Computer application in mgt www.it-workss.com

COMPUTER APPLICATION IN MANAGEMENT
MBA–1st SEMESTER, M.D.U., ROHTAK
SYLLABUS
External Marks : 70
Time : 3 hrs.
Internal Marks : 30
UNIT-I
Introduction to Computer : Components, Classification, Organisation, Capabilities
Characteristics & Limitations, Operating System, Application of Computer in Business,
Computer Languages.
Network Fundamentals, Analog & Digital Signals, Bandwidth, Network Topology,
PacketTransmission, Long Distance communication, NetworkApplication.
Introduction to database : Concept, Objectives, Advantage & limitations, entities,
attributes, schema, subschema
Internet : Internet working, Concepts, Internet Protocol Addresses, WWW Pages &
Browsing, Security, Internet Application, E-Commerce : Fundamentals; Framework,
Application.
Lab : Operating Systems Commands, Internet Surfing, MS Office, point, Tallyy
(latest version)
UNIT-II
UNIT-III
UNIT-IV
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MBA 1st Semester (DDE)
UNIT – I
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Q.1 What is Computer? Explain its Characteristics and Limitations?
Ans. Definition :–
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(1) Speed: -
A computer is a fast electronic device, processing the Input data
according to the Instructions given by the Programmer/User and provides the desired
information as an output.
The word 'Computer' is basically derived form the word 'computer', which means to
calculate some thing. But in today's scenario if we told that computer is just a calculation
machine, it is not true. We can do a lot more than calculation. Let's take few examples —
Your Bio-Data, Examination Records,Admission Register,Airlines and Rail Reservation etc.
In all these cases yo will find apart form just calculation the computer is managing
information and data. So, Computer is electronic devices (Machine) which accept our data,
process them and gave output.
Input Process Output
Cloth Tailoring Wearable
Veg Cooking Eatable
Data :– Collection of facts or figures.
Information Processed data is known Information.
Input Data and instructions given to computer.
Process Manipulation of data.
Output Information obtained after processing of data.
A computer is very fast device. It can perform large amount of work in a few
seconds. Where human being worked a particular work for whole day, computer does the
same in very short time. Today, computers can perform 100 million computations in one
second. The speed of computers are measured in terms of microseconds, Nano seconds
and even in Pico seconds.
Terminology used in Definition of Computer
Characteristics of Computer:-
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Where 1 second=10 micro second
=10 nano second
=10 Pico second
( The computer is 100% accurate and capable to perform arithmetical
calculation and logic operations with the same accuracy. It can never make mistakes.
All mistakes are done by users. The cause of errors may be due to inaccurate feeding
data or due to wrong setting of the programmer. The accuracy of a computer is
Illustrated well by the term GIGO; i.e. Garbage In Garbage Out, which means if faulty
instruction are provided for processing the data, obviously wrong answer will be given.
computer can operate twenty four hours continuously without taking
any rest. It has no feelings or no emotions, if you work continuously for 3 hours, you
feel lack of concentrate but a computer is free from these and you will get the result you
want with the same speed and same accuracy.
Versatility is one of the most wonderful features about the computer.
One moment, it is preparing the results of a particular examination, the next moment it
is busy in preparing electricity bills, and in between it may be helping an office
secretary to trace an important letter is seconds. It can do multiple works at a same
time. It also used in data processing jobs, weather fore casting, ticket reservation
purpose, multimedia designing, animations, accountancy etc.
A computer has made more memory or storage capacity than
human beings. It can store millions of data and instructions, which can be retrieved
and recalled even after a number of years. This is not possible in case of human brain.
Computers are automatic in operation. It means once the data and
instructions are fed to a computer, human interventions are not required. The
computers manipulate the data according to the instructions and continue doing so till
the last instruction is executed.
( Computer hardware is manufactured with the best
materials by the most sophisticated processor. It has superiority of manufacture as
compared to other machines.
The use of computer reduces lot of paper work in any
organizations.
Computer solved those problems which are not solved
by human being computer solved the computer solved the problems in seconds.
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2) Accuracy :–
(3) Diligence :– A
(4) Versatility :–
(5) High Memory :–
(6) Automation
7) Superiority of Manufacture
(8) Reduce the Paper Work
(9) Solve Complete Problems
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Limitations of Computer:-
The main limitations of computers are as follows :–
Fully Dependent upon human beings.
Computers do not have their own Intelligence and hence cannot
think for example, a computer can create music but cannot tell its quality. In other words,
computer has no brain.
Computer can detect only syntax error, it cannot detect flaw or
error in logic.
It has no Capability to take any decision by itself, like a human being, it
cannot judge by itself for any valid or non-valid data.
A computer is not a magical device. It can only perform tasks that a human being
can. The difference is that it performs these tasks with unthinkable speed and accuracy. It
possesses no intelligence of its own. It I.Q. is zero, at least today.Acomputer cannot take its
own decision in this regard.
Computers have no feelings and no emotion because they are machine.
It does not have intuition and cannot draw
conclusion without going through all the intermediate steps.
Computers don't learn form experience.
A computer is a fast electronic device, processing the Input data
Or
Dependency :–
Lack of Intelligence
Lack of Detecting Errors
Lack of Capability
No I.Q.
No Feelings :
Lack of Creativity and imagination :–
Experience :–
Q. 2 What is Computer? What are variousApplications of Computer?
Or
What is Computer? What is the scope or impact of computer in business
application?
Ans. Definition :–
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The word 'Computer' is basically derived form the word 'computer', which means
to calculate some thing. But in today's scenario if we told that computer is just a calculation
machine, it is not true. We can do a lot more than calculation. Let's take few examples —
Your Bio-Data, Examination Records,Admission Register,Airlines and Rail Reservation etc.
In all these cases yo will find apart form just calculation the computer is managing
information and data. So, Computer is electronic devices (Machine) which accept our data,
process them and gave output.
Input Process Output
Cloth Tailoring Wearable
Veg Cooking Eatable
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Application of Computer in Business
Scope of Computers in Business offices
Computers have completely altered the structure of business. Large volumes of accounting
and record keeping data can be manipulated, organized, stored, retrieved and used for
specific purposes. Bills and statements can be processed and sent to customers in much
less time and much less effort than would be required for doing the same process manually
financial projections is made with greater ease. Planning and decision making thus be
cover more efficient and accurate.
In manufacturing industries, Computers direct production, guide machine tools,
control quality design parts and monitor inventory levels. Modern banking would be
impossible without computers. In modern officer, word processing saver time for people at
all levels in organization and helps ensure more accurate letters, reports and memos.
Manpower Planning
Human Resource Development
Selection and Recruitment
Compensation and benefits
Skill Inventory Management
Establishment and Personnel records
Placement Modules
Training and development
Career Planning/Promotion
Invoicing, Sales Ledgers and Statements
Stock Control and Evaluations
Payroll, Pay slips,Tax Statement
Purchase Ledger
Credit Control
Sales and Purchase LedgerAnalysis
Budgetary Control
Cost accounting, Job costs, Standard costs, Work in Progress, Labors registers
Asset Registers
Hire Purchase Records
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(1) Personal Management
(2) Financial Management
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(3) Office Management
(4) Material Management
(5) Purchasing Management
(6) Marketing Management
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Budget
Annual Reports
Production Schedules
LoanAnalysis
GraphicTrends
Managing Reports, Directories, Catalog's, Bulletins, Letters, Memos
To Minimize Inventories
Material Planning/Specifications
CallingTenders
ComparingTenders
Supplies Evaluation
Placing Orders/Recorders
Demand forecasting
Sales Management
Consumer behavior
Channels of Distribution
Pricing decisions
Market Research
TransportAnalysis
Advertising Strategies
Product Mix
Planning and Control of sales
Q.3 What is Computer? Describe the functioning of computer with its block
diagram?
Ans. Definition :– A computer is a fast electronic device, processing the Input data
Or
The word ‘Computer’ is basically derived from the word ‘compute’, which means to
calculate some thing. But in today’s scenario if we told that computer is just a calculation
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machine, it is not true. We can do a lot more than calculation. Let’s take few examples – Your
Bio-Data, Examination Records,Admission Register,Airlines and Rail Reservation etc. In all
these cases you will find apart from just calculation the computer is managing information
and data. So, Computer is electronic devices (machine) which accept our data, process
them and gave output.
Acomputer System is defined as a set of interacting elements, responding to inputs so
as to produce outputs.The computer system also consist of the following elements.
Hardware
C.P.U (Central Processing Unit)
Input Devices
Output Devices
Storage Devices
Software
System Software
Application Software
Utility Software
Humanware
Trained Computer Professionals
Hardware refers to all the physical parts and components of the computer.
The Central Processing Unit (CPU) or Microprocessor is
the heart of the computer, where all the processing of the data is carried out. The data
and instructions that are entered into the computer system are fed into the CPU before
the final results are displayed on the Output Unit. The CPU stores the data and
instructions, does all the calculations and problem solving, and also controls the
functions of all other units.
The components of the CPU are as follows:
The data and instructions that are entered into the
computer system through input units have to be stored inside the computer before the
actual processing starts. Similarly, the results produced by the computer after
processing must also be kept somewhere inside the computer system before being
passed on to the output units. It provides space for storing data and instructions, space
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Hardware:-
Central Processing Unit :–
(1) Memory Unit or Storage Unit
(2) Arithmetic & Logical Unit (ALU)
(3) Control Unit
(1) Memory Unit or Storage Unit :–
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for intermediate results, and also space for the final results.
1. All the data to be processed and the instructions required for processing
(received from input devices).
2. Intermediate results of processing.
3. Final result of processing these results are released to an output device.
This unit performs all the basic arithmetic
operations like addition, subtraction, multiplication, division and also logical
operations such as comparison of numbers etc. The ALU is responsible for actual
execution of instructions during processing operation. The data and instructions that
are stored in memory unit are transferred into ALU for processing when needed and
transferred back to memory when processing is over. After the completion of
processing, the final results are stored in memory before sent to the output unit. ALU
also consist a number of small storage locations termed as registers. This register is
of very small capacity and contains the data and instructions which are to be executed
next.
(1) It operates on data available in main memory.
(2) It caries out all arithmetic operations like addition, subtraction, multiplication and
division.
(3) It caries out all logic operations like comparison, selection and merging of data
(4) After processing the data, it sends back the processed data to main memory.
The control Unit in every computer is the supervising element. It does
not perform any processing but acts as a central control system for all other
components of a computer system. This unit maintains the exact sequence in which
the instructions are to be executed and directs the operations of the entire computer
system. It co-ordinates all the activities of various elements of computer system skill.
It is termed as heart of computer as in controls all hardware operation.
(1) It gives command to transfer data from the input device to memory and from
memory to arithmetic & Logical Unit.
(2) It transfers the results from memory to Output Unit.
(3) It stores the program in memory, takes instruction one by one, interprets them
and issue appropriate signals to the other units of computer to the other units of
computer to execute them.
In short, the specific functions of the storage unit are hold (store) :
(2) Arithmetic Logic Unit (A.L.U) :–
Following are the main functions ofALU :–
(3) Control Unit :–
Functions of Control Unit are :–
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Storage Devices
Data and
instruction
MEMORY
CONTROL UNIT
A.L.U
Output
INPUT DEVICE OUTPUT DEVICE
Unprocessed
Data
Processed
Data
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Block Diagram of Computer
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- In a computerized system, before any processing takes place, the
data and instructions must be fed. This is achieved through the which
provide a communication medium between the user and the machine.
The most common of Input devices keyboard, which resembles a typewriter. The help
of a keyboard, the user types data and instruction. The other commonly Input devices
are mouse, magnetic ink character reader, magnetic tape, magnetic disk, optical mark
reader and optical character reader.
1) Text Input Devices
2) Cursor Control Devices
• In text input devices the mainly used keyboard.
Cursor control devices are mouse, joystick, scanner etc.
In brief, the following functions are performed by the input unit:-
It accepts (reads) data from user.
It converts the instructions and data into computer acceptable form.
It passes the converted instructions and data to the computer for processing.
INPUT DEVICES:
Input Devices,
Input devices are divided into two categories
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When Processing is complete in the CPU, the information
produced is stored in the Memory in a computer understandable format. This
information has to be transcribed into a form that can be read by the user, which is
achieved by The most commonly used Output Devices are VDU
(Visual Display Unit), Printer, Plotter etc.
(1) Hard Copy
(2) Soft Copy
An output produced on a printer or a plotter.
An output on the VDU or stored on magnetic media (Disks andTapes).
In brief, the functions of the Output units are:-
To accept the results processed by CPU which is in coded form?
To convert coded results to human acceptable form.
To produce the results to users.
As we aware, that whenever data or instruction is fed to the
computer, it is stored within it. Computers store data, instruction and the output of a
process in a storage device.
Primary Storage Devices
Secondary Storage Devices
Primary storage device often referred to as the main
memory is the work area within the computer, where the data and instructions are
stored. These devices are made up of Capacitors, Transistors and Silicon Chips. This
makes access of data and instructions from these devices very efficient. The different
kind of primary storage devices available are listed below:
RAM (RandomAccess Memory)
ROM (Read Only Memory)
The secondary storage device is a storage medium
used for storing data, instruction and output for archival purposes, so that whenever any
data or instruction is required in the future. Different kind of secondary storage devices
available are Floppy Disk, Hard Disk, Optical Disk etc.
The non-tangible components of the computer system are
referred as
The personnel involved in using and maintaining the computer system form
the Humanware.They are the trained computer professionals and can be a:
Output Devices :-
Output Devices.
There are two types of outputs produced by these devices:
Hard Copy: -
Soft Copy:-
Storage Devices :-
Storage devices are categorized as:
Primary Storage Devices:-
Secondary Storage Devices:-
Software :–
Software.
Humanware :–
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Classification
Purpose
General
Purpose
Computer
Special
Purpose
Computer
Technology User
Analog
Computer
Digital
Computer
Hybrid
Computer
Size & Capacity
Super
Computer
Mainframe
Computer
Mini
Computer
Micro
Computer
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Who takes care of the various components of the computer.
Who manages and handles the software loaded onto the
computer.
Who designs various types of the software required to work on the
computer.
Who is the actual user of the computer.
Hardware Engineer:
Software Engineer:
Programmer:
User:
Q.4 Describe the classification of Computer?
Or
Write a short note on the following.
i) Analog, digital, Hybrid Computers
ii) Super, Mainframe, Micro, Mini Computers
iii) General, Special Purpose Computers
Ans. Classification of Computers
The classification of computers is based on the following three categories:-
(1) According to Purpose
(2) According to technology used
(3) According to size and capacity.
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(1) : –
(i) General Purpose Computers :–
(ii) Special purpose computers :–
(2) :–
(i)
Thermometer :–
Speedometer
Analog Computers Digital Computers
According to Purpose
According to technology used
Analog computers
Digital Computers
Difference between Analog and Digital Computers
According to the utilization of compute for different uses,
computers are of following two types:-
Computers that follow instructions for general
requirement such as sales analysis, financial accounting, invoicing, inventory,
management information etc are called general purpose computers. Almost all
computers used in offices for commercial, educational and other applications
are general purpose computers.
Computers designed from scratch to perform
special tasks like scientific applications and research, weather forecasting,
medical diagnostic etc are called special purpose computers.
according to the technology used, computes are
of following three types :–
Analog computers are special purpose computers that
represent and store data in continuously verifying physical quantities such as
current, voltage or frequency. These computers are programmed for measuring
physical quantities like temperature, speed etc and to perform computations on
these measurements. Analog computers are mainly used for scientific and
engineering applications. Some of the examples of analog computers are given
below:–
a) It is a simple analog computer used to measure
temperature.
b) Car's speedometer is another example of analog
computer. Where the position of the needle on dial represents the speed
of the car.
Digital computers are mainly general purpose computers that
represent and store data in discrete quantities or numbers. In these computers, all
processing is done in terms of numeric representation (Binary digits) of data and
information. Although the user enters data in decimal or character form, it is converted into
binary digits (O's and I's). Almost all the computers used now days are digital computers.
Analog Computer accepts, processes The Digital Computer accepts, processes
and generates continuous data (Air, and produce discrete data (AIr, Prices,
Water, Distance) Incomes etc)
Computation of Physical quantity Computation of Numerical Digits
Accuracy of Computation is quite limited Accuracy of Computation is more
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Slow Systems Fast Systems
Used in limited number of applications Used in Unlimited number of applications
Outputs is Continuous Output is obtained after complete
computation is carried out.
Measure &Answer (How much) Counts &Answer (How much)
Hybrid computers combine the technology of both analog and digital
computers. These computers store and process analog signals which have been converted
into discrete numbers using analog-to-digital converters. They can also convert the digital
numbers into analog signals or physical properties using digital to analog converters.
Hybrid computers are faster than analog computers but much slower than digital computers.
It finds applications are special areas.
In a hospital, analog devices measure the heart functions, temperature and
other vital signs of the patients. These measurements are converted into numbers and
supplied to a digital computer. This is used to monitor the patient's vital signs and it gives an
immediately signal if any abnormal reading is detected.
According to size and memory/storage capacity, computers are of following four types :–
Super computers are the biggest and fastest computer, which is
mainly designed for complex scientific applications. It has many CPUs (central processing
units- main part of computer) which operate in parallel to make it as a fastest computer.
These computers are very expensive and more powerful than mainframe computers. It is
typically used fall the following applications:-
Weather forecasting
Petroleum Exploration and production
Energy Mgt
Defense
Nuclear Energy Research
Weapons research and development
Earthquake prediction (seismology)
PARAM andANURAG are Super Computers produced by India. CRAY 3, CRAY-XMP
14, NEC 500, are the another example of super computers.
Mainframe computers are very large and fast computers but
smaller and slower the super computers. These are used in a centralized location where
Hybrid Computers
According to size and capacity
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For example
Super Computers
Mainframe Computer
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many terminals (Input/Output devices) are connected with one CPU and thus, allow different
users to share the single CPU. They have a very high memory (several hundred
megabytes) and can support thousands of users. These computers are faster and more
powerful than minicomputers. They are mainly used for following applications:-
Railway andAirline Reservations
BankingApplications
CommercialApplications of large industries/companies
Some examples of Mainframe Computers are- MEDHA Series, DEC, IBM 3090, IBM
4381, IBM 4300 and IBM ES-9000.
Minicomputers are medium scale, smaller and generally slower than
mainframe computers. Like Mainframes, they have many terminals which are connected
with one CPU and can support many users. The cost of minicomputer is very less as
compared to mainframe. These computers are faster and more powerful than
microcomputers. These computers are suitable for medium class organizations, banks,
data processing centers etc.
Some of the examples of minicomputers are PDP-1, IBM AS/400, and DEC MICRO
VAX, IBM AS/400 is actually a midi computer (computer with performance between a
mainframe and minicomputer) is becoming very popular among minicomputers.
It is a low cost small digital computer. This type of compute contains a
microprocessor as its CPU, a memory Unit, Input and Output device. These are also called
personal computer system. Maximum speed of micro computers is up to 1 million bytes per
second. These types of computers can be used to play games, teach children math, make a
painting, create net musical sounds etc.
They are very inexpensive families or home business can afford to buy a small system
to use at home.
Micro-Computers can be classified into the following tow categories:-
Desktop Micro Computes
Portable Micro Computers
Common type of Micro Computes, which can easily be
accommodated on the top of a desk, is called desktop computers. The usage of such
computers is quite common is offices, markets, homes etc.
These Computes are small is size and looks like a briefcase
o a notebook. They are very light in weight and easy to carry from one place to another.
They use batteries or electronic current.
Examples of these computers are :–
Laptop Computers
Notebook Computers
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Mini Computer: -
Micro Computers
Desktop Micro Computers
Portable Micro Computers
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User
Application Program
Operating System
Hardware
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Laptop Computers sometimes called briefcase computes, can be used on your lap
and are very portable. Like a desktop computers, laptop computers have a full typewriter
keyboard. Laptop computers can be connected to larger peripherals. For example- A
regular size printer or a large monitor etc.
Notebook Computes are smaller is size than laptop computers. These computers are
idle for user who has to wok away from their offices. The users of these computers might be
a student, a journalist and a salesman etc. Example- IBMThinkPad.
Operating system is a program that acts as an interface
between the users and computes hardware and controls the execution of all kinds of
programs. It is the most important program in the computer System. It is one program that
executes all the time always as the computer is operational and it exit only when the
computer is shut down. OS are the programs that makes the computer work hence the name
OS. It takes instructions in the form of commands from user and translates into machine
understandable instructions. It gets the instructions executed by the CPU and translates the
result back into user understandable form.
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In other words, an operating system is a large collection of software,
which manages resources of the computer system, such as memory, processor, file system
and input/output devices. It is the program with in a computer system which helps users to
run their applications.
The diagram clearly shows that the operating system directly controls computer
hardware resources and other programs depend on the facilities provided by the operating
system to gain access to computer system resources.
Q.4 Describe Operating System. What are various types and functions of Operating
System?
Or
“Operating System as resource manager.” Describe.
Ans.
Definition “An operating system is a set of programs, which are used to manage the
overall operations of a computer, in order to achieve maximum efficiency of the
computer system.”
The position of operating system in overall computer is following :–
Operating System :–
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Types of Operating System
Single Program Operating System
Limitation of the Operating System
The operating systems are classified as-
1. Single program operating system.
2. Batch processing system.
3. Multiprogramming operating system.
4. Multiuse or Multi-access operating system.
5. Multiprocessing operating system.
6. RealTime operating system.
7. Network operating system.
8. Distributed operating system.
Single program operating system refers to single
pertaining to single user for example-MS-DOS. It has a single processor runs a single
program and interacts with a single use at a time.
Only one program resides in the computer memory and it remains these till it is
executed. It is also called Unit Programmed operating system. It is the simplest operating
system because-
The whole memory space is allocated to one program so memory management is not
very difficult.
The CPU has to execute only one program at a time so the CPU management also
does not have any problem.
In single program operating system, the CPU remains idle most of the time because as
compared to CPU speed, the speed of I/O devices is quite slow.
Jobs with similar requirements were batched together and run
through the computer as a group.The operating system handling a batch of programs known
as Batch or Concurrent operating system.This operating system relieves the user from the
difficult task of loading the next program after the execution o a previous program is
completed. It must be remembered that a batch program operating system is a single
program system because at a time only one program is being executed by the CPU.
In this operating system :–
Memory is usually divided into two parts. One part is fixed for containing
operating parts. One part is fixed for containing operating system and the other
part contains use programs to be executed. When one program is executed,
another program is loaded into same memory area.
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Batch Operating System :–
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The CPU has to execute only one program at a time, so the CPU management
also does not have problem.
Non-Interactive Environment :– Batch operating system allows on interaction
between users and executing programs.
High Turn around Time The turn around time taken between Job submission
and completion is very high.
Off-Line debugging This means that a programmer can not correct bugs the
moment it occurs.
Multiprogramming operating systems as
compared to batch operating system are fairly better but sophisticated. Multiprogramming
increases CPU utilization y organizing a number of jobs such that CPU always has one to
execute.
Different forms of multiprogramming operating system are :–
Multitasking or Multiprocessing operating system
Time sharing operating system.
A running state of a program is called a process or a
task. A multitasking operating system supports more than one active process
simultaneously with a single CPU. It is also called serial multitasking or context switching
which implies stopping one temporarily to work on another.
In these operating systems, CPU switches from one task to another so quickly that it
gives the illusion to the use of executing all the tasks at the same ties example- windows
95/98, windows NTetc.
Time Sharing is a special case of multiprogramming
operating system with a quick response time. It allows many users to simultaneously share
the computer resources. It provides each user with a small portion of a time-shared
computer. In a time shared system since each action or command take a very small fraction
of time, only a little CPU time is needed for each user.
As the CPU switches rapidly from one user to another user, each user is given
impression that he has his own computer, whereas actually one computer is being shared
among many users.
Multi user operating system allows
simultaneous access to a computer system through two or more terminals.
Disadvantages
Multi Programming Operating System
Multitasking operating system
Time-Sharing Operating System
Multi user of multi-access operating system
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Example: -
Real Time operating system: -
Railway Reservation System & Airline reservation system support hundreds of
active terminals under control of a single program. Although it is associated with
multiprogramming multitasking operating system does not imply multiprogramming or
multitasking.
In multiprocessing operating system,
multiple, CPUs perform more than one job at one time it differs from the time-sharing
operating system in the manner that it refers to utilization of multiple CPUs.
In it the resources are allocated comfortable to the competing processes in a manner
which results in a high throughput e.g.: - UNIX, MVS etc. Some mainframe and Supermini
computers have multiple CPUs, each of which can handle several jobs.
Real Time system is a special purpose operating system. It
is used in those environments, are accepted and processed in a short time, or within a
specified time. Real time operating system has well defined, fixed time constraints. Its main
characteristics are:-
Fast response time
Feedback mechanism
Reliability
It has to handle a process within the specified time limit otherwise the system fails,
resulting in a disaster many a times. Such applications include- Scientific experiments,
flight control, few military applications, industrial control etc.
a network operating system is a collection of S/W and
associated protocols that allow a set of computers which are interconnected by a computer
network to be used together. In a network operating system the uses are aware of existence
of multiple computers.
Capabilities of network operating system :–
Allowing users to access the various resources of the network nodes.
Allowing the users to copy files from one machine to another machine.
Controlling access to ensure that only users in the proper authorization access
particular resources.
A distributed operating system looks like an ordinary
centralized operating system that runs on multiple independent CPUs. It is collection o
processors that do not share memory. Each processor has its own local memory.
The use of multiple processors is invisible to the user i.e. the users are not aware of
where their programs are being run or where there files are residing. These are handled
automatically and efficiently by the operating system.
Multiprocessing (Parallel) operating system
Network Operating System
Distributed Operating System
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Advantages :–
Reliable :–
1. Process Management
2. Memory Management
3. File Management
4. Device Management
5. Security
6. I/O Management
7. Scheduling
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Resource Sharing
Powerful and cheap microprocessor technology
Better services to users
Communication and information sharing
Operating System as Resource Manager
a process is an executable program. During execution, a
process requires certain resources like CPU Time, Memory Space, and I/O Devices.
At a particular instance of time, a computer system normally consists of a collection of
processes. The process Management module of the operating system takes care of
the creation and deletion of processes, scheduling of various resources to the different
processes requesting them, and providing mechanisms for synchronization and
communication among processes.
To execute a program, it must be loaded; together with the
data is accesses, in the main memory. To improve CPU utilization and to provide better
response time to its user, a computer system keeps several programs in main
memory. The memory management module of an operating system takes care of the
allocation and de-allocation of memory space to the various programs in need of the
resource.
All computer systems are used for storage, retrieval and sharing
of information. A computer normally stores such information in units called files.
Processes can read the information from the files and can create new files for storing
the new information in the files. The file management module of an operating system
takes care of file related activities such as organizing, storing, retrieval, naming,
sharing and protection of files.
A computer system consists of various I/O devices as
terminals, printers, disks and tapes. The device management module of the operating
system takes care of controlling all the computer's I/O devices.
Computer system stores a large amount of information, some of which is
highly sensitive and valuable for their user. User can trust the system and rely on it only
if the various resources and information of a computer system are protected against
unauthorized access.The security module of the operating system ensures it.
Operating system also manages input output devices. The
function of input output devices are controlled by the operating system.
Operating system is responsible for the scheduling of the input output
devices.
Functions of Operating System
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Q.5 Give a complete overview of computer languages.
Ans:-Language :–
We can classify them in to the following categories
1. Low-Level Language
2. High-Level Language
3. Object Oriented Language
4. 4GL or User Friendly Languages
5. A.I.
it is a mechanism that is used to exchange the ideas and thoughts
between two or more entities. Like we human being use so many sort of languages such as
Hindi, English, French, Japanese, Chinese etc. similarly to communicate with the machine
we require language. From the very beginning of the origin of the computer the languages
are developing side by side.There are so many types of computer programming languages.
.
1. Low-Level Language
2. High-Level Language
3. Object Oriented Language
4. 4GLLanguage or User Friendly Language
5. AI (Artificial Intelligence )
They are the languages which are compatible with the
machine not with human being means machine can understand these languages very
easily but for human being they are difficult to understand.
Or
Using the low level languages it is easier to develop the system software but the
development of application software is not possible.
There are two languages which fall in the low-level language category :–
i. Machine Language
ii. Assembly Language
They are the languages which are written in human
understandable natural English language. For machine it is difficult to understand
these languages directly. So some system utility called translators are used to convert
the human understandable code into machine understandable code. They are
Assembler, Compiler and Interpreter. Following are some example of high level
language. BASIC, COBOL, FORTRAN, PASCALetc.
These languages includes some of the concepts of our
real life like Class, Object, Abstraction, Inheritance, Polymorphism, Encapsulation
etc. some example of OOLare C++, Java etc.
These languages are easier to learn by the
programmers and the development of the software is very quick. It supports the
concept of RAD (Rapid Application Development). Visual Basic, Oracle is the 4GL
Languages.
presently our researchers are working with the generation of AI Programming
Languages. These languages are used to develop the intelligent machines which may
behave in some way of human being like vision, listening, speaking, thinking, walking
etc. LISP, PROLOG is AI programming languages which are used for Robotics and
Expert System Development.
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Q.1 What is networking? What are various types of networking?
Ans.
In summary, all networks must have the following:-
1. File Sharing :–
Example –
2. Peripheral Sharing
Example-
3. Fast Communication
Networking
Need for Networking
Networking is the concept of sharing resources and services. A
network of computes is a group of interconnected systems sharing resources and
interacting using a shared communication link. A network, therefore, is a set of
interconnected systems with something to share. The shared resources can be data, printer,
a fax modem, or a service. Such as database or an email system. The individual systems
must be connected through a pathway (called the transmission medium) that is used to
transmit the resource or service between the computers. All systems on the pathway must
follow a set of common communication rules for data to arrive at its intended destination and
for the sending and receiving systems to understand each other. The rules governing
computer communication are called protocols.
Aresources to share (resource)
Apathway to transfer data (transmission medium)
Aset of rules governing how to communicate (protocols)
There is great need for networking.The main aim of networking is:-
Networks serve as an effective means to share the files with different
uses.
In an organization one file can be shared by the different departments if it is
placed on network systems.
Some Computer Peripheral are very expensive. We should
share there costly Computer Peripheral on the network.
laser printer and large hard disks are quite costly. Network enables to
share these costly devices.
It is possible that the mail from one place to another could
take several days. But through networking messages can be sent speedily.
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4. High Reliability
Example
5. Fax Facilities
6. Backups
File Server
Printer Server
Modem Server
Networking provides high reliability by using alternate sources of
supply.
All files could be copied on two or three machines, so that if one of them is
unavailable due to hardware or any other failure, the other copies could be used for
applications such as military, banking, air traffic control and many other applications
this is of great importance.
Compute can have fax systems integrated with networking. This
allows them to send pictures along with the text.
Thus the newspaper reports can be prepared and sent over the world at a very
high speed by composing and publishing them from different centers.
As all data is stored on a sever backing up critical data becomes a simple
process.
One of the major benefits of implementation of LAN is sharing
expensive resources such as storage devices, printers etc. This is achieved through
providing servers on the LAN. It is dedicated computer that controls one or more resources.
Three major categories of services used in LANs are-
In networking file server is used to share storage space for files.
Similarly printer server is used to handle printing woks of all workstation connected in
the network.
In LAN environment also modem is required to get connected to other network or
simply to use a telephone.
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LocalArea Network (LAN)
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Metropolitan Area Network (MAN)
WideArea Network (WAN)
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- Data Services
(SMDS).
LocalArea Network 1 LocalArea Network 2
Metro Area Network
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WideArea Network
A metropolitan area network (MAN) is designed to
extend over an entire city. It may be a single network such as a cable television network, or it
may be a means of connecting a number of LANs into a larger network so that resources
may be share LAN to LAN as well as device-to-device. For example, a company can use a
MAN to connect the LANs in its entire officer throughout a city.
A MAN may be wholly owned and operated by a private company, or it may be a
service provided by a public company such as local telephone company. Many telephone
companies provide a popular MAN service called switch Multi Megabit
Wide are networks connect computes and smaller network to
large networks over greater geographic areas, including different continents. These
computers may be linked by means of cables, optical fibers or satellites.
To access the networks, the users use a modem which is a device that allows
computers to communicate over telephone lines.
The largest wide area network is the internet, a collection of networks linking millions
of compute users on every continent.
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Transmission Channel for WAN
Hardware Requirements for WAN
Network Topologies
Mesh
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Q.2 What are various topologies are used for networking? Explain with their
advantages and disadvantages?
Ans. :–
Figure:
For transmission in a WAN, three types of channels
are used. These are :
Radio waveTransmission
MicrowaveTransmission
Communication Satellite
There are mainly four H/W devices which are
required to establish linkage between geographically separated computers these are-
Bridges
Routers
Gateways
X.25 Standard Interface
The term topology refers to the way of network is level out,
either physically or logically. Two or more devices connect to a link, two or more links form a
topology. The topology of a network is the geometric representation of the relationship of all
the links and linking devices to each other. There are five basic topologies possible: Mesh,
Star,Tree, Bus and Ring.
In a mesh topology, every device has been dedicated point to point link to every
other device. The term dedicated means that the link carries traffic only between the two
devices it connects. A fully connected mesh network therefore has n (n-1)/2 physical
channels to link n deice.
- fully connected mesh topology.
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A mesh offers several advantages over other network topologies.
Star
Figure Star Topology
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First, the use of
dedicated links guarantees that each connection can carry its own data load, thus
eliminating the traffic problems that can occur when links must be shared by multiple deices.
Second, a mesh topology is robust if one link becomes unusable, it does not affect the entire
system. Another advantage is privacy or security when every message sent travels along
dedicated lie; only the intended recipient sees it.
The main disadvantage of a mash are related to the amount of cabling and the number
of I/O ports required first, because every device must be connected to ever other device,
installation and reconfiguration are difficult. Second, the sheer bulk of the wiring can be
greater than the available space (in walls, ceilings, or floors) can accommodate for these
reasons a mesh topology is usually implemented in a limited places.
In a star topology, each device has a dedicated point-to-point link only to a central
controller, usually called a hub. The devices are not directly linked to each other. Unlike a
mesh topology, a star topology, a star topology does not allow direct traffic between devices.
The controller acts as an exchange if one device the data to the controller, which then relays
the data to other connected.
A star topology is less expensive than a mesh topology. In a star, each device needs
only one link and one I/O ports to connect it to any number of others. This factor also makes
it easy to install and reconfigure. For less cabling needs to e housed, and additions, moves
and deletions involve only one connection: between that device and the hub.
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Other advantages include robustness if one link fails, only that link is affected. All
other links remain active. As long as the hub is working, it can be used to monitor link
problems.
However, although a star requires for less cable than a mesh, each node must be
linked to a central hub. For this reason more cabling is required in a star than in some other
topologies (such as tree, ring or bus).
It is a network in which computers are interconnected tree structure.
To transfer information from node 4 to node 6. Information goes to node 2 then root
then node 1 finally to node 6.
A tree structure facilities functional grouping. For example- one branch may contain
all the general ledger terminals, another branch may have all the accounts receivable
terminals and so on if one branch stops functioning, and the other branches in a tree network
will not be affected.
It is easy to add new nodes or branches to it.
Disadvantage: - Data movement through this network can be slow.
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 the data packet copies the data on to its disk and fees the line.
Tree
Advantage
Bus Topology
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Advantages :–
Disadvantages
The main advantage of this method is the reduction in physical lines.
Awide range of equipment can be attached to the LAN without any problem.
A new node can be added to the LAN without disturbing the network and other
nodes.
Low cabling cost because of short cable length to be used.
Not requiring that every computer be cp and running in order for the network to
function.
In this topology, fault detection is very difficult because the network is not
centralized in any particular node. This means that detection of a fault may have to be
performed from many points in the network.
Only one message can travel at a time.
When a message from two nodes comes on the line, a collision occurs. The
chances of collision taking place are always there.
Low reliability. Abreak or short circuit in the cable and Holt the whole network.
The ring is a circular topology; each device connects directly to the ring.
The ring topology is also called a loop in this case; each node is connected to the only two
neighboring nodes.
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A ring may be unidirectional or bi-directional. In a unidirectional ring, data moves in
one direction. Only, whereas in a bi-directional ring data may move in both directions, but
one direction at a time.
The data is accepted from one of the neighboring node and is transmitted onward to another.
if E receives data from and it examines whether it is addressed to itself. If it is,
then E uses it else it passes the message to D.
Short cable length. This means that fewer connections will be needed,
which will in turn increase network reliability.
As thee is only one able connecting each node to its immediate neighbors, it is not
necessary to allocate space in the building for wiring closets.
It is very simple to install.
There may be large communication delays as the number of nodes
increases.
Each node on the ring must handle the data being transferred by other nodes.
If one node fails to handle the transfer of data then whole of network fails.
It is difficult to diagnose faults. We have to check each and every node to know
which node is faulty.
It is not possible to shut down a small selection of the ring while keeping the
majority of its working normally.
Example-
Advantages
Disadvantages
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Q.3 Describe the various application of Networking?
Ans. Network Applications Thee is a long list of application areas which can be
benefited by establishing networks few of the applications of computer networks are:-
Information retrieval systems which search for books, technical reports, papers
and articles on particular topics.
News access machines which can search past news, stories or abstracts with
given search criteria.
Airline reservation, hotel-booking, railway reservation, car rental etc.
A writer's aid; a dictionary, thesaurus, phrase generator, indexed dictionary of
quotations etc.
Stock market information systems which allow searches for stocks that meet
certain criteria, performance comparisons, moving averages, and various
forecasting techniques.
Electronic financial transactions (FFT) between banks and via cheque clearing
house.
Electronic mail messages systems (EMMS).
Corporate information systems such as marketing information system, customer
information system, product information system, personnel information system
etc.
Corporate systems of different systems such as order-entry system centralized
purchasing, distributed inventory control etc.
On-line systems for investment advice and management, tax minimization etc.
Resources of interest to a home user.
Sports results.
Theater, movies and community events information.
Shopping information, prices, and advertisements.
Restaurants, good food guide.
Household magazine, book reviews, film reviews etc.
Holidays, hotels, travel booking.
Radio &TV programs.
Medical assistance service.
Insurance information
Transmission channel
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Network interface unit (NIU)
Servers
Workstations
Like the data they represent, signals can be either
analog or digital. An analog signal has infinitely many levels of intensity over a period of
time. As the waves moves from value A to value B. It passes through and includes an
Infinite number of values along its path. A digital signal, on the other hand, can have only a
limited number of defined values. Although each value can be any number, it is often as
simple as 1 and 0.
Analog signals are continuous electrical signals that vary in time as shown in figure .
Most of the time, the variations follow that of the non-electric (original) signal. Therefore, the
two are analogous hence the name analog.
Not all analog signals vary as smoothly as the waveform shown in Figure 4a. Analog
signals represent some physical quantity and they are a 'MODEL' of the real quantity.
Telephone voice signal is analog. The intensity of the voice causes electric current
variations. At the receiving end, the signal is reproduced in the same proportion. Hence the
electric current is a 'MODEL' but not one's voice since it is an electrical representation or
analog of one's voice.
Q.4 Write a Short note on the following.
I. Analog and Digital Signal
ii. Bandwidth
Ans.
Comparison ofAnalog and Digital Signal
Analog and Digital Signals
Program
Example:
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Analog Signals
Figure : Analog Signal
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Digital Signals
Bandwidth
Frequency: -
Digital signals are non-continuous, they change in individual steps. They consist of
pulses or digits with discrete levels or values. The value of each pulse is constant, but there
is an abrupt change from one digit to the next. Digital signals have two amplitude levels
called nodes. The value of which are specified as one of two possibilities such as 1 or 0,
HIGH or LOW, TRUE or FALSE and so on. In reality, the values are anywhere within specific
ranges and we define values within a given range.
Difference between the maximum and minimum frequency of a frequency
spectrum of the signal is known as bandwidth of the signal.
Here the term frequency spectrum of a signal means the set of all frequencies that
constitutes it. Asimple signal has only a single frequency; however a complex signal can be
broken down into simple signals having different frequencies. The set of these frequencies
are known as spectrum of the signal.
In other words, we can say that the difference between the highest frequency and the
lowest frequency is known as bandwidth. To calculate the bandwidth, subtract the lowest
frequency from the highest frequency of the range.
Figure : Digital Signal
:–
The frequency is the rate at which the signal repeats.
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Q.4 Write a short note on the following.
I. Packet Transmission
ii. Long Distance Communication
Ans.
Virtual circuit transmission is implemented in two formats
SVC
Packet Transmission
Datagram Approach
Virtual Circuit Approach
PVC (Permanent Virtual Circuit)
In a packet transmission, data are transmitted in discrete
units of potentially variable. Variable length blocks called packet is established by the
network. Longer transmission are broken up into multiple packets each packets contains
not only data but also a header with control information (such as priority codes and source
and destination addresses). The packets are sent over node to node.
Two popular approaches of packet switching:-
Datagram approach
Virtual circuit approach
In Datagram approach, to packet transmission, each packet is
treated independently from all others. Even when one packet represents just a piece of multi
packet transmission, the network treats it as though it existed alone. Packets in this
technology are referred to as datagram's.
This approach can cause the datagram's of a transmission of a transmission to arrive
at their destination out of order.
In the virtual circuit approach to packet transmission, the
relationship between all the packets belongs to a message. A single route is chooses
between sender and receiver at the beginning of the session. When the data are sent, all the
packets of the transmission one after another along that route.
SVC (Switch Virtual Circuit)
PVC (Permanent Virtual Circuit)
In this method, a virtual circuit is created whenever it is needed. For example-
Imagine that station a wants to send four packets to station X. First, A requests the
establishment of a connection to X. Once the connection is in place, the packets are sent
one after another and are sequential order. Only one single rate exists for the duration of
transmission.
Each time that a wishes to communicate with X, a new route is established. The route,
many be the same each time or it may differ in response to varying network conditions.
Permanent Virtual Circuits are comparable to leased
lines in circuit switching. In this method the same virtual circuit is provided between two
users on a continuous basis. The circuit is dedicated to the specific users. No one else can
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use it and, because it is always in place. It can be used without connection establishment
and connection termination. Where as two SVC users may get a different route every time
they request a connection,Two PVC users always get the same route.
Ii) -
The use of long-distance communication using electric signals started with the
invention of the telegraph by Morse in the 19th century.
We can divide long distance communication in to following groups:
a) Microwaves :– Microwaves are very short waves of electromagnetic energy that
travel at the speed of light (186,282 miles per second). Microwaves used in
microwave ovens are in the same family of frequencies as the signals used radio
and television broadcasting.
The theory of electromagnetic energy can be illustrated by what happens when a
pebble is tossed into a quiet pond. The pebble striking the still surface causes the water to
move up and down in the form of ripples, or waves, that radiate in ever-widening circles over
the surface of the pond. These waves, which move up and down at right angles to the
direction they are traveling, are called transverse waves. Microwaves are examples of
transverse
The disturbance resulting from the pebble landing in the water is transmitted through the
water in the form of ripples or waves. The water serves merely as a medium through which
the disturbance travels. In this sense, these ripples are more like sound waves, which also
need a medium to travel through, normally using the molecules that exist in the air or water.
That is why, for example, thundering rocket engines that would deafen the ears under
normal circumstances, would be inaudible in the quiet vacuum of space.
Long Distance Communication:
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On the other hand, electromagnetic forms of energy, such as
microwaves, radar waves, radio and TV waves, travel millions
of miles through the emptiness of space without the need of
any material medium through which to travel. This is because,
simply put, electromagnetic waves are, in themselves, stored
energy in motion.
a. They require no right of way acquisition between
towers.
b. They can carry high quantities of information due to
their high operating F
c. Low cost land purchase: each tower occupies small
area.
d. High frequency/short wavelength signals require
small antenna.
a. Attenuation by solid objects: birds, rain, snow and
fog.
b. Reflected from flat surfaces like water and metal.
c. Diffracted (split) around solid objects
Refracted by atmosphere, thus causing beam to be projected away from receiver
Satellites are transponders that are set in a geostationary orbit directly
over the equator. A transponder is a unit that receives on one frequency and
retransmits on another. The geostationary orbit is 36,000 km from the Earth's surface.
At this point, the gravitational pull of the Earth and the centrifugal force of Earths
rotation are balanced and cancel each other out. Centrifugal force is the rotational
force placed on the satellite that wants to fling it out to space.
The following are five major components in a satellite: -
1. Transponder
2. Antenna System
3. Power Package
4. Control and information system
5. Rocket thruster system
Advantages:
requencies.
Disadvantages:
b) Satellites :–
Satellite components :–
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Q.1 Explain the concepts of database with its relevant advantages and
disadvantages. What are the characteristics of an ideal database?
Ans. Database :–
Data
Data Item
Record
File
A database is a collection of related information stored so that it is
available to many user for different purposes. The content of a database is obtained by
combining data from all the different sources in an organization. Database plays a critical
role in almost all areas where computers are used, including business, law, engineering,
medicine, education, library science etc.
The role of the DBMS as an intermediate between the users and the database is very
much like the function of a salesperson in a consumer's distributor system. A consumer
specified desired items by filling out an order from which is submitted to a salesperson at the
counter. The salesperson presents the specified items to consumer after they have been
retrieved from the storage room. Similarly, the database use needs to know only what data
he or she requires; the DBMS will take care of retrieving it.
Data can be defined as a representation of facts, concepts or instruction in a
formalized manner suitable for communication or processing by human or electronic
machine. Data is represented with the help of characters likeAlphabets (a-z), digits (0-9) or
special characters (1, -, 1, *, <, >, = etc.)
Aset of character which are used together to represent a specific data element.
Example Name of a student in a class is represented by the data item, say NAME.
Record is a collection of related data items e.g.-Apayroll record for an employee
contains such data fields as name, age, qualification, sex, basic pay, DA, HRA, PF etc.
File is a collection of related records stored in secondary storage that is available for
future use e.g. - Payroll file might consist of the employee pay records for a company.
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Information
Data Processing
Definition of Database
ADatabase Management System (DBMS) consists of
Minimal Redundancy
Information is classified data so that it has some meaningful values.
Data Processing means manipulating the data (raw data) to make it
more useful. Data Manipulation consists of such operation as classification, sorting &
calculations etc.
Adatabase is well organized collection of data that are related in
a meaningful way which can be accessed in different logical orders but are stored only once.
In this definition, it is clear that data in a database has the following features:-
It is well organized.
It is related.
It is accessible in different orders.
It is stored only once.
Adatabase system consists of a collection of interrelated data and a set of programs to
access the data. Hence, database system is the DBMS S/W together with the data itself. It
is an S/W that assists in maintaining and utilizing a database.
A collection of interrelated data. This part of DBMS is usually referred to as the
database.
A set of application programs used to access, update and manage that data.
This portion forms the Data Management System.
The goal or purpose of a database system is to provide an environment that is both
convenient and efficient to use in.
Retrieving information from the database, and
Storing information into the database.
In other words, a DBMS allows you to store update and retrieve data hence making it
easy to maintain and retrieve information from a database.
In file systems each application has its own private files.
This can often lead to considerable redundancy in stored data, with renitent waste in
storage space. For example, a personnel application and an education-records
application may each own a file containing department information for employees.
These two files can be integrated, and the redundancy eliminated, if the DBA is aware
of the data requirements for both applications.
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Sharing of Data
Standards can be enforced
Search Capability
Integrity
Privacy & Security
The Interface with the Past
Data Migration
Faster development of new application
It means not only that existing applications can share the data in
the database, but also that new applications can be developed to operate against that
same stored data. In other words, the data requirements of new applications may be
satisfied without having to create any new stored files.
With central control of the database, the DBA can
ensure that all applicable standards are followed in the representation of the data such
as format of data items, documentation standards etc. Which will result in uniformity
of the entire database as well as its usage?
The user of a database may ask wide variety of the questions
about the data if a quick answer is needed at a terminal the search will have to be fast
the capability to search a database quickly. An objective of database organization,
then, may be achieving fast flexible search capability.
By integrity we mean unification of several files into one file. When a
database contains data employed by many different users it is important that the data
items & associations between data items not be destroyed. Hardware failures various
types of accidents will occur occasionally. The storage of data it's updating & insertion
procedures, must be such that the system can recover from these circumstances
without harm to the data. This integration eliminates inconsistency.
Data in database systems must be kept secure & private. Data
security refers to protection of data against accidental or intentional disclosure to
unauthorized persons or unauthorized modifications.
Organizations which have been using data processing
for some time having a major investment in their existing programs, procedures and
data. When an organization installs new data-base S/W it is important that it can work
with the existing programs & procedures and that the existing data can be converted.
Some data are referenced very frequently and others only
occasionally. It is desirable to store the frequently reference data in such a manner
that they can be accessed quickly conveniently. The rarely accessed data can be
stored in a cheaper fashion. The rarely accessed data can be stored on magnetic tape
& frequently accessed data may be on disk or drum. The process of adjusting the
storage of data is called data migration.
When a new application is proposed, it is
likely that the data required is already stored in the database. Therefore, development
time is reduced as no file creation phase is required for the new application.
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More control over concurrency:-
.
High Cost of DBMS
High Hardware Cost
High Programming Cost
.
Complex
Backup & Recovery are More Difficult
Confidentiality, Privacy and Security
Characteristics of an Ideal Database
In a file system, if two users permitted to access
the data simultaneously or both attempt to perform updates, they will interfere, with
each other and one might overwrite the value recorded by the other. A DBMS has
subsystems to control concurrency so that transaction are not lost or performed
incorrectly
Because a complete DBMS is very large and sophisticated
piece of S/W, it is expensive to purchase.
Additional memory and processing power may be required to
run the DBMS, resulting in the need to upgrade the H/W.
Because a DBMS is a complex tool with many features, it
requires experienced programmers resulting in extra payment for their heir and
expertise
Another major disadvantage is that database processing tends to
complex, large amounts of data in many different formats can be interrelated in the
database.
Determining the exact state of the
database at the time of failure may be a problem. It may be even more difficult to
determine what should be done next.
Even the failure of just one application program may pose serious problems.
When information is centralized and is
made available to users from remote locations, the possibilities of abuse are often
more that in conventional data processing system.
A database represents some aspect of the real
world, sometimes called the mini world or the In, general, an
ideal database should provide the following facilities:-
a. Creation of a file, addition to data, deletion of data, creation, addition and
deletion of entire file.
b. Retrieving data collectively or selectively.
c. Sorting and indexing of data.
d. Reports generation facilities.
e. Mathematical functions can be performed on the data to fetch the desired
calculation.
f. To maintain the data integrity.
Disadvantages of Database System
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Universe of Discourse (U.D.).
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Q.2 Write a short note on the following
I. Schema and Sub-schema
ii. Entity andAttributes
Ans. Schema and Instance of the Schema or Database State :–
The overall logical data base description is referred to as a schema. It is sometimes
also referred to as an overall model of the data.
Aschema is a chart of the types of data that are used. It gives the names of the entities
and attributes, a specifies the relation between them. It is a framework into which the value
of the data items can be fitted like the display at an airport giving arrival and departure
information. The schema will remain the same while the value fitted into. It changes from
instant to instant. When the scheme framework is filled in with data-item values, it is referred
to as an instance of the schema.
S
S# Sname Status City
Part
P# Pname Color Weight City
S# P# QTY
A schema diagram is shown above, displays only name of record types (Entity) and
names of data items (Attributes) and does not show the relationships among the various
files.
Instances of table S is shown below. The data in the database at a particular moment
in time is called a database state or snapshot. It is also called the current set of instances in
the database.
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S1 Amit 10 KARNAL
S2 Sunita 20 PANIPAT
S3 Sohan 10 ROHTAK
The term subschema refers to an application programmer's view of the data
he uses. The application programmer does not need to know about the entire data-base
schema. It is often highly complex and we do not want him involved in arguments about that
complexity.
The DBAmust ensure that the subschemas they use are derivable from Schema.
An entity is a person, place, thing, event or concept about which information is
recorded.
In a banking environment, examples of entities are USTOMERS, BANKACCOUNTS,
and LOANS etc. In a warehouse the entities are SUPPLIERS, PARTS, SHIPMENTS and the
like.
Attributes gives the characteristic of the entity. In other words, every entity has
some basic attributes that characterize it eg-
a) Ahouse can be described by its size, color, age & surroundings.
b) A customer of a bank may be described by such attributes as Name, Address &
Possible a customer identification number.
c) Abank account can be represented by an account type, an account number & an
account balance.
So in example (a) size, color, age surroundings are attributes of the entity house. In eg
(b) customer identification no, customer name & customer address are three attributes
describing the entity “CUSTOMER” of a bank.
An attribute is often called a data element, a data field, a data item etc.
An attributes which have a single
value for a particulars entity is known as single valued attributes. For example, age of
an employee entity.
S# SNAME STATUS CITY
:–
Entity
1.
Subschema
Attributes
Types of Attributes
Single valued versus multi valued attributes
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An attributes which have a set of values for the same entity is known as multi valued
attributes. For example, colors for a car entity.
The attributes which can be
divided into smaller independent attributes are called composite attributes. For
example, address of the employee entity as show in figure below
The attributes which can not be divided into smaller supports are called simple or
AtomicAttributes. For example,Age of an employee entity.
An attributes which can be derived from another
attribute is known as derived attribute. For example,Age of an employee entity can be
determined from the today's data and Birth date of the same employee entity.
An attribute which can not be derived from another attribute is known as stored
attribute. For example, Birth date of an employee entity.
: -An attribute for an entity has NULLvalue if either the value of that attribute
is now known (missing) or not applicable to that entity. For example, if a person does
not have any degree then college degree attribute value will be Null or even if it not
known it is again NULL.
: - If an attribute for an entity is built using composite and multi
valued attributes, such an attributes are called complex attributes. For example, if a
person can have more than one residence and each residence can have multiple
phones.
2.
Address
SectorAddress City State Pin
Sector Number House Number
3. Stored versus DerivedAttributes: -
4. Null Value
5. Complex Attributes
Composite versus simple (Atomic) Attributes :–
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Q.1 What is Internet? What are various applications of Internet?
Ans.
APPLICATIONS OF INTERNET
1. On-line communication
2. On-line Shopping
3. Video Conferencing
4. Advertising and Publishing
5. Product Promotion
Internet is the network of networks. It links computers of every model and operating
system together to facilitate the sharing of information. The variety of information served,
various from the current research documents to the latest sports and news features. The
term internet can be thought of as shorthand for Interconnected Networks.
One can find many applications on the internet. Some of the important current
strategic uses are given below:
E-Mail and chatting is extensively used now-a-days around the world to communicate
with each other.
On-line shopping is also becoming very popular. Many people instead of going round
and wasting their precious time in shopping just on the system and place the order for the
require stuff.
A new emerging service on the Internet which allows a group of users located in
different parts of the world to communicate with each other as if they are sitting in a single
room. In this way one can discuss any topic sitting anywhere in the world.
The Internet has become the first global venue for advertising and publishing
information.
Internet is the cheapest means to promote ones product
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6. Technical Support/Customer Support Service
7. Feedback
8. Online Registration and Examination
9. Software Sharing
10. Group Discussion
Q.2 Write a short note on the following:-
I. Web Browser
ii. World Wide Web
iii. Internet ProtocolAddresses
Ans.
1. Microsoft Internet Explorer
One can get technical support for product one is using. Many organizations provide
customer support.
Commercial organizations are using Internet to gather customer satisfaction of
existing products, market opportunities of new products, and ideas for new products.
Many universities and institutions provide training and also online enrolment forms.
Some companies like Thompson parametric, VUE provides online examination for the
various products of software & hardware.
Many software developing organizations provides trial software versions on the
Internet.
Anumber of Newsgroups are available on the Internet which allows exchanging views
on topics of common interest.
A Web Browser interprets the markup of files in HTML, formats them into We pages,
and displays them to the end user. Some browsers also permit end users to send and
receive e-mail, read newsgroups, and play sound or video files embedded in Web
documents.
Web browser give you access to Web sits, which comprise Web pages. A Web page
may contain text, graphics, animations, sounds, movies and a variety of interactive
elements. A Web browser makes it easy to navigate (or “surf”) the Web and to download
items. Some of the popular Web browsers are:
It is Microsoft a new browser Internet Explorer, also as Explorer. Explorer runs on all
versions of Windows operating system, and Macintosh.
WEB BROWSER
A software application that provides a graphical view of the Internet is called a Web
Browser.
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Netscape Navigator
2. Lynx
3. Mosaic
Netscape navigator is available for Windows, Macintosh, and for many different
versions of UNIX running the X Window System.
Lynx is an excellent browse for text-only Internet connections such as dial-up UNIX
accounts. Lynx gives you nothing but the text and the links.
Mosaic was the first full-color graphical browser. NcSAMosaic is free or personal use
and comes in versions for Windows, Macintosh, and UNIX (the X Window System).
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Most major browsers offer a number of toolbar buttons to help you navigate the Web.
The exact names and functions of these various buttons vary from browser to browser, but
the most-used buttons are usually the same. Given below are the name and functions of the
common buttons.
The World Wide Web was developed in 1989 by Tim Berners-Lee of the European
Particle Physics Lab (CERN) in Switzerland. The initial purpose of the Web was to use
networked hypertext to facilitate communication among its members, who were located in
several countries. Word was soon spread beyond CERN and a rapid growth in the number
of both developers and users ensued. In addition to hypertext, the Web began to
incorporate graphics, video, and sound. The use of the Web has now reached global
proportions.
The World Wide Web (abbreviated as the Web or WWW or W3) is probably the most
popular place to be on the Internet. It is the factor most responsible for the huge growth of
the Internet. The World Wide Web is an easy to use method for storing and retrieving the
information that resides on systems in the Internet. Three developments fueled the growth
of the Web:
– the ability to link to other documents.
– the ability to include text, audio, video, images and graphics in a
document.
Browsers to view the Hypertext/Hypermedia documents.
WWW (WORLD WIDE WEB)
Hypertext
Hypermedia
Graphical (GUI)
Asystem for exploring the Internet by using hyperlinks. When you use a web browser,
the web appears as a collection of text, pictures, sounds, and digital movies.
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W3 is a system of Internet servers that supports hypertext to access several Internet
protocols on a single interface. Almost every protocol type available on the Internet is
accessible on the Web. This includes e-mail FTP, Telnet, and Usenet News. In addition to
these, the World Wide Web has its own protocol: HyperTextTransfer Protocol, or HTTP.
The operation of the Web relies primarily on hypertext as its mean of information
retrieval. Hypertext is a document containing words that connect to other documents.
These words are called links and are selectable by the user. A single hypertext document
can contain links to many documents, in the context of the Web, words or graphics may
serve as links to other documents, images, video, and sound. Links may or may to follow a
logical path, as each connection is programmed by the creator of the source document.
Overall, the Web contains a complex virtual web of connections among a vast number of
documents, graphics, videos, and sounds.
Producing hypertext for the Web is accomplished by creating documents with a
languages called Hypertext Markup Language, or HTML With HTML, tags are placed within
the text to accomplish document formatting, visual features such as font size, italics and
bold, and the creation of hypertext links. Graphics and multimedia may also be incorporated
into an HTMLdocument. HTMLis an evolving language, with new tags being added as each
upgrade of the language is developed and released. The World Wide Web Consortium
(W3C). Led by Web founder Time Berners-Lee. Coordinates the efforts of standardizing
HTML. The W3C now calls the language XHTML and considers it to be an application of the
XMLlanguage standard.
The WWW uses special software called a Browser (client) and TCP/IP, HTTP and a
Web Server to function.
TCP/IP (Transmission Control Protocol/Internet Protocol) is the communication
protocol used by the Internet and is a must for the World Wide Web to function.
HTTP (Hyper Text Transfer Protocol) is a protocol which makes the
communication possible between the Web Server and a Web Browser. It is the
protocol used to transfer information over the WWW.
Web Server is special software, which runs on a computer and responds to
requests made by other computers on the network.
A Web Browser is a special software application that provides a graphical view of
the Internet.
The WWW is based on three mechanisms that are uses to make resources available
to users. These are:
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MECHANISM OF WWW
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Protocols
Addresses
Protocols are the standard to be followed for communication.
The WWW follows a uniform naming scheme to access resources on the Web called
URL(Uniform Resource Locator).
The computers on a network have to be able to talk to each other. To do that they use
protocols that are just the rules or agreements on how to communicate. Hypertext Transfer
Protocol (http) is the protocol used by the Internet.
This addressing system is used to identify pages and resources on the Web. An
Internet or Web address (called as URL, or Uniform Resource Locator) typically is
composed of four parts:
A protocol name (a protocol is a set of rules and standards that enable computers to
exchange information)
The location of the site
The name of the organization that maintains the site
A suffix that identifies the kind of organization it is (such a .com for a commercial
organization)
For example, the address provides the following
information:
http://www.zadcomputers.co.in
http://www.zadcomputers.co.in
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Http
www
Zad computers
Co
In
HTML
,This Web sever uses HypertextTransfer Protocol (HTTP).
,this site is one the World Wide Web.
, this is the name of the site i.e. host name
, this is a commercial site
, stands for country location India
When you are viewing a Web page, the page's address appears in the Address bar in
Internet Explorer. (For more details on this topic refer Unit 2).
The HTML document is created using the HTML tags and elements. The file is saved
with the . or file name extension on the Web Server. The Client Browser sends a
request for a page to the Web Server using the URL of the page. The Server processes the
request and sends back the requested HTML document. The document is displayed in the
browser or client.
Further the programming languages such as Java, JavaScript, and Visual Basic.
Cold Fusion and XMLre extending the capabilities of the Web.
·
Hyper Text Markup Language is used to create web pages that can be accessed over
the Web.
html .html
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Internet ProtocolAddresses :–
The Network Part of the IPAddress
The Local or Host Part of the IPAddress
IPAddress Classes and Their Formats
The (IANA) manages the IP address space
allocations globally.
An IP address is a 32- number that identifies each sender or receiver of information
that is sent in s across the Internet. When you request an HTML page or send e-mail,
the Internet Protocol part of includes your IP address in the message (actually, in
each of the packets if more than one is required) and sends it to the IP address that is
obtained by looking up the in the you requested or
in the e-mail address you're sending a note to. At the other end, the recipient can see the IP
address of the Web page requestor or the e-mail sender and can respond by sending
another message using the IPaddress it received.
An IP address has two parts: the identifier of a particular network on the Internet and
an identifier of the particular device (which can be a server or a workstation) within that
network. On the Internet itself - that is, between the that move packets from one point
to another along the route - only the network part of the address is looked at.
The Internet is really the interconnection of many individual networks (it's sometimes
referred to as an ). So the Internet Protocol ( ) is basically the set of rules for
one network communicating with any other (or occasionally, for broadcast messages, all
other networks). Each network must know its own address on the Internet and that of any
other networks with which it communicates. To be part of the Internet, an organization needs
an Internet network number, which it can request from the Network Information Center
(NIC). This unique network number is included in any packet sent out of the network onto the
Internet.
In addition to the network address or number, information is needed about which
specific machine or host in a network is sending or receiving a message. So the IP address
needs both the unique network number and a host number (which is unique within the
network). (The host number is sometimes called a or .)
Part of the local address can identify a subnetwork or address, which makes it
easier for a network that is divided into several physical subnetworks (for examples, several
different local area networks or ) to handle many devices.
Since networks vary in size, there are four different address formats or classes to
consider when applying to NIC for a network number:
Internet Assigned Numbers Authority
bit
packet
TCP/IP
domain name Uniform Resource Locator
router
IP
subnet
internetwork
local machine address
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ClassA
Class B
Class C
Class D
ClassA
Class B
Class C
Class D
addresses are for large networks with many devices.
addresses are for medium-sized networks.
addresses are for small networks (fewer than 256 devices).
addresses are multicast addresses.
The first few bits of each IP address indicate which of the address class formats it is
using.The address structures look like this:
0 Network (7bits) LocalAddress (24bits)
10 Network (14 bits) LocalAddress (16 bits)
100 Network (21 bits) LocalAddress (8 bits)
1110 MulticastAddress (28 bits)
The IP address is usually expressed as four decimal numbers, each representing
eight bits, separated by periods. This is sometimes known as the and, more
technically, as . For Class A IP addresses, the numbers would
represent "network.local.local.local"; for a Class C IP address, they would represent
"network.network.network.local". The number version of the IP address can (and usually is)
represented by a name or series of names called the .
The Internet's explosive growth makes it likely that, without some new architecture,
the number of possible network addresses using the scheme above would soon be used up
(at least, for Class C network addresses). However, a new IP version, , expands the size
of the IP address to 128 bits, which will accommodate a large growth in the number of
network addresses. For hosts still using IPv4, the use of s in the host or local part of
the IP address will help reduce new applications for network numbers. In addition, most sites
on today's mostly IPv4 Internet have gotten around the Class C network address limitation
by using the Classless Inter-Domain Routing ( ) scheme for address notation.
dot address
domain name
IPv6
subnet
CIDR
dotted quad notation
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Relationship of the IPAddress to the PhysicalAddress
Static Versus Dynamic IPAddresses
Q.3 What is E-Commerce? What is the frame work of E-Commerce? Also describe
the advantage and disadvantages of E-Commerce. What is security concern
with E-Commerce?
Ans. E-Commerce
.
FRAMEWORK OF E-COMMERCE
The machine or physical address used within an organization's local area networks
may be different than the Internet's IP address. The most typical example is the 48-bit
address. TCP/IP includes a facility called the Address Resolution Protocol ( )
that lets the administrator create a table that maps IP addresses to physical addresses. The
table is known as the .
The discussion above assumes that IP addresses are assigned on a static basis. In
fact, many IP addresses are assigned dynamically from a pool. Many corporate networks
and online services economize on the number of IP addresses they use by sharing a pool of
IP addresses among a large number of users. If you're anAmerica Online user, for example,
your IP address will vary from one logon session to the next because AOL is assigning it to
you from a pool that is much smaller thanAOL's base of subscribers.
E-Commerce is any form of business exchange or transaction in
which the parties interact electronically
E-commerce or E-business includes electronic trading of physical goods and of
intangibles such as information. This encompasses all the trading steps such as online
marketing, ordering, payment, and support for delivery. E-commerce includes the electronic
provision of services, such as after sales support or online legal advice. E-commerce also
includes electronic support for collaboration between companies, such as collaborative
online design and engineering, or virtual business consultancy teams. E-commerce can be
between Business to Customer (B2C), Business to Business (B2B), Business to
Administration (B2A), Business to Government (B2G), and Customer to Customer (C2C).
In simple words, E-commerce refers to “Doing business electronically”.
AN E-commerce framework can be explained in two
basic parts;
1. The E-commerce core consisting of basic infrastructure which will enable the e-
commerce activities.
2. Afive-corner web of basic issues that will ultimately shape all e-commerce efforts.
Ethernet ARP
ARPcache
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:–
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Financial
Issues
Legal &
Regulatory
Issues
Network
Protocol and
Technical
E-COMMERCECORE
Business Application
Service Enabling
Infrastructure
Content Development,
Deployment and
Distribution Infrastructure
Market
Access
Cultural
Issues
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E-commerce core can be described as a three-layer
hierarchical architecture where each subsequent layer is based upon the lower layers.
The three layers, starting from the lowest layer are:-
This
layer will include all hardware and network infrastructure that will act as physical
infrastructure to enable e-commerce transaction.This will include: -
It include: -
1) Multimedia publishing infrastructure (to create multimedia contents for
business applications)
2) Multimedia storage infrastructure (to provide for efficient and organized
storage facilities for efficient and retrieval and deployment of multimedia
contents)
Framework of E-commerce
1. The E-commerce core: -
a) Content development deployment and distribution infrastructure: -
i) Content development infrastructure, deployment:-
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3) Multimedia deployment infrastructure (to search and retrieve multimedia
contents from their storage locations)
ii It include: -
1) Network access device infrastructure (independent and internally
controlled by merchants and consumers)
2) Infrastructure installed by network service providers (includes local-on-
ramp service providers, national data and information carriers, third party
value added networks and other network service providers)
3) Global information delivery networks (includes sub-marine cables,
intercontinental optic fiber networks, satellite networks and other such
networks forming backbone of global communication networks)
This layer will include all vendors and other
parties engaged in the business activities which facilitate e-commerce
transactions in any fashion. The list of such business activities may include
following: -
i) Securing business transactions by providing hardware and software solutions
to counter both physical and logical security threats.
ii) Development of secure electronic payments fund transfer systems
iii) Third party verifications and authentications services
iv) Developing standards and formats for content creation, distribution and
deployment.
v) Offline support services provided by traditional 'brick-and-mortar' support
service providers.
This layer correspondence to the real business
transactions that take place is using the digital messaging technologies. A few of
the common business applications that can be offered online can be listed as
below: -
i) Online education and learning
ii) Online marketing communications and promotion
iii) Online shopping
iv) Online retailing and sales
v) Online banking services.
) Distribution infrastructure : –
b) Services enabling infrastructure
c) Business applications
: –
: –
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2. Five corner issues : –
a) Financial issues
b) Legal and regulatory issues
c) Market Related Issues: -
d) Network Protocols and Technical Standards
e) Socio Cultural Issues
ADVANTAGES OF E-COMMERCE
The five corner issues are described below :
it include :
i) Customs and taxation
ii) Electronic payments and fund transfers
It include :
i) Uniform commercial code
ii) Intellectual property protection
iii) Privacy
iv) Security, confidentiality and integrity
v) Protection of consumer rights and interests
vi) Dispute resolution and jurisdiction
It includes :
i) Competition
ii) Customer orientation
iii) Trust and reliability
: - It includes :
i) Multimedia formats
ii) Hardware standards
iii) Documentation specifications
iv) Acceptability of standards
It includes :
i) Lifestyle
ii) Demographic of target market
iii) Purchase potential
iv) Attitude towards e-commerce
1. Throughout the world.
2. Low cost medium disseminating information and processing transactions.
3. Provides the buyers a wider range of choices than traditional commerce.
4. Help protect against frauds and theft losses because electronic payments can be
easier to monitor than payments made by cheques.
5. Enables people to work from home and has an added benefit of reduction in traffic and
pollution caused by employee who has to communicate to office.
: –
: –
: –
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DISADVANTAGES OF E-COMMERCE
TYPES/LEVELS OF E-COMMERCE
B2B (BUSINESS TO BUSINESS)
B2C (BUSINESS TO CUSTOMER)
C2C (CUSTOMER TO CUSTOMER)
1. Things like food, jewelry, antiques etc. can never turn to e-commerce because it is not
possible to inspect them from remote locations.
2. Many firms have had trouble recruiting and retaining employees with the
technological, design, and business process skills needed to create an effective
electronic commerce presence.
3. Frauds are not completely eliminated in the e-commerce transactions.
4. Cyber laws are not properly enacted and the existing ones are not clearly defined.
Following are the types of E-Commerce:
1. B2B (Business to Business)
2. B2C (Business to Customer)
3. C2C (Customer to Customer)
Businesses can often deal with hundreds or thousands of other businesses, either as
customers or suppliers. Carrying out these transactions electronically gives obvious
advantages over traditional methods. It's faster, cheaper and more convenient.
Electronic mails, virtual storefronts allow individual
consumers to browse for products and shop using credit cards. It is more like an extension
of catalogue shopping, through mail order and telephone ordering using credit cards for
making payments. This form of ecommerce is Internet based, with unrestricted access to
consumers. An example of an Indian store is fabmart.com which first sold music cassettes.
CDs and now books and other items. These Inter-net base shops are also called cyber-
shops, dot.com shops, virtual shops, e-stores, etc.
You put an announcement at any of the “Consumer Exchange” website that you
are selling, say second hand Laptops. Others with similar interest then “bid” against each
other for the object, so you get a price you normally couldn't dream of.
B2B stands for Business-to-Business and refers to Electronic Commerce between
businesses rather than between a business and a consumer.
By business to customer (B2C) e-commerce we mean e-commerce involving an
individual and a shop selling goods
This type of e-commerce takes place on the Internet, without any business as
middleman.
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One of the most – successful online auctioneers is e-bay ( ) essentially
a national classified listings in USA; e-bay had more than 900,000 for sale in 1086
categories in 2000. The Web site received 140 million hits a week.
Steal confidential documents not intended for them.
Execute commands on the server host machine, allowing them to modify the system.
Gain information about the Web server's host machine that will allow them to break
into the system.
Launch denial-of-service attacks, rendering the machine temporarily unusable.
Browser-side risks, including:
Active content that crashes the browser, damages the user's system, breaches the
user's privacy, or merely creates an annoyance.
The misuse of personal information knowingly or unknowingly provided by the end-
user.
Interception of network data sent from browser to server or vice versa via network
eavesdropping. Eavesdroppers can operate from any point on the pathway between
browser and server including:
The network on the browser's side of the connection.
The network on the server's side of the connection (including intranets).
The end-user's Internet service provider (ISP).
The server's ISP.
Either ISP's regional access provider.
It's important to realize that “secure” browsers and servers are only designed to
protect confidential information against network eavesdropping. Without system security
on browser and server sides, confidential documents are vulnerable to interception.
If you are a Webmaster, system administrator, or are otherwise involved with the
administration of a network, the single most important step you can take to increase your
site's security is to create a written security policy. This security policy should concisely lay
out your organization's policies with regard to: who is allowed to use the system what they
are allowed to do (different groups may be granted different levels of access) procedures for
granting access to the system procedures for revoking access (e.g. when an employee
leaves) what constitutes acceptable use of the system. Remote and local login methods
system monitoring procedures protocols for responding to suspected security breaches.
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