UNIT 1 Ques & Ans

INFORMATICS PRACTICES (065)

CLASS-XII

UNIT I – NETWORKING AND OPEN STANDARDS

Q1. Define network. Why is it needed?

                                    OR

What are goals of network?

Ans. A network is an interconnected collection of autonomous computers. Major reasons that emphasize on the need of network are:-

1. Resource Sharing – Through a network, data software and hardware resources can be shared irrespective of the physical location of the resources and the user.

2. Reliability – A file can have its copies on two or more computers of the network, so if one of them is unavailable, the other copies could be used. That makes a network more reliable.

Q2. Define the following terms:-

1. Node - A computer that is attached to a network is known as Node.

2. Workstation – A node is also called a workstation.

3. Server – A computer that facilitates sharing of resources on a network.

4. NIU (Network Interface Unit) -  It is an interpreter that helps establish communication between the server and the workstations.

Q3. What are the uses of microwave signals?

Ans. Microwave Signals are used to transmit data without the use of cables. The microwave signals are similar to radio and television signals and are used for long distance communication. Moreover these signals prove cheaper than dragging trenches for laying cables and their maintenance.

Q4. Define the following:-

a. Data Channel - It is the medium used to carry information or data from one point to another.

b. Band - It is the unit of measurement for the information carrying capacity of a communication channel of analog type. It is synonymous with bps (bits per second) of digital type circuits.

c. Bps – Bits per second. It refers to a thousand bytes transmitted per second.

d. Bandwidth – It refers to the difference between the highest and lowest frequencies of a transmission channel.

Q5. What is meant by internetworking?

Ans. Internetworking is the connection of two or more networks.

Q6. What is a gateway?

Ans. A gateway is a device that connects dissimilar networks.

Q7. What is a bridge?

Ans. A bridge is a device that links two networks together.

Q8. Define:-

a. Hub - Hub is a hardware device used to connect several computers together.

b. Switch – It  is a device used to segment networks into different sub-networks called subnets.

Q9. Give full forms of following:-

a. Modem– Modulation/Demodulation

b. FM – Frequency Modulation

c. FTP – File Transfer Protocol

d. NFS – Network File Server

e. AM – Amplitude Modulation

Q10. What are repeaters?

Ans. A repeater is a device that amplifies a signal being transmitted on the network. It is used in long network lines which exceed the maximum rated distance for a single run.

Q11. Two neighbourhood schools, at a distance of 120 metres from each other, divide to join their LAN’s using UTP cable so that they can share their e-learning resources. But after joining their LAN’s they are not able to share the resources due to loss of signal in between. Which device should they use so that signal is amplified in between?

Ans. Repeater

Q12. Two doctors in the same room have connected their Palm Tops using Bluetooth for working on a group presentation. Out of the following what kind of network they have formed – LAN, MAN, PAN, WAN?

Ans. PAN (Personal Area Network)

Q13. What is the purpose of using moderm?

Ans. Modem converts digital signals to A/F (Audio Frequency) tones which are in the frequency range that the telephone lines can transmit and also it can convert transmitted tones back to digital information.

Q14. What are the two types of modems?

Ans. Modem comes in two varieties:-

a. Internal Modem - the modem that are fixed within the computer.

b. External Modem – the modem that are connected externally to a computer as other peripherals are connected.

Q15. What is the Job of Switch?

  Ans. A switch is responsible for filtering i.e. transmitting/ transforming data in a specific way and for forwarding packets of message bring transmitted between LAN segments.

Q16. What is MAC address?

Ans. The MAC address refers to the physical address assigned by NIC manufacturer. For eg. 10:B5:03:63:2E:FC is a MAC address.

Q17. How would you extract manufacturer id and card from MAC address?

Ans. The first three bytes of a MAC address provide or represent manufacturer id and the last three bytes provide the manufacturer card no.

Q18. On a network, this is your computer’s unique hardware number. What is it?

Ans. MAC address

Q19. This is the numbered address (four parts separated by periods) that identifies a website uniquely. What is it?

Ans. An IP address

Q20. This is the mechanism that obtains an IP address using a URL of a website. What is it?

Ans.  Domain Name Resolution

Q21. What is IP address?

Ans. Every machine on a TCP/IP network has a unique identifying number called an IP address for eg. 202.27.94.137 is an IP address.

Q22. Sujats says that the following numbers indicate an address 208.77.186.166.What is the above address called? To which object/device is it assigned?

Ans. Te above address is called an IP address or Internet Protocol. It is a numerical label that is assigned to devices participating in a network.

Q23. Jai Khanna is confused between the terms Domain Name and URL. Explain the difference with the help of appropriate examples of each.

Ans. A URL (Uniform Resource Locator) is the complete address of a document on the web, whereas a domain name specifies the location of a document’s web server. A domain name is a component of the URL used to access websites. For eg. http://www.example.net/index.html. In this www.example.net is the domain name.

Q24. Name two transmission media for networking.

Ans. a. Coaxial Cable                         b. Microwave

Q25. How is coaxial cable different from optical fibre cable?

Ans. Coaxial cable have solid wire core surrounded by one or more foil or wire shields whereas optical fibres consists of thin strands of glass or glass like material. Coaxial cables transmit electrical signals where optical fibres transmit light signals or laser signals.

Q26. Arrange the following communication channels in ascending order of their data transmission rates. Ethernet cable, Optical fibre, Telephone cable, Coaxial cable.

Ans. Telephone cable, Ethernet cable, Coaxial cable and Optical fibre.

Q27. What do you understand by firewall?

Ans. The system designed to prevent unauthorized access to or from a private network is called firewall.

Q28. Define Snooping and Eaves Dropping

OR

Define any two threats to the network security.

Ans. Snooping – It refers to the unauthorized access of someone else’s data, e-mail, computer activity, or data communication.

Eaves Dropping – It is the act of secretly listening / intercepting someone’s else private communication/data/information.

Q29. What are DOS attacks?

Ans. Denial of Service (DOS) attacks are those attacks that prevent the legitimate users of the system, from accessing or using the resources, information or capabilities of the system.

Q30. What is OSS?

Ans. OSS refers to open source software, which is modifiable, redistributable software but it may not be free of charge.

Q31. Which protocol is used for the transfer of hypertext documents on the internet?

Ans. HTTP (Hyper Text Transfer Protocol)

Q32. Expand the following:-

OSI - Open Source Initiative

FLOSS - Free Libre/ Livre and Open Source Software

FSF - Free Software Foundation

GNU - GNU’s not Unix

GPL - General Public Licence

W3C - World Wide Web Consortium

OSS - Open Source Software

Q33. What for are these software used?

Ans.  a. LINUX – It is an operating system. It is the most famous example of free software and open source software, as it is not only freely available but also its source code is available to all and anyone can freely openly use it, modify it and re-distribute it.

b. GNU – GNU refers to GNU’s not unix. GNU project was initiated by Richard M Stallman with an objective to create a system compatible to unix but not identical with it. With time GNU project expanded and now it is not limited to only an operating system. It offers a wide range of software including applications apart from operating system.

c. Mozilla – Mozilla is another software which is freely available. It is cross platform, internet software suite that includes:-

1. Web Browser

2. An e-mail client

3. An HTML editor

4. IRC client Mozilla’s Web Browser is called Firefox.

d. Apache – Apache Web Server or Apache HTTP Server is an open source web server available for many platforms such as BSD, Linux, Unix, Microsoft Windows. It is developed and maintained by an open community of developers under the auspices of Apache Software Foundation. (apache.org)

Apache is the web server component of the popular web server component of the popular web server set of programs – LAMP (Linux, Apache, MySQL and PHP)

e. POSTgreSQL – It is a free object oriented relational database server (RDBS) released under the flexible BSD style license. It offers an alternative to other open source database systems (such as MySQL and Firebird) as well as proprietary systems such as Oracle, Sybase, Microsoft SQL server.

f. Python – Python is an interpreted, interactive programming language created by Guido Van Rossum in 1990, originally as a scripting language for Amoeba OS capable of making system calls. Python is often compared to TCL, Perl, Scheme, Java. It is developed as an open source project, managed by non-profit Python Software Foundation.

g. PHP – A recursive acronym for (PHP: Hypertext Preprocessor) is a widely used open source programming language primarily for server side applications and developing dynamic web content. Famous examples of PHP applications include phpBB and Mediawiki.

h. Open Office – Open Office or open office.org is an application’s suite. It is intended to be compatible and directly compete with Microsoft Office. It is free software under LGPL or SISSL and is available for Microsoft Windows.

i. OSI – Open Source Initiative. It is an organization dedicated to cause of promoting open source software. Bruce Perens & Erics Raymond were the founders of OSI that was founded in February 1998. OSI specifies criteria for open source software and properly defines the terms and specifications of Open Source Software.

j. Tomcat – Tomcat functions as a servlet container developed under the Jakarta Project at the Apache Software Foundation. Tomcat implements the servlet and the Java Server Pages (JSP) specifications from Sun Micro-Systems. It is considered to be an application server.

Q34. What is open office.org?

Ans. It is an open source office applications suite compatible with Microsoft Office.

Q35. What is a standard? What are the different types of standard?

Ans. It refers to an established set of rules for/approved by a recognized body and is widely used across various software platforms eg. PDF is a technical standard.

They can be of following types:-

1. Proprietary Standard – These are those for which users have to buy license to use them. In other words, their specifications are available to users under restrictive contract terms. Their specifications is not publicly available. They are owned by a single company standards like Microsoft Office formats. (eg. doc, docx, ppt etc.) are proprietary standards.  
2. Open Standard- These are internationally accepted technical standards that guarantee that data can be exchanged / is accessible across platforms and applications, even as technologies change. In simple words the specification of open standards is open to all. It  is publicly and freely available without any restrictions.

Q36. Which of the following are open standards and which are proprietary standards?

Ans.

1. AIFF - Proprietary (Apple Macintosh’s)
2. ASX - Proprietary ( Microsoft’s )
3. OGG - Open
4. FLAC - Open
5. RM - Proprietary (Real Media)
6. HTML - Open
7. Plain Text - Open
8. WMA - Proprietary (Microsoft)
9. SVG - Open
10. JPEG - Open
11. PNG - Open
12. DVI - Open

Q37. Name an open standard for the following:-

Ans.

i. Web page. HTML

ii. Office document.DDF

iii. Vector Images.SVG

iv. Audio Compression.OGG

v. Any image type.PNG

Q38. Which of the following softwares are Open Source:-LINUX, MS WINDOWS 7, Photoshop, MySQL

Ans. Linux and MySQL

Q39. What is a font?

Ans. A font refers to a set of displayable text characters (called glyphs) having specific style and size.

Q40. What are font categories?

Ans. Fonts can be categorized on the basis of two parameters:-

1. On the basis of technical specifications.
2. On the basis of font configurations.

Technical Specifications                                             Font Configurations

1. True Type Font (TTF)                                                 1. Static Font
2. Open Type Font (OTF)                                               2. Dynamic Font

Q41. Define the following terms:-

Ans. ODF – It refers to an open document file format for saving and exchanging office documents such as memos, reports, spreadsheets, databases, charts and presentations.

Open document is an open XML based file format. It is an open standard, supported by the OASIS and ISO standard groups.

Ogg Vorbis – It is a new audio compression format. It is roughly comparable to other formats used to store and play digital music such as MP3, VQF, AAC and other digital audio formats. It is different from these other formats because it is completely free, open and free lossy audio compression project by xiph.org foundation.

TTF (True Type Font) – It is a font format developed by Apple and licensed to Microsoft. True Type is the native operating system font format for windows and MaCOS. True Type fonts are normally 8 bits fonts.

OTF (Open Type Font) - This format is an extension of the True Type font. Open Type fonts are 16 bit fonts that allow the handling of large glyph sets Unicode encoding.

Q42. What is an Indian script key map known as?

Ans. Inscript key maps

Q43. Name any two encodings used for Indian languages computing.

Ans. Unicode and ISCII (Indian Standard Code for Information Interchange)

Q44. Name any four Indian scripts included in Unicode.

Ans. Bengali, Malayalam, Devnagri, Gurmukhi, Gujarati, Tamil. Telugu, Kannada

Q45. In how many ways one can type Indian script on a computer?

Ans. In two different ways, the Indian scripts can be entered:-

1. Using phonetic text entry
2. Using keymap based entry

Q46. Which of the following is not a characteristics of Open Source Software?

1. It is owned by a company or by an individual.
2. It’s source code is available for modification.
3. It can be downloaded from internet.

Ans. It is owned by a company or an individual.

Q47. What are different types of networks?

Ans. Networks vary widely in their size, complexity and geographical spread. On the basis of geographical spread, they can be categorized as:-

LAN (Local Area Network) - They are computer networks confined to a localized are such as an Office or a factory.

MAN (Metropolitan Area Network) - These are the networks that link computer facilities within a city.

WAN (Wide Area Network) - These are the networks that spread over large distances, say across countries or even continents. It can even include a group of LAN’s connected together. It can even include a group of LAN’s connected together.

Q48. What is a communication channel? What choices do you have while choosing a communication channel for a network?

Ans. Communication channels mean the connecting cables that link various workstation. There are three basic types of cables:-

1. Twisted Pair Cable – These cables consist of two insulated copper wires twisted around each other. These are also used for short and medium range telephone communication.
2. Coaxial Cable – A coaxial cables consists of one or more small cables in protective covering. These are more expensive than twisted pair cables but perform better.
3. Fibre Optic Cable – These cables are made of plastic or glass and are about as thick as human hair. These cables are highly durable and offer excellent performance but are expensive.

Q49. What is a server? What is its role?

Ans. A computer that facilitates the sharing of data, software and hardware resources since resource sharing is the key purpose of a network, a server plays this key role. There can be two types of server:-

1. Non-dedicated Server – It is a workstation on a small network that can double up as a server.
2. Dedicated Server – On bigger networks, a computer is reserved for the cause of serving which is called a dedicated server.

Q50. What do you mean by Topology? What are the most popular topologies?

Ans. Topology refers to the way in which the workstations attached to the network are inter-connected. The most popular topologies are:-

1. Bus Topology – In this topology, all devices on network are connected to a single continuous cable called a bus. Transmission from any station travels the length of the bus in both directions and can be received by all other stations. The destination device, on identifying the address on data packet copies the data onto its disk. When the data packet reaches at either and the terminator on that end absorbs the signal, removing it from the bus. This topology can be used for smaller networks.
2. Ring Topology – A LAN using the ring topology is connected in the closed loop. The data packets transmitted, circulate along the ring. The destination station copies the packet content on recognizing its address on the packet. After a packet travels a full circle, it is removed at the source station.
3. Star Topology – In this topology each workstation is directly linked to a central node. Devices can be easily plugged or unplugged to the central node as need dictates. Any communication between the stations must pass through the central node.
4. Tree Topology – In this topology the network is shaped as an inverted tree with the central root branching and sub branching to the extremities of the network. Transmission in this topology takes place in the same way as in bus topology.

Q51. Give two advantages and disadvantages each of the following topologies.

Ans. Bus Topology – Advantages

1. Short cable length and simple layout.
2. Easy to extend.

  Bus Topology – Disadvantages

1. Fault diagnosis is difficult.
2. Fault isolation is difficult.

Star Topology – Advantages

1. It has a number of concentration points, which provide easy access for service or re-configuration of the network.
2. One device per connection.

Star Topology – Disadvantages

1. Long cable length
2. Difficult to expand
3. Central Node Dependency

Tree Topology – Advantages

1. Simulates hierarchical flow of data.
2. Easy to extend

Tree Topology – Disadvantages

1. Long cable length
2. Root dependency

Ring Topology – Advantages

1. Short Cable Length
2. No wiring closet space required.
3. Suitable for optical fibres.

Ring Topology – Disadvantages

1. Node failures causes network failure
2. Difficult to diagnose faults.
3. Network re-configuration is difficult.

Q52. What do the following protocols do?

Ans.

1. DNS (Domain Name Service) is a network service that translates domain name to associated IP address.
2. HTTP (Hyper Text Transfer Protocol) is the hyper text mark up language protocol that controls how web servers and web browsers communicate with one another. It is also responsible for transferring hyper text i.e. combination of text, audio, video, graphics, animations, images, hyper links etc. on the web.
3. HTML (Hyper Text Markup Language) that defines the structure and contents of a web page.
4. SMTP (Simple Mail Transfer Protocol) is a protocol that controls the transfer of e-mail message on internet.
5. FTP (File Transfer Protocol) is a protocol that transfers files to and from a remote host.
6. TCP/IP (Transmission Control Protocol/ Internet Protocol) is the most commonly used protocol on internet that ensures reliable end to end communication across the internet.

Q53. What are bridges? How do they differ from repeaters?

Ans. A bridge is a device that lets you think that two networks are linked together. Bridges are smart enough to know which computers are on which side of the bridge, so they only allow those messages that need to get to the other side to cross the bridge. This improves performance on both sides of the bridge. As a packet arrives at the bridge, the bridge enables examination of the physical destination address of the packet. The bridge then decides whether or not to let the packet cross.

So bridge differs from repeaters in their capability of deciding whether a particular message is to be communicated on other side or not whereas a repeater just amplifies the signal and pass it to other side.

Q54. What are hubs? How are active hubs different from passive hubs?

Ans. A hub is a device that is used to connect several computers together. Hubs can be either active or passive.

1. Active Hubs – electrically amplify the signal as it moves from the connected device to another. Active concentrators are used like repeaters to extend the length of a network.
2. Passive Hubs – allow signal to pass from one computer to another without any change.

Q55. Write short note on network security.

Ans. Network security refers to making efforts to make sure that only legal or authorized users and programs gain access to network or network resources. Various protection methods that are used for network security are:

1. Authorization – It determines whether the service provider has granted access to the web service to the requestor. Basically, authorization confirms the service requestor’s credentials.
2.  Authentication – It ensures that each entity involved in using a web service – the requestor, the provider and the broker (if there is one) is what it actually claims to be.
3. Encrypted Smartcards – It is a hand held smart card that can generate a token that a computer system can recognize. Every time a new and different token is generated, which even though cracked or hacked cannot be used later.
4. Bio-metric Systems – It forms the most secure level of authorization. The bio-metric system involves some unique aspect of a person’s body such as finger prints, retinal patterns etc to establish his/her identity.
5. Firewall – A system designed to prevent unauthorized access to or from a private network is called firewall.

Q56. When would you prefer:-

i.                    Hubs over repeaters- When more than two computers are to be networked. Hubs can connect multiple computers simultaneously.

ii.                  Bridges over hubs – When we do not want to broadcast data frames. Bridges can filter network traffic based on MAC addresses.

iii.                Switch over other network devices – A switch can replace multiple bridges and offer dedicated bandwidth to each LAN segment. Thus switches are preferred when we want to have dedicated bandwidth for each LAN segment.

Q57. Which of the following i) is not a broadcast device ii) offers a dedicated bandwidth

a)      Repeater

b)      Bridge

c)      Hub

d)     Switch

Ans.

i) Bridge is not a broadcast device, as it filters traffic depending upon the receiver’s MAC address.

ii) Switch offers dedicated bandwidth

Q58. What are open source based software?

Ans. Open source software are the software that can be freely used in terms of making modifications, constructing business models around the software and so on, but it may not be free of charge. Important thing is that in open source software, the source code is freely available to the customer.

Q59. What is free software? How it is different from OSS?

Ans. Free software means the software is freely accessible and can be freely used, changed and distributed by all who wish to do so. And no payments are needed to be made for free software. OSS is difficult from free software in the sense that it does not have to be free of charge.

Q60. How is free software different from freeware?

Ans. Free software is the software available at no cost and no restrictions i.e. it can be copied, modified and re-distributed also. Freeware on the other hand is free of cost, can be copied and re-distributed but can’t be modified as no source code is available.

Q61. Compare and contrast:-

1. OSS and Floss – OSS refers to Open Source Software which refers to the software whose source code is available to customers and it can be modified and re-distributed without any limitations. An OSS may come free of cost or with a payment of nominal charges that its developers may charge in name of development, support of software.

Floss – Free libre and open source software is used to refer to a software which is both free software as well as open source software. Here libre means freedom.

2. Proprietary & Free software – Proprietary software is the software that is neither open nor freely available. Its use is regulated and further distribution and modification is either forbidden or requires social permission by the supplier or vendor. Source code of proprietary software is normally not available.

Free software – means the software that is freely accessible and can be freely use, changed or improved, copied and distributed by all who wish to do so. And no payments are needed to be made for free software.

3. Freeware and Shareware – The term freeware has no clear definition but is generally used for software which is available free of cost and which allows copying and further distribution but not modification and whose source code is not available. Freeware should not be mistaken for open software or free software.

Shareware is software which is made available with the right to re-distribute copies, but it is stipulated that if one intends to use the software, often after a certain period of time then a license fee should be paid.

Q62. Discuss different categories of technological standards?

Ans.  The technical standards can be broadly categorized into:-

1. Proprietary Standard – They are those for which users have to buy license to use them. In other words their specifications are available to users under restrictive contract terms. Their specification is not publically available. They are owned by single company/person/vendor/or group of vendors.
2. Open Standard – Open standards are internationally accepted technical standards that guarantee that data across platforms and applications, even as technologies change. In simple words the specifications of open standard is open to all i.e. publicly and freely available without any restrictions.

Q63. Mention some advantages of open standards.

Ans.

1. The data is accessible to all without any restrictions.
2. No hidden information

Q64. What are different font categories?

Ans. Fonts can be categorized on the basis of two parameters:-

1. On the basis of technical specifications

a.       TTF (True Type Font)

b.      OTF (Open Type Font)

2. On the basis of font configuration

a.       Static Font

b.      Dynamic Font

Q65. Compare and contrast between the Static and Dynamic font.

Ans.

1. In static font the characters are designed and digitized and then stored in font files. Every time printing takes place, same character will appear with same shape.
2. Dynamic fonts – In dynamic fonts the characters are re-defined at each occurance (i.e. every time they are displayed or printed) rather than when the font is created and digitized. Dynamic fonts generate different font shape using certain parameter values.

Q66. What is the significance of Unicode?

Ans. Unicode provides a unique number for every character, no matter what the platform, no matter what the program, no matter what the language. The Unicode standard has been adopted by such industry leaders as Apple, HP, IBM, Microsoft.

Like other languages across the world, Unicode has also incorporated many Indian scripts such as Bengali, Malayalam, Devnagri, Gurmukhi, Gujarati, Tamil. Telugu, Kannada.