For SLC 2072-MCQ - COMPUTER SCIENCE

1. Which is not a unguided media?

                i) Fiber Optic                       ii) Microwave                       iii) Infrared                            iv) Radio wave

2. Which is the internet service?

                i) IRC                     ii) Telnet                                iii) E-mail                               iv) All of above

3. Which is not related to multimedia?

                i) Printer                               ii) Sound Card                      iii) Microphone                     iv) CD-ROM

4. Which virus infects boot sector files?

                i) Macro virus             ii) Multi partite virus                 iii) Boot sector virus                   iv) Program virus

5. Which of the following is not a guided data communication media?

                i) Coaxial cable                    ii) Fiber optic                         iii) Twisted pair                     iv) Satellite

6. Process of arranging the scattered parts of the file into a contiguous manner.

                i) Backup                              ii) Defragmentation           iii) Debugging                        iv) All of the above

7. Which of the following is remote login service?

                i) Video conference             ii) Telnet                                iii) FTP                   iv) All of the above

8. Which of the following is an anti-virus program?

                i) NAV                    ii) Windows                           iii) Photoshop                       iv) All of the above

9. Which of the following is not a protocol?

                i) POP                     ii) TCP/IP                              iii) NOS                  iv) FTP

10. Which device protects hardware?

                i) UPS                     ii) MODEM                           iii) Gateway                          iv) All of the above

11. In which communication media data transfer is high?

                i) Twisted pair                       ii) Co-axial cable                 iii) Fiber optics                    iv) Microwave

12. Which computer virus that damages the master boot record?

                i) Macro virus                       ii) File virus                   iii) New folder virus              iv) Boot sector virus

13. E-commerce is ___________

                i) a type of business            ii) a type of virus  iii) both i) and ii)                   iv) None of the above

14. Email is a/an __________

      i) organization which controls internet      ii) protocol to access internet        iii) service of internet         iv) None

15. Which one is not a type of virus?

                i) message carrying virus   ii) boot sector virus   iii) system infector    iv) special purpose application infector

Full Form of extensions that are used in different files.

Extension	Full Form
.3GP	3rd generation protocol
.AAC	Advanced audio codec
.AC3	Dolby digital sound file
.AIIF	Audio interchange file format
.AMR	Adoptive multi rate
.AWM	Adoptive multi rate wideband
.AVI	Audio video interleaved
.CDA	Compact disk audio
.DLL	Dynamic link library
.EXE	Executable format
.FLAC	Free lossless audio codec
.FLV	Flash live video
.GIF	Graphics interchange format
.JAD	Java application development
.JAR	Java archive
.MIDI	Musical instrument digital interface
.MMF	Music mobile format
.MP2	Mpeg audio layer 2
.MP3	Mpeg audio layer 3
.MP4	Mpeg layer 4
.MPGE	Motion picture experts group
.PDF	Portable document format
.PNG	Portable network/new graphics
.RM	Real media
.SIS	Symbian installation source
.SWF	Shock wave flash
.VOB	Video object
.WAV	Waveform pcm audio
.WMA	Windows media audio
.ZIP	Zone improvement plan
.TXT	Text file
.JPG	Joint photographic experts group
.PSD	Photoshop standard document

Why is computer known as electronic device ?

Why is computer known as electronic device instead of electric though it works with the help of electricity?

Transistor and Integrated circuits(IC) are Electronic components which are used in computer, that the reason we use word "Electronic Device" for computer. 

In electronics, a transistor is a semiconductor device commonly used to amplify or switch electronic signals. A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much larger than the controlling (input) power, the transistor provides amplification of a signal. 

An integrated circuit (IC) is a small electronic device made out of a semiconductor material. The first integrated circuit was developed in the 1950s by Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor. 

in other words 

In electronics, an integrated circuit (also known as IC, microcircuit, microchip, silicon chip, or chip) is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as passive components) that has been manufactured in the surface of a thin substrate of semiconductor material. Integrated circuits are used in almost all electronic equipment in use today and have revolutionized the world of electronics.

Difference between electrical devices and electronic devices?

The answer lies in how devices manipulate electricity to do their work. Electrical devices take the energy of electric current and transform it in simple ways into some other form of energy — most likely light, heat, or motion. The heating elements in a toaster turn electrical energy into heat so you can burn your toast. And the motor in your vacuum cleaner turns electrical energy into motion that drives a pump that sucks the burnt toast crumbs out of your carpet.
In contrast, electronic devices do much more. Instead of just converting electrical energy into heat, light, or motion, electronic devices are designed to manipulate the electrical current itself to coax it into doing interesting and useful things.

That very first electronic device invented in 1883 by Thomas Edison manipulated the electric current passing through a light bulb in a way that let Edison create a device that could monitor the voltage being provided to an electrical circuit and automatically increase or decrease the voltage if it became too low or too high.

One of the most common things that electronic devices do is manipulate electric current in a way that adds meaningful information to the current. For example, audio electronic devices add sound information to an electric current so that you can listen to music or talk on a cellphone. And video devices add images to an electric current so you can watch great movies until you know every line by heart.

Keep in mind that the distinction between electric and electronic devices is a bit blurry. What used to be simple electrical devices now often include some electronic components in them. For example, your toaster may contain an electronic thermostat that attempts to keep the heat at just the right temperature to make perfect toast.

And even the most complicated electronic devices have simple electrical components in them. For example, although your TV set's remote control is a pretty complicated little electronic device, it contains batteries, which are simple electrical devices.

Dial-up Internet Access

 Recently, Nepal Telecom has doubled the capacity of its backbone connectivity, resulting in much improved speeds in browsing and other data transfer over the internet.

Dial-up Internet Access

Currently, two categories of Dialup internet access are being provided. PSTN Dialup is one out two available service

1) PSTN Dial-up

PSTN Dialup involves Dialing over normal telephone lines with modems to our number 15000. We have different Internet Packages/Rates as below in provision as per subscribers comfort and choice.

1. Fixed hour Package
   In this package, the user can use Internet for a fixed number of hours in each month during the subscribed period of six months or one year. If the fixed number of hours are utilized before the lapse of the month, this package will be inactive for the rest of the month. For example, if the subscription is for 10 hours per month for 1 year, the user can use maximum of 10 hours in each month for a year. This is also a multiple login package.
2. Home Surfing package This package offers National Roaming facility. The user can login from 19.00 to 8.00 am next day morning. This is a single user package.
3. Fixed hour / month Package
   In this package, the user can use Internet for a fixed number of hours in each month during the subscribed period of six months or one year. If the fixed number of hours are utilized before the lapse of the month, this package will be inactive for the rest of the month. For example, if the subscription is for 10 hours per month for 1 year, the user can use maximum of 10 hours in each month for a year. This is also a multiple login package.
4. Unlimited Single User Package 
   In this package, the user can surf the Internet for unlimited period of time during the subscribed period of one month, six months, one year or two years. This is a single user package.
5. Yearly email Package
   This is an e-mail package with restriction to internet surfing. The user can login into NEPAL TELECOM homepage http://www.ntc.net.np/ for changing passwords online.

2) ISDN Dial-up

ISDN dialup involves dialing over ISDN lines to our number 4241095. ISDN dialup provides connection speeds comparable to dedicated leased-lines but it can be used as required and hence comes cheaper than leased lines with comparable speeds. Can be used for high-speed Internet access, data transfer as well as video conferencing. ISDN dialup is possible over ISDN lines using special ISDN modems.

Dial 1413

Dial 1413 & Recharge

NTC Customers can now recharge there GSM Postpaid/ Prepaid Mobile, ADSL Internet 

Account, PSTN Landline bill from anywhere simply by dialing 1413.

Who owns the Internet?

Imagine you're in a room full of people from different countries, and everyone only speaks his or her native language. In order to communicate, you'd have to come up with a standard set of rules and vocabulary. That's what makes the Internet so remarkable: It's a system that lets different computer networks communicate with each other using a standardized set of rules. Without rules, these computer networks wouldn't be able to communicate with each other.

Think for a minute about the scope of the Internet. It's a collection of inter-networked computer systems that spans the entire globe. It depends on several sets of rules called protocols. These protocols make it possible for computer communication across networks. It also relies on a huge infrastructure of routers, Network Access Points (NAPs) and computer systems. Then there are the satellites, miles of cable and hundreds of wireless routers that transmit signals between computers and networks.

It's a truly global system. Cables crisscross countries and oceans, crossing borders and linking some of the world's most remote locations to everyone else. And the Internet is still growing. More computers link to it every day, and various organizations and companies are working to extend Internet access to countries that aren't yet connected.

The Internet is a giant system made up of much smaller systems. If it's one thing, does it have a single owner? Is there some person or entity that controls the Internet? Is it possible for someone to own something that spans nations and oceans? Keep reading to find out…..

The Internet's Owners

So who actually owns the Internet? There are two answers to this question:

       1.    Nobody

       2.    Lots of people

If you think of the Internet as a unified, single entity, then no one owns it. There are organizations that determine the Internet's structure and how it works, but they don't have any ownership over the Internet itself. No government can lay claim to owning the Internet, nor can any company. The Internet is like the telephone system -- no one owns the whole thing.

From another point of view, thousands of people and organizations own the Internet. The Internet consists of lots of different bits and pieces, each of which has an owner. Some of these owners can control the quality and level of access you have to the Internet. They might not own the entire system, but they can impact your Internet experience.

The physical network that carries Internet traffic between different computer systems is the Internet backbone. In the early days of the Internet, ARPANET served as the system's backbone. Today, several large corporations provide the routers and cable that make up the Internet backbone. These companies are upstream Internet Service Providers (ISPs). That means that anyone who wants to access the Internet must ultimately work with these companies, which include:

       ·         UUNET

       ·         Level 3

       ·         Verizon

       ·         AT&T

       ·         Qwest

       ·         Sprint

       ·         IBM

Then you have all the smaller ISPs. Many individual consumers and businesses subscribe to ISPs that aren't part of the Internet backbone. These ISPs negotiate with the upstream ISPs for Internet access. Cable and DSL companies are examples of smaller ISPs. Such companies are concerned with what the industry calls the last mile -- the distance between the end consumer and Internet connectivity.

Within the backbone are Internet Exchange Points (IXPs), which are physical connections between networks that allow data exchanges. For example, while Sprint, Verizon and AT&T provide part of the Internet backbone's infrastructure, the three networks aren't intertwined. They connect together at an IXP. Several companies and non-profit organizations administer IXPs.

The individual computer networks that make up the Internet can have owners. Every ISP has its own network. Several nations' governments oversee computer networks. Many companies have local area networks (LANs) that link to the Internet. Each of these networks is both a part of the Internet and its own separate entity. Depending on local laws, the owners of these networks can control the level of access users have to the Internet.

You might consider yourself to be an owner of the Internet. Do you own a device that you use to connect to the Internet? If so, that means the device you own becomes part of the enormous inter-networked system. You are the proud owner of part of the Internet -- it's just a very small part.

If no one owns the Internet, who is responsible for making sure everything works? Find out in the next section.

IN THE BEGINNING, THERE WAS ARPANET

ARPANET was a network of computers housed in various universities, government agencies and research facilities. The people who built ARPANET designed many of the protocols that the Internet uses today. ARPANET connected to several other computer networks and the Internet was born. The agency responsible for ARPANET was the Defense Advanced Research Projects Agency (DARPA), a branch of the United States Department of Defense (DoD). Since ARPANET began as a U.S. government-sponsored project, you could argue that at one time, the U.S. government owned the Internet.

…………..

The Internet's Caretakers

As mentioned earlier, the Internetworks because of a system of rules called protocols. By following these protocols, computers can send information across the network to other computers. If there were no protocols, then there'd be no guarantee that the information sent from one computer could be understood by another, or that it'd even reach the right destination.

As the Internet evolves, these protocols must also change. That means someone has to be in charge of the rules. There are several organizations that oversee the Internet's infrastructure and protocols. They are:

      ·         The Internet Society: A nonprofit organization that develops Internet standards, policies and education.

      ·         The Internet Engineering Task Force (IETF): An international organization with an open membership policy that has several working groups. Each working group concentrates on a specific topic, such as Internet security. Collectively, these working groups try to maintain the Internet's architecture and stability.

      ·         The Internet Architecture Board (IAB): An IETF committee, the IAB's mission is to oversee the design of Internet protocols and standards.

      ·         The Internet Corporation for Assigned Names and Numbers (ICANN): A private nonprofit corporation, ICANN manages the Internet's Domain Name System (DNS). ICANN is responsible for making sure that every domain name links to the correct IP address.

The Internet Society and IETF are open membership organizations. Both welcome the participation and input of Internet experts. They shape the way the Internet works and evolves.

ICANN, on the other hand, is a private organization. The exclusive nature of ICANN concerns some people. They argue that ICANN holds a lot of power over anyone who wants to register a domain name. ICANN makes money by accrediting vendors called registrars. These registrars then sell domain names to consumers and businesses. If you want to register a specific domain name, ultimately ICANN decides if you can have it.

While none of these organizations own the Internet, they each influence how the Internet works. The Internet has no central owner. While its structure remains carefully designed and maintained, the actual content on the Internet continues to be the untamed cyberspace we all know and love.

DOMAIN NAMES

Think of the Internet as a massive map. Every computer connected to the Internet is a location with a physical address on that map. On the Internet, this address is a series of numbers called an IP address. It's not easy to remember a list of seemingly random numbers. Fortunately, the people who created Internet protocols recognized this problem and came up with a solution: Domain names. A domain name uses words instead of numbers for Internet addresses.