Computer Aplication

Embed Size (px)

Citation preview

  • 7/27/2019 Computer Aplication

    1/64

    COMPUTERAPPLICATIONINMANAGEMENTMBA1stSEMESTER,M.D.U.,ROHTAK

    SYLLABUS

    ExternalMarks:70Time:3hrs.

    InternalMarks: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,

    Packet Transmission, 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

    241

    footer

  • 7/27/2019 Computer Aplication

    2/64

    COMPUTERAPPLICATIONINMANAGEMENT

    MBA1stSemester(DDE)

    UNIT I

    242

    Q.1 Whatis Computer? Explain its Characteristics and Limitations?

    Ans. Definition :

    :

    (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 isknown Information.Input Data a nd i nstructions g iven to c omputer.Process Manipulation of data.Output Informationobtained 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:-

    ::

    ::

    footer

  • 7/27/2019 Computer Aplication

    3/64

    243

    COMPUTER APPLICATIONINMANAGEMENT

    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, youfeel 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 retrievedand 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 anyorganizations.

    Computer solved those problems which are not solved

    by human being computer solved the computer solved the problems in seconds.

    -6

    -9

    -12

    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

    :

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    4/64

    244

    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 cannotthink 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 orerror in logic.

    It has no Capability to take any decision by itself, like a human being, itcannot judgeby itself for any valid or non-validdata.

    A computer is not a magical device. It can only perform tasks that a human beingcan. 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. A computer cannot take itsown decision in this regard.

    Computers have no feelings and no emotion because they are machine.

    It does not have intuition and cannot drawconclusion without going through all the intermediate steps.

    Computers don't learn form experience.

    A computer is a fast electronic device, processing the Input dataaccording to the Instructions given by the Programmer/User and provides the desiredinformation as an output.

    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 variousApplicationsof Computer?

    Or

    What is Computer? What is the scope or impact of computer in businessapplication?

    Ans. Definition :

    :

    :

    :

    :

    The word 'Computer' is basically derived form the word 'computer', which meansto calculate some thing. But in today's scenario if we told that computer is just a calculationmachine, 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 managinginformation 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

    footer

  • 7/27/2019 Computer Aplication

    5/64

    245

    COMPUTER APPLICATIONINMANAGEMENT

    Application of Computer in Business

    Scope of Computers in Business offices

    Computers have completely altered the structure of business. Large volumes of accountingand 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 ControlCost accounting, Job costs, Standard costs, Work in Progress, Labors registers

    Asset Registers

    Hire Purchase Records

    :

    (1) Personal Management

    (2) Financial Management

    footer

  • 7/27/2019 Computer Aplication

    6/64

    246

    (3) Office Management

    (4) Material Management

    (5) Purchasing Management

    (6) Marketing Management

    Budget

    Annual Reports

    Production Schedules

    LoanAnalysis

    Graphic Trends

    Managing Reports, Directories, Catalog's, Bulletins, Letters, Memos

    To Minimize Inventories

    Material Planning/Specifications

    Calling Tenders

    Comparing Tenders

    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

    according to the Instructions given by the Programmer/User and provides the desired

    information as an output. OrThe word Computer is basically derived from the word compute, which means to

    calculate some thing. But in todays scenario if we told that computer is just a calculation

    footer

  • 7/27/2019 Computer Aplication

    7/64

    247

    COMPUTER APPLICATIONINMANAGEMENT

    machine, it is not true. We can do a lotmore than calculation. Lets 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.

    A computer 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 DevicesSoftware

    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 dataand 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

    v

    v

    v

    Hardware:-

    Central Processing Unit :

    (1) MemoryUnit orStorageUnit

    (2) Arithmetic & Logical Unit (ALU)

    (3) Control Unit

    (1) Memory Unit or Storage Unit :

    footer

  • 7/27/2019 Computer Aplication

    8/64

    248

    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 ofprocessing, 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 availablein 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 functionsof 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 :

    footer

  • 7/27/2019 Computer Aplication

    9/64

    StorageDevices

    Dataand

    instructionMEMORY

    CONTROL UNIT

    A.L.U

    Output

    INPUT DEVICE OUTPUT DEVICE

    UnprocessedData

    ProcessedData

    249

    COMPUTER APPLICATIONINMANAGEMENT

    BlockDiagramofComputer

    - 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) CursorControlDevices

    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

    footer

  • 7/27/2019 Computer Aplication

    10/64

    250

    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 and Tapes).

    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 arestored. 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 (Random Access 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.

    T he n on -t an gi bl e c om po ne nt s o f t he c om pu te r s ys te m a rereferred 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 :

    footer

  • 7/27/2019 Computer Aplication

    11/64

    Classification

    Purpose

    General

    Purpose

    Computer

    Special

    Purpose

    Computer

    TechnologyUser

    Analog

    Computer

    Digital

    Computer

    Hybrid

    Computer

    Size&Capacity

    Super

    Computer

    Mainframe

    Computer

    Mini

    Computer

    Micro

    Computer

    251

    COMPUTER APPLICATIONINMANAGEMENT

    Who takes care of the various components of the computer.

    Who manages and handles the software loaded onto thecomputer.

    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 PurposeComputers

    Ans. Classification o f Computers

    The classification of computers is based on the following three categories:-

    (1) Accordingto Purpose

    (2) Accordingto technology used

    (3) Accordingto size andcapacity.

    footer

  • 7/27/2019 Computer Aplication

    12/64

    252

    (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

    Differencebetween AnalogandDigitalComputers

    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 thatrepresent 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 continuousdata (Air, and produce discretedata (AIr, Prices,

    Water, Distance) Incomes etc)

    Computation ofPhysical quantity Computation ofNumericalDigits

    Accuracy of Computation is quite limited Accuracy of Computation is more

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    13/64

    253

    COMPUTER APPLICATIONINMANAGEMENT

    Slow Systems Fast Systems

    Used in limited number of applications Used in Unlimited number of applications

    Outputs i s Continuous Output is o btained a fter 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 istypically used fall the following applications:-

    Weather forecasting

    Petroleum Exploration and production

    Energy Mgt

    Defense

    Nuclear EnergyResearch

    Weapons research and development

    Earthquake prediction (seismology)

    PARAM andANURAG are Super Computers produced by India. CRAY 3, CRAY-XMP14, 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

    :

    :

    :

    :

    :

    For example

    Super Computers

    Mainframe Computer

    footer

  • 7/27/2019 Computer Aplication

    14/64

    many terminals (Input/Output devices) are connected with one CPU and thus, allow differentusers 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 morepowerful 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, IBM4381, IBM4300 and IBM ES-9000.

    Minicomputers are medium scale, smaller and generally slower thanmainframe computers. Like Mainframes, they have many terminals which are connectedwith 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 thanmicrocomputers. 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 MICROVAX, IBM AS/400 is actually a midi computer (computer with performance between amainframe and minicomputer) is becoming very popular among minicomputers.

    It is a low cost small digital computer. This type of compute contains amicroprocessor as its CPU, a memory Unit, Input and Output device. These are also calledpersonal computer system. Maximum speed of micro computers is up to 1 million bytes persecond. These types of computers can be used to play games, teach children math, make apainting, create net musical sounds etc.

    They are very inexpensive families or home business can afford to buy a small systemto 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 beaccommodated on the top of a desk, is called desktop computers. The usage of suchcomputers is quite common is offices, markets, homes etc.

    These Computes are small is size and looks like a briefcaseo 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

    Mini Computer: -

    Micro Computers

    Desktop Micro Computers

    Portable Micro Computers

    :

    :

    :

    254

    footer

  • 7/27/2019 Computer Aplication

    15/64

    User

    ApplicationProgram

    OperatingSystem

    Hardware

    255

    COMPUTER APPLICATIONINMANAGEMENT

    Laptop Computers sometimes called briefcase computes, can be used on your lapand are very portable. Like a desktop computers, laptop computers have a full typewriter

    keyboard. Laptop computers can be connected to larger peripherals. For example- Aregular size printer or a large monitor etc.

    Notebook Computes are smaller is size than laptop computers. These computers areidle for user who has to wok away from their offices. The users of these computers might bea 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 ofprograms. 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.

    : -

    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 :

    footer

  • 7/27/2019 Computer Aplication

    16/64

    256

    TypesofOperatingSystem

    Single Program Operating System

    LimitationoftheOperatingSystem

    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 operatingsystem.

    6. RealTimeoperatingsystem.

    7. Network operating system.

    8. Distributed operating system.

    Single program operating system refers to singlepertaining 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

    doesnot 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.

    :

    Batch Operating System :

    footer

  • 7/27/2019 Computer Aplication

    17/64

    257

    COMPUTER APPLICATIONINMANAGEMENT

    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. Multiprogrammingincreases CPU utilization y organizing a number of jobs such that CPU always has one to

    execute.

    Different forms of multiprogramming operating systemare :

    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 impliesstopping 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 NT etc.

    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 sharedamong 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

    :

    :

    :

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    18/64

    258

    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 maincharacteristics 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

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    19/64

    259

    COMPUTER APPLICATIONINMANAGEMENT

    Advantages :

    Reliable :

    1. Process Management

    2. Memory Management

    3. FileManagement

    4. Device Management

    5. Security

    6. I/O Management

    7. Scheduling

    Resource SharingPowerful 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, aprocess 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 ofthe creation and deletion of processes, scheduling of variousresources to the differentprocesses requesting them, and providing mechanisms for synchronization andcommunication among processes.

    To execute a program, it must be loaded; together with thedata is accesses, in the main memory. To improve CPU utilization and to provide betterresponse time to its user, a computer system keeps several programs in mainmemory. The memory management module of an operating system takes care of theallocation and de-allocation of memory space to the various programs in need of theresource.

    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 storingthe new information in the files. The file management module of an operating systemtakes 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 asterminals, printers, disks and tapes. The device management module of the operatingsystem takes care of controlling all the computer's I/O devices.

    Computer system stores a large amount of information, some of which ishighly sensitive and valuable for their user. User can trust the system and rely on it onlyif the various resources and information of a computer system are protected againstunauthorized access. The security module of the operating system ensures it.

    Operating system also manages input output devices. Thefunction of input output devices are controlled by the operating system.

    Operating system is responsible for the scheduling of the input outputdevices.

    FunctionsofOperatingSystem

    :

    :

    :

    :

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    20/64

    260

    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. ObjectOriented Language

    4. 4GL or User Friendly Languages

    5. A.I.

    it is a mechanism that is used to exchange the ideas and thoughtsbetween two or more entities. Like we human being use so many sort of languages such asHindi, English, French, Japanese, Chinese etc. similarly to communicate with the machinewe require language. From the very beginning of the origin of the computer the languagesare developing side by side. There are so many types of computer programming languages.

    .

    1. Low-Level Language

    2. High-LevelLanguage

    3. ObjectOriented Language

    4. 4GL Languageor UserFriendly Language

    5. AI( ArtificialIntelligence )

    They are the languages which are compatible with themachine not with human being means machine can understand these languages veryeasily but for human being they are difficult to understand.

    Or

    Using the low level languages it is easier to develop the system software but thedevelopment of application software is not possible.

    There are two languages which fall in the low-level language category :

    i. MachineLanguage

    ii. AssemblyLanguage

    They are the languages which are written in humanunderstandable natural English language. For machine it is difficult to understand

    these languages directly. So some system utility called translators are used to convertthe human understandable code into machine understandable code. They are

    Assembler, Compiler and Interpreter. Following are some example of high levellanguage. BASIC, COBOL, FORTRAN, PASCALetc.

    These languages includes some of the concepts of ourreal life like Class, Object, Abstraction, Inheritance, Polymorphism, Encapsulationetc. some example of OOLare C++, Java etc.

    These languages are easier to learn by theprogrammers and the development of the software is very quick. It supports theconcept of RAD (Rapid Application Development). Visual Basic, Oracle is the 4GLLanguages.

    presently our researchers are working with the generation of AI ProgrammingLanguages. These languages are used to develop the intelligent machines which maybehave in some way of human being like vision, listening, speaking, thinking, walkingetc. LISP, PROLOG is AI programming languages which are used for Robotics andExpert System Development.

    :

    :

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    21/64

    UNIT II

    COMPUTERAPPLICATIONINMANAGEMENT

    MBA1stSemester(DDE)

    261

    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.

    A resources to share (resource)

    A pathway to transfer data (transmission medium)

    A set 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 toshare 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.

    :

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    22/64

    SERVER CLIENT CLIENT CLIENT CLIENT

    CLIENT CLIENT CLIENTCLIENTCLIENT

    262

    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 majorbenefits 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.

    :

    :

    :

    :

    :

    TypesofNetworking

    Local Area Network (LAN)

    footer

  • 7/27/2019 Computer Aplication

    23/64

    263

    COMPUTER APPLICATIONINMANAGEMENT

    Metropolitan Area Network (MAN)

    Wide Area Network (WAN)

    :

    - Data Services

    (SMDS).

    Local Area Network 1 Local Area Network 2

    Metro AreaNetwork

    :

    Wide Area 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.

    footer

  • 7/27/2019 Computer Aplication

    24/64

    Topology

    Mesh Star Tree Bus Ring

    264

    Transmission Channel for WAN

    Hardware Requirements for WAN

    Network Topologies

    Mesh

    :

    :

    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 wave Transmission

    Microwave Transmission

    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.

    -fullyconnectedmeshtopology.

    :

    footer

  • 7/27/2019 Computer Aplication

    25/64

    HUB

    265

    COMPUTER APPLICATIONINMANAGEMENT

    A mesh offers several advantages over other network topologies.

    Star

    Figure Star Topology

    :

    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; onlythe 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 usuallyimplemented in a limited places.

    In a star topology, each device has a dedicated point-to-point link only to a centralcontroller, 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 onlyone connection: between that device and the hub.

    footer

  • 7/27/2019 Computer Aplication

    26/64

    Root

    1 2

    3 45 6

    266

    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 finallyto 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, andthe other branches in a tree network

    will not be affected.

    Itis easyto add new nodes orbranches toit.

    Disadvantage: - Data movement through this network can be slow.

    In this topology, all devices on network are connected to a singlecontinuous 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

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    27/64

    267

    COMPUTER APPLICATIONINMANAGEMENT

    Advantages :

    Disadvantages

    The main advantage of this method is the reduction in physical lines.

    A wide 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. A break 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.

    :

    :Ring Topology

    footer

  • 7/27/2019 Computer Aplication

    28/64

    SERVER

    A

    B

    D

    C

    E

    268

    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.

    Itis 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 othernodes.

    Ifone 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 knowwhich 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

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    29/64

    269

    COMPUTER APPLICATIONINMANAGEMENT

    Q.3 Describe the various application of Networking?

    Ans. Network Applications Thee is a long list of application areas which can bebenefited 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 variousforecasting 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, moviesand community eventsinformation.

    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

    :

    footer

  • 7/27/2019 Computer Aplication

    30/64

    Voltage

    t

    +V

    V

    o 1/f 2/f

    270

    Network interface unit (NIU)

    ServersWorkstations

    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

    simpleas1and0.

    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 Shortnote on the following.

    I. Analog and Digital Signal

    ii. Bandwidth

    Ans.

    Comparison of Analog and Digital Signal

    Analog and Digital Signals

    Program

    Example:

    :

    :

    AnalogSignals

    Figure:AnalogSignal

    footer

  • 7/27/2019 Computer Aplication

    31/64

    Application10Voltages

    100 300 500 700 900

    v

    0 0 00

    1 1 1 1

    271

    COMPUTER APPLICATIONINMANAGEMENT

    Digital Signals

    Bandwidth

    Frequency:-

    Digital signals are non-continuous, they change in individual steps. They consist ofpulses 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.

    Differencebetweenthemaximumandminimumfrequencyofafrequency

    spectrumofthesignalisknownasbandwidthofthesignal.

    Here the term frequency spectrum of a signal means the set of all frequencies that

    constitutes it. A simple signal has only a single frequency; however a complex signal can be

    broken down into simple signals having different frequencies. The set of these frequenciesare 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:DigitalSignal

    :

    Thefrequencyistherateatwhichthesignalrepeats.

    footer

  • 7/27/2019 Computer Aplication

    32/64

    272

    Q.4 Write a short note on the following.

    I. Packet Transmissionii. 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

    technologyare 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

    betweensender 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 varyingnetwork 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

    :

    :

    :

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    33/64

    273

    COMPUTER APPLICATIONINMANAGEMENT

    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.

    Wecandividelongdistancecommunicationintofollowinggroups:

    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 whichthe 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:

    footer

  • 7/27/2019 Computer Aplication

    34/64

    274

    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. Theyrequirenorightofwayacquisitionbetween

    towers.

    b. Theycancarryhighquantitiesofinformationdueto

    theirhighoperatingF

    c. Lowcostlandpurchase:eachtoweroccupiessmall

    area.d. Highfrequency/shortwavelengthsignalsrequire

    smallantenna.

    a. Attenuationbysolidobjects:birds,rain,snowand

    fog.

    b. Reflectedfromflatsurfaceslikewaterandmetal.

    c. Diffracted(split)aroundsolidobjects

    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 :

    footer

  • 7/27/2019 Computer Aplication

    35/64

    UNIT III

    COMPUTERAPPLICATIONINMANAGEMENT

    MBA1stSemester(DDE)

    275

    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 isavailable 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

    specialcharacters (1, -, 1, *, , = etc.)

    A set 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.- A payroll record for an employeecontains 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 payrecords for a company.

    Definitions :

    :

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    36/64

    276

    Information

    Data Processing

    Definition of Database

    A Database 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 itmore useful. Data Manipulation consists of such operation as classification, sorting &

    calculationsetc.

    A database 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.

    A database 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 instorage 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.

    :

    :

    :

    :

    :

    :

    Data Base System, Concept and Meaning

    AdvantagesofDatabaseSystem

    footer

  • 7/27/2019 Computer Aplication

    37/64

    277

    COMPUTER APPLICATIONINMANAGEMENT

    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. Therarely 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.

    :

    :

    :

    :

    :

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    38/64

    278

    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, resultingin the need to upgrade the H/W.

    Because a DBMS is a complex tool with many features, itrequires 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 ismade 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 indexingof data.

    d. Reports generation facilities.e. Mathematical functions can be performed on the data to fetch the desired

    calculation.

    f. To maintainthe dataintegrity.

    DisadvantagesofDatabaseSystem

    :

    :

    :

    :

    :

    :

    :

    Universe of Discourse (U.D.).

    footer

  • 7/27/2019 Computer Aplication

    39/64

    279

    COMPUTER APPLICATIONINMANAGEMENT

    Q.2 Write a short note on thefollowing

    I. Schemaand Sub-schemaii. EntityandAttributes

    Ans. Schema andInstance of theSchema 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.

    A schema 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.

    footer

  • 7/27/2019 Computer Aplication

    40/64

    280

    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 DBAmustensure 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, BANK ACCOUNTS,

    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) A house 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 berepresentedby anaccounttype,an account number& an

    account balance.

    So in example (a) size, color, agesurroundings are attributes of the entity house. In eg

    (b) customer identification no, customer name & customer address are three attributes

    describing the entity CUSTOMER ofa 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

    Typesof AttributesSingle valued versus multi valued attributes

    :

    :

    :

    footer

  • 7/27/2019 Computer Aplication

    41/64

    281

    COMPUTER APPLICATIONINMANAGEMENT

    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

    Sector Address City State Pin

    Sector Number HouseNumber

    3. Stored versus Derived Attributes: -

    4. Null Value

    5. Complex Attributes

    Composite versus simple (Atomic) Attributes :

    footer

  • 7/27/2019 Computer Aplication

    42/64

    UNIT IV

    COMPUTERAPPLICATIONINMANAGEMENT

    MBA1stSemester(DDE)

    282

    Q.1 What is Internet? Whatare variousapplications of Internet?

    Ans.

    APPLICATIONS OF INTERNET

    1. On-line communication

    2. On-lineShopping

    3. VideoConferencing

    4. Advertising andPublishing

    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 onecan discuss any topic sitting anywhere in the world.

    The Internet has become the first global venue for advertising and publishinginformation.

    Internet is the cheapest means to promote ones product

    footer

  • 7/27/2019 Computer Aplication

    43/64

    283

    COMPUTER APPLICATIONINMANAGEMENT

    6. Technical Support/Customer Support Service

    7. Feedback

    8. Online Registration and Examination

    9. SoftwareSharing

    10. GroupDiscussion

    Q.2 Write a short note on the following:-

    I. WebBrowser

    ii. World Wide Web

    iii. Internet Protocol Addresses

    Ans.

    1. Microsoft Internet Explorer

    One can get technical support for product one is using. Many organizations providecustomer 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 likeThompson parametric, VUE provides online examination for the

    various products of software & hardware.

    Many software developing organizations provides trial software versions on theInternet.

    A number 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 (orsurf) 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.

    footer

  • 7/27/2019 Computer Aplication

    44/64

    284

    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. NcSA Mosaic is free or personal use

    and comes in versions for Windows, Macintosh, and UNIX (the X Window System).

    footer

  • 7/27/2019 Computer Aplication

    45/64

    285

    COMPUTER APPLICATIONINMANAGEMENT

    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 buttonsare usuallythe same. Given beloware 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 numberof 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 adocument.

    Browsers to