Foundation Courses - ICT 2

Unit-I :

Fundamentals of Internet : Networking Concepts, Data Communication – Types of Networking, Internet and its Services, Internet Addressing – Internet Applications – Computer Viruses and its types – Browser –Types of Browsers.

Q) Explain Data Communication and its components.

Data communication is nothing but the exchange of data between two devices.

·      Communication devices must be part of communication system.

·      It is made up of a combination of software and hardware.

Characteristics are delivery, accuracy, timelines and jitter.

1.    Delivery: The system must deliver data to the correct destination

2.    Accuracy:The system must deliver the data accurately.

3.    Timelines:The system must deliver data in a timely manner

4.      Jitter:Jitter refers to the variation in the packet arrival time.

Data communication refers to the exchange of data between a source and a receiver via form of transmission media such as a wire cable. The device that transmits the data is known as source and the device that receives the transmitted data is known as receiver.

The Figure is an illustration of a simple data communication system.

 

Components of data communication system

A Communication system has following components: 

1. Message: It is the information or data to be communicated. It can consist of text, numbers, pictures, sound or video or any combination of these.

2. Sender: It is the device/computer that generates and sends that message.

3. Receiver: It is the device or computer that receives the message. The location of receiver computer is generally different from the sender computer. The distance between sender and receiver depends upon the types of network used in between.

4. Medium: It is the channel or physical path through which the message is carried from sender to the receiver. The medium can be wired like twisted pair wire, coaxial cable, fiber-optic cable or wireless like laser, radio waves, and microwaves.

5. Protocol: It is a set of rules that govern the communication between the devices. Both sender and receiver follow same protocols to communicate with each other.

Q) Explain types Different Types of Networks

A network is simply a group of two or more computer systems linked together in some way so that they can share data between them.

Types of Communication Networks

 

 

 

1. Local Area Network (LAN):  It is also called LAN and designed for small physical areas such as an office, group of buildings or a factory. LANs are used widely as it is easy to design and to troubleshoot. Personal computers and workstations are connected to each other through LANs. We can use different types of topologies through LAN, these are Star, Ring, Bus, Tree etc.

LAN can be a simple network like connecting two computers, to share files and network among each other while it can also be as complex as interconnecting an entire building. LAN networks are also widely used to share resources like printers, shared hard-drive etc.

2. Metropolitan Area Network (MAN):  It was developed in 1980s.It is basically a bigger version of LAN. It is also called MAN and uses the similar technology as LAN. It is designed to extend over the entire city. It can be means to connecting a number of LANs into a larger network or it can be a single cable. It is mainly hold and operated by single private company or a public company.

3. Wide Area Network (WAN): It is also called WAN. WAN can be private or it can be public leased network. It is used for the network that covers large distance such as cover states of a country. It is not easy to design and maintain. Communication medium used by WAN are PSTN or Satellite links. WAN operates on low data rates.

Q) Explain internet and its services.

Internet: It is a network of networks or inter connected computer networks.

Internet Services allows us to access huge amount of information such as text, graphics, sound and software over the internet. Following diagram shows the four different categories of Internet Services.

Important services of the internet are

1. World Wide Web:

 This also called web or www.

 The collection of all web pages.

 Those web pages provide a information in the form of text, pictures and audio.

2. E-mail:

 E-mail stands for electronic mail. It is most popular fastest mailing service.

 We can send and receive messages is seconds.

3. News groups:

 They are discussion groups on internet.

 They are used for free exchange of information.

4. E-commerce:

 It stands for Electronic commerce.

 Buying and selling can be done through internet. Ex: online shopping and banking.

5. FTP:

 FTP stands for file transfer protocol. It can be used to transfer files easily.

 Multimedia files can be uploaded and downloaded using FTP.

6. Telnet:

 It is used to access remote computer.

7. Chat:

Two or more users can live chat with each other.

8. Gopher:

 Gopher is used to search for files via menus.

Q) Write a note on INTERNET ADDRESSING:

·      An internet address uniquely identifies a computer on the internet.

·      It may also referred to the name or IP address of a website.

·      Format of IP address is a 32 bit numeric address written as 4 numbers separated by dots.

·      Ex: 1.160.10.240

·      4 numbers in an IP address are used in different ways to identify a particular network and a host on that network.

Three classes of IP address:

Class A: supports 16 million hosts on each of 126 networks

Class B: supports 65 thousand hosts on each of 16 thousand networks.

Class C:suppors 254 hosts on each of 2 million networks

Q)What are the applications of internet:

The internet is treated as one of the biggest invention. It has a large number of uses.

1.    Communication

2.    Job searches

3.    Finding books and study material

4.    Health and medicine

5.    Travel

6.    Entertainment

7.    Shopping

8.    Stock market updates

9.    Research

10. Business use of internet: different ways by which intenet can be used for business are:

•      Information about the product can be provided can be provided online to the the customer .

•      Provide market information to the business

•      It help business to recruit talented people

•      Help in locating suppliers of the product .

•      Fast information regarding customers view about companies product

•      Eliminate middle men and have a direct contact with contact with customer .

•      Providing information to the investor by providing companies back ground and financial information on web site.

Q) Explain Computer Virsus and What are the different types of computer viruses?

A computer virus is a program which can replicate and attach itself to a program or files infecting the system without its knowledge. A Computer virus can be spread from one host to another by sharing infected file or by downloading infected files from un-trusted sources .All computer viruses are man-made, they spread only with human assistance and support.

 

1. Boot sector virus:  This type of virus can take control when you start — or boot — your computer. One way it can spread is by plugging an infected USB drive into your computer.

2. Web scripting virus: This type of virus exploits the code of web browsers and web pages. If you access such a web page, the virus can infect your computer.

3. Browser hijacker: This type of virus “hijacks” certain web browser functions, and you may be automatically directed to an unintended website.

4. Resident virus: This is a general term for any virus that inserts itself in a computer system’s memory. A resident virus can execute anytime when an operating system loads.

5. Direct action virus: This type of virus comes into action when you execute a file containing a virus. Otherwise, it remains dormant.

6. Polymorphic virus:  A polymorphic virus changes its code each time an infected file is executed. It does this to evade antivirus programs.

7. File infector virus: This common virus inserts malicious code into executable files — files used to perform certain functions or operations on a system.

8. Multipartite virus: This kind of virus infects and spreads in multiple ways. It can infect both program files and system sectors.

9. Macro virus: Macro viruses are written in the same macro language used for software applications. Such viruses spread when you open an infected document, often through email attachments.

Q) Explain briefly about we browser and its types

Web Browser : A web browser is an interface that helps a computer user gain access to all the content that is on the Internet and the hard disk of the computer. It can view images, text documents, audio and video files, games, etc. More than one web browser can also be installed on a single computer. The user can navigate through files, folders and websites with the help of a browser. When the browser is used for browsing web pages, the pages may contain certain links which can be opened in a new browser. Multiple tabs and windows of the same browser can also be opened.

There are four leading web browsers: Explorer, FireFox, Netscape and Safari but there are many others browsers available.

·         Netscape : Netscape is one of the original Web browsers. This is what Microsoft designed Internet Explorer to compete against. Netscape and IE comprise the major portion of the browser market. Netscape was introduced in 1994.

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

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

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

·         Opera : Opera is smaller and faster than most other browsers, yet it is full- featured. Fast, user-friendly, with keyboard interface, multiple windows, zoom functions, and more. Java and non Java-enabled versions available. Ideal for newcomers to the Internet, school children, handicap and as a front-end for CD-Rom and kiosks.

·         Google Chrome :This web browser was developed by Google. Its beta and commercial versions were released in September 2008 for Microsoft Windows. It has soon become the fourth-most widely used web browser with a market share of 1.23%. The browser versions for Mac OS X are under development. The browser options are very similar to that of Safari, the settings locations are similar to Internet Explorer 7, and the window design is based on Windows Vista.