Assistant Maintenance Engineer at the Department of ICT-2014

(Only Department Part)

Q-1.What is private IP Address ? Mention the class B private IP range.

Ans:Private IP address of a system is the IP address which is used to communicate within the same network. Using private IP data or information can be sent or received within the same network.

-Scope is local.It is available in free of cost

-It works only in LAN.

Range:

Class A: 10.0.0.0- 10.255.255.255

Class B: 172.16.0.0- 172.31.255.255

Class C: 192.168.0.0- 192.168.255.255

Q-2.What is difference between layer 2 and layer 3 switch?

Ans:

layer 2 Switch	layer 3 Switch
Operate on layer 2 (Data link) of OSI model.	Operate on layer 3 (Network Layer) of OSI model.
Send packet to detination on the basis of MAC address.	Route Packet with help of IP address
Work with MAC address only	Can perform functioning of both 2 layer and 3 layer switch
Used to reduce traffic on local network.	Mostly Used to implement VLAN (Virtual Local area network)
Quite fast as they do not look at the Layer 3 portion of the data packets.	Takes time to examine data packets before sending them to their destination
It has single broadcast domain	It has multiple broadcast domain.
Can communicate within a network only.	Can communicate within or outside network.

Q-3.What is data transmission ? Distinguish between simplex and duplex

Ans: Data transmission refers to the process of transferring data between two or more digital devices. Data is transmitted from one device to another in analog or digital format.

BASIS FOR COMPARISON	SIMPLEX	HALF DUPLEX	FULL DUPLEX
Direction of Communication	Communication is unidirectional.	Communication is two-directional but, one at a time.	Communication is two directional and done simultaneously.
Send/Receive	A sender can send data but, can not receive.	A sender can send as well as receive the data but one at a time.	A sender can send as well as receive the data simultaneously.
Performance	The half duplex and full duplex yields better performance than the Simplex.	The full duplex mode yields higher performance than half duplex.	Full duplex has better performance as it doubles the utilization of bandwidth.
Example	Keyboard and monitor.	Walkie-Talkies.	Telephone.
Direction of Communication	Communication is unidirectional.	Communication is two-directional but, one at a time.	Communication is two directional and done simultaneously.
Send/Receive	A sender can send data but, can not receive.	A sender can send as well as receive the data but one at a time.	A sender can send as well as receive the data simultaneously.
Performance	The half duplex and full duplex yields better performance than the Simplex.	The full duplex mode yields higher performance than half duplex.	Full duplex has better performance as it doubles the utilization of bandwidth.
Example	Keyboard and monitor.	Walkie-Talkies.	Telephone.

Q-4.Sate the advantage and disadvantage of broadband.

Ans:

Advantages:

High speed "always on" connection
Fixed monthly cost
Phone line is separate
More than 1 PC can
Faster for surfing & downloading, up to x10 faster
Ability to work from home
Value for money

Disadvantages:

Not available to everybody (approx. 81% household coverage )
Contended service could result in variable speeds depending upon time of day

Q-5.What is database ? State the DBMS with example .

Ans:Database: Database is a systematic collection of data. Databases support storage and manipulation of data. Databases make data management easy. Let's discuss few examples.

An online telephone directory would definitely use database to store data pertaining to people, phone numbers, other contact details, etc.

Your electricity service provider is obviously using a database to manage billing , client related issues, to handle fault data, etc.

Database Management System (DBMS):Database Management System (DBMS) is a collection of programs which enables its users to access database, manipulate data, reporting / representation of data .

It also helps to control access to the database.

Database Management Systems are not a new concept and as such had been first implemented in 1960s.

Charles Bachmen's Integrated Data Store (IDS) is said to be the first DBMS in history.

Q-6.Explain with example of one-to-many relationship with E-R diagram

A one-to-many relationship refers to the relationship between two entities X and Y in which an instance of X may be linked to many instances of Y, but an instance of Y is linked to only one instance of X. The figure below shows an example of a one-to-many relationship.

Q-7.What is difference between while and do while loop ?

Ans:

BASIS FOR COMPARISON	WHILE	DO-WHILE
General Form	while ( condition) { statements; //body of loop }	do{ …. statements; // body of loop. ….. } while( Condition );
Controlling Condition	In 'while' loop the controlling condition appears at the start of the loop.	In 'do-while' loop the controlling condition appears at the end of the loop.
Iterations	The iterations do not occur if, the condition at the first iteration, appears false.	The iteration occurs at least once even if the condition is false at the first iteration.
Alternate name	Entry-controlled loop	Exit-controlled loop
Semi-colon	Not used	Used at the end of the loop

Q-8.Write a program in C/C++ to calculate the factorial of any integer.

Ans:

#include<iostream>

using namespace std;

int main()

{ {

int num, factorial=1;

cout<<" Enter Number To Find Its Factorial: ";

cin>>num;

for (int a=1;a<=num;a++) {

factorial=factorial*a;

}

cout<<"Factorial of Given Number is ="<<factorial<<endl;

return 0;

}

Q-9.What are the properties of weak password ?

Ans: properties of weak password:-

v It appears in the English dictionary

v Keyboard patterns and swipes (i.e., 123456 or QWERTY)

v It is the name of a well-known city anywhere in the world

v It is the name of any professional sports team

v It is a calendar date or date of birth

v It is the same as the username

v It is less than six characters long

v Repeating previously used passwords

Q-10.Define worms and Trojan horse.

Ans: Worms:
Worms is also a computer program like virus but it does not modify the program. It replicate itself more and more to cause slow down the computer system. Worms can be controlled by remote. The main objective of worms to eat the system resources.

Trojan Horse:
Trojan Horse does not replicate itself like virus and worms. It is a hidden piece of code which steal the important information of user. For example, Trojan horse software observe the e-mail ID and password while entering in web browser for logging. The main objective of Trojan horse to steal the information.

Q-11.What is the difference of RAID Level 2 and RAID Level 3 ?

Q-12.Explain GSM mobile Network.

Ans: GSM stands for Global System for Mobile Communication. It is a digital cellular technology used for transmitting mobile voice and data services.

GSM is the most widely accepted standard in telecommunications and it is implemented globally.

GSM makes use of narrowband Time Division Multiple Access (TDMA) technique for transmitting signals.

GSM provides basic to advanced voice and data services including roaming service. Roaming is the ability to use your GSM phone number in another GSM network.

Features provided by the GSM network include:

· Phone call encryption,

· Data networking,

· Caller ID,

· Call forwarding,

· Call waiting,

· SMS, and

· Conferencing.Etc

GSM architecture and working:

Followings are the main components of GSM architecture

Mobile Station (MS):

MS grant access to the GSM network. It is main component of GSM architecture.It contains the following two components.

Mobile Equipment (ME)
Subscriber Identity Module (SIM)

Mobile stations (MS), mobile equipment (ME) or as they are most widely known, cell or mobile phones are the section of a GSM mobile communications network that the user sees and operates. In recent years their size has fallen dramatically while the level of functionality has greatly increased. A further advantage is that the time between charges has significantly increased.

Base Station Subsystem (BSS):

With air interface BSS provides MS and NSS (Network Station Subsystem). BSS consists of following elements.

· One or more BTS( Base Transceiver Station )

· One BSC (Base Station Controller).

· One TRAU (Transcoding Rate and Adaptation Unit)

Network Switching Subsystem (NSS): The GSM system architecture contains a variety of different elements, and is often termed the core network. It is essentially a data network with a various entities that provide the main control and interfacing for the whole mobile network. The major elements within the core network include:

Mobile Services Switching Centre (MSC):

Home Location Register (HLR):

Visitor Location Register (VLR):

Equipment Identity Register (EIR):

Authentication Centre (AuC):

SMS Gateway (SMS-G)etc

Operation and Support Subsystem (OSS):

The OSS or operation support subsystem is an element within the overall GSM mobile communications network architecture that is connected to components of the NSS and the BSC.

Q-13.How you can calculate the total storage capacity of magnetic disk ?

Ans: Formula:Disk capacity = total number of surfaces * no. of tracks per surface * amount of data per track .

Example:A disk pack has 19 surfaces and storage area on each surface has an outer diameter of 33cm and inner diameter of 22cm .The maximum recording storage density on any track is 200 bits/cm and minimum spacing between tracks is 0.25 mm , then how to calculate the capacity of disk pack ?

Solution:Disk capacity = total number of surfaces * no. of tracks per surface * amount of data per track
Total number of tracks per surface = (outer radius - inner radius)/ inter track gap = (33cm/2 - 22cm/2 )/0.25mm = 220
Perimeter of inner track = 2 * pi * inner radius = 2 * (22/7 )*11 cm
Density = 200 bits/ cm
Amount of data present in single track = perimeter * density = 13829 bits (approximately)
Disk capacity= 19 * 220 * 13829 bits = 6.89 MB

Q-14.What are the advantages of microcontroller over microprocessor?

Ans:

Microprocessor	Microcontroller
Microprocessor is heart of Computer system.	Micro Controller is a heart of embedded system.
It is just a processor. Memory and I/O components have to be connected externally	Micro controller has external processor along with internal memory and i/O components
Since memory and I/O has to be connected externally, the circuit becomes large.	Since memory and I/O are present internally, the circuit is small.
Cannot be used in compact systems and hence inefficient	Can be used in compact systems and hence it is an efficient technique
Cost of the entire system increases	Cost of the entire system is low
Since memory and I/O components are all external, each instruction will need external operation, hence it is relatively slower.	Since components are internal, most of the operations are internal instruction, hence speed is fast.
Generally microprocessors are not used in real time systems as they are severely dependent on several other components.	Microcontrollers are used to handle real time tasks as they are single programmed, self sufficient and task oriented devices.
Mainly used in personal computers	Used mainly in washing machine, MP3 players, lighting sensing and controlling device like LED, Temperature sensing and controlling device like microwave oven, Measuring devices like volt meter .