic bomb e. Script virus and polymorphic virus
Approved by Curriculum Development Centre 171 Oasis Radiant Computer Science, Book 8 4. Fill in the blanks. a. ____________ virus infects executable program files having extension name .exe and .com. b. The full form of MBR is ____________. c. A virus that can change its appearance with every infection is called ____________ virus. d. ____________ virus infects the bootable system files. e. A virus that can change its appearance with every infection is called ____________. 5. State True or False. a. Threats are the attacks from hackers and viruses. b. Viruses are the micro programmes that infect the computer system. c. Macro virus infects the bootable system files. d. Hackers are password crackers to access to the system. e. Script virus infects the executable files. f. Stealth virus encrypts itself to hide from antivirus. g. Worm is the malicious program that infects the computer system. h. Logic bomb is based on the logic or the date and time to be active. i. Computer will become slow due to the infection of virus. j. Virus spreads from email and networking system. 6. Project Work. a. Make a list of antivirus software available in the market. b. List some viruses that infect your computer and write the technique to remove such viruses. c. Explain some techniques to spread viruses on computer system and discuss the methods of protection from viruses.
Oasis Radiant Computer Science, Book 8 172 Approved by Curriculum Development Centre Webpage Designing Using HTML 13 Chapter 8 Terms and uses of internet 8 Process to develop web pages 8 Tags of HTML 8 Process to work with HTML
Approved by Curriculum Development Centre 173 Oasis Radiant Computer Science, Book 8 Internet International network that links various networks throughout the world is called internet. It is also termed as the network of networks in the global form. By using this global network structure we can integrate different network structures. Terms used Web page: The internet page displayed on the web site is called a web page. It is part of the website and it includes text, texture, audio, video, images, etc. to store information. Web site: It is the collection of web pages with unique location addresses and names. It includes complete information about the organisation using multiple web pages. Protocol: The standard set of rules and regulations that controls and defines the network structure is called the protocol. The internet structure is possible due to the protocol associated with the global network structure. Popular protocols are File Transfer Protocol (FTP), Transmission Control Protocol (TCP) and the Internet Protocol (IP). WWW: World Wide Web is the setup that addresses the web pages and their unique location on the internet structure. HTTP: Hyper Text Transfer Protocol directs the web pages on internet structure and the web location specified on uniform resource locator. Hyper Text Markup Language (HTML) HTML stands for Hypertext Mark Up Language. Hypertext is just a fancy way of saying that an HTML document can link to other HTML documents or even other resources on the internet. HTML Tags All HTML tags are enclosed in the < and the > symbols. For example, the HTML bold tag looks like this: <B>, and the italics tag looks like this: <I>. Usually, HTML tags are used in pairs < > an opening tag and a closing tag. These tags can also be called the start tag and the end tag. The closing tag looks just like Webpage Designing Using HTML 13 Chapter
Oasis Radiant Computer Science, Book 8 174 Approved by Curriculum Development Centre the opening tag except that it has a forward slash right after the first angle bracket. For example, the closing bold tag looks like this: </B>, and the closing italics tag looks like this: </I>. Create an HTML File An HTML file is a plain text file with either .htm or .html as its file extension. The three letter extension (.htm) calls back to a time when computers would only allow up to three letters in the file extension. You can use either the .htm or the .html extensions. It doesn’t matter which one you use, but it is more common to use the .html extension now a days. Requirement for HTML To develop HTML files or develop the web page we need: ● Text Editor like notepad to type the HTML codes ● Web browser like internet explorer to view the webpage Create an HTML File with Notepad HTML does not have its own text editor and working environment like other programmes so we have to use a separate text editor. Start note pad and type the HTML tags to prepare the webpage. ● Start > All programmes > Accessories > Notepad. Type the HTML Tags on the notepad system. Notepad system creates a text file which has extension name .txt. So to make a web page you have to save the file with extension .HTML. ● Click on File > Save As to open the file-save-as dialogue box. ● Type the file name with extension name .HTML like test.html and save it. View it on the web browser like Internet Explorer. The Basic Structure of an HTML Page Every webpage has three essential parts: the heading, the title, and body. To make these three essential parts, we will need to become familiar with four different HTML tags: the HTML tag, the HEAD tag, the TITLE tag, and the BODY tag.
Approved by Curriculum Development Centre 175 Oasis Radiant Computer Science, Book 8 The most essential tag of them all is the HTML tag itself. Every webpage must be contained within a pair of HTML tags (<HTML></HTML>). <HTML> </HTML> Everything else that we type is going to be inside the opening and closing HTML tags. The HTML tags define the HTML document. Every webpage has a HEAD section. The head section can contain the title text to display on the title of web page. <HTML> <HEAD> <TITLE> This is first page </TITLE> </HEAD> <BODY> Atlantic Int’l College offers BBA and BBA-BI courses. </BODY> </HTML> After typing the above tags, save the file to make web page. Suppose save it as test1.html. View the page on Internet explorer. Basic HTML Codes There are certain HTML codes (or tags) that you’ll use very frequently called the basic HTML codes. Skeleton of HTML
Oasis Radiant Computer Science, Book 8 176 Approved by Curriculum Development Centre HTML is a tag based scripting language. The skeleton is its basic structure; without it, it cannot be constructed. The minimum requirement for HTML designing and its position in document can be discussed here. The <HTML> and </HTML> tags are backbone or main platform on which other tags are located. All the elements of HTML are written within <HTML > and </HTML >. We place following tags: <HTML> <HEAD>- - -</HEAD> <TITLE>- - -</TITLE>: written within <HEAD>tags. <BODY> - - -</BODY> </HTML> The <BODY> is the main body of HTML documents in which applet, multimedia, link and several other elements are placed. We can say that the HTML document has following two important sections: HEAD section BODY section HEAD section contains TITLE. A BODY section contains APPLET section and many other sections. The TEXT, BGColour, BAKGROUND, LINK, VLINK, ALINK are attributes of <BODY> tags. The TEXT attribute is used to control text colour, BGColour is used for background colour, BACKGROUND is used for wall-paper (background image) and LINK, VLINK and ALINK are used anchor text colour. Some Important Tags These tags are usually used in every web document. The concept of test tags is basic requirement for any web programmer. Hn(Header) The Header of HTML documents is controlled by <Hn) and </Hn> tags. The value of n ranges from 1 to 6. The H1 is largest size of header and H6 is smallest of all. <HN> HEADER TEXT</HN> where,N = 1,2,3,4,5, and 6. Example <<HTML> <HEAD><TITLE> Working with heading</TITLE></HEAD>
Approved by Curriculum Development Centre 177 Oasis Radiant Computer Science, Book 8 <BODY > <H1>Radiant Computer Science Grade 8</H1> <H2>Radiant Computer Science Grade 7</H2> <H3>Radiant Computer Science Grade 6</H3> <H4>Radiant Computer Science Grade 5</H4> <H5>Radiant Computer Science Grade 4</H5> <H6>Radiant Computer Science Grade 3</H6> </BODY> </HTML> Header alignment is also used. Header is aligned to left by default, but it can be aligned centre, right or justify. <HN ALIGN=”LEFT/Centre/RIGHT/JUSTIFY”> - - - -</HN> Example <HTML> <Head><Title> Working with heading alignment</TITLE></HEAD> <BODY > <H1 ALIGN=Centre>Computer Science for School</H1> </BODY> </HTML>
Oasis Radiant Computer Science, Book 8 178 Approved by Curriculum Development Centre P(Paragraph) It is used to move cursor to new line leaving blank space. It is used in the beginning of text. In this way, it is used to separate different paragraphs. <P> - - - -</P> <P ALIGN=”LEFT/Centre/RIGHT/JUSTIFY”> - - - - -</P> BR(break) This tag moves the cursor to new line without leaving blank spaces. Example Line Break Option Atlantic Book Store<BR> Computer Science for School Line Break<BR> HR(Horizontal Ruler) It is used to draw horizontal line to separate section. Its attributes are: Colour : colour name Size: number Example <HR SIZE =”6” Colour =”RED”>:It draws 6 pixels thick red line. <Centre>--- </Centre> <Centre> is used to place text in central position. The text written within <Centre> and <Centre> is aligned to the central part of the document.
Approved by Curriculum Development Centre 179 Oasis Radiant Computer Science, Book 8 Grammar: <Centre> - - - </Centre> Example <Centre><H1>SLC TOPPER-2060</H1></Centre> <HTML> <HEAD><TITLE>This is example page </TITLE></HEAD> <BODY> <P> This is a paragraph and we are making it to develop the webpage. Computer science is very useful field of science. It demonstrates the basic concept and skill of computer. It helps the students to learn theoretical and practical application</P> <P align=left>This is Left</P> <P align=right>This is Right</P> <P align=justify>This is Justify</P> <p align=centre>This is centre text</p> Line Break Option Atlantic Book Store<BR> Computer Science for School Line Break<BR> Insert Ruler <Br> <HR SIZE =”6” Colour =”red”>:It draws 6 pixels thick red line. <Centre>This is centre </Centre> <Centre><H1> Centre with Heading One: Hi School Topper</H1></centre> </BODY> Document Decoration
Oasis Radiant Computer Science, Book 8 180 Approved by Curriculum Development Centre There are two types of ground for desktop presentation: background and foreground. The background is lik blackboard and foreground is text. There are three types of techniques applied for background decorations: (a) colour, (b) image, and (c) sound. Colour The background colour is defined at the time of declaration of BODY tabs. The colour name or RGB code is used for colour. The light colour is appropriate for background colour. If we use dark colour as background, the existence of foreground cannot be attractive and clear. <BODY BGColour = ”colourName or code”> --- </BODY> Example <BODY bgcolour =”red”> --- </BODY> or <BODY bgcolour = ”#FF0000”> --- </BODY> Image The background image is introduced in BODY tags. The background image is displayed side-by-side and top-to-bottom to fill the whole page. The GIF file is the best format for background (wallpaper). We use image of light colour for background. Grammar: <BODY BACKGROUND = ”imgFile” > - - - - </BODY> Example
Approved by Curriculum Development Centre 181 Oasis Radiant Computer Science, Book 8 <BODY BACKGROUND = ”cloud.gif ” >- - - - </BODY> We can create our GIF image for background using any standard graphics package. The Adobe Photoshop, Corel Photo-Paint, Painter, PhotoPro, etc are standard graphics software in market. Sound The background sound is used with bgsound tags and some attributes. The loop attribute is used to define number of times of sound production. It supports .mid, .au, .wav sound. < BGSOUND SRC = ”soundFile ” LOOP = ” number / infinite ”> Example <BGSOUND SRC = ”autum.mid ” LOOP= ”infinite”> Example <HTML> <HEAD><TITLE> Working with background picture and colour</TITLE></HEAD> <BODY BACKGROUND=”pic1.jpg”> <BGSOUND SRC=”autum.mid” loop=”infinite”> This tag is used to give the background of web page. We can give background colour and background picture on the web page. Here you can view the background picture. This picture will display on whole page as background picture. You can give either background picture or background colour on the web page.<BR> Body BGSOUND gives the background sound name autum.mid that plays infinite times when open the webpage. </BODY> <HTML> Inserting Picture on the Web Page We can insert the picture in the document using following tags. <Img SRC=”Image File Name”> <Img SRC=” Image File Name” height= size width= size>
Oasis Radiant Computer Science, Book 8 182 Approved by Curriculum Development Centre <HTML> <Head><Title> This is Picture page </Title></Head> <Body> <centre> <Img SRC=1.jpg height= 400 width= 300> </centre> </Body> </Html> Working with Marquee The movement of text on the page is called the marquee. We can move the text either towards right or left or some time alternate from right to left and again left to right. <Marquee>………………………….……………………………..</Marquee> <Marquee direction = right> ……………………………………..</Marquee> <Marquee behaviour=alternate> ……………………………….. </Marquee>
Approved by Curriculum Development Centre 183 Oasis Radiant Computer Science, Book 8 <HTML> <Head><Title> This is Marquee page </Title></Head> <Body> <Marquee direction=right>This is towards right</Marquee> <Marquee direction = left> This is towards Left</Marquee> <Marquee behaviour=alternate>Alternate</Marquee> </Body> </Html> Font Style The font is the type face or a special type of symbol that represents script of language. Three types of style are placed in toolbar of all word processor: bold, italic, and underline. HTML browsers support the subscript, superscript, big, strong, and small, and many other styles. Sr. Style Comments 1. <B> -- </B> It displays text in bold typeface. Grammar: <B> text </B> Example: <B>University Books</B>
Oasis Radiant Computer Science, Book 8 184 Approved by Curriculum Development Centre 2. <I> - -</I> It displays text in italic typeface. Grammar: <I> text </I> Example: <I>Magician of Web</I> 3. <U> - - </U> It displays text in underline typeface. Grammar: <U> text </U> Example: <U><B>Computer Section</B></ U> 4. <BIG> - -</BIG> It is used to display text in larger font. Grammar: <big> text </big> 5. <SMALL> - -</SMALL> It is used to display text in smaller font. Grammar: <small> text </small> 6. <STRONG> - - </STRONG> The text within <strong> and </strong> tags are rendered as bold. Grammar: <strong> text <strong> 7. <BLINK> - -</BLINK> It is used to provide blinking effect to the text. It was first introduced for Netscape1.0. Grammar: <blink> text</blink> Example: <blink>Congratulation</blink> 8. <SUB> - - </SUB> It is used for subscript. Grammar: <sub> text </sub> Example: H<sub>2</sub>O: results H2 O 9. <SUP> - - </SUP> It is used for superscript. Grammar: <sup> text </sup> Example: (a + b)<sup>2</sup>: results (a + b)2 10. <S> - - </S> It is used for strike out text. Grammar: <s> text </s> Example: <s>Cigarette smoking</s> It displays: Cigarette smoking 11. <Font size=5> ……</Font> To change the font size into 5 point 12. <Font colour=red> </Font> To change the font colour into red
Approved by Curriculum Development Centre 185 Oasis Radiant Computer Science, Book 8 <HTML> <Head><Title> This is text formatting page</Title></Head> <Body> <B> This is bold </B><br> <I> This is Italic</I><BR> <U> This is Underline</U><BR> <BIG> Big size Big</BIG><BR> <SMALL> Small Size Small</SMALL><BR> <STRONG> Strong forced text</STRONG><BR> This is <SUB>sub script</SUB><BR> This is <SUP>sub script </SUP><BR> <S> strike out text </S><BR> <Font size=5> This is font size tag</Font><BR> <Font colour=red>This is font colour tag </Font><BR> </Body> </Html>
Oasis Radiant Computer Science, Book 8 186 Approved by Curriculum Development Centre Table <TABLE> - - - </TABLE> The whole contents of table is enclosed within <TABLE> and </TABLE> tags. Some attributes of table’s tags are: Example <HTML> <BODY> <TABLE BORDER=2> <TR> <TD >1</TD> <TD>Mr.Jagan Adhikary</TD> <TD>12000</TD> </TR> <TR> <TD>2</TD> <TD>Mr. Mani Kumar Rai</TD> <TD> 11500</TD> </TR> <TR> <TD>3</TD> <TD>Mrs. Lachhima Adhikary</TD> <TD>11500</TD> </TR> <TR> <TD>4</TD> <TD >Mr.Suyash Adhikary</TD> <TD>11500</TD> </TR> </TABLE> </BODY> </HTML>
Approved by Curriculum Development Centre 187 Oasis Radiant Computer Science, Book 8 The Concept of Link The link is a process to relate one document to other documents for communication. In the world of Internet, the term Link has very broad meaning. We do all the works to link with others. We link one computer to another computer, computer to Internet, document to document, graphics to document, etc. In this way, all the processes are linking process. We discuss about internal and external link. The e-mail is also external link. The e-mail is the most popular use of Internet in which message of one person is sent to others through SMTP (Simple Mail Transfer Protocol). So, we can say the Link can link everything (documents), even broken hearts. <A> and </A> tags are used for anchoring elements. It has some important attributes like HREF, TITLE, TARGET, NAME, etc. Internal link When we link one document to other documents of same site, it is termed as internal link. This type of link is used to connect several HTML documents to each other. It has two types: Document to Document Link, and One part to other part of same document Document to document link. We link one document with others using anchor text. Grammar: <A HREF =? > Text </A>
Oasis Radiant Computer Science, Book 8 188 Approved by Curriculum Development Centre Example <A HREF=”hello.html”>Hello! World</A> <A HREF=”student.html”>School Students</A> Hello! World and School Students are appeared in the form of anchor text. When Hello! World is clicked, hello.html document is opened and when we click School Students, student.html is opened. <HTML> <BODY> <A HREF= ”hello.html”>Hello! World</A><BR> <A HREF= ”student.html”>School Students</A> </BODY> </HTML> The Linking of Parts of Same Long Document In long document, only screen full document is displayed and rest of the document hidden. When we need information not displayed currently, it can be accessed through HREF link and a NAME. The linking of two or more parts of same document is very easy. We can navigate large documents easily from one parts to other part using the link between source (hypertext) and target text. <A HREF=”#bottom”> - - -</A> contains source (hypertext) and <A NAME= "bottom”>- - -</A> contains target text. Example language for<A HREF="#bottom" > laymen because of its simple syntax structures</A>, that is not verbose <A NAME="bottom">The Main Features</A> of Qbasic External Link The external link is capability of HTML to link one site to other sites through Internet. The HTML is not language for desktop publishing and clerical drafting work, but it is a language for Internet. The web page is designed and linked to Internet. All the activities of HTML are related to designing and linking. Example <A HREF = ” http://www.Yahoo.com/”> Yahoo Site Surfing</
Approved by Curriculum Development Centre 189 Oasis Radiant Computer Science, Book 8 Key Points · Page displays on the internet web sites are called web pages. They consist different information using graph, audio, text and video, etc. · Collection of web pages with certain unique address is called web page. · Command like phrases used to create the web contents on the web pages are called tags. · To develop web page using HTML, we need a text editor and to view the pages we need Internet Browser. · Note pad is the best example of text editor to develop the web page. · Web browser is a system which is used to display the web pages. Popular web browser is Internet Explorer. · To make web pages we have to type the HTML tags on the text editor and save with HTML extension. · It is possible to modify the web pages using HTML text editor. Exercise 1. Answer the following questions. a. What is HTML? b. Define HTML tags. c. What is web page? d. Define web site. e. Write the use of text editor and web browser to develop the web page. f. What is web browser? g. Define Internet. h. What is protocol? i. Write the skeleton of HTML structure. j. List any five HTML tags to apply text formatting. 2. Write the steps to do the following. a. To give header text b. To align text at centre and right c. To break line
Oasis Radiant Computer Science, Book 8 190 Approved by Curriculum Development Centre d. To give horizontal ruler e. To make text bold and italic f. To give background picture g. To give background music h. To make super and sub script of text i. To change font size and colour j. To insert a picture in document 3. Differentiate between: a. Web pages and web site b. Tags and general text c. Body text and title text d. Web browser and text editor e. Background picture and background music. 4. Write the functions of following tags. a. <Sup> ………</Sup> b. <Sub> ……..</Sub> c. <Font colour = red>…..</font> d. <P> …..</P> e. <HR> f. <BR> g. <Img Src= “Img file”> h. <Centre> …..</Centre> i. <TD Bgcolour=red>….</TD> j. <Table> …….</Table> 5. Fill in the blanks. a. Full form of HTTP is __________. b. __________ is the collection of text, audio, video and animation on a single page. c. __________ is the collection of web pages. d. The contents display on the title of page is called __________ part of web page. e. The contents display on the page is __________ part of web page. 6. State true or false. a. Web pages is the name of protocol. b. Internet is the global network. c. We can display the web page in text editor. d. Table tag is used to create table. e. MS Word is the best example of web browser. 7. Project Work a. Prepare a web page to display your Bio-Data. b. Design a web page that has text, picture, music, horizontal line and marquee. c. Visit the web site of your school and analyze its contents like text, picture, audio, video, animation, etc.
Approved by Curriculum Development Centre 191 Oasis Radiant Computer Science, Book 8 Computer Networking System 14 Chapter 8 Discuss the networking system 8 Describe the types of computer network 8 Describe the network topologies 8 Describe the advantages and limitation of networking
Oasis Radiant Computer Science, Book 8 192 Approved by Curriculum Development Centre Introduction Multiple computers connected to one another for sharing resources is called a computer network. It is a system where computers from different locations are connected so that we can transfer and share the data between various users. It helps us to share the hardware, software, database and people resources using a structured networking system. Advantages and Disadvantages of Networking Advantages ● It helps to share printer, disk space, programme, etc. So it reduces the cost. ● It helps to share information between various computers. ● It provides central control over the various computers using server computer. ● It helps to share hardware and software between users. ● It is faster and cheaper communication system. Disadvantages ● Data security may be lost due to more access into the system. ● It needs technical persons to control and handle the networking system. ● It is expensive to install. Devices Required for Computer Networking To connect the computer network we need following devices: 1. Computers: We need some computers to make server and clients on the computer network structure. Server computer is the main computer that controls and serves the data to the clients. Computer Networking System 14 Chapter
Approved by Curriculum Development Centre 193 Oasis Radiant Computer Science, Book 8 2. Communication media:The path to transfer data from one computer to another computer is communication media. There are two types of communication media or channel to connect the computers. These are wired and wireless communication media. 3. NIC (Network Cards): Network Interface Card popularly known as Network Card is essential to connect the computers using communication media. 4. Signal conversion devices: Different devices like Modem, Router, and Gateway are used to convert the signals from analogue to digital and vice versa. 5. Network connecting devices: Different devices like Hub, Switch, Bridge and Repeaters are used to connect the computer network structure. 6. Communication software: Different software like Windows, Linux, etc. are used to connect the computers making a network structure. Types of Networking Computer Networks can be classified on the basis of geographical area in three broad categories. ● Local Area Network (LAN) ● Metropolitan Area Network (MAN) ● Wide Area Network (WAN) Local Area Network A local area network is a private, low coverage network that exists in a single office and building within a limited area. Depending on the needs of an organisation and the type of technology used, a LAN can be as simple as two PCs and printer. It can extend throughout a company and include voice, sound, and video processing devices.
Oasis Radiant Computer Science, Book 8 194 Approved by Curriculum Development Centre Basically LAN structure uses the simple wired network connection. It has a main computer that works like a server and different work stations where users are located. Most of the LAN is inside a room like your lab and within a building like your school. Now a days, it is possible to establish a wireless LAN within a building. Advantages ● The reliability of network is high because the failure of one computer in the network does not affect the functioning of other computers. ● Addition of new computer to network is easy. ● High rate of data transmission is possible. ● Other computers can share peripheral devices like magnetic disk and printer. Disadvantages ● If the communication line fails, the entire network system breaks down. ● User authority and users identification is poor. ● It is not applicable for long distance network connection. Metropolitan Area Network A metropolitan area network is designed to extend over an entire city. It may be a single network such as a cable television network, or it may be a means of connecting a number of LANs into a larger network so that resources may be shared LAN-to-LAN as well as device-to-device.
Approved by Curriculum Development Centre 195 Oasis Radiant Computer Science, Book 8 A MAN may be wholly owned and operated by a private company, or it may be operated by a public company, such as a local telephone company. Many telephone companies provide a popular MAN service called Switched Multi-megabit Data Services (SMDS). Advantages ● MAN (Metropolitan Area Network) falls in between the LAN and WAN. It therefore increases the efficiency of handling data while at the same time saves the cost attached to establish a wide area network. ● MAN (Metropolitan Area Network) offers centralised management of data. It enables you to connect many fast LANs together. ● It is possible to use Cable TV and telephone system using MAN. Disadvantages ● More cable is required for a man connection from one place to another. ● It is difficult to make the system secure from hackers and industrial espionage. ● The larger the network becomes the more difficult to manage. Wide Area Network The term Wide Area Network (WAN) is used to describe a computer network spanning a regional, national or global area. For example, for a large company the headquarters might be in Kathmandu and regional branches at Pokhara, Biratnagar, Dharan and Lamjung Bhorletar. Here regional centres are connected to headquarters through WAN. The distance between computers connected to WAN is larger. Therefore the transmission medium used is normally telephone lines, microwaves and satellite links. A wide area network provides long-distance transmission of data, voice, image, and video information over a large geographical area that may comprises a country, a continent or even the whole world. In contrast to LAN, WANs may utilise public, leased, or
Oasis Radiant Computer Science, Book 8 196 Approved by Curriculum Development Centre private communication devices, usually in communication and can therefore span an unlimited number of miles. Popular example of WAN is Internet. Advantages ● Messages can be sent very quickly to any where. These messages can have pictures, sounds etc. ● Covers a large geographical area so long distance businesses can connect on the one network. ● Shares software and hardware resources with connecting workstations. ● Share information and files over a larger area. ● Large network coverage. Disadvantages ● Expensive and generally slow. ● Need a good security to restrict outsiders from entering and disrupting the network. ● Security is a real issue when many different people have the ability to use information from other computers. Protection against hackers and viruses adds more complexity and expense. ● Once set up, maintaining a network is a full-time job which requires network supervisors and technicians to be employed. Network Topologies In networking, the term topology is the way of connecting computers or nodes on a network. There are many ways in which computers are connected together in a computer network. Therefore network topology is defined as: the schemes of joining a number of computers in the form of a network. It is the standard configuration to connect the computer in a network structure. The topology of a network is the geometric representation of the relationship of all the links and the nodes to one another. There are four commonly used network topologies. These are: ● Star topology ● Ring topology ● Bus topology ● Mesh topology
Approved by Curriculum Development Centre 197 Oasis Radiant Computer Science, Book 8 Star Topology In a star network, each node (computer or other device) is directly connected to the central computer or Hub that provides connection points for nodes on the network. The star topology is the most common topology in use today. In star network, information or data is communicated from one computer to another through Hub. This forms a network configuration that looks like a star as shown in the figure. Advantages The main advantages of star topology are: ● It is easy to install and to maintain. ● You can easily add and remove nodes or computers to and from the network without affecting the network. ● If any node or computer fails, other nodes are not affected. Disadvantages The main disadvantages of star topology are: ● This type of network depends upon the central Hub. If the Hub fails the entire network will fail. ● Each computer is directly connected to the Hub through a cable, so it becomes more costly. Ring Topology In ring network, each node is connected to two adjacent nodes in the form of a closed ring or loop. In ring topology, the last node connects to the first node or computer to complete the ring. In ring topology, each node has a dedicated point-to-point connection only with the two devices on either side of it. In this network, data is communicated in one direction from node or computer to node or computer around the entire Star Topology Ring Topology
Oasis Radiant Computer Science, Book 8 198 Approved by Curriculum Development Centre ring. When a computer in ring network sends message to another computer on the network, the message travels to each node or computer until it reaches its destination. The ring network configuration is shown in figure above. Advantages The main advantages of ring topology are: ● It is less expensive than star topology. ● Nodes or computer can be easily added or removed. Disadvantages The main disadvantages of ring topology are: ● It is more difficult to install and maintain. ● If a node or computer fails, it affects the entire network. Bus Topology In bus network, all nodes are connected to a common communication medium or central cable. The central physical cable that connects the nodes is called Bus. The data is communicated between nodes in both directions through bus. A bus topology uses the multipoint connection. The central single cable (or bus) acts as backbone to link all the devices to the network. In bus network, when a computer sends a message to another computer it also attaches the address of the destination computer. In bus topology, a special device called a terminator is attached at the cable’s start and end points. A terminator stops the network signals. In LAN, bus topology is mostly used. In this topology, each computer is assigned a unique address. The bus network configuration is given in above figure. Advantages The main advantages of bus topology are: ● It is less expensive and easy to install and maintain. ● When nodes are added and removed to and from the network, the network is not affected. ● If one node fails other nodes are not affected. Bus Topology
Approved by Curriculum Development Centre 199 Oasis Radiant Computer Science, Book 8 Disadvantages ● The main disadvantages of bus topology are: ● It supports only a small number of nodes. ● Entire network fails if there is any problem in the central cable. Mesh Topology In this topology, every node has a dedicated point-to-point connection to every other node on the network. In mesh network, each node is directly connected to all nodes on the network. This type of network involves the concept of routes. In this type of network, each node may send message to destination through multiple paths. It means that each node of mesh network has several possible paths to send (or to receive) message, but in Bus, Star, Ring and Tree topologies each node has only one path. Advantages ● Mesh topology has the following advantages: ● It has multiple links, so if one route is blocked then other routes can be used for data communication. ● Each connection can have its own data load, so the traffic problem is eliminated. ● It ensures the data privacy or security, because every message travels along a dedicated link. ● It is high speed data transmission network. ● Its performance is not affected with heavy load of data transmission. Disadvantages ● Mesh topology has the following disadvantages: ● It becomes very expensive because a large number of cabling and 110 ports are required. ● It is difficult to install and it is very complex. Mesh Topology
Oasis Radiant Computer Science, Book 8 200 Approved by Curriculum Development Centre Key Points ● Connection of multiple computers to share the resources is called computer networking. ● User is allowed to share hardware, software, people and data resources using a networking system. ● A node is a connection point of networking system that can generate process and transfer data. ● Server computer hosts all networking system. It serves the disk space, file and data to other users. ● Client is user terminal who utilises the resources given by the server. Client has its own disk space, file and data but if required it gets from the server. ● Basically there are two sides on networking, server side and client side. ● Some components required to connect computer networking are network interface card (NIC), server and client computers, communication media, network connecting devices and signal conversion devices. ● A client server network is a network where at least one computer works like server that controls other computers work like client. ● Peer to peer network is simple connection of computers where all computers work like server and clients. ● Network topology is the connection configuration of computer in a network structure. ● Wide area network (WAN) connects the computers that span multiple geographic locations. ● MAN (Metropolitan area network) connects the computers that spans in different locations of metropolitan city. ● LAN (Local Area Network) connects the computers in a limited location locally like within a building or near by buildings.