computer Network Abbreviations in class XII.pdf

All about the network abbreviations.

1. COMMUNICATION TECHNOLOGY – 10 MARKS
Write the Full Form of the following :
ARPANET – Advanced Research Project Agency Network
DOD – Department of Defence
LAN – Local Area Network
MAN – Metropolitan Area Network
WAN –Wide Area Network PAN–
Personal Area Network
E – MAIL –Electronic Mail
ISP – Internet Service Provider
WWW – World Wide Web
TCP – Transmission Control Protocol
IP – Internet Protocol
FTP – File Transfer Protocol
PPP – Point to Point Protocol
SLIP – Serial Line Internet Protocol
IMAP – Internet Mail Access Protocol
POP – Post Office Protocol
MODEM – Modulator De-Modulator
BPS – Bits Per Second
GSM – Global System for Mobile
GPRS – General Packet Radio Switching
SMS – Short Message Service
FDM – Frequency Division Multiplexing
TDM – Time Division Multiplexing
WDM – Wavelength Division Multiplexing
SMTP – Simple Mail Transfer Protocol
URL – Uniform Resource Locator
HTTP – HyperText Transfer Protocol
ISDN – Integrated Service Digital Network
HTML – HyperText Markup Language
Cc – Carbon Copy
BCc – Blind Carbon Copy
VERONICA-Very Easy Rodent Oriented Net-wide Index to Computer Archives
WAIS – Wide Area Information System
DHTML – Dynamic Hyper Text Mark-up Language
XML – Extended Mark-up Language
DBMS – Database Management System
CB – Citizen Band
GHz – GigaHertz
KBPS – Kilo Bits Per Second
IMAP – Internet Mail Access Protocol
POP – Post Office Protocol
CDMA – Code Division Multiple Access
WLL – Wireless Local Loop
UMTS – Universal Mobile Telecommunications System
FDDI – Fiber Distributed Data Interface
NFS – Network File System
IETF – Internet Engineering Task Force

2. VSNL – Videsh Sanchar Nigam Limited
DNS – Domain Name System
MTNL – Mahanagar Telephone Nigam Limited
EDI – Electronic Data Interchange
EFT – Electronic Funds Transfer
NCSA – National Center for Supercomputer Application
VOIP – Voice Over Internet Protocol
GNU – GNU‟s Not Unix

Q1. What is a Network?
Ans : A network is an interconnected collection of autonomous computers which are
capable of exchanging information and resources.
Q2. What is the need for Networking?
Ans : Networking is necessary for the following reason :
(i) To share computer files.
(ii) To share computer peripheral.
(iii) To enable different computers to communicate with each other.
(iv) Access to remote database.
(v) To improve communication speed and accuracy.
(vi) To reduce cost transfer.

Q3. What is ARPANET?
Ans : ARPANET acronym for Advanced Research Projects Agency Network. It is the first
network designed in 1960 by the DOD (Department of Defence) in USA. By 1983,
the ARPANET was stable and successful with over 200 IMPs (Mini Computers called
Interface Message Processors) and hundreds of hosts. It eventually connected
hundreds of universities and government installations using leased telephone lines.
Q4. What are Nodes?
Ans : Nodes refers to the computers that are attached to a network and are seeking to share
the resources of the network. A node is also called Workstation.
Q5. What is Server?
Ans : A remote computer that facilitates the sharing of data, software and hardware
resources on the network, is called as server .

Q6. Define the different types of Networks?
Ans : There are three types of networks .
(i) LAN: LAN stands for Local Area Network. It is confined to relatively small areas
such as a building or a group of buildings. It is a computer network designed to cover
small geographical area and connect a relatively small number of computers. The
hardware as well as software resources are shared through LANs. The main
communicating media used in this network is the twisted pair wire or coaxial cable.
(ii) MAN: MAN stands for Metropolitan Area Network. MAN covers Metropolitan
cities or a town. The scope of MAN lies between LANs and WANs. It covers larger
geographical area than LAN. The main communicating media used in this network is
the Optical Fibres.
(iii) WAN: WAN stands for Wide Area Network. It is a computer network that
connects two or more LANs, usually across long geographic distance. It covers the
whole world. Communicating media used in this network are artificial satellite and
public telephone lines. Internet is in the category of this network. Large number of
computers can be connected in this network which is capable of sharing data and
information.

Q7. What is the difference between LAN and MAN?
Ans : LAN and MAN are different in their geographical area and the speed of transfer. LAN
is restricted to one building or nearby two or three buildings but MAN can cover one
Metropolitan city or a town.

3. Q8. What is the difference between LAN and WAN?
Ans : (i) LAN covers small geographical area while WAN covers large geographical area.
(ii) In LAN the distance between the nodes is limited. But there is no upper limit in
WAN.
(iii) LAN operates between 1 and 10 mbps while WAN operates at a speed of less
than 1 mbps.
Q9. What is a Network Interface Unit (NIU) ?
Ans: A Network Interface Unit is an interpreter that helps to establish communication
between the Server and Workstations. It is a device that is attached to each of the
workstations and the server. Each NIU is attached to a workstation has a unique
number identifying it which is known as the node address. The NIU is also called NIC
(Network Interface Card).
Q10. What is MAC Address ?
Ans: The NIC manufacturer assigns a unique physical address to each NIC Card; this
address is known as MAC address.
Q11. How data are transmitted across networks ?
Ans: For transmitting data across networks, various switching techniques are used.
Different switching techniques are employed to provide communication between
computers. These are – Circuit switching, Message switching and Packet switching.
Q12. Define Circuit switching.
Ans: In this technique, first the complete physical connection between two computers is
established and then data are transmitted from the source computer to the destination
computer. The important property of this technique is to setup end-to-end connection
between computers before any data can be sent.
Q13. Define Message Switching.
Ans: In this technique, the source computer sends data or the message to the switching
office first, which stores the data in its buffer (Hard disk). It then looks for a free link
to another switching office and then sends the data to this office. This process is
continued until the data are delivered to the destination computers. This process is
similar to the post-office mailing system.
Q14. Define Packet Switching?
Ans: A packet switching places a tight upper limit on block size. A fixed size of packets
which can be transmitted across the network is specified. In this switching, all the
packets of fixed size are stored in main memory first and then transmitted onwards to
their destination. This improves the performance as the access time of data packets is
reduced.
“OR”
Packet switching technique that simultaneously routes and transmits data packets
from different customers over a communication channel or telephone lines, thus
optimizing the use of line. Packet switching is a form of store and forward switching
system in which messages are stored at the switch nodes (i.e. RAM) and then
transmitted onwards to their destination . A packet switching system deletes the
message from memory as soon as it reaches correct recipient. In other words, message
or data to be transmitted is divided into small packets and then send.
Q15. What is the difference between Message Switching Technique and Packet Switching
technique?
Ans: In message switching , there is no limit on block size, in contrast, packet switching
places a tight upper limit on block size. In packet switching the data packets are stored
on the hard disk where as in packet switching all the packets of fixed size are stored in
main memory first and then transmitted onwards to their destination. In message
switching the access time is more whereas in packet switching the access time is
reduced.
Q16. Define Twisted pair cable.
Ans: The twisted pair cable is a transmission medium consisting of two insulated wires
arranged in a regular spiral pattern.

4. Q17. Define Coaxial cable.
Ans : A coaxial cable consisting of one conductor, usually a small copper tube or wire ,
within and insulated from another conductor of large diameter, usually copper tubing
or copper braid. The data transmission characteristics of coaxial cable are
considerably better than those of twisted pair wire.







Q18. Define Optical Fibers cable.
Ans : Optical fibers consist of thin strands of glass or glass like material which are so
constructed that they carry light from a source at one end of the fiber to a detector at
the other end. The light sources used are either light emitting diodes (LEDs) or laser
diodes (LDs). The data to be transferred is modulated onto the light beam using
frequency modulation technique. The signal can then be picked up to the receiving
end by pin field effect transistor (Pin FET) and demodulated.
Q19. What is Microwave transmission?
Ans: Microwave is a direct line of sight radio transmission. For long distance,
communication microwave radio transmission is widely used as an alternative to
coaxial cable. It is used in the telephone system. Television transmission also utilized
microwave transmission, because microwave transmission is above the 1 GHz
frequency band and provides the capacity for video transmission.

Q20. What is Radio wave?
Ans: Radio waves are easy to generate, can travel long distances and penetrate buildings
easily. So they are widely used for communication. Radio waves are omni-directional,
i.e. they travel in all directions.

5. Q21. What is the use of Satellites in communication system?
Ans: Satellites offer a number of features not readily available with other means of
communications. Because very large areas of the earth are visible from a satellite, the
satellite can form the star point of a communications net linking together many users
simultaneously. The same feature enables satellites to provide communications links
to remote communications in sparsely populated areas who are difficult to access by
other means.






Q22. Define the term Bandwidth. Give unit of Bandwidth.
Ans: Bandwidth is the capability of a medium to transmit an amount of information over a
distance in a network. Bandwidth of a medium is generally measured in bytes per
second (bps) or more commonly in Kilobytes per second (Kbps).
Q23. What is Ethernet ?
Ans: Ethernet is a LAN architecture developed by Xerox corp. in association DEC and
Intel. It is a network device used to connect computers in LAN. It uses Bus or Star
topologies and can support data transfer rates of upto 100 Mbps.
Q24. What is a switch? Write its function.
Ans: Switch is a device used to segment networks into different sub-networks called
subnets. A switch is responsible for filtering i.e., transforming data in a specific way
and for forwarding packets of message being transmitted, between LAN segments.
Q25. What is Hub? What are its type ?
Ans: Hub is a hardware device used to connect several computers together. Hubs are multi-
slots concentrators into which a number of multi-port cards can beplugged to provide
additional access as the network grows in size. Two types of hubs are: Active Hub
and Passive Hub.
Q26. What is RJ-45 connector ?
Ans: RJ-45 stands for Registered Jack-45. It is an eight-wire connector, used to connect
computers on LANs especially Ethernets.



Q27. Define NIU.
Ans: NIU means Network Interface unit. It is an interpreter that helps to establish
communication between the server and the workstations. NIU is attached to the server
and all the workstations to maintain connection between them.
Q28. What is MAC address ?
Ans : The address for a device as it is identified at the MAC layer in the network architecture. MAC
address is usually stored in ROM on network adopter card and is unique.
Q29. What is Bluetooth?
Ans: Some companies got together to designed a sort range wireless network called
Bluetooth to connect different components without wires. The Bluetooth allows
digital cameras, headsets, mobiles, scanners and other devices to connect to a
computer by merely being brought within range. No cables, No driver installations,
just put them down, turn them on and the work.
Q30. What is Wi-Fi?
Ans: Wi-Fi stands for wireless Fidelity. It is a wireless communication system. It is a type
of wireless networking protocol that allows devices to communicate without cables.
Wi-Fi is technically an industry term that represents a type of wireless local area
network protocol based on the 802.11 IEEE network standard. It is the most popular
needs of communicating data wirelessly, within fixed locations.

6. Q31. Define Baud.
Ans: Baud is the unit of measurement for the information carrying capacity of a
communication channel. It is synonymous with bps(bits per second) . Term Baud
commonly used in data communication.
Q32. Define Data Transfer Rate.
Ans: A data transfer rate is the amount of digital data that is moved from one place to
another in a given time, usually in a second‟s time. The data transfer rate can be
viewed as the speed of travel of a given amount of data from ne place to another.

Q33. What is the function of a MODEM?
Ans: Modem acronyms for Modulation and Demodulation. It is used to convert digital
form of data into analog form (Modulation) and analog form of data into digital form
(Demodulation).So, when we use analog facility for data communication between two
digital devices we require two modems near each digital device.

Q34. What is a Bridge?
Ans: A Bridge is a network device that establishes an intelligent connection between two
local area networks with the same standard but with different types of cables. It is
placed between two LANs and acts as an address filter which picks up packets from
sender LAN.
Q35. What is a Router?
Ans: A router is a device which is used to connect two or more different logical networks.
It accomplishes the connection by organizing the large networks into logical network
segments. Each of these segments is given a logical address. A Router works like a
bridge but can handle different protocols.
Q36. What is the function of a Repeater ?
Ans: A Repeater is a network device that amplifies and restores and restores signals for
long distance transmission. It is used in long network lines, which exceeds the
maximum rated distance for a single run.
Q37. What is Gateway ?
Ans: A Gateway is a network device that connects dissimilar networks. It establishes an
intelligent connection between a local area network and external networks (Internet)
with completely different structures.
Q38. Differentiate between Serial and Parallel data transmission.
Ans: In serial transmission, each unit of data being transferred travels in sequence. When
data to be transmitted is at large distance, serial transmission option is chosen.
In parallel data transmission the transmission of characters of a word is transmitted
over different lines and usually simultaneously. In data communication, parallel data
transmission means simultaneous transmission of a certain number of signal elements
constituting the same data signal.

Q39. Differentiate between Synchronous and Asynchronous data transmission.
Ans: In Synchronous transmission, characters are transmitted as groups, preceded and
followed by control characters.
In asynchronous transmission, each character is transmitted separately, that is, one
character at a time. The character is preceded by a start bit, which tells the receiving
device where the character coding begins and is followed by a stop bit, which tells the
receiving bit where the character coding ends.

Q40. What is topology? Name the different types of topologies.
Ans: The pattern of interconnection of nodes together in a network is called the topology.
The different types of topologies are : Star Topology , Bus Topology , Ring Topology
, Tree Topology and Star-Ring Topology.
Q41. Define Star topology? What are its advantages and disadvantages?
Ans: This topology consists of a central node to which all other nodes are connected by a
single path. It is the topology used in most existing information networks involving
data processing or voice communications.

7. Advantages:
(a) They provide easy service or re-configuration of the network.
(b) Failure of a single connection typically involves disconnecting one node from an
otherwise fully functional network.
(c) In this topology central node is connected directly to every other node in the
network means that faults are easily detected and isolated.
(d) Any given connection in this network involves only the central node and one
peripheral node. So, access protocols are very simple.
Disadvantages:
(a) Long cable length increases installation cost, and also difficult to maintain.
(b) It is difficult to expand.
(c) If the central node in a network fails, the entire network is rendered inoperable.
Q42. Define Bus topology? What are its advantages and disadvantages?
Ans: Bus topology is a popular topology for data networks. This consists of a single length
of the transmission medium called BUS onto which the various nodes are attached.
Advantages:
(a) A very short cable length is used as it is a single common data path connecting all
nodes.
(b) If one of the nodes is failed then other nodes work.
(c) Additional nodes can be connected to an existing bus network at any point along
its length.
Disadvantages:
(a) Fault diagnosis is difficult.
(b) If the fault is in the network itself, an entire segment of the bus must be
disconnected.
(c) Repeater configuration.
(d) Nodes must be intelligent.
Q43. Define Ring topology? What are its advantages and disadvantages?
Ans: The ring topology is also called loop as each node is connected to two and only two
neighboring nodes. Data is accepted from one of the neighboring nodes and is
transmitted onwards to another. Thus, data travels in one direction only, from node to
node around the ring. After passing through each node, it returns to the sending node,
which removes it.



Advantages:
(a) Short cable length is needed.
(b) No wiring closet space required.
(c) Suitable for optical fibres.
Disadvantages:
(a) Node failure causes network failure .
(b) Difficult to diagnose faults.
(c) Network re-configuration is difficult.

8. Q44. Define Tree topology? What are its advantages and disadvantages ?
Ans: The shape of the network of tree topology is that of an inverted tree with the central
root branching and sub branching to the intermediates of the network.







Advantages:
(i) Easy to extend because it is easier to add new nodes or branches to it .
(ii) It is easier to isolate a defective node.
(iii) Easy to access.
Disadvantages:
(i) If the headed device fails to operate, the entire network is rendered inoperable.
(ii) Long cable length.
(iii) Central node dependency.
Q45. Define Star-Ring topology ? What are its advantages and disadvantages ?
Ans: In star-Ring Topology, two topologies are combined to achieve the best of both star
and ring topology. The configuration consists of a number of concentration points
connected together in a ring .

Advantages:
(i) It is easy to find the fault in this network and also isolation of the faulty node is
very easy.
(ii) Easy for expansion .
Disadvantages:
(i) Intelligent concentration points required.
(ii) The inter-closet cabling in a star-ring is critical to its operation.
Q46. Differentiate between Internet and Intranet?
Ans: Internet is a network of networks consisting of thousands or lakhs of networks
throughout the world. It is a wide area network. It connects the small network to
prepare a big network.
Intranet is a network that is the part of Internet. It is a small network which is
consisted in internet.
Q47. Define Telnet .
Ans: Telnet is an older Internet utility that lets us log onto remote computer systems. It is
an internet facility that facilitates remote login. Remote login is the process of
accessing a network from a remote place without actually being at the actual place of
working. If we have permitted access, then we can work on that system.
Q48. Define 1 G Mobile System ?
Ans: The 1G Mobile System was introduced in late 1970s and early 1980s.The 1G mobile
system was based on the analog cellular technology. They only had voice facility
available and were based on circuit-switched technology. In 1G mobile systems voice
was modulated to a frequency of about 150MHz and higher. They used radio towers
for transmission. The major drawbacks of the 1G system were its low capacity, poor
voice links and no security.

9. Q49. Define 2 G Mobile System ?
Ans: The 2G mobile system was introduced in early 1990s. They used digital signals for
transmissions of voice. 2G enabled the mobile systems to provide paging, SMS,
voicemail and fax services. Both voice and data conversations were digitally
encrypted. The 2G system was based on GSM technology. GSM standard was defined
by ETSI in 1989. GSM stands for Global System for Mobile Communication. GSM
technology is a combination of FDMA and TDMA. With GSM, all subscriber and
wireless provider information is stored on interchangeable modules known as SIM
(Subscriber Identification Module) cards.
Q50. Define 3 G Mobile System ?
Ans: The 3G technology adds multimedia facilities to 2G phones by allowing video, audio,
and graphics applications. With the advent of 3G technology watching streaming
video or video telephony became a reality. The idea behind 3G is to have a single
network standard instead of the different types adopted in the US, Europe, and Asia.
3G mobile systems are also known as Universal Mobile Telecommunications System
(UMTS) or IMT-2000.
Q51. Define 4 G Mobile System ?
Ans: 4G networks will be based on packet switching only. It will be able to support faster
transmission. They are projected to provide speeds up to 100 Mbps while moving and
1Gbps while stationary. It is a wireless access technology. 4G can provide better-than-
TV quality images and video-links.
Q52. What is WWW?
Ans: WWW refers to World Wide Web. It is a set of protocols that allows us to access any
document on the Net through URLs. It specifies a way, the HTTP, that allows
multimedia and hypertext documents to be opened in web browsers.
Q53. What is a Web server?
Ans: A web server is a WWW server that responds to requests made by web browsers.
Q54. What is a protocol ?
Ans: Protocol is the set of rules helps for exchanging information from one computer to
another over a network.
Q55. What is URL ? What are the different types of URL ?
Ans: URL stands for Uniform Resource Locator. It stores the address of a web page on
WWW. It gives the exact location of a web page in the server. There are two types of
URLs – Absolute URL and Relative URL.
Q56. Which two protocols are used in internet ?
Ans : TCP (Transmission Control Protocol) and IP (Internet Protocol) .
Q57. What is Web hosting ?
Ans: Web hosting is the process of uploading/saving the web content on a web server to make it
available on WWW. In case a individual or a company wants to make its website available on
the internet, it should be hosted on a web server.
Q58. What is a web browser?
Ans: A web browser is a WWW client that navigates through the World Wide Web and
displays web pages. Types of Brower‟s are Google chrome, Mozila firebox etc.
Q59. Name some web browsers .
Ans: Google Chrome, Netscape Navigator, Internet explorer, Mozilla Firefox , Opera,
Safari, Microsoft Edge, SeaMonkey, Maxthon, NetSurf etc.

Q60. Explain the terms: FTP and URL.
Ans: FTP: It is a network protocol which is used to transfer files from a computer at one
location to a remote computer usually over the internet. It Stands for File Transfer
Protocol.
URL: URL stands for Uniform Resource Locator which helps in locating and
identifying interact resources on WWW through letters, words, numbers, punctuation
etc. Basically there are 2 types of URL Absolute URL and Relative URL.
Q61. What is ISP?
Ans: ISP stands for Internet Service Provider. It is a company or organization who provides
access to the internet. To avail the facility of Internet, first an account has to be open
with Internet Service Provider. Ex: BSNL, MTNL, Satyam Online, Mantra Online etc.

10. Q62. What is Video conferencing?
Ans: When two or more participants are able to converse in real-time through video-
phones, it is called video conferencing.
Q63. What is VoIP ?
Ans: VOIP stands for voice over internet protocol. It enables the transfer of voice using
packet switched network rather than using public switched telephone network. By
using VOIP software, phone calls can be done using standard internet connection.
This method of making phone calls is much cheaper than convectional way because the
service of Telecommunication Company is not used.
Q64. What is e-mail?
Ans: E-mail stands for electronic mail. It is a medium by which we can send message from
one computer to another electronically on a network. E-mail is instantaneous and cost
effective communication medium. It can be checked and replied at one‟s convenience.
It does not have to be replied to at that very moment, unlike the telephone. It can be
reused , by either importing or cut and pasting, into reports etc. also, any type of a file
can be attached and sent.
Q65. What is spam ? How can it be avoided ?
Ans: Spam refers to the electronic junk mail or junk newsgroup postings. These are the unwanted
mails stored in the Inbox of e-mail. One way to help avoid spam mail is to create a filter that
finds and does something to e-mail that you suspect as spam.

Q66. What is Search Engine?
Ans: Search Engines are a bottom-up approach to find our way around the web. We give a
search engine a list of keywords or phrases (called a query), and it returns to us a list
of web pages that contain those words or phrases. Web search engines are actually
databases that contain references to thousands of resources. Ex : Hotbox, Yahoo,
Google, Alta Vista, WebCrawler , Magellan , Lycos , Info seek etc.
Q67. Define GSM.
Ans: Global System for Mobile Communications is a technique that uses narrowband
TDMA (Time Division Multiple Access), which allows eight simultaneous calls on
the same radio frequency. TDMA technology uses time division multiplexing and
divides a radio frequency into time slots and then allocates these slots to multiple calls
thereby supporting multiple, simultaneous data channels.

Q51. Define CDMA (Code Division Multiple Access) .
Ans: It is a digital cellular technology that uses spread-spectrum techniques. It simply
means that data is sent in small pieces over a number of the discrete frequencies
available for use at any time in the specified range.
Q68. What is chatting?
Ans: This is one of the important services by internet where users could chat with other
users who were logged into at that time. The chat service uses specialized software
that allows the user to type some comment in one window and receive the replies in
another form someone who is accessing the same software.
Q69. Define E-commerce.
Ans: The conducting of business activities online, including shopping , banking, investing
and any other venture that uses either electronic money or electronic data exchange.
Q70. What are IP addresses?
Ans: This is numbers based addressing system. Apart from there DNS (Domain Name
System) based URL‟s, the websites may also be addressed through there IP (internet
Protocol) addresses. An IP addresses may look like 203.127.54.9 or 255.154.67.4. and
so on.

Q38. What is the signification of Cyber Law?
Ans: In Internet, the communication technology uses the means of transferring textual
messages, pictures and many more. Each time there may be threats on either from the
senders or receivers side which creates a bridge between networking communication.
To short out these problems, the internet Security Council made number of
precautions, i.e. rules. These predefined rules called Cyber Law or Law of Internet.

11. Q71. What do you understand by the terms, Hackers and Crackers?
Ans: Hackers: Hackers are IT experts who work for the development of Net related
activities. The word hacker is now widely used and recognized over the world as a
computer user breaching (breaking) a system‟s security and stealing valuable
information.
Crackers: Crackers are the destructive Internet experts whose activities are breaking
passwords and destroying the Web sites of Internet. They are a malicious programmer
who breaks the server security on Net.
Q72. What do you understand by the terms Cookies and Firewall?
Ans: A small piece of information that a server sends to a client when we visit a website
with cookie capabilities, its server sends certain information about us to our browser,
which is stored on our hard drive as a text file. After some later time, the server
retrieves the cookies. It‟s a way for the server to remember things about us.
“OR”
Cookies are the messages that a web server transmits to a web browser so that the web
server can keep track of the user‟s activity on a specific web site. The browser stores
the message in a text file. The message is then sent back to the server each time the
browser requests a page from the server.

A system designed to prevent unauthorized access to or from a private network is
called Firewall. Firewall‟s are frequently used to prevent unauthorized internet user‟s
from accessing private networks connected to the internet .It is considered a first line
of defense in protecting private information.
Q73. What is computer VIRUS?
Ans: Computer VIRUS is a malicious program that requires a host and is designed to make
a system sick, just like a real virus. VIRUS„s can spread from computer to computer,
and they can replicate themselves .some VIRUS‟s are categorized as harmless pranks,
while others are far more malicious. Broadly they are 3 types of VIRUS‟s
1. File infectors.
2. Boot sector VIRUS‟s.
3. Micro VIRUS‟s
Q74. What is a Trojan Horse ? How Trojan Horses spread ?
Ans: A Trojan Horse is code hidden in a program such as a game or spreadsheet that looks
safe to run but has hidden side effects. It is generally spread through e-mail and
exchange of disks and information between computers.
Q75. What is worm ?
Ans: A worm is a program designed to replicate. These are the programs that run
independently and travel from computer to computer across network connections.It is
self –contained and does not require a host. If it is a network worm, it can replicate
across communication links.

Q76. Define Client-Side Scripting and Server -Side Scripting .
Client-Side Scripting
On some web pages the contents change in response to an action done by the user, for
example a click from the mouse or a key press from a keyboard action. Such pages use client-
side scripting. In this technology, the content is generated on the user's local computer. VB
Script and Java Script are examples of client-side scripting languages.
Server -Side Scripting
Some web pages use applications running on the server to generate the web content. Such
pages use server-side scripting language. Web page display the current time and date, forums,
submission forms, shopping carts etc., use server-side scripting. ASP,JSP, PHP are examples
of server-side scripting languages.
Q77. What is Web 2.0 ? Write some of its applications.
Ans: The term web 2.0 was given by O'Reilly Media in 2004. Web 2.0 refers to new generation of
dynamic and interactive websites. Web 2.0 websites uses a new programming language called
AJAX (Asynchronous JavaScript and XML). AJAX helps a dynamic website connect to the
web server and download small amount of data based on the interaction with the user. In this
technology only the part of the website which is updated is reloaded. The entire page does not
get reloaded each time. This helps in making the website interactive.

12. Applications supported by web 2.0 are as followings:
 blogging
 social bookmarking
 RSS
 wikis and other collaborative applications
 interactive encyclopaedias and dictionaries
 Advanced Gaming
Q78. What is cloud computing ?
Ans: Cloud computing is internet based computing, whereby shared resources , software and
information are provided to computers and other devices on demand, like the electricity grid.
The “cloud” represents the Internet.