Tuesday, 17 July 2012

123 Short Questions and their Answers about Computers


123 Short Questions and their Answers about Computers by Muhammad Waqas at muftarticles

1.    What is Networking?
Collection of computer and devices connected via communication devices and transmission media called Networking.
2.    What is Networking Devices?
Common devices are used in networking following:
Modem, Hub, Repeater, Bridges, Router, and Gateway.                                       
3.    What is Computer Communication?
The process in which two or more Computer or devices transfer data instruction and information is called Computer Communication.
4.    Why we need the networking?
Computer networks help users on the network to share the resources and in communication. Can you imagine a world now without emails, online news papers, blogs, chat and the other services offered by the internet?
The following are the important benefits of a computer network.
File sharing, Hardware sharing, application sharing, user communication.
5.    What is LAN?
LAN Stands for (Local Area Network). Network that limited geographical area such as home or office building Metro is called LAN.  Data transmission speed of LAN is 1 to 100 Mb per second.
6.    What is WAN?
WAN  stands for (Wide Area Network). Network that covers large geographical area using many types of media is called WAN. Data transmission speed of WAN is 56Kbps To 45Mbps.
Internet is World‘s Largest WAN.
Basic Elements of Data Communications:
7.    What is sender?
The sender is the device that sends the information. It is also called source. Normally computer is used as sender in data communication system.
8.    What is medium?
The medium is the physical device path that connects the sender and receiver. It is used to transmit the data. The medium can be a copper wire, a fiber optic cableairwaves etc.
9.    What is Receiver?
The receiver is the device that accepts the information. It is also called sink. The receiver can be computer, printer or another computer related device.
Message



10.                   What is Clint/Server Network?
One or more computer act as server and other computer, or Clint , access server is called Clint/server Network.
11.                   What is Peer-to-Peer Network?
Simple network that connect fewer than 10 Computers.
Each computer or, peer has equal Capabilities is Called Peer-to-Peer Network.
12.                   What is Topology?
The physical layout or arrangement of connected devices in a network is called topology. It is the shape of a network.
13.                   What is bus Topology?
All Computer and devices are connected to central cable, or bus is called Bus Topology. Bus Topology is mostly used in peer-to-peer networks.
Example of network topology (Layout of devices in networks.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          

14.                   What is Ring Topology?
In ring Topology, each computer is connected to the next computer with the last one connected to the first .Thus is called ring Topology.
Data travel from device to device around entire ring in one direction
                                                          
15.                   What is Ethernet?
The Ethernet "access method" is used to connect computers in a company or home network as well as to connect a single computer to a cable modem or DSL modem for Internet access.  Ethernet is a physical and data link layer technology for local area networks (LANs)   It defined by the IEEE as the 802.3.
16.                   What is Token ring?
Token ring technology, control access to network by requiring devices to pass a special signal called Token ring. Token Ring is a data link technology for local area networks (LANs). It operates at layer 2 of the OSI model.
A local area network (LAN) access method developed by IBM. Conforming to the IEEE 802.5 standard, Token Ring uses a token ring access method and connects up to 255 nodes in a star topology at 4, 16 or 100 Mbps.

17.                   What is Star Topology?
All computers in star topology are connected with central device called hub. All data transferred from one computer to another passes through a hub. Star topology is mostly used in Clint/server  Networks.
                                                  
18.                   What is Mesh Topology?
In mesh topology network each terminal is directly connected with the central computer as well as with other terminals. In this ways information can be directly accessed from any terminal or from the central computer.
                                                  
19.                   What is drawback of bus Topology?
Ø  It is difficult to troubleshoot.
Ø  It only supports small number of computers.
Ø  When the cable is damaged the whole network fails.
20.                   What is drawback of star Topology?
Ø  It central hub fails, the entire network breaks down.
Ø  It requires a large length of cable to connect computers.
Ø  It is more expensive.
21.                   What is drawback of ring topology?
Ø  Failure of one computer in the ring can affect the whole network.
Ø  It is difficult to troubleshoot.
Ø  More expensive.
22.                   What is drawback of mesh topology?
Ø  Overall cost of this network is way too high as compared to other network topologies.
Ø  Set-up and maintenance of this topology is very difficult..

23.                   Write the advantages of bus Topology?
Ø  It is simple and easy to use.
Ø  It requires small length of cable to connect computer.
Ø  It is less expensive.
24.                   Write the advantages of star Topology?
Ø  It is easy to maintain and modify network.
Ø  Finding fault becomes very simple.
Ø  It is more flexible than other topologies.
25.                   Write the advantages of ring topology?
Ø  It is less expensive than star topologies.
Ø  Every computer has equal access to the network.
26.                   Write the advantages of mesh topology?
§  Data can be transmitted from different devices simultaneously. This topology can withstand high traffic.
2) Even if one of the components fails there is always an alternative present. So data transfer doesn’t get affected.

27.                   What is Hub?
Hub stands for (Helping U Better) A device used with the universal serial bus or in a star network topology that allow multiple devices connection. Hub is also called Multistation access unit (MAU).
28.                   What is Switch?
A network switch is a small hardware device that joins multiple computers together within one local area network (LAN). Technically, network switches operate at layer two (Data link layer) of the OSI model.

.
29.                   What is Modem?
Modem Stands For Modulation and demodulation .Modem is a device that converts digital signal into analogue signal and analogue signal into digital.
30.                   What is Cable Modem?
Send and receives data over cable television network is called cable Modem.
Much faster than dial-up modem or ISDN.                  
Sometimes called a broadband modem.
                                        
Types of Transmission Mode:                                            
31.                   What is Simplex Mode?
A

B

In simplex mode, data can flow in one direction. It cannot be moved in both directions. The direction of flow never changes.

32.                   What is Half-duplex mode?
A

B
In half-duplex mode, data can flow in both directions but not at the same time. It is transmitted one-way at one time.

33.                   What is Full-duplex mode?
A

B
In full duplex mode, data can travel in both directions simultaneously. Full duplex mode is a faster way of data transmission as compared to half duplex. A telephone is full duplex device.

34.                   What is Network cabling?
Cabling in normally used as a medium for transporting network data . The most  common types are twisted-pair and fiber-optic , although coaxial is still used in some old networking.
35.                   What is Twisted-Pair cable?
Network cable of eight copper wires twisted into four pairs to prevent crosstalk.
36.                   What is Analogue signal?
An analogue signal takes the form of a waves, which curves smoothly from one value to the next is called analogue signal.
                                                  
37.                   What is Digital signal?
Digital signals are the language of modern day computers. Digital signals comprise only two states. These are expressed as ON or OFF, 1 or 0 respectively. Examples of devices having two states in the home are,
Light switches: Either ON or OFF
Doors: Either OPEN or CLOSED
                                                     
Types of Data Transmission:
38.                   What is Digital data transmission ?
The transfer of data in the form of digital signal in called digital data transmission. Digital signal is a sequence of voltage represented in binary form.
+                      0                    0                      
-            1                    1                  1
39.                          What is Analogue data transmission?
The analogue data transmission is the transmission of data in a continuous wave. Analogue signals measured in volts and  its frequency is in hertz(Hz).
                                                      
40. What is data encoding?
The method by which certain communication devices (such as modems) encode digital data onto an analog signal for transmission.  A converter mechanism is necessary for computer data to be transported over a variety of networks. The most popular of these "converter mechanisms" is a modem. Fax machines use built-in modems.
Types of Twisted-Pair cable:
40.                   What is UTP cable?
UTP Stands for Unshielded Twisted-Pair cable. Most common network cable that come in different categories for different uses.
41.                   What is STP?
STP Stands for Shielded Twisted-Pair cable. Same as UTP Cable, but with extra foil to prevent outside noise from interfering with data on the cable.
42.                   What is Fiber Optic cable?
This cable is made up of super- thin filaments of glass or other transparent materials that can carry beams of light. Data transfer rate of Fiber optic cable is very fast. There is no chance of data loss.
Types of fiber optic cable
43.                   What is single Mode?
A type of fiber optic cabling that send one light bean down that cable used for longer distance application..
44.                   What is multimode?
A type of fiber-optic cabling that allows multiple light signals to be sent along the same cable. Used for shorter distances.
45.                   What is guided media?
Communication is in the form of electromagnetic waves, with guided media, the waves are guided along a physical path, and example of guided medium is twisted pair, coaxial cable and fiber optic cable.
46.                   What is Coaxial Cable?
Coaxial cable is kind of Copper cable used in older Ethernet networks as well as mainframe and minicomputer connection. Coaxial cable is sometimes used is Telephone companies and other types of local area networks.
47.                   What is Networking Protocols?
Specification that define the network those communication procedures to follow when sending and receiving data is called Networking Protocols.
48.                   What is TCP/IP Protocol?
TCP/IP Stands for (Transmission Control Protocol/Internet Protocol). The most common network protocol used by most companies and home user as a standard protocol used to access the internet.
49.                   What is IPX/SPX?
IPX/SPX Stands for (Internetwork Packet Exchange/ Sequenced Packet Exchange).
Original protocol used for connecting to Novell network. Now TCP/IP is standard protocol used.
50.                   What is Net BEUI?
Net BEUI Stand for ( Net Bios Extended User Interface). Is a non-routable protocol used in simple networks commonly found in Pee-to-Peer networks
Short range radio waves transmit data between Bluetooth devices. The name of Bluetooth is borrowed from Herald Bluetooth, a king of Denmark.
51.                   What is networking Addresses?
Network devices have to be able to identify each other in order to communications across a network. They do this through this various network addressing schemes.
52.                   What is Mac Address?
The Mac address stands for (Media  access control address). The Mac address is the physical address assigned to the network adapter usually during production is called Mac address. It is also known as
IP address: 192.168.1.22
Mac address: 00-26-B9-9B-61-BF
53.                   What is IP Address?
A type of network adapter’s address when multiple networks are linked. It is a 32- bit Binary number with groups of 8- bit separated by dot.
                                                                            Or
 (Internet Protocol address) The address of a device attached to an IP network (TCP/IP network). Every client, server and network device is assigned an IP address, and every IP packet traversing an IP network contains a source IP address and a destination IP address.
54.                   What is braodcast Address?
The address is the highest numeric value of the address format being used. An Ethernet broadcast address is all binary 1's. An IP broadcast address is the highest number in its class; for example, the broadcast address of a Class C 192.168.16.0 network is 192.168.16.255.
55.                   What is subnet Mask?
he technique used by the IP protocol to create a subnet address. The subnet mask is a binary pattern that is stored in the client machine, server or router.
Class C Mask for Six Subnets
255.255.255.224
11111111.11111111.11111111.11100000

56.                   What is Network portion?
Portion of an IP address that represents which network the computer in on.
57.                   What is Host portion?
Portion of IP address that representive the specific network devices.
58.                   What is Broadcast portion?
IP address used to communicate with all devices on a particular network.
59.                   What is Subnet portion?
A number the computer uses to determine which part of an IP address representive the network and which portion represents the Host.
 Wireless network overview:
60.                   What is Wireless network?
Transmit data over air using either infrared or radio frequencies. Wireless network operate at layer 1 and 2 of the OSI Model.
61.                   What is Infrastructure of wireless network?
Wireless network that connects multiple wireless network devices through an access point.
62.                   What is Access Point?
Access point is similar to a network hub and connects wireless network devices.
63.                   What is BSS?
BSS Stands for (Basic Service Set). Configuration when multiple devices connect to an access point.
64.                   What is ESS?
ESS Stands for (Extended Service Set). The network design when multiple access point connects to the same main network.
65.                   What is SSID?
SSID Stands for (Service Set Identifier). A set of 32 alpha numeric character used to differentiate b/w wireless network.
What is ANSI?
ANSI stands for (American National Standard Institutes) is the primary organization for fostering the development of technology standard in the united states.
66.                   What stands for ARP?
ARP stands for( Address Resolution Protocol) used to convert an IP address into a physical address (called a DLC address), such as an Ethernet address. A host wishing to obtain a physical address.
67.            What is CSMA/CD?
CSMA/CD stands for ( Carrier Sense Multiple Access/Collision Detection). A network access method for managing collision of data packets is known as CSMA/CD.
68.                   What is CSMA/CA?
CSMA/CA is stands for (Carrier Sense Multiple Access/Collision Avoidance) is a network access method that request before sending to control media Access.CAU see Controlled access unit)
69.                   What is FDDI?
FDDI stands for (Fiber Distributed Data Interface). An FDDI network uses fiber optic cable in a ring topology with token passing. FDDI operates at 100Mbps and can support two counter rotating rings.
70.                   What is HDLC?
HDLC stands for (High Data Link Control) is communication protocol defined for high level, synchronous connection to X.25 Packet network.
71.                   What is ICMP?
ICMP stands for ( Internet Control Message Protocol) provides error reporting for TCP/IP.
72.                   What is ISDN?
ISDN stands for (Integrated Services Digital Network) allows you to send voice, data and video over normal copper telephone lines by sending digital signals instead of analogue.
73.                   What is RJ-45?
RJ stands for( Register Jack) cable that looks very much like a normal telephone connector but larger. It uses twisted pair cabling with four pairs of wires.
74.                   What is FDM?
FDK stands for ( Frequency Division Multiplexing) is a method used in broadband transmission to transmit analogue signals.
75.                   What is CSU/DSU?
CSU/DSU stands for ( Channel Service unit/ Data Service unit) a connect a LAN to a digital data service (DDS) line.
76.                   What is UDP?
UDP stands for (User Datagram Protocol) is a connectionless transport protocol that is used when the overhead of TCP is not needed. UDP is just responsible for transporting datagram.
77.                   What is TDM?
TDM stands for (Time-Division Multiplexing) multiplexing uses time slots to separate channels. Each device is given a time slot to transmit using the entire available bandwidth.
78.                   What is PPP?
PPP stands for (Point-To-Point protocol) for communication between two computers using a serial interface, typically a personal computer connected by phone line to a server. PPP allows for dynamic host configuration and supports multiple protocols.
79.                   What is ANSI?
ANSI stands for (American National Standards Institute) a membership organization founded in 1918 that coordinates the development of U.S. voluntary national standards in both the private and public sectors.
80.                   What is OSI model?
OSI stands for (Open System Interconnection). The OSI model is for network communications consisting for seven layers that describes what happens when computers communicate with one another.
81.                   What is Application layers?
The application layer is the top layer of the network protocol stack. The application layer is connected with the semantics of work.
82.                   what is  presentation layer?
The sixth layer of the OSI model, it negotiates and establishes the format that data I exchanged in.
83.                   what is session layer?
The fifth layer of the OSI model, this layer users establish a connection between devices. This connection is called session.
84.                   What is transport layer?
The fourth layer of OSI model, is the transport layer. It provides a transport services between the session layer and the network layer.
85.                   What is network layer?
The third layer of OSI model is responsible for routing information from one network device to another.
86.                   What is data link layer?
The 2nd  layer of OSI model. Data link layer is responsible for moving frames from one source to next destination
87.                   What is physical layer?
The first layer of OSI model is the physical layer. The function of this layer is the transmission of bits over the network media. It provides a physical connection for the transmission of data among the network device.
88.                   What is media?
Media is the means used to transmit data. Media can include cable, microwaves, radio waves, infrared rays, among other devices.
89.                   What is Microwaves?
These waves travel at frequencies than radio waves and provide better throughput as a wireless network media is called microwaves.
90.                   What are oscilloscopes?
An instrument used to show voltage over time. While uses frequency diagnosing problem with electrical equipment, they can also be used to test for faulty network cable.
91.                   What is Multiplexing?
It is the process of sending signals from two or more different sources simultaneously over a single communication channel is called multiplexing.
92.                   What is Multiplexer?
Multiplexing is a device that is used to combining the several electrical signals into one signal is called multiplexer.
93.                   What is packet switching?
A discipline for controlling and moving messages in a large data-communication network. Each message is handled as a complete unit containing the address of the recipient and the originator.
94.                   What is parity?
Parity is a way to check for small errors in data that utilizes one bit to specify whether the byte has an even or odd value is called parity.
95.                   What is repeater?
A device to amplify or regenerate digital signals received while sending them from one part of a network into another. Works on OSI layer 1.
                                               
96.                   What are resources?
A resource is any item on the network that can be shared or accessed is called resources.
97.                   What is server?
A server is a computer in a network that is shared by multiple users, such as a file server, print server or communication server. In IT, a server is a computer program that provides services to other computer programs (and their users) in the same or other computers.





98.                   What is sliding windows?
The sliding window method of flow control allows two communicating devices to negotiate the number of allowable outstanding frames.
99.                   What is switches connection?
Switched connections allow multiple people to use a connection at once. They require special hardware to manage the connections but give you the benefit of lower cost for the connection to the service provides.
100.              What is user?
Users are human beings or computer process that possess the right to log in to a particular computer system.
101.              What is user-level security?
User-level security requires the proper user name and password to access a resource is called user-level security.
102.              What is virtual circuit?
A virtual circuit is a communication arrangement in which data configurations during a single period of communication (during a single session).
103.              What is workgroup?
A workgroup is a group of users on a network who have information or resources that they wish to share among themselves.
Types Of Data Transmission:
104.              What is Parallel Transmission?
Transmitting several bits simultaneously using multiple lines (8, 16,32,etc). The pathways b/w the CPU and memory are parallel, and b/w the CPU and peripheral devices they are typically, but may also be serial Contrast with serial Transmission.
105.              48. What is Serial Transmission?
Transmitting data one bit at a time (one bit after the other).Contrast with “parallel transmission,” which uses multiple lines to transmit several bits simultaneously (8, 16,32 etc).External communications networks use serial transmission.
                                                            OR
Data transmission in which data bits travel over a single wire in one direction  coordinated by start and stop  bits preceding and following each eight –bits character. 
Types Of Serial Transmission:
106.              What is Asynchronous?
The timing of the signals is an unimportant instead information is received at translated by agreed upon pattern.
0 is representing to the start bit.
1.         1 is representing to the stop bit.

                              

                                                                                                                                                  
107.              What is synchronous?
Data transmitted as unbroken strings of ones and zeros and the receiver separate that string into byte or characters it need to reconstruct the information.

                                 
108.              What is Attenuation?
The degeneration of a signal over distance on a network cable is called attenuation.
                                                                                Or
The attenuation is the fading of the electrical signal over a distance is called attenuation.



                     P1 watts                                                            p2 watts
                                                                                                             Db loss        
       Transmitter                                                                                   Receiver






109.              What is back up?
Backing up is the process of copying data to another location. Important data is often backed up to a tape device, which allows for restoration if the original data is lost.
110.              What is Asynchronous transfer mode (ATM)?
ATM is a new type of network that uses fixed-size packets called cells and supports dynamic bandwidth allocation is called ATM.
111.              What is centralized?
A computer network with a central processing node through which all data and communications flow is described as centralized.
112.              What is checksum?
A checksum is fixed length block produced as a function of every bit in as encrypted message; a summation of a set of data items for error detection; a sum of digits or bits used verify the integrity of data.
113.              What is collision?
Collision occurs when two devices try to transmit at the same time in the DNA protocol suite is called collision.
114.              What is distance vector routing?
Distance vector routing is a routing method that simply calculates the shortest number of hops between two points.
115.              What is fast Internet?
A fast Ethernet network uses star topology with UTP cable. Fast Ethernet required special adapter card and hub capable of 100Mbps transfer.
116.              What is flow control?
Flow control is the process of controlling the amount of data sent to a device so that it does not exceed the capabilities of the receiving system.
117.              What is frame relay?
A new WAN connection technology, frame relay took the features of X.25 and stripped the error control and accounting from it to increase performance. See also X.25.
118.              What is full backup?
A full backup is a method of file backup used to back up all selected files. This process marks the files as archived.
119.              What is Gateway?
Gateway can Operate at all seven layer of the OSI model. Their function is to do any necessary conversion of protocols between network. There is no limit.





120.              What is circuit switching?
Circuit switching is a switching method in which a dedicated connection is made between the two communicating devices is called circuit switching.
A connection between two systems A & D formed from 3 link

121.What is Bridge?
An internetwork device used to split a network segment to control traffic is called bridge. Data is passed through or rejected depending on the destination devices MAC address.                                                                                                                     
122.     What is Bluetooth?
Bluetooth is an example of short-hand-range broadcast radio communications. It uses short range radio waves to transmit at a rate of 1 Mbps among Bluetooth enabled device.
123.   What is uplink and downlink?
The transmission from satellite to earth station is called downlink. The transmission from earth station to satellite is called uplink.