Computer Applications in Management

Computer Applications in Management
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Computer Applications in Management
Subject: COMPUTER APPLICATIONS IN MANAGEMENT
Credits: 4
SYLLABUS
Introduction to Computer Systems
Introduction: Evolution of Computers, Characteristics, Classification Generations; Computer Architecture:
Components of Computer Systems (I/O Devices); Computer Memory; Data Representation
Computer Software
Introduction to Software: Relation Between Hardware and Software; Types of Software: System Software,
Application Software; Software Development Life Cycle; Introduction to Algorithm; Flow chart
Operating Systems
Operating System: Functions of OS, Measuring System Performance; Evolution of Operating Systems : Serial
Processing, Batch Processing, Multiprogramming; Types of Operating System; Operating System Techniques
Multitasking, Multithreading, Multiprocessing; Some Popular Operating Systems: DOS (Disk Operating
System), UNIX Operating System, Linux, Microsoft Windows, Microsoft Windows NT
Business Data Processing
Data Processing; File Management System: File Types, File Organization, File Utilities; Database Management
System: Database Models, Main Components of a DBMS, Creating and Using a Database
Data Communications
Basic Elements of a Communication System: Data Transmission Modes, Transmission Basics; Types of Data
Transmission Media; Modulation Techniques, Modems, Analog versus Digital Transmission; Multiplexing
Techniques
Computer Networks
Need for Computer Communication Networks; Types of Network; Network Topologies; Network Protocol; OSI
and TCP/IP model ; The Future of Internet Technology; Internet Protocol; World Wide Web; E-mail; Search
Engines
Suggested Readings:
1. Fundamentals of Computers by Rajaraman, Publisher: Prentice Hall of India, New Delhi
2. Data Communication & Computer Network by White, Publisher: Thomas Learning, Bombay
3. Business Data Communication by Shelly, Publisher: Thomson Learning, Bombay
4. Computer Fundamentals by B.Ram, New Age Int.
5. Computer Fundamentals by P.K Sinha, Priti Sinha, Publisher Kalyani Publishers, 2nd Edition,
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INTRODUCTION TO COMPUTER SYSTEM
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1.1 Introduction
1.1.1 Evolution of Computers
1.1.2 A Brief History of Computers
1.1.3 Characteristics
1.1.4 Classification
1.1.5 Generations
1.2 Computer Architecture
1.2.1 Components of Computer System
1.2.2 Computer Memory
1.3 Data Representation
1.3.1 Number Systems
1.4 Review Questions
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1.1 INTRODUCTION
-----------------------------------------------------------------------------------------------------------Computer has been the premier invention of this century. Now a days Computer plays an
important role in almost every part of our lives, and their importance is so great that
without them we would not be able to live the way we do. Look around you and you
would find computers scattered all over the places, starting with the machine of computer
to washing machine to refrigerator to car to mobile and to life saving devices with the
doctors; everywhere a small computer working for your convenience and they seem
performing almost any task in the world. Computers have had a tremendous impact on
the way information is processed with in the organization. Although information have
been processed manually throughout the history but with modern management where
decision-making is so fast and the era of corporate governance is not possible without the
help of information system managed by computers.
The word “computer” comes from word compute, which means to calculate. “A
computer is a programmable machine (or more precisely, a programmable sequential
state machine) that operates on data and is used for wide range of activities”.
Computer is an electronic device or combination of electronic devices, which solves
problem after accepting the data and supply the result to the user. Computer is a
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tool, which can be used to read and write stories, draw and look at images, and send and
receive e-mail. They can store large information and perform various scientific and
mathematical tasks.
Basically Computer system are a combination of the five elements i.e. Hardware,
Software, People, Procedure and Data / information. The computer organization often
compared with the human brain. Just think of a human brain how it works, first of all it
can store the data with its five senses (Just like input devices in computer), it can process
the gathered information and could reach to some conclusion drawing from the raw data
(Just like the processing of computer system) and then it can deliver the output or result
with speech or with expression (Just like the output device).
Fig. 1.1: A Basic Personal Computer System
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1.1.1 Evolution of Computers
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1.1.2 A Brief History of Computers
"History reveals a clear pattern in the evolution of computers. Processing power increases
rapidly after the introduction of the new technology. The rate of growth eventually slows
down as the technology is exploited to its full potential. While in the background other
technologies are nurturing and one ultimately supersedes the other to become the
dominant technology and this cycle is repeated.
Under the right conditions the shift to the new technology can lead to possible increase in
processor speed of hundred to thousand times. In order to have a better idea of the
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evolution of computers it is worthwhile to discuss some of the well- known early
computers. These are as follows:
1. The Mark I Computer (1937-44): Also known as Automatic Sequence Controlled
calculator, this was the first fully automatic calculating machine designed by Howard A.
Aiken of Harvard University in collaboration with IBM (International Business
Machines) Corporation. It was an already developed for punched card machines.
Although this machine proved to be extremely reliable, it was very complex in design
and huge in size. It used over 3000 electrically actuated switches to control its operations
and was approximately 50feet long and 8 feet high. It was capable of performing five
basic arithmetic operations: addition, subtraction, multiplication, division, and table
reference on numbers as big as 23 decimal digits. It took approximately 0.3 second to add
two numbers and 4.5 seconds for multiplication of two numbers. Obviously, the machine
was very slow as compared to today’s computers.
2. The Atanasoff- Berry Computer (1939-42): Dr. John Atanasoff developed an
electronic machine to solve certain mathematical equations. The machine was called the
Atanasoff Berry Computer or ABC after its inventor’s name and his assistant, Clifford
Berry. It used 45 vacuum tubes for internal logic and capacitors for storage.
3. The ENIAC (1943-46): The Electronic Numerical Integrator and Calculator (ENIAC)
was the first all electronic computer. It was constructed at the Moore School of
Engineering of the University of Pennsylvania, U.S.A by a design team led by Professors
J. Presper Eckert and John Mauchly.
The team developed ENIAC because of military needs. It was used for many years to
solve ballistic related problems. It took up wall space in a 20 x 40 square feet room and
used 18,000vacuum tubes. It could add two numbers in 200 microseconds and multiply
them in 2000 microseconds.
4. The EDVAC (1946-52): A major drawback of ENIAC was that its programs were
wired on boards that made it difficult to change the programs. Dr. John Von Neumann
later introduced the” stored program” concept that helped in overcoming this problem.
The basic idea behind this concept is that a sequence of instructions and data can be
stored in the memory of a computer for automatically directing the flow of operations.
This feature considerably influenced the development of modern digital computers
because of the ease with which different programs can be loaded and executed on the
same computer. Due to this feature, we often refer to modern digital computers as stored
program digital computers. The Electronic Discrete Variable Automatic Computer
(EDVAC) used the stored program concepts in its design. Von Neumann also has a share
of the credit for introducing the idea of storing both instructions and data in binary form(
a system that uses only two digits – 0 and 1 to represent all characters), instead of
decimal numbers or human readable words.
5. The EDSAC (1947-49): Almost simultaneously with EDVAC of U.S.A.; the
Britishers developed the Electronic Delay Storage Automatic Calculator (EDSAC). The
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machine executed its first program in May 1949. In this machine, addition operations
took 1500 microseconds and multiplication operations took 4000 microseconds. A group
of scientists headed by Professor Maurice Wilkes at the Cambridge University
Mathematical Laboratory developed this machine.
6. The UNIVAC I (1951): The Universal Automatic Computer (UNIVAC) was the first
digital computer that was not “one of a kind”. Many UNIVAC machines were produced,
the first of which was installed in the Census Bureau in 1951 and was used continuously
for 10years. The first business use of a computer, a UNIVAC I, was by General Electric
Corporation in 1954.
In 1952, the International Business machines (IBM) Corporation introduced the IBM-701
commercial computer. In rapid succession, improved models of the UNIVAC I and other
700- series machines were introduced. In 1953, IBM produced the IBM-650, and sold
over 1000 of these computers. UNIVAC marked the arrival of commercially available
digital computers for business and scientific applications.
1.1.3 Characteristics
The ever-increasing use of computer is due to its special characteristics. Computer is not
just a calculating machine; they also have the capability of doing complex activities and
operation. Main characteristics of the computer are given bellow:
1. Speed: Computer is very fast and accurate device. Since electronic pulses travel
at incredible speed and they are electronic device its internal speed is virtually
instantaneous. A microcomputer can process millions of instruction per seconds
over and over again without any mistake.
2. Accuracy: Computers physical circuits rarely make errors, if the data and
instruction are correctly fed. Most errors which occur in computers are either
hardware error or human error
3. Storage: Computers have a large amount of memory to hold a very large amount
of data, we can store large amount of data information in the secondary storage
device.
4. Programmability: A computer is programmable; i. e. what computer does
depend on the lines of instruction (Program) it is using.
5. Diligence: Computer is free from problems like lack of concentration, and
confusions etc. Computer is never confused like humans and it can perform
instruction again and again without failing or getting bored.
6. Versatility: We can perform many different types of tasks on computer, one
moment it might be busy in calculating the statistical date for annual performance
evaluation of a business organization and next moment it might be working on
inventory control.
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7. Power of remembrance: Unlike humans, computer can store things for unlimited
period of time. It has great remembering power.
1.1.4 Classification
Computers can be classified many different ways -- by size, by function, and/or by
processing capacity. We will study the classification of computers by size. The size of a
computer often determines its function and processing capacity. The size of computers
varies widely from tiny to huge and is usually dictated by computing requirements. For
example, it is clear that the IRS will have different requirements than those of a college
student.
There are two basic kinds of computers: analog and digital.
A. Analog computers
Analog computers are analog devices. That is, they have continuous states rather than
discrete numbered states. An analog computer can represent fractional or irrational values
exactly, with no round off. Analog computers are almost never used outside of
experimental settings. They handle or process information, which is of physical nature.
Fig. 1.2 Analog Computers
B. Digital Computer
Digital computer is a programmable-clocked sequential state machine. A digital
computer uses discrete states. A binary digital computer uses two discrete states, such as
positive/negative, high/low, on/off, used to represent the binary digits zero and one. They
process data, which is essentially in a binary state.
Now these days, we rarely came across of analog computers in routine life. Digital
computer does not get evolve in sparks time. It took more than five decades to emerge it
as the most usable devise today. Let’s take the glimpse of its siblings.
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Fig.1.3 Digital Computer
1) Micro Computers: A microcomputer’s CPU is a microprocessor. The microcomputer
originated in late 1970’s. The first microcomputers were built around 8-bit
microprocessor chips. What do we mean by an 8-bit chip? It means that the chip can
retrieve instructions/data from storage, manipulate, and process an 8-bit data at a time or
we can say that the chip has a built- in 8-bit data transfer path. 8088 was a 8/16 bit chip
i.e. an 8-bit path is used to move data between chip and primary storage (external path),
but processing is done within the chip using a 16-bit path (internal path) at a time 8086 is
a 16/16 bit chip i.e. the internal and external paths both are 16 bit wide. Both these chips
can support a primary storage capacity of up to 1 Mega byte (MB).
Fig. 1.4 Micro Computer
2) Minicomputers: The term minicomputer originated in 1960s when it was realized
that many computing tasks do not require an expensive contemporary mainframe
computers but can be solved by a small, inexpensive computer. Initial minicomputers
were 8 bit and 12 bit machines but by 1970’s almost all minicomputers were 16 bit
machines. The 16 bit minicomputers have the advantage of large instruction set and
address field; and efficient storage and handling of text, in comparison to lower bit
machines. Thus, 16-bit minicomputer was more powerful machine, which could be used
in variety of applications and could support business applications along with the scientific
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applications. With the advancement in technology the speed, memory size and other
characteristics developed and the minicomputer was then used for various stand alone or
dedicated applications. The minicomputer was then used as a multi-user system, which
can be used by various users at the same time. Gradually the architectural requirement of
minicomputers grew and a 32-bit minicomputer, which was called super mini, was
introduced. The super mini had more peripheral devices, larger memory and could
support more users working simultaneously on the computer in comparison to previous
minicomputers.
Fig. 1.5 Mini Computer
3) Workstation is a powerful stand-alone computer of the sort used in computer aided
design and other applications requiring a high-end, expensive machine with considerable
calculating or graphics capability. Machines using Intel Processor P2 at 400 MHz is an
example of workstation. Now these day’s computers having P-4 or AMD Athlon type
microprocessor also come in the classification of workstation.
4) Mainframe Computers are very powerful, large-scale general-purpose computers.
Their word length may be 48,60 or 64 bits, memory capacity being in some megabytes
and storage capacity in some terabytes etc. A mainframe is simply a very large computer.
And totally different from what you have on your desk. Don't say: what seems to be a
mainframe today is on your desktop tomorrow. Apart from the CPU's (processors) that is
far from true. Mainframe is an industry term for a large computer. The name comes from
the way the machine is build up: all units (processing, communication etc.) were hung
into a frame. Thus the main computer is build into a frame, therefore: Mainframe and
because of the sheer development costs, mainframes are typically manufactured by large
companies such as IBM, Amdahl, and Hitachi. Their main purpose is to run commercial
applications of Fortune 1000 businesses and other large-scale computing purposes. Think
here of banking and insurance businesses where enormous amounts of data are processed,
typically (at least) millions of records, each day. They are used where large amount of
data are to be processed or very complex calculations are to be made and these tasks are
beyond the capacities of mini computers. They are used in research organizations, large
industries, airlines reservation where a large database has to be maintained. Examples are
IBM 4300 series, IBM Enterprise system/9000 series.
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Fig. 1.6 Mainframe Computer
5) Super Computers processing capabilities lies in the range of GIPS2, word length
64-128 or may be in 256 or so. Memory capacity in some gigabytes or in
terabytes and storage capacity in pixabytes. It contains a number of CPU’s, which
operate in parallel to make it faster, giving them their speed through parallel
processing. They are used for weather forecasting, weapons research and
development, rocketing, aerodynamics, atomic, nuclear and plasma physics.
Supercomputers have limited use and limited market because of their very high
price.
Fig.1.7: Super Computer
They are being used at some research centers and government being used at some
research centers and government tasks. Examples of users of these computers are
governmental agencies, such as the IRS, the National Weather Service, and the
National Defense Agency. Also, they are used in the making of movies, space
exploration, and the design of many other machines. Supercomputers are used for
tasks that require mammoth data manipulation.
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1.1.5 Generations
‘Generation’ in computer talk is a step of changing technology. It provides the framework
for the growth of computer industry. There are five generations of computer with the first
generation computers being those, which became commercially available in the early
1950s.
First Generation Computers (1951- 1958)
The first generation of computer was marked by the use of vacuum tubes for the
electronic components and by the use of either electrostatic tubes (i.e., cathode ray tubes)
or mercury delay lines for storage. Examples of such first generation machines are
EDSAC (operational in 1949), SEAC (1950, the first stored program computer
operational in the US), EDV AC (1951) and IAS (1952). This generation lasted until the
end of the 1950s and computers in this era had their basis in wired circuitry and
thermionic valves.
Their outstanding features were:
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Vacuum Tubes Circuit
Drum Primary Storage
Batch processing
Few thousand instructions per second is the processing speed
Machine language was the language used
It produce large amount of heat
Very expensive
Poor reliability
ENIAC, EDVAC, EDSAC, UNIVAC are some of the first generation computers
Quite large and, because they generated a lot of heat, required special housing
The medium of internal storage was magnetic drum.
Second Generation Computers (1959-1964)
The second-generation machines were initially marked by either magnetic drum or
magnetic core storage and, later, by the use of the transistor in place of vacuum tubes.
The second generation, which covered the first half of the 1960s, saw the introduction of
printed circuits and the replacement of vacuum by transistors. Typical computers were
the ICT (ICL) 1300 and the IBM 140J.
The outstanding features of this generation were:
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Transistors and diodes were used
Magnetic primary storage
Tape secondary storage
One million instructions per second is the processing speed
Assembly and Fortran were the language used
Very expensive
Better reliability
Faster then the faster generation
Reduced generated heat
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Required less power to operate
Increase storage capacity
Third Generation Computers (1965- 1975)
The arrival of the third generation in the mid-1960s proved to be an important milestone
in the evolution of computers. The advances over the previous generation were very
significant and, although relatively expensive, allowed an increasing number of
organizations to reap the undoubted benefits which computerization could bring. Because
of the 'high costs involved and the need to get maximum utilization from the machine, the
computer service bureau business was spawned. This in itself was important in that it
allowed companies to avail themselves of the new technology and to take advantage of
the continuing developments. Many of the computers acquired by companies during this
period are still in use.
The following are the outstanding features of this generation:
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Magnetic Disk Secondary Storage
On-Line Real Time Processing
Used operating System
Multiprogramming Operating System
Development of the micro computer
Integrated Circuits
Faster than the previous generation of the computer
Better storage device (tape)
Improved input and output device
Transistor replaced by Integrated Circuits
IBM- 370, NCR 395 were the third generation computers
Fourth Generation Computers (1975- present)
The fourth generation of computers arrived in the mid-1970s. The distinguishing
marks were the introduction of standard architecture, which was provided for greater
mobility of systems, the introduction of micro-technology and significant software
developments. The IBM-4300 and ICL-2900 ranges coincided with the start of this
era. Micro-technology gave rise to the availability of microcomputers, word
processors and intelligent terminals.
The outstanding features of this generation are:
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Further reductions in the size of the hardware
Better price performance
Large scale and very large scale Integrated Circuits (LSI/VLSI)
Semiconductor primary storage
Online real time processing
User friendly software
Widespread use of CRT terminals
Development of t electronic spreadsheet
High-level languages
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Microprocessor used
Increase cost of software
Data base management system
Distributes processing
Graphics manipulation
Pentium/AMD based are the fourth generation computers
Fifth Generation Computer
It is very difficult to define the fifth generation of the computer. The most famous
example of this generation computer is fictional HAL9000 from Arutur C. Clarke’s novel
HAL performed all of the functions currently envisioned for real time fifth generation
computer
• Organic chips
• Decreasing cost of software
• Decreasing cost of hardware
• Artificial Intelligence
• Multi point input-output
• Large storage facility
• Auto decision
• High speed
• Under development in USA, Japan and UK
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1.2 COMPUTER ARCHITECTURE
-------------------------------------------------------------------------------------------We have seen that computer affects our life in a big way by increasing the efficiency and
enhanced ability. Now we will have to look for the anatomy of computer. What it is made
up of? The architecture of a simple and basic computer system. The parts of computer as
we know did not appear all at once in one machine by one person. It is a continuously
evolving process starting as early as 17th century when people began to work on
machines that would automate task and to your surprise the first such machine was
developed in 17th century by mathematician and philosopher Blaise Pascal but it was not
an electronic device. It was purely a mechanical machine, which used meshed gears to
add and multiply the numbers. But after him there was a long gap when an idea emerged
from Charles Babbage to process information although he could never successfully
develop such mechanical machine but his idea was of million dollar worth. That’s why he
is known as a first father of computer. Modern electronic computer started taking shape
in 1940 with the invention of Mark – I Computer since then there have been a lot of
research and new inventions in the technology of computer.
1.2.1 Components of Computer System (I/O Devices)
A computer system has the following main components:
¾ Input Unit/Devices
¾ Output Unit/Devices
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¾ Central Processing Unit
¾ Memory Unit/Storage Devices
All these components are basically the integral parts of general-purpose computers. These
may be the Desktop systems or Workstations. The diagram of a generalized architecture
of a computer system is shown here
Fig. 1.8: Architecture of a Computer System
Input/ Output Unit
We know that the computer is a machine that processes the input data according to a
given set of instructions and gives the output. Before a computer does processing, it must
be given data and instructions. After processing, the output must be displayed or printed
by the computer. The unit is used for getting the data and instructions into the computer
and displaying or printing output is known as an Input/Output Unit (I/O Unit).
There are many peripheral devices, which are used as input/output units for the computer.
The most common form of input device is known as a terminal. A terminal has an
electronic typewriter like device, called keyboard along with a display screen, called
Visual Display Unit (VDU) or monitor. Keyboard is the main input device while the
monitor can be considered both as an input as well as an output device.
A) Input Devices
Input unit performs following functions:
a) It accepts (or reads) instructions and data from outside world.
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b) It converts these instructions and data in computer acceptable form.
c) It supplies the converted instructions and data to computer system for further
processing.
Input Devices are used to input data, information and instructions into the RAM. We
may classify these devices into the following two broad categories:
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Basic Input Devices
Special Input Devices
Basic Input Devices
The input devices, which have now days become essential to operate a PC, may be called
as Basic Input Devices. These devices are always required for basic input operations.
These devices include Keyboard and Mouse.
Special Input Devices
The input devices, which are not essential to operate a PC, are called as Special Input
Devices. These devices are used for various special purposes and are generally not
required for basic input operations. These devices include Trackball, Light Pen, Touch
Screen, Joystick, Digitizer, Scanner, OMR, OCR, Bar Code Reader, MICR and Voice
Input Devices.
B) Output Devices
An Output unit performs following functions:
a) It accepts the results produced by a computer, which are in coded form and hence, we
cannot easily understand them.
b) It converts these coded results to human acceptable (readable) form.
c) It supplies the converted results to outside world.
Output devices are hardware components, which are used to display or print the
processed information. We are discussing below the structure, working and uses of the
common output devices:
Monitor
Visual Display Unit (VDU) commonly called, as monitor is the main
output device of a computer. It consists of a Cathode Ray Tube (CRT),
which displays characters as an output. It forms images from tiny dots,
called pixels that are arranged in a rectangular form. The sharpness of the
image (screen resolution) depends upon the number of pixels.
Printer
Printer is the most important output device, which is used to print information on paper.
Printers are essential for getting output of any computer-based application.
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PRINTER
Impact
Non Impact
Example: Dot Matrix, Daisy Wheel
Example: Inkjet, Laser,
Thermal, LED
Table 1.9 Classifications of Printers
Central Processing Unit
Central Processing Unit (CPU) is the main component or "brain" of a computer, which
performs all the processing of input data. Its function is to fetch, examine and then
execute the instructions stored in the main memory of a computer. In microcomputers,
the CPU is built on a single chip or integrated Circuit (IC) and is called as a
Microprocessor. The CPU consists of the following distinct parts:
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Arithmetic Logic Unit (ALU)
Control Unit (CU)
Registers
Buses
Clock
Memory Unit
Memory Unit is that component of a computer system, which is used to store the data,
instructions and information before, during and after the processing by ALU. It is
actually a work area (physically a collection of integrated circuits) within the computer,
where the CPU stores the data and instructions.
It is also known as a
Main/Primary/internal Memory.
1.2.2 Computer Memory
Memory in a computer system is required for storage and subsequent retrieval of the
instruction and data. A computer system uses variety of devices for storing the instruction
and data, which are required for its operations. Normally we classify the information to
be stored on computer in two basic categories: Data and the instructions.
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“The storage device along with the algorithm or information on how to control and
manage these storage devices constitutes the memory system of computer”. A memory
system is a very simple system yet it exhibits a wide range of technology and types. But
unfortunately, faster memory technology is more costly. In addition fast memories
require power supply till the information needs to be stored. These things are not very
convenient, but on the other hand the memories with smaller cost have very high access
time, this is the time taken by CPU to access a location in the memory in high, which will
result in slower operation of the CPU. Thus, the cost versus access time anomaly has lead
to a hierarchy of memory where we supplement fast memories with larger, cheaper,
slower memories. This memory unit may have different physical and operational
characteristics, therefore, making the memory system very diverse in type, cost,
organization, technology and performance. This memory hierarchy will be fruitful if the
frequency of access to slower memories is significantly less than the faster memories.
Cache
Fast, Small,
Experience
Main Memory (RAM)
Magnetic Disk
Slow,
Large, Cheap
Magnetic Tape
Thus, a memory system can be considered to consist of three groups of memories. These
are:
1) Internal Processor Memories: These consist of the small set of high speed
registers which are internal to a processor and are used as temporary locations
where actual processing is done.
2)
Primary memory or main memory: It is a large memory, which is fast but not
as fast as internal processor register. Processor directly accesses this memory. It
is mainly based on integrated circuit.
3)
Secondary or Auxiliary Memory: Auxiliary memory is in fact much larger in
size than main memory but is, slower than main memory. It normally stores
system programs, and data files. These cannot be accessed directly by
processor.
Memory
Memory- is also known as the primary storage or main memory/ internal memory. It is a
apart of microcomputer that hold data for processing, instruction for processing the data
(the program) and information (processed data) .It is of the following three types:
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1. Read Only Memory (ROM)
2. Random Access Memory (RAM)
3. Complementary Metal Oxide Semiconductor Memory (CMOS)
1. Read Only Memory
Read Only Memory is an essential component of the memory unit. We know that the
computer, being a machine, itself has no intelligence or memory and requires
instructions, which are given by a person. Whenever the computer is switched on, it
searches for the required instructions. The memory, which has these essential
instructions, is known as Read Only Memory (ROM). This memory is permanent and is
not erased when the system is switched off. As appears with its name, it is read only
memory i.e. it can be read only and not be written by user/ programmer. The memory
capacity of ROM varies from 64 KB to 256 KB (I Kilobyte = 1024 bytes) depending on
the model of computer.
Types of ROM
There are many types of ROM available for microcomputers like Mask ROM, PROM,
EPROM, EEPROM and EAPROM.
Mask ROM: Mask ROM is the basic ROM chip. In this type of ROM, the information
is stored at the time of its manufacturing. So, it cannot be altered or erased later on.
PROM: PROM stands for Programmable Read Only Memory. In this type of ROM, the
information is stored by programmers after its manufacturing. It also cannot be altered or
erased later on.
EPROM: EPROM stands for Erasable Programmable Read Only Memory. It is similar
to PROM, but its information can be erased later on by ultra violet light and it can be
reprogrammed.
EEPROM: EEPROM stands for Electrically Erasable Programmable Read Only
Memory. It is similar to EPROM, but its information can be erased by using a high
voltage current.
EAPROM: EAPROM stands for Electrically Alterable Read Only Memory. As
compared to EPROM and EEPROM, the information stored in EAPROM can be altered
later.
2. Random Access Memory
Random Access Memory (RAM) is another important component of the Memory Unit.
It is used to store data and instructions during the execution of programs. Contrary to
ROM, RAM is temporary and is erased when the computer is switched off. RAM is a
read/ write type of memory, and thus can be read and written by the user/ programmer.
As it is possible to randomly use any location of this memory, therefore, this memory is
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known as random access memory. The memory capacity of RAM varies from 640 KB to
several megabytes (1 Megabyte = 1024 KB) with different models of PC.
Types of RAM
There are two types of RAM used in PCs - Dynamic and Static RAM.
Dynamic RAM (DRAM): The information stored in Dynamic RAM has to be refreshed
after every few milliseconds, otherwise it is erased. DRAM has higher storage capacity
and is cheaper than Static RAM.
Static RAM (SRAM): The information stored in Static RAM need not be refreshed, but
it remains stable as long as power supply is provided. SRAM is costlier but has higher
speed than DRAM.
3. Complementary Metal Oxide Semiconductor Memory
Complementary Metal Oxide Semiconductor (CMOS) memory is used to store the
system configuration, date, time and other important data. When the computer is
switched on, BIOS matches the information of CMOS with the peripheral devices and
displays error in case of mismatching.
------------------------------------------------------------------------------------------------------------
1.3 DATA REPRESENTATION
-----------------------------------------------------------------------------------------------------------We know that data is usually combination of numbers, characters and special
characters. This data has to be worked upon by the computer as well as it has to be
transported from place to place, i.e. data has to flow from place to place within the
computer hardware. As the computer is a electronic device and it works with electronic
pulses, this data or information should be in the form which is machine readable and
understandable, for this reason, data has to be represented in the form of electronic
pulses.
The data has to be converted into electronic pulses and each pulse should be identified
with a code. For these reasons, the data is converted into numeric format first, by using
world wide standard called ASCII i.e. American standard code for Information
Interchange, where each and every character, special character and keystrokes have
numerical equivalent. We will have a detail discussion on ASCII codes in the codes
section. Thus using this equivalent, the data can be interchanged into numeric format.
For the numeric conversion we use number systems, each number system has a radix or
base, which indicates the number of digits in that number system. Lets have a quick
look at number systems.
1.3.1 Number System
Most modern computer systems do not represent numeric values using the decimal
system. Instead, they typically use a binary or two’s complement numbering system. To
understand the limitations of computer arithmetic, you must understand how computers
represent numbers.
In any number system there is an ordered set of symbols known as digit with rules
24
defined for performing arithmetic operations like addition, multiplication etc. A
collection of these digits makes a number which in general has two parts
1.
2.
Integer part
Fractional part
These two parts are separated by a point (.).
(N)b = dn-1dn-2dn-3———————d1d0.d1d - 2d -3————————-d - m
Where
N = A number
b = radix or base of the number system
n = number of digits in integer portion
m = number of digits in fractional portion
d n -1 = most significant digit (msd)
d -m = least significant digit (lsd)
Let’s understand it:
You are quite familiar with the decimal number system that is the number system we
are using in our daily life. Here base is 10 as it has 10 digits (0…9)
Suppose you are having a number
N = 1 2 3. ……….8 9
d1 d0.d-1d-2
where d represents the digits
The base is 10
n is 3
m is 2
Now I think you got the basic criteria to distinguish the one number system from another.
Now based on this lets come to the types of number system
Types of Number Systems
Basically there are 4 types of number system. They are as follows
•
•
•
•
Binary number system;
Decimal number system;
Octal number system;
Hexadecimal number system.
25
Now lets see the characteristics of these number systems:
Number system
Base or radix (b)
Binary System
2
Octal System
8
Decimal System
10
Hexadecimal System
Symbols or digits used
(d)
0, 1
0,1,2,3,4,5,6,7
0,1,2,3,4,5,6,7,8,9
16
0,1,2,3,4,5,6,7,8,9,
A, B, C, D, E, F
Example
1011.11
3567.25
3947.89
3FA9.9A
Table 1.1
-------------------------------------------------------------------------------------------------------------
1.4 REVIEW QUESTIONS
--------------------------------------------------------------------------------------------1.
2.
What are supercomputers and where they are used?
What is the different between analog and digital computer? You have to explain in
your own words?
3. What is the difference between second and the fourth generation of the computer?
4. Do the comparative studies of the various generations of the computer based on power
and space occupied by them
5. What are the characteristics of computer?
6. Draw a block diagram to illustrate the basic organization of a computer
system and
explain the functions of various units.
7. Which component of a computer is generally called 'brain' of computer and Why?
Describe the functions of the distinct parts of this component.
26
---------------------------------------------------------------------------------------------------------
COMPUTER SOFTWARE
-----------------------------------------------------------------------------------------Structure
2.1 What is Software?
2.1.1 Relation between Hardware and Software
2.2 Types of Software
2.2.1 System Software
2.2.2 Application Software
2.3 Software Development Life Cycle
2.4 Introduction to Algorithm
2.5 Flowcharts
2.5.1 Problem Solving, Step by Step
2.5.2 How to Draw Flowcharts
2.5.3 Basic Flowcharting Shapes
2.5.4 Advantages of Flowcharts
2.6 Review Questions
---------------------------------------------------------------------------------------------------------
2.1 WHAT IS SOFTWARE?
--------------------------------------------------------------------------------------------------------A Computer cannot do anything on its own. It must be instructed to do a job desired by us.
Hence, it is necessary to specify a sequence of instructions a computer must perform to
solve a problem. Such a sequence of instructions written in a language understood by a
computer is called a computer program. A program controls a computer’s processing
activity, and the computer performs precisely what the program wants it to do. When a
computer is using a program to perform a task, we say, it is running or executing that
program.
The term software refers to a set of computer programs, procedures, and associated
documents (flowcharts, manuals, etc.) describing the program, and how they are to be used.
A software package is a group of programs that solve a specific type of job. For example, a
word processing package may contain programs for text editing, text formatting, drawing
graphics, spelling checking, etc. Hence, a multipurpose computer system, like a personal
computer in your home, has several software packages, one each for every type of job it
can perform.
27
2.1.1 Relation between Hardware and Software
For a computer to produce useful output its hardware and software must work together.
Nothing useful can be done with the hardware on its own, and software cannot be utilized
without supporting hardware.
To take an analogy, a cassette player and its cassettes purchased from the market are
hardware. However, the songs recorded on the cassettes are its software. To listen to a
song, that song has to be recorded on one of the cassettes first, which is then mounted on
the cassette player and played. Similarly, to get a job done by a computer, the
corresponding software has to be loaded in the hardware first and then executed.
Following important points regarding the relationship between hardware and software are
brought out by this analogy:
1.
Both hardware and software are necessary for a computer to do useful job. Both are
complementary to each other.
2. Same hardware can be loaded with different software to make a computer perform
different types of jobs just as different songs can be played using the same cassette
player.
3. Except for upgrades (like increasing main memory and hard disk capacities, or adding
speakers, modems, etc.); hardware is normally a one- time expense, whereas software
is a continuing expense. Like we buy new cassettes for newly released songs or for
songs whose cassettes, we do not have, we buy, new software to be run on the same
hardware as and when need arises, or funds become available.
---------------------------------------------------------------------------------------------------------
2.2 TYPES OF SOFTWARE
--------------------------------------------------------------------------------------------------------Software is broadly classified into following two types:
•
•
System Software
Application Software
2.2.1 System Software
Software that is required to control the working of hardware and aid in effective execution
of a general user's applications are called System Software. This software performs a
variety of functions like file editing, storage management, resource accounting, 1/0
management, database management, etc. Some of the examples of system software are
DOS (Disk Operating System), Windows, BASIC, COBOL and PC TOOLS. This
software is developed by System Programmers.
Types of System Software
System software can be further categorized into following three types:
•
System Management Software (Operating Systems, DBMSS, Operating
Environments)
28
•
•
System Development Software (Language Translators, Application Generators,
CASE Tools)
System Software Utilities
Assemblers: Assemblers translate the assembly language code (source program) into
machine language code (object program). After assembling, a linker program is used to
convert the object program into an executable program. The Microsoft assembler program
(MASM) and Borland Turbo assembler program (TASM) are two popular assemblers.
Assemblers are used mainly in development of system software.
Interpreters: Instructions of a high-level language are coded in many statements. At the
time of their execution, they are converted statement by statement into machine code, by
using system software, called Interpreters. For example, programs written in BASIC
language are executed by using BASICA or GWBASIC interpreters. Programs written in
some fourth generation languages, like dBase III plus are also executed using dBase
interpreter.
There are certain disadvantages of interpreters. As instructions are translated and executed
simultaneously using interpreters, they are very slow for executing large programs. Hence,
interpreters are not suitable for most of applications development.
Compilers: As contrast to interpreters, compilers provide faster execution speed.
Compilers do not translate and execute the instructions at the same time. They translate the
entire program (source code) into machine code (object code). Using linker, the object
code is converted into executable code. Compilers are widely used in translating codes of
high-level languages (e.g. COBOL, FORTRAN, PASCAL, Turbo/ Quick BASIC, Turbo/
Microsoft C etc.) and fourth generation languages (dBase IV, FoxPro etc.). As compared to
interpreters or assemblers, compilers are preferred in development of application software.
2.2.2 Application Software
Software that is required for general and special purpose applications like database
management; word processing, accounting etc. are called Application Software. Some of
the examples of application software are dBase, Word Star, Tally etc. Application software
is developed using system software by Application Programmers. Application software
can be further classified into following two types:
•
•
General Purpose Application Software (Database Management Packages, Word
Processors, Spreadsheets etc.)
Special Purpose Application Software (Accounting, Inventory, Production
Management etc.)
29
SOFTW
APPLICATION
SYSTEM
Operatin
g System
File
Mgmt
Assemble
Compilers
Debugger
Utilities
Word
P
Spreads
Communica
Image
P
Databas
Games
Fig 2.1 Types of Software
---------------------------------------------------------------------------------------------------------
2.3 SOFTWARE DEVELOPMENT LIFE CYCLE
--------------------------------------------------------------------------------------------------------Software Development Life Cycle or SDLC is a model of a detailed plan on how to create,
develop, implement and eventually fold the software. It’s a complete plan outlining how
the software will be born, raised and eventually be retired from its function. All software
needs to be developed by someone. Developing software and putting it to use is a complex
process involving following steps:
1. Analyzing the problem at hand, and planning the program (s ) to solve the problem;
2. Coding the program (s);
3. Testing, debugging, and documenting the program (s);
4. Implementing the program (s);
5. Evaluating and maintaining the program (s).
30
Fig 2.2 Software Development Life Cycle
Importance of Software Development Life Cycle
Because software can be very difficult and complex. We need the SDLC as a framework to
guide the development to make it more systematic and efficient.
We will be able to tell how long it will take to complete the project, to test and deploy. Not
only that, you'll have an easier time debugging and finding flaws in the software program
or make enhancement to it.
---------------------------------------------------------------------------------------------------------
2.4 INTRODUCTION TO ALGORITHM
--------------------------------------------------------------------------------------------------------Planning a program involves defining its logic (the correct sequence of instructions needed
to solve the problem at hand). The term Algorithm refers to the logic of a program. It is a
step – by – step description of how to arrive at a solution. To a given problem. It is defined
as a sequence of instructions that when executed in the specified sequence, the desired
results are obtained. In order to qualify as an algorithm, a sequence of instructions must
possess the following characteristics:
1. Each instruction should be precise and unambiguous.
2. Each instruction should be executed in a finite time.
3. One or more instructions should not be repeated infinitely. This ensures that the
algorithm will ultimately terminate.
4. After executing the instructions (when the algorithm terminates), the desired results
are obtained.
31
Therefore, in simple terms, we can say that an algorithm is a procedure to accomplish a
specific task. It is the idea behind any computer program. To be interesting, an algorithm
has to solve a general, well-specified problem. An algorithmic problem is specified by
describing the complete set of instances it must work on and what properties the output
must have as a result of running on one of these instances. This distinction between a
problem and an instance of a problem is fundamental. To gain insight into algorithms, let
us consider a simple example.
Example: There are 50 students in a class who appeared in their final examination. Their
mark sheets have been given to you. Write an algorithm to calculate and print the total
number of students who passed in first division.
Algorithm:
Step 1: Initialize TOTAL FIRST DIVISION and TOTAL MARKSHEETS CHECKED to
zero.
Step 2: Take the mark sheet of the next student.
Step 3: Check the division column of the mark sheet to see if it is FIRST. If no, go to step
5.
Step 4: Add 1 to TOTAL FIRST DIVISION.
Step 5: Add 1 to TOTAL MARKSHEETS CHECKED.
Step 6: Is TOTAL MARKSHEETS CHECKED = 50? If no, go to step 2.
Step 7: Print TOTAL \FIRST DIVISION.
Step 8: Stop.
It must be clear to you from this example that even for every simple problems, the
development of algorithms is not as simple as it might initially appear and requires some
thinking. It may also be noted from the given example that in order to solve a given
problem, each and every instruction must be strictly carried out in a particular sequence. It
is this fact, which a beginner to problem solving by computers finds difficult to appreciate.
---------------------------------------------------------------------------------------------------------
2.5 FLOWCHARTS
--------------------------------------------------------------------------------------------------------A Flowchart is a pictorial representation of an algorithm. Programmers often use it as a
program – planning tool for visually organizing a sequence of steps necessary to solve a
problem using a computer. It uses boxes of different shapes to denote different types of
instructions. The actual instructions are written within these boxes using clear and concise
statements. Solid lines having arrow marks connect these boxes to indicate the flow of
32
operation, that is, the exact sequence in which to execute the instructions. The Process of
drawing a flowchart for an algorithm is known as flowcharting.
2.5.1 Problem Solving: Step by Step
Before we begin to learn the kinds of steps that a computer has to perform to solve a
problem, let us think about problem solving, in general.
Think of what you might do if I asked you to write a set of instructions for brushing your
teeth. What are the steps you might write down? Would you write this down?
(1) Put toothpaste on toothbrush.
(2) Brush teeth with toothbrush.
(3) Put toothbrush away.
If you write only these three instructions, it means that the person must somehow know
where the toothbrush and toothpaste are located, how to get the toothpaste out of the tube,
what it means toothbrush, and how to put the toothbrush away. You cannot assume that the
person knows these things. You have not taken care of any possible problems that might
arise. You would have to be much more detailed in you writing. Let try it again
(1) Go to the bath-room.
(2) Open door.
(3) Take out toothpaste.
(4) If toothbrush is not there, look for toothbrush.
(5) If toothbrush is not found, go to step 18.
(6) Remove toothpaste.
(7) If toothpaste is not there, look for toothpaste.
(8) If toothpaste cannot be found, go to step 12.
(9) Take cap of toothpaste.
(10) Squeeze toothpaste onto toothbrush.
(11) If toothpaste does not come out of the tube, check tube.
(12) Put toothbrush into mouth and rub on teeth.
(13) Spit out.
33
(14) Fill glass with water.
(15) Rinse mouth with water.
(16) Wash face.
(17) Replace toothbrush.
(18) Put toothpaste away if you had toothpaste.
(19) Wash face.
(20) Clean sink.
(21) Rinse glass.
(22) Put glass back.
It took twenty-two instructions to replace the three instructions and I have left out one
instruction did you spot it?!Did not put the cap back on the toothpaste!
Sometimes, if you Java out a step like that, the computer will just stop. It may say
something to you or it may not. It may continue to do things, but they may not be the things
you want you do. It may give you an answer, but the answer may not be the correct one.
The computer did not make a mistake. It did all the steps you asked it to do. If the computer
does not do what you want it to do, it may be because you did not tell it the right steps. It
may be because you left out a choice that made a change in the program.
Did you notice that I included what you had to do if anything went wrong? If there were no
toothbrush or toothpaste or if the toothpaste did not come out of the tube, you were
instructed to do something. You must plan 'for all the things that could happen when the
computer is running its program. What if a number gets to be too big or someone gives the
wrong answer to a question? You must have something for the computer to do in every
base.
You are making a plan for the computer to follow, just as the architect makes a plan for the
carpenters to follow. Before we begin to make plans for a computer to follow, let’s try to
plan some things for people to do and then have you follow the plans. Some actions you
might write instructions for are typing a shoelace of a necktie, putting on makeup, or riding
bicycle. If you don’t put in enough steps, you may find someone in a very strange position.
2.5.2 How to Draw Flowcharts
A flowchart illustrates the steps in a process. By visualizing the process, a flowchart can
quickly help identify bottlenecks or inefficiencies where the process can be streamlined or
improved.
34
Example: Two Flowcharts for a Common Process
Suppose your research revealed that you always want fries and a drink with your burger.
You decide to streamline your process by ordering the combo meal, which automatically
includes fries and a drink. The two flowcharts show at a glance that you omit two decisions
and two order steps by using the streamlined order process.
2.5.3 Basic Flowcharting Shapes
Flowcharts use special shapes to represent different types of actions or steps in a process.
Lines and arrows show the sequence of the steps, and the relationships among them.
35
The terminator symbol marks the starting or ending point of the system. It usually
contains the word "Start" or "End."
A box can represent a single step ("add two cups of flour"), or and entire subprocess ("make bread") within a larger process.
A printed document or report.
A decision or branching point. Lines representing different decisions emerge
from different points of the diamond. The box where the computer can make
decisions like finding out which numbers is bigger or smaller or equal than
another number, depending on the information it receives. These are diamond –
shaped boxes. The computer can decide with the help of decision taken by the
diamond box, which route is to be followed further.
Represents material or information entering or leaving the system, such as
customer order (input) or a product (output).
Indicates that the flow continues on another page, where a matching symbol
(containing the same letter) has been placed.
Lines indicate the sequence of steps and the direction of flow.
36
Basic Flowchart
A basic Flowchart identifies the starting and ending points of a process, the sequence of
actions in the process, and the decision or branching points along the way.
2.5.4 Advantages of Flowcharts
The following benefits may be obtained from flow charts:
1. Better Communication
2. Effective analysis
3. Effective synthesis
4. Proper program Documentation
5. Effective coding
6. Systematic debugging
7. Systematic testing
37
---------------------------------------------------------------------------------------------------------
2.6 REVIEW QUESTIONS
-----------------------------------------------------------------------------------------1.
2.
3.
4.
Differentiate between system and application software. Give 4 examples of each
What are the various flowcharting symbols?
Draw a flow chart of getting the maximum of three numbers input.
What is algorithm? What are the characteristics necessary for a sequence of
instructions to qualify as an algorithm?
5. Define the terms hardware and software.
6. Describe the functions of the various basic flowcharting symbols.
38
---------------------------------------------------------------------------------------------------------
OPERATING SYSTEMS
---------------------------------------------------------------------------------------------------------
Structure
3.1 Introduction
3.1.1 Layers of Operating System
3.1.2 Functions of Operating Systems
3.1.3 Characteristics of an Operating System
3.1.4 Measuring System Performance
3.2 Evolution of Operating Systems
3.2.1 Serial Processing
3.2.2 Batch Processing
3.2.3 Multiprogramming
3.3 Types of Operating System
3.1 Batch Processing Operating Systems.
3.3.2 Time Sharing Operating Systems
3.3.3 Real Time Operating Systems
3.4 Operating System Techniques
3.4.1 Multiprogramming
3.4.2 Multiprocessing
3.4.3 Multitasking
3.5.4 Multithreading
3.5 Some Popular Operating Systems
3.5.1 Disk Operating System
3.5.2 UNIX
3.5.3 Linux
3.5.4 Microsoft Windows
3.5.5 Microsoft Windows NT
3.6 Review Questions
--------------------------------------------------------------------------------------------------------3.1 INTRODUCTION
--------------------------------------------------------------------------------------------------------What is human body without life giving Oxygen, the same is the case of a computer, its
existence is immaterial, without an operating system, such is the importance of the
Operating System. Operating System falls under the category of System software. The goal
of this unit is to introduce the concept related to operating system and what is the function
of operating system.
The Operating System is not the command interpreter alone, as people perceive. The
Operating System is the program that must be running all the time, and cannot be replaced
39
without it being a different O/S. Let us look into this most important component of the
Computer System, the Operating System.
Definition 1:
“An operating system can be defined as the set of instructions or programs, which make the
computer work”
Definition 2:
“An Operating System or OS is a software program that enables the computer hardware to
communicate and operate with the computer software”
Definition 3:
“An operating system is software, which controls the computer and its peripherals
and makes the computer ready to use by a process called booting”
Without an Operating System a computer would be useless.
An Operating System (OS) is an integrated set of programs that is used to manage the
various resources and overall operations of a computer system. It is designed to support the
activities of a computer installation. Its prime objective is to improve the performance and
efficiency of a computer and increase facility, the ease with which a system can be used.
As we have seen that an operating system is software, which makes the computer ready to
use by a process called booting. Before, discussing more on the operating systems, let us
first see what exactly do you mean by booting:
When we switch on the computer, the instructions stored in ROM are automatically
executed. These instructions help the computer to load the operating system from external
storage device (disk) to internal storage (RAM). This process of loading of operating
system from disk to RAM is called booting.
Fig 3.1 Component of Computer System
40
3.1.1 Layers of Operating System
Each group of computers may have its own and unique operating system although not
necessarily only one. Operating system programs are commonly stored in hard disk. When
we switch on the computer the booting program know as BIOS (Basic I/O System) which
is stored in the ROM (Read only memory) fetches the OS from hard disk to primary
storage (RAM). An OS tells the computer how to conduct him self. The architecture of
Operating System is designed with many layers in the core of it is Hardware/Kernel, above
it is loaded an OS which in turn controls everything inside a computer and make an
interface with the application program loaded in to the computer. It interconnects the
application program to CPU through Compiler or Interpreter.
Fig 3.2 Layers of Operating System
3.1.2 Functions of Operating Systems
Operating systems in general take care of all the housekeeping tasks. They do read and
write files, maintain disk directories, allocate memory to application programs, and usually
handle mechanical chores such as reading the keyboard when you press keys and updating
the screen when something needs to be displayed. These tasks require a surprising amount
of software and every computer requires software to do these jobs.
Due to the fact that there is close-knit cooperation between operating systems and
applications programs, each and every application program must be designed such that it is
able to work with a particular operating system. All operating systems essentially do the
same things but they do it in different ways, some features may be additional which add to
the functionality. This makes the point clear that an application program may work with all
operating systems, with slight modifications. An operating system performs, basically the
following functions:
1. Communication with the computer user or operator by means of terminals or
Consoles, and through the use of monitor commands and responses. It acts as
41
system start up device also. The operating system is automatically loaded into
hardware's main memory (RAM) when computer is turned on. Then the OS either
waits for you to give it a command of it brings a pre selected program into a read to
operate condition. This sequence is known as boot strapping or simply booting.
2. Assigning Priorities: Usually, the OS has several levels of priorities. For instance, a
report generating program may continue to run until the system receives a
command or query from the terminal, (a priority in computer lingo). Then the
system responds to the request from the terminal before continuing with the report
program.
3. The scheduling and loading of programs, or subprograms is necessary in order to
provide a continuous job processing sequence or to province appropriate responses
to events- job to job - processing and job as counting.
4. Control over hardware resources e.g. control over the selection and operation of all
peripheral devices used to input, or storage. The operating system also directs the
movement and processing of information required by your applications programs. It
transfers data to and from storage and input output devices like terminals or
printers.
5. Managing the data and program files: The operating system directs the information
storage and retrieval functions using one or more filing methods. These may include
sequential (magnetic tape), random (as on disk, units) or data base storage
structures.’ the latter method uses special identifiers for each file to locate
information more rapidly and to avoid- redundant information storage.
6. Provide utility functions that provide the user with tools for some operations like:
• Loading programs
• Transferring files from one floppy to another, backing up and copying.
• Formatting a disk to accept data Program.
• Sending information to I/O devices like printer, or a modem.
• Displaying the directory of contents of a disk.
7. Handling errors when they occur and using corrective routines where possible.
8. Protecting hardware, software and data from improper use.
9. Furnishing a complete Account of what has happened during operation. Some
details of this log may be stored for accounting purposes.
The more sophisticated a computer's operating system, the better the computer system can
manage itself, the less human intervention is required, and the more data computer can
process. This is one reason why today's mainframe operating systems are large, complex
programs involving thousands of instructions and costing thousands of dollars.
42
3.1.3 Characteristics of an Operating System
Let us try to identify the main characteristics of an operating system:
•
•
•
•
•
Concurrency: being able to handle events as they occur and executing multiple
tasks in parallel;
Sharing the resourced for a number of reasons:
1. Cost
2. Using the work of others
3. Sharing data: use the same data in several different programs possibly
used by several different users.
Removing redundancy;
Long-term storage of information (privacy, integrity, security);
Non determinacy: an operating system must be able to handle events occurring
in an unpredictable order.
3.1.4 Measuring System Performance
Efficiency of an operating system and overall performance of a computer system are
measured usually in terms of the following parameters:
1. Throughput: Throughput is the amount of work that a system is able to do per unit
time. It is measured as the number of jobs (processes) completed by the system per
unit time. For example, if a system is able to complete n processes in t seconds, its
throughput is n/t processes per second during that interval. Throughput is measured
normally in processes per hour. Note that the throughput of a system does not
depend on its jobs processing efficiency only, but also on the number of jobs
processed. For long process, throughput of a system may be one process/hour;
whereas for short processes, it may be 100 processes /hour for the same system.
2. Turnaround time: From the point of view of an individual user, an important
criterion is how long it takes a system to complete a job submitted by him/her.
Turnaround time is the interval between the time of submission of a job to the
system for processing to the time of completion of the job. Although, higher
throughput is desirable from the pointy of view of overall system performance,
individual users are more interested in better turnaround time for their jobs.
3. Response time: Turnaround time is not a suitable measure for interactive systems
because in such a system a process can produce some output early during its
execution and can continue executing while previous results are being output to the
user. Hence, another measure used in case of interactive systems is response time. It
is the interval between the time of submission of a job to the system for processing
to the time of the system producing the first response for the job. In any computer
system, it is desirable to maximize throughput and minimize turnaround time and
response time.
43
---------------------------------------------------------------------------------------------------------
3.2 EVOLUTION OF OPERATING SYSTEMS
-------------------------------------------------------------------------------------------------------An operating system may process its task serially (sequentially) or concurrently (several
tasks simultaneously). It means that the resources of the computer system may be dedicated
to a single program until its completion or they may be allocated among several programs
in different stages of execution. The feature of operating system to execute multiple
programs in interleaved fashion or different time cycles is called as multiprogramming
systems. In this topic, we will try to trace the evolution of operating system. In particular,
we will describe serial processing, batch processing and multiprogramming.
3.2.1 Serial Processing
Programming in 1's and 0's (machine language) was quite common for early computer
systems. Instruction and data used to be fed into the computer by means of console
switches or perhaps through a hexadecimal keyboard. Programs used to be started by
loading the program computer register with the address of the first instruction of a program
and its result (program) used to be examined by the contents of various registers and
memory locations of the machine. Therefore, programming in this style caused a low
utilization of both users and machine.
Advent of Input Output devices, such as punched cards paper tape and language translators
(Compiler/Assemblers) brought a significant step in computer system utilization. Program
started being coded into programming language are first changed into object code (binary
code) by translator and then automatically gets loaded into memory by a program called
loader. After transferring a control to the loaded program, the execution of a program
begins and its result gets displayed or printed. Once in memory, the program may be re-run
with a different set of input data. The process of development and preparation of a program
in such environment is slow and cumbersome due to serial processing and numerous
manual processing. In a typical sequence first the editor is called to create a source code of
user program written in programming language, translator is called to convert a source
code into binary code and then finally loader is called to load executable program into main
memory for execution. If syntax errors are detected, the whole process must be restarted
from the beginning. The next development was the replacement of card decks with
standard input/output and some useful library programs, which were further linked with
user program through system software called linker. While there was a definite
improvement over machine language approach, the serial mode of operation is obviously
not very efficient. This results in low utilization of resources.
3.2.2 Batch Processing
Utilization of computer resources and improvement in programmer's productivity was still
a major prohibition. During the time that tapes were being mounted or programmer was
operating the console, the CPU was sitting idle. The next logical step in the evolution of
operating system was to automate the sequencing of operations involved in program
execution and in the mechanical aspects of program development. Jobs with similar
requirements were batched together and run through the computer as a group. For example,
44
suppose the operator received one FORTRAN program, one COBOL program and another
FORTRAN program. If he runs them in that order, he would have to set up for FORTRAN
program environment (loading the FORTRAN compiler tapes) then set up COBOL
program and finally FORTRAN program again. If he runs the two FORTRAN programs as
a batch, however he could set up only once for FORTRAN thus saving operator's time.
Batching similar jobs brought utilization of system resources quite a bit. But there were still
problems. For example, when a job is stopped, the operator would have to notice that fact
by observing the console, determine why the program stopped and then load the card reader
or paper tape reader with the next job and restart the computer. During this transition from
one job to the next, the CPU sat idle.
To overcome this idle time, a small program called a resident monitor was created which is
always resident in the memory. It automatically sequenced one job to another job. Resident
monitor acts according to the directives given by a programmer through control cards
which contain information like marking of job's beginnings and endings, commands for
loading and executing programs, etc. These commands belong to job control language.
These job control language commands are included with user program and data. Here is an
example of job control language commands.
$COB - Execute the COBOL compiler
$JOB - First card of a job
$END - Last card of a job
$LOAD - Load program into memory
$RUN - Execute the user program
Figure 3.3 shows a sample card deck set up for a simple batch system.
With sequencing of program execution mostly automated by batch operating system, the
speed discrepancy between fast CPU and comparatively slows input/output devices such as
' card readers, printers emerged as a major performance bottleneck. Even a slow CPU
works in the microsecond range, with millions of instructions per second. But, fast card
45
reader, on the other hand, might read 1200 cards per minute. Thus, the difference in speed
between the CPU and its input/output devices may be three orders of magnitude or more.
The relative slowness of input/output devices can mean that CPU is often waiting for
input/output. As an example, an Assembler or Compiler may be able to process 300 or
more cards per second. A fast card reader, on the other hand, may be able to read only 1200
cards per minute. This means that assembling or compiling a 1200 card program would
require only 4 seconds of CPU time but 60 seconds to read. Thus, the CPU is idle for 56
out of 60 seconds or 93.3 per cent of the time. The resulting CPU utilization is only 6.7 per
cent. The process is similar for output operations. The problem is that while an input/output
is occurring, the CPU is idle, waiting for the input/output to complete; while the CPU is
executing, input/output devices are idle.
Over the years, of course, improvements in technology resulted in faster input/output
devices. But CPU speed increased even faster. Therefore, the need was to increase the
throughput and resource utilization by overlapping input/output and processing operations.
DMA (Direct Memory Access) chip which directly transfers the entire block of data from
its own buffer to main memory without intervention by CPU was a major development.
While CPU is executing, DMA can transfer data between high speed input/output devices
and main memory. CPU requires to be interrupted per block only by DMA. Apart from
DMA, there are two other approaches to improving system performance by overlapping
input, output and processing. These are buffering and spooling.
Buffering is a method of overlapping input, output and processing of a single job. The idea
is quite simple. After data has been read and the CPU is about to start operating on it, the
input device is instructed to begin the next input immediately. The CPU and input device
are then both busy. With luck, by the time that the CPU is ready for the next data item the
input device will have finished reading it. The CPU can then begin processing the newly
read data, while the input device starts to read the following data. Similarly, this can be
done for output. In this case, the CPU creates data that is put into a buffer until an output
device can accept it. For output, the CPU can proceed at full speed until, eventually all
system buffers are full. Then the CPU must wait for the output device. This happens with
input/output bound jobs where the amount of input/output relation to computation is very
high. Since the CPU is faster than the input/output device, the speed of execution is
controlled by the input/output device, not by the speed of the CPU.
More sophisticated form of input/output buffering called SPOOLING (simultaneous
peripheral operation on line) essentially use the disk as a very large buffer (figure 3.4) for
reading and for storing output files reading and for storing output files.
Buffering overlaps input, output and processing of a single job whereas Spooling allows
CPU to overlap the input of one job with the computation and output of other jobs.
Therefore this approach is better than buffering. Even in a simple system, the spooler may
be reading the input of one job while printing the output of a different job.
46
Fig 3.4 Spooling
3.2.3 Multiprogramming
Buffering and spooling improve system performance by overlapping the input, output and
computation of a single job, but both of them have their limitations. A single user cannot
always keep CPU or I/O devices busy at all times. Multiprogramming offers a more
efficient approach to increase system performance. In order to increase the resource
utilization, systems supporting multiprogramming approach allow more than one job
(program) to utilize CPU time at any moment. More number of programs competing for
system resources, better will be resource utilization. The idea is implemented as follows.
The main memory of a system contains more than one program (Figure 3.5).
Figure 3.5: Memory layout in multiprogramming environment
The operating system picks one of the programs and start executing. During execution
process program1 may need some I/O operation to complete. In a sequential execution
environment (Figure 3.6a), the CPU would sit idle. In a multiprogramming system, (Figure
3.6b) operating system will simply switch over to the next program (Program2).
When that program needs to wait for some I/O operation, it switches over to Program 3 and
so on. If there is no other new program left in the main memory, the CPU will pass its
control back to the previous programs.
47
Multiprogramming has traditionally been employed to increase the resource utilization of a
computer system and to support multiple simultaneously interactive users (terminals).
Compared to operating system which supports only sequential execution,
multiprogramming system requires some form of CPU and memory management strategies
Figure 3.6: Multiprogramming
---------------------------------------------------------------------------------------------------------
3.3 TYPES OF OPERATING SYSTEM
--------------------------------------------------------------------------------------------------------As computers have progressed and developed so have the types of operating systems.
Many types of operating systems are available for computers, which can be divided into the
following two broad categories (a)
(b)
Single-user operating systems.
Multi-user operating systems.
(a) Single-user operating systems: These operating systems are used for mainly
computers having only one terminal (stand-alone PCs). MS DOS (Microsoft Disk
Operating System) and PC DOS (Personal Computer Disk Operating System) are the two
important single user operating systems. Both systems are almost identical and are simply
called DOS. OS/2 and Windows NT are other popular single-user multi-tasking operating
systems for microcomputers.
48
(i)
(ii)
Microsoft DOS - MS DOS, developed by 'Microsoft Inc.' in 1981, is the
most widely used operating system of IBM-compatible microcomputers.
The latest version identification number of a release of software) of MS
DOS is 7.
PC DOS - PC DOS is essentially the same operating system as MS DOS,
but developed and supplied by IBM for its personal computers.
(b) Multi-user operating systems: These operating systems are used for those computers
(micro to mainframe), which have many terminals (multi-user systems). The popular
operating systems used for multi-user systems are UNIX, NETWARE, MVS, OS/400,
VMS and Linux.
Multi-user operating systems are used on networks of computers and allow many different
users to access the same data and application programs on the same network. It also allows
users to communicate with each other.
Modern computer operating systems may also be classified into three other groups, which
are distinguished by the nature of interaction that takes place between the computer user
and his or her program during its processing. The three groups are called batch, timeshared and real time operating systems.
3.3.1 Batch Processing Operating Systems.
If there was a lot of work to be done, then these works are pooled and the collections of
these instructions would be given to the computer to work on overnight. Since the
computer was working on batches of instructions, this type of operating system was called
a Batch Processing Operating System.
Batch processing operating systems are good at churning through large numbers of
repetitive jobs on large computers. Jobs like: printing of invitations for AGM,
consolidation of marks and presenting result, working out the pay of each employee in
large firm; or processing all the questionnaire forms in a large survey.
In a batch processing operating system environment users submit jobs to a central place
where these jobs are collected into a batch, and subsequently placed on an input queue at
the computer where they will be run. In this case, the user has no interaction with the job
during its processing, and the computer’s response time is the turnaround time-the time
from submission of the job until execution is complete, and the results are ready for return
to the person who submitted the job.
3.3.2 Time Sharing Operating Systems
Time-sharing is a mechanism to provide simultaneous interactive use of a computer system
by many users in such a away that each one feels that he/she is the sole user of the system.
It uses multiprogramming with a special CPU scheduling algorithm to achieve this.
A time-sharing system has many (even hundreds of) user terminals connected to the same
computer simultaneously. Using these terminals, multiple users can work on the system
49
simultaneously. Multiprogramming feature allows multiple user programs to reside
simultaneously in main memory, and special CPU scheduling algorithm allocates a short
period of CPU time one-by-one to each user process (from the first one to the last one, and
then again beginning from the first one). The short period during which a user process gets
to use CPU is known as time slice, time slot, or quantum, and is typically of the order of
10 to 100 milliseconds. Hence, when CPU is allocated to a user process, it uses the CPU
until the allotted time slice expires (system's clock sends an interrupt signal to CPU after
every time slice), or it needs to perform some I/O operation, or it completes its execution
during this period. Notice that CPU is taken away from a running process when the allotted
time slice expires. Figure 3.7 shows the process state diagram of a time-sharing system
Figure 3.7 Process state diagrams for a time-sharing system.
In this environment a computer provides computing services to several or many users
concurrently on-line. Here, the various users are sharing the central processor, the memory,
and other resources of the computer system in a manner facilitated, controlled, and
monitored by the operating system. The user, in this environment, has nearly full
interaction with the program during its execution, and the computer’s response time may be
expected to be no more than a few second.
Advantages of Time-sharing Systems: Although time-sharing systems are complex to
design, they provide the following advantages to their users:
1. Reduces CPU idle time. A user's thinking and typing speed is much slower than a
computer's processing speed. Hence, during interactive usage of a system, while a user is
engaged in thinking or typing his / her input, a time-sharing system services many other
users. Hence, time-sharing systems help in reducing CPU idle time and, in turn, provide
increased system throughput.
2. Provides advantages of quick response time. The special CPU scheduling algorithm
used in time sharing systems ensures quick response time to all users. This feature helps in
improving programmers' efficiency by making interactive programming and debugging
much simpler and quicker. Multiple programmers can work simultaneously for writing,
50
testing, and debugging their programs, or for trying out various approaches to a problem
solving.
3. Offers good computing facility to small users. Small users can gain direct access to
more sophisticated hardware and software than they could otherwise justify or afford. In
time-sharing systems, they merely pay a fee for resources used and are relieved of
hardware, software, and personnel problems associated with acquiring and maintaining
their own installation.
Multitasking Operating Systems: Multi-tasking operating systems are now very
common. They enable the computer to run more than one piece of software at the same
time. It is quite common to sit at your computer and have a word-processor open and
running, as well as an Internet browser, and an audio CD player all at the same time.
The operating system allows you to switch between the applications and even transfer data
between them (for example, it helps you to copy a picture from an internet site shown on
your browser application and paste it into your DTP application).
Multitasking Operating systems allow multiple software processes to be run at the same
time. Operating systems that would fall into this category are:
• System 7.x
• System 8.x
• UNIX
• Windows 2000
• Windows 95
• Windows 98
• Windows NT 4.0
Multitasking operating systems allow a user to do more than one thing at the same time.
Multi-user Operating Systems: Multi-user operating systems are used on networks of
computers and allow many different users to access the same data and application programs
on the same network. It also allows users to communicate with each other.
There are many different types of Network Operating System, each one suited to a
different.
Multi - User - Allows multiple users to utilize the computer and run programs at the same
time. Operating systems that would fall into this category are:
• System 7.x
• System 8.x
• UNIX
• Windows 2000
• Windows 3.1x
• Windows 95
• Windows 98
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• Windows NT
3.3.3 Real Time Operating Systems
A Real-Time Operating System (RTOS) is a multitasking operating system intended for
real-time applications. Such applications include embedded systems (programmable
thermostats, household appliance controllers), industrial robots, spacecraft, industrial
control (see SCADA), and scientific research equipment. It is another form of operating
system which is used in environments where a large number of events mostly external to
computer systems, must be accepted and processed in a short time or within certain
deadlines. Examples of such applications are flight control, real time simulations etc. Real
time systems are also frequently used in military application.
Real Time Operating Systems are designed to service those applications where response
time is of the essence in order to prevent error, misrepresentation or even disaster.
Examples of real time operating systems are those, which handle airlines reservations,
machine tool control, and monitoring of a nuclear power station. The systems, in this case,
are designed to be interrupted by external signal that require the immediate attention of the
computer system.
A primary objective of real-time system is to provide quick response times. User
convenience and resource utilization are of secondary concern to real-time system. In the
real-time system each process is assigned a certain level of priority according to the relative
importance of the event processes. The processor is normally allocated to the highest
priority process among those which are ready to execute. Higher priority process usually
pre-empte execution of lower priority processes. This form of scheduling called, priority
based pre- emptive scheduling, is used by a majority of real-time systems.
In fact, many computer operating systems are hybrids, providing for more than one of these
types of computing service simultaneously. It is especially common to have a background
batch system running in conjunction with one of the other two on the same computer. A
number of other definitions are important to gaining an understanding of operating
systems:
A multiprogramming operating system is a system that allows more than one active user
program (or part of user program) to be stored in main memory simultaneously. Thus, it is
evident that a time-sharing system is a multiprogramming system, but note that a
multiprogramming system is not necessarily a time-sharing system. A batch or real time
operating system could, and indeed usually does, have more than one active user program
simultaneously in main storage. Another important, and all too similar, term is
‘multiprocessing’.
A multiprocessing system is a computer hardware configuration that includes more than
one independent processing unit. The term multiprocessing is generally used to refer to
large computer hardware complexes found in major scientific or commercial applications.
This Operating system allows multiple processors to be utilized. Operating systems that
would fall into this category are:
52
•
•
•
UNIX
Windows 2000
Windows NT 4.0
A networked computing system is a collection of physical interconnected computers. The
operating system of each of the interconnected computers must contain, in addition to its
own stand-alone functionality, provisions for handing communication and transfer of
program and data among the other computers with which it is connected.
A distributed computing system consists of a number of computers that are connected
and managed so that they automatically share the job-processing load among the
constituent computers, or separate the job load as appropriate particularly configured
processors. Such a system requires an operating system, which, in addition to the typical
stand-alone functionality, provides coordination of the operations and information flow
among the component computers.
The networked and distributed computing environments and their respective operating
systems are designed with more complex functional capabilities. In a network operating
system the users are aware of the existence of multiple computers, and can log in to remote
machines and copy files from one machine to another. Each machine runs its own local
operating system and has its own user (or users).
A distributed operating system, in contrast, is one that appears to its users as a traditional
unprocessed system, even though it is actually composed of multiple processors. In a true
distributed system, users should not be aware of where their programs are being run or
where their files are located; that should all be handled automatically and efficiently by the
operating system.
Network operating systems are not fundamentally different from single processor operating
systems. They obviously need a network interface controller and some low-level software
to drive it, as well as programs to achieve remote login and remote files access, but these
additions do not change the essential structure of the operating systems.
---------------------------------------------------------------------------------------------------------
3.4 OPERATING SYSTEM TECHNIQUES
--------------------------------------------------------------------------------------------------------There are several techniques used in Multi-user operating systems for enabling many users
to concurrently share the single or multiple CPU (e.g. Multiprogramming and
Multiprocessing). Some techniques are used in single-user operating system to handle
multiple tasks (Multitasking). We will now discuss these common techniques used in
different operating systems.
3.4.1 Multiprogramming
It is a process by which single CPU works on two or more programs simultaneously.
Using this technique, the operating system keeps the CPU busy. Multiprogramming allows
the processor to handle either multiple batch jobs at a time (Batch Multiprogramming) or
53
multiple interactive jobs shared among multiple users (Time Sharing Multiprogramming).
Time-sharing is a technique that allows a CPU to simultaneously support the activities of
several users by allocating fixed time slots (in milliseconds). Examples of operating
systems that support multiprogramming are OS/2, UNIX and Macintosh System 7.
3.4.2 Multiprocessing
It refers to the use of two or more CPUs to perform a coordinated task simultaneously.
Figure 3.8 shows the architecture of a computer with its CPU, memory, and I/O processors.
Fig 3.8 Architecture of a computer system with its CPU, memory, and I/O processors.
The idea of using I/O processors to improve system performance was carried a step further
by designing systems with multiple CPUs. Such systems are called multiprocessing
systems because they use multiple processors (CPUs) and can execute multiple processes
concurrently. Multiple CPUs of these systems are used to process either instructions from
different and independent programs or different instructions from the same program
simultaneously. Figure 3.9 shows basic organization of a typical multiprocessing system.
Figure 3.9 Basic organization of a typical multiprocessing system
For example, MVS, VMS and Windows NT support multiprocessing.
3.4.3 Multitasking
It refers to the ability of an operating system to execute two or more tasks concurrently. In
multitasking environment, the user opens new applications without closing the previous
ones and the information can be easily moved among a number of applications.
54
Technically speaking, multitasking is same as multiprogramming. Many authors do not
distinguish between multiprogramming and multitasking because both refer to the same
concept. However, some authors prefer to use the term multiprogramming for multi-user
systems (systems that are used simultaneously by many users such as mainframe and server
class systems), and multitasking for single-user systems (systems that are used by only one
user at a time such as a personal computer or a notebook computer). Note that even in a
single-user system, it is not necessary that the system processes only one job at a time. In
fact, a user of a single-user system often has multiple tasks being processed by the system.
For example, while editing a file in foreground, a sorting job can be given in background.
Similarly, while compilation of a program is in progress in background, user may be
reading his/her electronic mails in foreground. In this manner, a user may work
concurrently on many tasks. In such a situation, status of each of the tasks is viewed on
computer's screen normally by partitioning the screen into multiple windows. Progress of
different tasks is viewed on different windows in a multitasking system.
Hence, for those who like to differentiate between multiprogramming and multitasking,
multiprogramming is interleaved execution of multiple jobs (of same or different users) in
a multi-user system, while multitasking is interleaved execution of multiple jobs (often
referred to as tasks of same user) in a single-user system. Typically, computer systems used
for such purposes are uni-processor systems (having only one CPU). Typically, computer
systems used for such purposes are uni-processor systems (having only one CPU). For
example, Windows NT and OS/2 operating systems use this technique.
3.5.4 Multithreading
Threads are a popular way to improve application performance. In traditional operating
systems, the basic unit of CPU utilization is a process. Each process has its own program
counter, its own register states, its own stack, its own address space (memory area allocated
to it). On the other hand, in operating systems, with threads facility, the basic unit of CPU
utilization is a thread. In these operating systems, a process consists of an address space
and one or more threads of control [see Figure 3.10(b)]. Each thread of a process has its
own program counter, its own register states, and its own stack. However, all the threads of
a process share the same address space. Hence, they also share the same global variables.
In addition, all threads of a process also share the same set of operating system resources,
such as open files, signals, accounting information, etc. Due to sharing of address space,
there is no protection between the threads of a process. However, this is not a problem
because process (and hence all its threads) is always owned by a single user. Therefore,
protection between multiple threads of a process is not necessary. Protection between
multiple processes is needed because different processes may belong to different users.
Threads share a CPU in the same way as processes do. At a particular instance of time, a
thread can be in anyone of several states - running, blocked, ready, or terminated. Due to
these similarities, threads are often viewed as mini processes. In fact, in operating systems
with threads facility, a process having a single thread corresponds to a process of a
traditional operating system [see Figure 3.10(a)]. Threads are often referred to as
lightweight processes and traditional processes are referred to as heavyweight processes.
55
Fig 3.10 (a) Single-threaded and (b) Multithreaded processes.
Operating systems that allow different parts of software program to run concurrently.
Operating systems that would fall into this category are:
• UNIX
• Windows2000
• Windows95
• Windows98
• Windows NT 4.0
---------------------------------------------------------------------------------------------------------
3.5 SOME POPULAR OPERATING SYSTEMS
---------------------------------------------------------------------------------------------------------
3.5.1 Disk Operating System
What is DOS and what do DOS mean? DOS is an acronym for Disk Operating System.
Though this doesn't say exactly what DOS does it tells you what it is. An operating system
is a program that is run on a computer that allows the user to communicate with it in a way
the user understands. Imagine if you had to talk to the computer on its level! No one would
want to work with computers if that were the case.
DOS allows you to perform tasks on the computer by telling the computer what to do in
terms of English like commands such as COPY and MOVE are infinitely better than
10001110101110111! Designed for microcomputers (your PC is a microcomputer), DOS
makes it easier for you to work with the information on your disks whether they are floppy
disks or hard disks. But before we look deeper into how to use DOS we need to have a little
background on how DOS looks at information on the computer.
Rebooting the Computer: Sometimes it may happen that your system crashes down
because of any reason. In This process is called Warm Boot or Reset. This will again get
things going. But it is advisable to use it as a last alternative when all other efforts of
resuming work fail. At times, Warm Boot also fails to restart the computer. This means the
instructions that are given by the keyboard are no longer valid and are not interpreted by
the system. In this case, switch off the power supply such a situation, hit < Ctrl + Alt + Del
56
> Keys together. This will restart your computer and wait for a few minutes. Then turn on
the power supply and start working. Sometimes, due to unknown reasons the system is
unable to boot from the hard disk, in such a situation, you are required to boot the system
from the bootable floppy (floppy that contains DOS).
Concept of Files and Directories: File is a collection of related information. Any kind of
text, data or program that is entered is stored in a file. Now, it is very essential to organize
your files in an ordered manner. This makes file search easier. Otherwise, it can really be a
difficult and time consuming job to search for a particular file out of the whole lot of files
stored on the disk. An example of library can make the explanation of the concept clearer.
As you must have already observed, the books in a library are put in big cabinets. Each
cabinet is divided into many shelves and sub shelves. Each shelve or sub-shelve contains
books on a particular subject. So, the required book on a particular subject can be found out
very easily without wasting much time and effort.
On similar grounds, all the files that are related to each other are clubbed at one place. This
is known as a Directory Structure or simply a Directory. A directory structure resembles
an inverted tree. The main directory becomes the Root directory. The directories and files
become the branches of this directory tree. Any number of files and directories can be
added to it, thus, making the tree grow big downwards. Let us take an example. Suppose
we wish to store two kinds of files on our disk: ACCOUNT and EXPENSE. Further, we
wish to keep two more kinds of files (say CASHSALE and CREDSALE) under
ACCOUNT sub-directory. DOS can very much help you in organizing your files through
directory structure.
1. On the top of the directory structure, there is a Root directory. This directory is
always present and is shown by \(backslash) for referencing. Any file or directory
that is created is always under the Root directory.
2. EXPENSE is the sub-directory of the Root directory.
3. ACCOUNT is the parent directory of the directories CASHSALE and CREDSALE.
It can also be said that the CASHSALE and CREDSALE are the sub-directories of
the ACCOUNT directory. Thus, a directory under a directory is called a subdirectory / (Root).
• ACCOUNT EXPENSE
• CASHSALE CREDSALE WEST.TXT
• EAST.TXT
It can be clearly seen that the files relating to a particular subject can be put under a
directory. For example, all the files relating to expenses can be put under EXPENSE
subdirectory whereas all the files relating to cash sales can be stored under the subdirectory
CASHSALE.
Referencing Files
It’s time to learn as to how to locate a file. The directory structure has two sub-directories
under the Root directory. The sub-directory EXPENSE has two files under it. DOS allows
you to go from one directory to another by following a certain path. In the beginning, the
user is always resident in the Root directory. While traveling from one directory to another
57
certain rules have to be followed. A user cannot go directly from ACCOUNT subdirectory
to EXPENSE sub-directory. To go from one sub-directory to another, you have to first go
to its parent directory or the Root directory. Thus, for going from ACCOUNT sub-directory
to EXPENSE sub-directory, you first have to go to Root directory. Similarly for going from
the file EAST.TXT to WEST.TXT, you have gone to the EXPENSE sub-directory first.
Thus, in other words, while moving from one directory to another, you have to its parent
directory first. Now, in order to reach out to the file WEST.TXT the following path has to
be followed:
C:\>Expense\West.txt
12345
Here,
1. Is the drive name where the file is resident in;
2. Is the path which DOS takes to reach for a file;
3. Is the directory under the Root;
4. Is the primary name of the file that is to be accessed;
5. Is the extension name of the same file.
The \ (backslash) has to be used for tracing out the path. First backslash takes you to the
Root directory. The subsequent backslashes separate the directories, sub-directories and the
filename that are given in the whole path. File Naming Conventions There are certain rules
that have to be followed while giving names to your files. A filename has two parts:
1. Primary Name
2. Extension (Secondary Name)
A dot (.) separates a primary name from an extension. Let see the two parts of the file
named DRAGON.TXT. A primary name cannot have more than eight characters and
similarly an extension can contain only up to three characters. Filename having only the
primary name and no extension is absolutely valid because it is absolutely optional to give
an extension to a filename. An extension is generally given by language or software used
by the file. For example, if you entering BASIC and PASCAL programs, their filenames
would have extension BAS and PAS respectively. A filename can contain the following
characters:
1. An Alphabet (A-Z) or (a-z)
2. A number (0-9)
3. Special characters such as etc.
Except *, ?, full stop (.) and space
It is a good practice to give meaningful names to your files. However, no two files can have
exactly the same name on disk. Thus, a name given to a file on a disk has to be unique. A
look at a few valid and invalid filenames:
58
The rules for naming a directory are the same as that of naming files.
Dos Commands:
DOS offers a variety of commands to perform various functions. With the help of DOS
commands, you can display the list of files and directories that are present on the disk,
create new files and directories; remove unwanted files and directories and much more.
DOS commands can be entered either in uppercase or lowercase letters. The format of a
DOS command is called syntax. All DOS commands begin with command name. When
DOS carries out the instructions given by you, is called the execution of DOS command.
All DOS commands can be classified into two categories: Internal Commands and External
Commands.
Internal Commands
The commands which are a part of the main files of DOS COMMAND.COM and two
hidden files) are known as Internal Commands. They are loaded in the RAM as soon as the
computer is switched on. The important internal commands are DIR, COPY, DEL, REN,
MD, CD, RD, TYPE, COPY CON, DATE, TIME, CLS, ECHO, PROMPT and PATH.
External Commands
External commands are those commands, which are stored disks as separate program files.
These files have the same primary name as the command name. The extension of these
files is either COM or EXE. So, at the time of execution of these commands, the
corresponding program file should be present in the DOS sub-directory of the hard disk and
DOS sub-directory should also be in the path search. The commonly used external
commands are- FORMAT, DISKCOPY, CHKDSK, XCOPY and LABEL.
Let us discuss some of the important DOS commands in detail.
• CD or CHDIR
To change the directory path.
Syntax
CHDIR [drive:][path]
or
CD [drive:][path]
Switches Used
cd\ - Goes to the highest level the root of the drive.
cd.. - Goes back one directory. For example if you are within
C:\WINDOWS\COMMAND> directory this would take to C:\WINDOWS>
59
CD windows - If present would take you into the Windows directory. Windows can be
substituted with any other name. Example Suppose you are under the EXPENSE subdirectory and you want to access the files or directories in the ACCOUNT subdirectory.
This would involve the changing of directory from EXPENSE to ACCOUNT. This will
make the ACCOUNT directory active. The task of changing directories can be
accomplished with the help of CD command. Look at the following example:
C:\>CD ACCOUNT <Enter>
The above command will take you to the sub-directory ACCOUNT as shown by following
prompt:
C:\ACCOUNT>
If you want to go to the sub-directory CASHSALE from the sub-directory EXPENSE,
issue the following command:
C:\>CD ACCOUNT\CASHSALE <Enter>
After the above command, the following prompt C:\ACCOUNT\CASHSALE>
The command for going to the root directory from prompt is:
C:\ACCOUNT\CASHSALE>CD\ <Enter>
But, the command for going to the parent or previous (whether it is root or subdirectory) is:
C:\ACCOUNT\CASHSALE>CD.. <Enter>
If you are in the sub-directory CASHSALE, the command will take you to ACCOUNT
sub-directory below:
C:\ACCOUNT>
Suppose you are under the EXPENSE sub-directory want to access the files or directories
in the ACCOUNT subdirectory. This would involve the changing of directory.
EXPENSE to ACCOUNT. This will make the directory active. The task of changing
directories accomplished with the help of CD command. Look following example:
C:\>CD ACCOUNT <Enter>
where CD stands for Change Directory
The above command will take you to the sub-directory ACCOUNT as shown by following
prompt:
C:\ACCOUNT>If you want to go to the sub-directory CASHSALE from the sub-directory EXPENSE,
issue the following command:
C:\>CD ACCOUNT\CASHSALE <Enter>
After the above command, the following prompt
60
C:\ACCOUNT\CASHSALE>_
The command for going to the root directory from prompt is:
C:\ACCOUNT\CASHSALE>CD\ <Enter>
But, the command for going to the parent or previous
(whether it is root or subdirectory) is: C:\ACCOUN-RCASHSALE>CD.. <Enter>
If you are in the sub-directory CASHSALE, the command will take you to ACCOUNT
sub-directory below:
C:\ACCOUNT>The command for displaying the name of the currently directory is:
C:\>CD <Enter>
• DIR
Displays a list of files and subdirectories in a directory.
Syntax
DIR [drive:][path][filename] [/P] [/W] [/A[[:]attributes]] [/
O[[:]sort order]] [/S] [/B] [/L] [/V]
Example
dir = Lists all files and directories in the directory that you are currently in.
dir /ad = List only the directories in the current directory.
61
dir /s = Lists the files in the directory that you are in and all sub directories after that
directory, if you are at root “C:\>” and type this command this will list to you every file and
directory that is on the computer.
dir /p = If the directory has a lot of files and you cannot read all the files you can use this
command and it will display all files one page at a time.
dir /w = If you don’t need the info on the date / time and other information on the files you
can use this command to list just the files and directories going horizontal taking as little as
space needed.
dir /s /w /p = This would list all the files and directories in the current directory and the sub
directories after that in wide format one page at a time.
• COPY CON
This command is used to create a file.
Syntax
Copy con <filename>
Once you have entered the above command this will create the file by the name specified.
Once you have typed all the lines you wish to be in the file press and hold CTRL + Z. This
should enter ^Z, once on the screen press the enter and one file should be copied.
Example
C:\>copy con file1.txt
• MD
This command is used t make a directory.
Syntax
MD <directoryname>
Example
C:\>md dir1
This will create a directory named dir1 under root.
• COPY
Copies one or more files to another location.
Syntax
COPY Source Destination
Example
copy *.* a: = This would copy all files in the directory currently in to the floppy disk in
drive a:
copy file1.txt c:\dir1\file2.txt = This would copy file1.txt to a directory dir1 under root
with a different name file2.txt.
62
copy myfile1.txt+myfile2.txt = This command would copy the contents in myfile2.txt and
combine it with the contents in
myfile1.txt
• DEL
Deletes one or more files.
Syntax
DEL [drive:][path]filename
Examples
del test.tmp = Deletes the test.tmp in the directory that you currently are in, if the file
exists.
del c:\windows\test.tmp = Delete the c:\windows\test.tmp in the windows directory if it
exists.
del c:\windows\temp\*.* = (* is for wild character(s)) *.* indicates that you would like to
delete all files in the c:\windows\temp directory.
del c:\windows\temp\?est.tmp = (? is a single wild character for one letter) This command
would delete any file ending with est.tmp such as pest.tmp or zest.tmp
• EDIT
Edit allows a user to view, create and or modify their computer files. The disadvantage of
copy con is that you cannot modify a file. So we use edit.
Syntax
EDIT <filename>
Example
Using edit you can also create files, for example if you wanted to create a file called
myfile.txt you would type:
edit myfile.txt <press enter>
This would bring up a blank edit screen, as long as the file is saved upon exit this will
create the file myfile.txt.
• MOVE
Allows you to move files or directories from one folder to another or from one drive to
another.
Syntax
MOVE source destination
Example
C:\>move file.txt c:\dir1\file1.txt
This would move a file named file1.txt to directory dir1 with the same name.
• REN OR RENAME
Used to rename files and directories from the original name to a new name.
Syntax
Ren oldfilename newfilename
Example
C:\>ren file1.txt file2.txt
This will change the name of file1.txt to file2.txt.
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• CLS
cls is a command that allows a user to clear the complete contents of the screen and leave
only a prompt.
Syntax
cls
• Format
Format is used to erase all of the information off of a computer diskette or fixed drive.
Syntax
Format <drive>
Example
C:\>Format a:
This will erase all the contents of the floppy disk inside floppy drive.
3.5.2 UNIX
UNIX was developed by some of the members of the Multics team at the bell labs starting
in the late 1960’s by many of the same people who help created the C programming
language. The UNIX today however is the not just the work of a couple of programmers.
Many other organizations, institutes and various other individuals contributed significant
additions to the system we now know to day.
UNIX is primarily a command line oriented operating system you can get additional
applications such as X-Window which allows you to have a graphic oriented operating
system similar to Windows 3.x / Windows 95 / Windows 98. However while this is
available UNIX is still primarily used from the command line. Because the UNIX
operating system is an open operating system you will discover that there are various
shells. A shell is a large add-on / modification of the UNIX operating system, to determine
the shell you can type echo $shell at the UNIX prompt. When typing this you will receive a
response such as / bin/csh which in this case indicates that the UNIX you are logged into is
a C shell. Another popular shell is the Borne shell which is / bin/ sh and Korn shell that the
UNIX you are logged into is a C shell. Another popular shell is the Borne shell which is /
bin/sh and Korn shell.
3.5.3 Linux
Linux is an open- source operating system enhanced and backed by thousands of
programmers worldwide. It is a multi tasking, multiprocessing operating system designed
originally for use on personal computers. The name “Linux” is derived from its inventor
Linus Torvalds. Torvalds was a student at the University of Helsinki, Finland in early
1990s when he wrote the first version of an UNIX- like kernel as a toy project. He later
posted the code on the Internet and asked programmers across the world to help him build
it into a working system. The result was Linux. Torvalds holds the copyright but permits
free distribution of source code. That is, he oversees development of kernel and owns its
trademark. When someone submits a change or a feature, Torvalds and his core team of
kernel developers review the merit of adding it to kernel source code.
64
3.5.4 Microsoft Windows
It is a series of software operating systems and graphical user interfaces produced by
Microsoft. It was developed by Microsoft to overcome the limitations of its own MS-DOS
operating system. Microsoft first introduced an operating environment named Windows in
November 1985 as an add-on to MS-DOS in response to the growing interest in graphical
user interfaces (GUIs). Microsoft Windows came to dominate the world's personal
computer market, overtaking Mac OS, which had been introduced previously. The most
recent client version of Windows is Windows Vista; the most recent server version is
Windows Server 2008. Vista's successor, Windows 7 (currently a release candidate), It is a
family of operating systems for personal computers. Windows dominates the personal
computer world, running, by some estimates, on 90% of all personal computers. The
remaining 10% are mostly Macintosh computers. Like the Macintosh operating
environment, Windows provides a graphical user interface (GUI), virtual memory
management, multitasking, and support for many peripheral devices. Main Features of
Microsoft Windows are as follows:
Its native interface is a GUI. Hence, for a new user it is easier to learn and use a computer
system.
A Microsoft window was designed to be not just an operating system but also a complete
operating environment. That is, all its programs conform to a standard way of working. For
example, a Microsoft Windows word processor works similarly the way a Microsoft
windows spreadsheet (or any other type of Windows program) works. This means that
experience gained by learning one Windows program is useful while using any other
Microsoft Windows program.
It is single- user, multitasking operating system. That is, a user may run more than one
program at a time. For example, while editing a file in foreground, a sorting job can be run
in background. Monitor’s screen can be portioned into multiple windows and progress of
different programs can be viewed on different windows.
65
Fig 3.11 Microsoft Windows
3.5.5 Microsoft Windows NT
Windows NT is a family of operating systems produced by Microsoft, the first version of
which was released in July 1993. It is an operating system developed by Microsoft for
high-performance processors and networked systems. In 1993, when it was first released,
Microsoft Windows NT was Microsoft's platform of choice for high-end systems. The
current version, 4.0, is intended for use as a network server (NT Server) or a workstation
(NT Workstation). Windows NT did not replace Windows 95. While Windows NT
contains the Windows 95 interface, it is entirely 32-bit.
Technical features of Windows NT
• Interface
o Contains the Windows 95 interface and features like the Start button,
Taskbar, Explorer, Network Neighborhood, and Briefcase
• Networking
o NetWare client and login script support
o Enhanced meta-file (EMF) spooling for improved network printing speed
66
Support for 15 network protocols
Peer-to-peer and FTP server capabilities
Client software for both telnet and FTP services
Messaging Capabilities
o Windows Messaging Subsystem
o Microsoft Exchange and Microsoft Schedule+ included
o WINCHAT, NET MESSAGE, or Net DDET
Remote Management
o Remote management utilities such as Event Viewer, Performance Monitor,
Service Controller, and Registry Editor
o Dial-out capability to remote servers
o Remote dial-in capability
Remote Access Services (RAS)
o Internet access to Windows NT Server and DNS names for resource
connections
o Dial-out capability to remote servers, including Internet services
o Remote dial-in ability to any workstation
o Full network functionality over remote links using NetBEUI, IPX/SPX, and
TCP/IP protocols
o Dial-in capability to remote NetWare servers using RAS
o Multi-link capability for channel aggregation of multiple modem
connections
Security
o Per-file and per-directory security with the NT file system (NTFS)
o Local desktop security; user ID and password required for access
o Account lockout capabilities to prevent unlimited login attempts
o Network security with single network login using challenge/response
protocol
Application Support
o Native support for all applications based on Windows 95, Win32, 16-bit
Windows, 16-bit MS-DOS, 16-bit OS/2, and POSIX 1003.1
o Separate memory spaces for 16-bit applications (multiple virtual MS-DOS
machines)
o Preemptive multitasking for 16-bit and 32-bit applications
o 486 emulator allows 386-enhanced 16-bit applications to run on RISC
machines
o OLE support between all 16-bit and 32-bit Windows based applications
o Asynchronous I/O queue for improved responsiveness
o Structured exception handling for easy troubleshooting
Graphics and Multimedia
o Significant performance gains for graphic intensive applications
o OpenGL APIs for high-performance three-dimensional color graphics
o 16-bit and 32-bit API support for the Video for Windows 1.1 feature set
Utilities
o File compression with NTFS
o User Manager for configuration and security
o
o
o
•
•
•
•
•
•
•
67
Disk Administrator for graphical disk configuration
Diagnostics utility that details basic system information
Performance Monitor for local and remote troubleshooting
Tape backup
Event Viewer and logging utility for local and remote troubleshooting
Long filename support on FAT and NTFS
Configuration details managed in registry database
Hardware Support
o Multiple hardware configuration; you can specify a hardware profile at start
time, including services, devices, and video resolutions
o Intel, Alpha AXP, MIPS, and PowerPC platforms
o Symmetric multiprocessing (SMP) support
o
o
o
o
o
o
o
•
---------------------------------------------------------------------------------------------------------
3.6 REVIEW QUESTIONS
--------------------------------------------------------------------------------------------------------1. Discuss about the role of System Software?
2. Comment on the role of Operating System as a System Software.
3. What components are involved in determining the performance of computer
system?
4. What factors affect the performance of computer system?
5. Explain the role of classifying criteria for the Operating Systems.
6. Explain the working of Single User Operating Systems.
7. Explain the working of Multi User Operating Systems.
8. Explain the Concept of Multi Tasking
9. List some of the Technical features of Microsoft Windows NT.
68
----------------------------------------------------------------------------------------BUSINESS DATA PROCESSING
--------------------------------------------------------------------------------------------------------
Structure
4.1 Data Processing
4.1.1 Types of Data Processing
4.2 File Management System
4.2.1 File Types
4.2.2 File Organizations
4.2.3 File Utilities
4.3 Database Management System
4.3.1 Data Base
4.3.2 Purpose of Database System
4.3.3 Database Management Systems (DBMS)
4.3.4 Database Models
4.3.4.1 Hierarchical Database
4.3.4.2 Network Model
4.3.4.3 Relational Model
4.3.4.4 Object-Oriented Model
4.3.5 Main Components of a DBMS
4.3.5.1 Data Definition Language (DDL)
4.3.5.2 Data Manipulation Language (DML)
4.3.6 Creating and Using a Database
4.3.6.1 Creating a Database
4.3.6.2 Viewing, Modifying, Deleting and Adding Records
4.3.6.3 Searching For Desired Information
4.4 Review Questions
---------------------------------------------------------------------------------------------------------
4.1 DATA PROCESSING
--------------------------------------------------------------------------------------------------------Computer data processing is any computing process that converts data into information
or knowledge. The processing is usually assumed to be automated and running on a
computer. Because data’s are most useful when well-presented and actually informative,
data-processing systems are often referred to as information systems to emphasize their
practicality. Nevertheless, the terms are roughly synonymous, performing similar
conversions; data-processing systems typically manipulate raw data into information, and
likewise information systems typically take raw data as input to produce information as
output. Data can be seen as a raw material, which is later converted to information. e.g. For
a company that wants to produce Bornvita, such company will need to make use of cocoa,
which means that cocoa is the raw material for the production of Bornvita, likewise data is
69
the raw material for information. Data has to pass through a specific process before it could
be changed to information, and it is called a process.
Fig 4.1 Data Processing Chart
Data is a collection of facts - unorganized, but able to be organized into useful information.
A collection of sales orders, employee time sheets, and class attendance cards are a few
examples. Data can be manipulated to produce output, such as bills, employee salary slips,
and student attendance reports. This output, called information, is an organized fact that
helps people to make decisions. Hence, information is data arranged in an order and form
that is useful to people who receive it.
Processing, in general terms, is a series of actions or operations that converts some input
into useful output. In data processing, input is data, and useful output is information.
Hence, data processing is a series of actions or operations that converts data into
information. It consists of three sub-activities - capturing input data, manipulating it, and
producing output information. A data processing system includes resources such as
people, procedures, and devices used to process input data for producing desirable output.
4.1.1 Types of Data Processing
Basically there are two types of data processing
1. Batch Processing: With batch processing, changes and queries to file are stored for a
period of time, and then a processing run is made periodically to update the file and to
produce responses to the queries. Batch runs can be made on a scheduled basis, such as
daily, weekly, or-monthly, or they can be made on an as required basis.
Examples of batch processing include generation of mark-sheets of students. Mark-sheets
and results of school examinations are given to students only at the end of an academic
year. So, a programmer can develop a program for this and the results can he printed at the
required time.
2. Online or immediate processing: In immediate processing, transactions are processed
to update the file immediately or shortly after a real-world event occurs. Information
processing applications that use immediate processing are often called real time
application. A real time application can immediately capture data about ongoing events or
70
processes and provide the information necessary to manage them. An airline-reservation
system is an example of a real time application.
Real time systems must have real time files that are updated immediately after the event
occurs. Consequently, at any point in time, the data in real time files should accurately
reflect the status of the real world variables they represent. For example, when a customer
reserves a seat on an airline flight, the reservations agent keys in that fact and the inventory
of non reserved seats on the flight is immediately changed to reflect one less available seat.
Immediate processing requires direct-access files, since immediate processing with
sequential files would be impractical because of the time required to search for individual
records. Batch processing; on the other hand, can occur with either sequential or direct
access files.
Examples of immediate processing or interactive processing include air traffic and banking.
In air traffic, as the flying speed increases control decisions have to be taken. Hence, data is
raw material of information, and just as a manufacturing process transforms raw materials
into more quickly. Therefore, interactive processing is the only suitable system for air
traffic control. In banking, where a customer is at the counter and the time to update his
bank account will naturally take more time if done by human, so a computer can give full
updated details of the customer's account within seconds. For this, a customer' is given the
wanted information mostly by interactive processing.
---------------------------------------------------------------------------------------------------------
4.2 FILE MANAGEMENT SYSTEM
--------------------------------------------------------------------------------------------------------In file-oriented approach of organizing data, a set of programs is provided to facilitate users
to organize, create, delete, update, and manipulate their files. All these programs together
form a File Management System (FMS). Features found commonly in file management
systems are described below.
4.2.1 File Types
Data files are categorized according to the way an application uses them. A file
management system typically supports following types of files:
1. Transaction File: A transaction file stores input data until it can be processed. For
example, in a payroll application for generating monthly pay slips of employees, current
month's transaction file contains this month's data of each employee, such as details of
hours worked, normal and overtime hours, and if piecework is involved, quantity of
goods made.
2. Master File: A master file contains all current data relevant to an application. For
example, in payroll application mentioned above, master file contains permanent details
of each employee (name, address, employee-code, pay-rate, income-tax-rate, etc.), and
also current gross-pay-to-date total and tax-paid-to-date total. When payroll program is
processed, it consolidates both master and current month's transaction files to generate
this month's pay-slips, and updates master file to make it ready for following month's
processing.
71
3. Output File: Some applications use multiple programs for data processing. In such
applications, output produced by one program is fed often as input to another program.
Hence, output produced by former program is stored in a file known as output file,
which is used later by the latter' program.
4. Report File: A report file holds a copy of a report generated by a data processing
application in computer-accessible form. A report file can be printed to obtain hard
copy of the report whenever desired. It is advantageous to keep report files instead of
paper documents because files are easier to store and carry.
5. Backup File: A backup file is a copy of a file created as a safety precaution against
loss of data due to corruption or inadvertent deletion of original file. Regular creation
of backup files is extremely important.
4.2.2 File Organizations
File organization deals with physical organization of records of a file for convenience of
their storage and retrieval. System designers choose to organize, access, and process
records of various files in different ways, depending on application type and users' needs.
Three file organizations used commonly in business data processing applications are
sequential, direct/random, and indexed sequential.
Selection of a particular file organization depends on application type. The best file
organization for an application is one that meets the application's data access and
processing requirements in the most effective and economical manner. Hence, an
application designer must evaluate the strengths and weaknesses of each file organization,
before making a choice of file organization type for the application
File organization requires use of some key field in every record in a file. The key field
value must be unique for each record of the file because duplications would cause serious
problems. In payroll example, employee-code field may be used as the key field.
4.2.3 File Utilities
File utilities are routines to perform generalized operations on data files. Normally, they are
quite general in nature in the sense that they can deal with different data formats and
different types of storage medium. Operations performed by some commonly used file
utilities are described below.
Sorting: A file sorting utility is used to arrange records of a file in some defined sequence.
Values of certain specified fields (known as keys) in each record determine this sequence.
The simplest case of sorting is ordering of records in a file on a single key. For example,
records of employee file in Figure 4.2 are sequenced by ascending order of employee-code.
A more complex sorting would be ordering of records in a file on two or more keys. For
example, records of employee file in Figure 4.3 are sequenced by ascending order of
employee-code within department-code. This means that all records for the lowest
department-code are listed first for each employee belonging to that department in
ascending sequence of employee-code, then all records for next department-code, and so
on. Out of these two keys used in this sorting example, department-code is called primary
key, and employee-code is called secondary key, because order of sorting is employee-code
72
within department-code.
A sorting utility enables users to specify their sequencing requirements for a file by means
of input parameters. Input parameters such as size and number of keys, and type of
ordering (ascending, descending) vary from one sorting utility to another. These parameters
decide the extent and sophistication of sorting utilities.
Sorting utility reads un-sequenced records of an input file, and by means of various
copying techniques, ultimately produces an output file containing records of the input file
ordered in desired sequence.
Employee Code
101
123
124
176
178
202
213
Department Code
2
3
1
2
1
3
1
Other
fields
(Name,
Address,
Qualification,
Basic Salary, etc)
-----------------------------
Fig 4.2 Sorting on one key in ascending employee- code sequence
Employee Code
124
178
213
101
176
123
202
Department Code
Other fields (Name,
Address, Qualification,
Basic Salary, etc)
1
1
1
2
2
3
3
-----------------------------
Fig 4.3 Sorting on two keys: Ascending employee - code (secondary key) within
ascending department - code (primary key)
Searching: A file searching utility is used to find a particular record in a file. Searching is
carried out by matching the values of certain specified fields (known as keys) in each
record with desired values. For example, in employee file of Figure 4.2, a user can specify
value 202 for employee-code field to search corresponding employee's record.
Efficiency of a search algorithm depends on file organization. For example, to search a
particular records sequential file, records in the file are scanned sequentially, beginning
with the first record, and specified key field value is compared one-by-one with the key
field value of each record. Search process terminates when a record with matching key is
found. On the other hand, direct or index sequential file organizations enable immediate
73
access to desired record with the help of either a hashing algorithm (in case of direct file
organization) or an index file (in case of index sequential file organization). Users need to
specify a file and key field value as input parameters to a search utility, which searches
through the file and produces the desired record (s}. Normally, the time required for
searching a particular record from a direct or index sequential file is much less, than the
time required to search it from a sequential file.
Merging: A file merging utility is used to combine records of two or more ordered (sorted)
files into a single ordered file. Records of each of the input files must be sorted in same
order, although their record layout need not be identical. A merging utility places records
from each of the input files in their correct relative order, producing an output fill having
all records in same order as input files. Figure 4.4 illustrates merging of two input files A
and B to produce an output file C.
Input file
Output file
Input file
Othe
r
Employ
ee code
…
112
…
112
…
127
…
119
…
119
…
137
…
125
…
129
…
127
…
139
…
Emplo
yee
125
Other
fields
Employ
ee code
Other
fields
146
…
129
…
150
…
159
…
137
…
152
…
139
…
146
…
150
…
152
…
159
…
File A
File B
File C
Fig 4.4 Merging of files A and B to produce file C
Copying: A file copying utility is used to produce a copy of a file either from one unit of a
storage device to another similar unit (such as from one tape reel or floppy disk to another),
or from one storage medium to another (such as from tape to hard disk, or from CD-ROM
to hard disk).
File copying utilities are used often to take back-up copies of files. For example, a file may
be copied from a hard disk to a tape or floppy for back-up purpose. File copying utilities
74
are also known as peripheral interchange programs (PIP) since they are used often to
copy a file from one peripheral device to another.
Printing: A file printing utility is used to print a file on a printer to produce hard copy of
its contents. Printing utilities often provide facility to print file contents in different
formats. They often provide some selection and editing facilities to enable printing of parts
of files (such as specified number of records and only certain fields of records). Special
printing facilities are often provided to print files that contain program instructions rather
than data.
Maintenance: A file maintenance utility is used to copy data from one or more files to a
new file selectively, or to update a file's contents selectively. For example, a file
maintenance utility may provide features to combine data from more than one file into a
single file, delete records in a file identified by record key values or record count, and
select specific fields of records to be copied from an existing file to a new file.
---------------------------------------------------------------------------------------------------------
4.3 DATABASE MANAGEMENT SYSTEM
---------------------------------------------------------------------------------------------------------
4.3.1 Data Base
A database can be defined in various ways, for example
•
A database is a collection of structured data. The structure of the data is
independent of any particular application.
•
A database is a file of data; structured in such a way that it may serve a
number of applications without its structure being dictated by any one of those
applications, the concept being that programs are written round the database
rather than files being structured to meet the needs of a particular programs
The centre of any information system is its database, which is a collection of the data
resources of an organization designed to meet the requirements of the company for
processing and retrieving information by decision makers. One important use of database is
to target more precisely marketing efforts. In the USA the later trend in management
information systems is the executive information system which is used by senior managers.
A database can be termed as a repository of data. A collection of actual data which
constitutes the information regarding an organization is stored in a database. For example,
there are 1000 students in a college & we have to store their personal details, marks details
etc., these details will be recorded in a database.
75
Actual data
Storage
A collection of programs that enables you to store, modify, and extract information from a
database is known as Data Base Management System (DBMS).The primary goal of a
DBMS is to provide a way to store & retrieve database information that is both convenient
& efficient.
Database systems are designed to manage large bodies of information. Management of data
involves both defining structures for storage of information & providing way for
manipulation of data. In addition, the database system must ensure safety of data.
Good data management is an essential prerequisite to corporate success.
Data
Information
Information
Knowledge
Knowledge
Judgment
Judgment
Decision
Decision
Success
Provided that data is:
•
•
•
•
Complete;
Accurate;
Timely; and
Easily available
4.3.2 Purpose of Database system
A file system is one in which we keep the information in operating system files. Before the
evolution of DBMS, organizations used to store information in file systems. A typical file
processing system is supported by a conventional operating system. The system stores
permanent records in various files & it need application program to extract records, or to
add or delete records.
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We will compare both systems with the help of an example.
There is a saving bank enterprise that keeps information about all customers & saving
accounts. Following manipulations has to be done with the system
•
•
•
•
A program to debit or credit an account
A program to add a new account.
A program to find balance of an account.
A program to generate monthly statements.
As the need arises new applications can be added at a particular point of time as checking
accounts can be added in a saving account. Using file system for storing data has got
following disadvantages:1. Data Redundancy & Inconsistency:Different programmer’s works on a single project, so various files are created by different
programmers at some interval of time. So various files are created in different formats &
different programs are written in different programming language.
Same information is repeated. For ex name & address may appear in saving account file as
well as in checking account. This redundancy results in higher storage space & access cost.
It also leads to data inconsistency which means that if we change some record in one place
the change will not be reflected in all the places. For ex. a changed customer address may
be reflected in saving record but not any where else.
2. Difficulty in accessing data:Accessing data from a list is also a difficulty in file system. Suppose we want to see the
records of all customers who has a balance less than $10,000, we can either check the list &
find the names manually or write an application program .If we write an application
program & at some later time, we need to see the records of customer who have a balance
of less than $20,000, then again a new program has to be written.
It means that file processing system do not allow data to be accessed in a convenient
manner.
3. Data Isolation:As the data is stored in various files, & various files may be stored in different format,
writing application program to retrieve the data is difficult.
4. Integrity Problems
Sometimes, we need that data stored should satisfy certain constraints as in a bank a
minimum deposit should be of $100. Developers enforce these constraints by writing
appropriate programs but if later on some new constraint has to be added then it is difficult
to change the programs to enforce them.
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5. Atomicity Problems
Any mechanical or electrical device is subject to failure, and so is the computer system. In
this case we have to ensure that data should be restored to a consistent state. For example
an amount of $50 has to be transferred from Account A to Account B. Let the amount has
been debited from account A but have not been credited to Account B and in the mean
time, some failure occurred. So, it will lead to an inconsistent state.
So, we have to adopt a mechanism which ensures that either full transaction should be
executed or no transaction should be executed i.e. the fund transfer should be atomic.
6. Concurrent access Problems
Many systems allow multiple users to update the data simultaneously. It can also lead the
data in an inconsistent state. Suppose a bank account contains a balance of $ 500 & two
customers want to withdraw $100 & $50 simultaneously. Both the transaction reads the old
balance & withdraw from that old balance which will result in $450 & &400 which is
incorrect.
7. Security Problems
All the user of database should not be able to access all the data. For example a payroll
Personnel needs to access only that part of data which has information about various
employees & are not needed to access information about customer accounts.
Table 4.1 Comparison of File Management Systems with Database Systems
File Management
Examples:-C++, VB or COBOL
program
Small systems
Often PC based
Relatively cheap
Few 'files'
Files are files
Simple structure
Little preliminary design
Integrity left to application programmer
No security
Simple, primitive backup/recovery
Often single user
Database Management
Examples:- Postgres, Oracle
Large systems
Mini-Mainframe
Relatively Expensive
Many 'files'
Files not necessarily files
Complex structure
Vast preliminary design
Rigorous inbuilt integrity checking
Rigorous security
Complex & sophisticated
backup/recovery
Multiple users
Files tend to contain duplication. Therefore they are susceptible to a loss of INTEGRITY
if all files are not updated at the same time. Programs are bound to a file. If a files
structure is modified then all programs that access it need to be modified. Thus alterations
to file structures are difficult and expensive.
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Data base systems originated in the late 1950s and early 1960s largely by research and
development of .IBM Corporation. Most developments were responses to needs of
business, military, government and educational institutions which are complex
organizations with complex data and information needs.
4.3.3 Database Management Systems (DBMS)
This is the interface between the users (application programmers) and the database (the
data). A database is a collection of data that represents important objects in a user's
business. A database management system (DBMS) is a program that allows users to define,
manipulate, and process the data in a database in order to produce meaningful information.
DBMS is collection of programs that enables you to store, modify, and extract important
information from a database. There are many different types of DBMS, ranging from small
systems that run on personal computers to huge systems that run on mainframes.
Fig 4.5 Data Base Management System
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Following are the examples of DBMS:
•
•
•
•
Computerized library systems
Automated teller machines
Flight reservation systems
Computerized parts inventory systems
A database contains a no. of files & certain programs to access & modify these files. But
the actual data is not shown to the user; the system hides actual details of how data is stored
& maintained.
4.3.4 Database Models
We saw that multiple related files are integrated together to form a database. A database
model defines the manner in which various files of a database are linked together. Four
commonly used database models are hierarchical, network, relational, and object-oriented.
Also known as database structures or database structuring techniques, they are briefly
described below.
4.3.4.1 Hierarchical Databases
The hierarchical data model organizes data in a tree structure. There is a hierarchy of
parent and child data segments. This structure implies that a record can have repeating
information, generally in the child data segments. Data are in a series of records, which
have a set of field values attached to it. It collects all the instances of a specific record
together as a record type. These record types are the equivalent of tables in the relational
model, and with the individual records being the equivalent of rows. To create links
between these record types, the hierarchical model uses Parent Child Relationships. These
are a 1: N mapping between record types. This is done by using trees, like set theory used
in the relational model, "borrowed" from mathematics. For example, an organization might
store information about an employee, such as name, employee number, department, salary.
The organization might also store information about an employee's children, such as name
and date of birth. The employee and children data forms a hierarchy, where the employee
data represents the parent segment and the children data represents the child segment. If an
employee has three children, then there would be three child segments associated with one
employee segment. In a hierarchical database the parent-child relationship is one to many.
This restricts a child segment to having only one parent segment. Hierarchical DBMSs
were popular from the late 1960s, with the introduction of IBM's Information Management
System (IMS) DBMS, through the 1970s.
For example, in Figure 4.6 employees are categorized by their department, and within a
department, they are categorized by their job function, such as managers, engineers,
technicians, and support staff. If personnel department faces shortage of support staff on a
day, producing a list of all support staff, to take a decision to use some support staff from
other departments for this department, would not be directly possible. Instead, support
staff assigned to each department would have to be determined department-bydepartment.
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Fig.4.6. An example of a hierarchical database.
4.3.4.2 Network Model
In the network model of a database it is possible for a record to have multiple parents,
making the system more flexible compared to the strict single-parent model of the
hierarchical database. The model is made to accommodate many to many relationships,
which allows for a more realistic representation of the relationships between entities. Even
though the network database model enjoyed popularity for a short while, it never really
lifted of the ground in terms of staging a revolution. It is now rarely used because of the
availability of more competitive models that boast the higher flexibility demanded in
today’s ever advancing age. In 1971, the Conference on Data Systems Languages
(CODASYL) formally defined the network model. The basic data modeling construct in
the network model is the set construct. A set consists of an owner record type, a set name,
and a member record type. A member record type can have that role in more than one set;
hence the multi parent concept is supported. An owner record type can also be a member or
owner in another set. The data model is a simple network, and link and intersection record
types (called junction records by IDMS) may exist, as well as sets between them. Thus, the
complete network of relationships is represented by several pair wise sets; in each set some
(one) record type is owner (at the tail of the network arrow) and one or more record types
are members (at the head of the relationship arrow). Usually, a set defines a 1: M
relationship, although 1:1 is permitted. The CODASYL network model is based on
mathematical set theory.
Figure 4.8 shows an example of a network database maintaining relationships among
courses offered and students enrolled for each course in a college. Notice that parent and
child elements can have many-to-many relationships. That is, each student may be enrolled
for several courses, and each course may have a number students enrolled for it. With this
database structure used for this example, both course-wise-student report ( a report showing
all students enrolled for each course) and student-wise-course report (a report showing all
courses taken by each student) can be produced easily. For example, it is easy to tell from
the figure that in this semester, the students enrolled for Mathematics course are Seeta,
Geeta, Ram, and Sohan; and Geeta has taken three courses Hindi, Mathematics, and
Computer Science.
81
.
(a)
(b)
Fig 4.7 Hierarchical Model
The example also shows a child element that has no parent element (student named Raju he might be a research student who has not taken any course in this semester).
82
College
English
Seeta
Hindi
Geeta
Mathematic
s
Ram
Moha
n
Sohan
Computer
Science
Raju
A child element can have more than one parent element
This child element has no parent element
Fig 4.8 An example of a network database
Fig 4.9 Network Model
4.3.4.3 Relational Model
A database based on the relational model developed by E.F. Codd. A Relational database
allows the definition of data structures, storage and retrieval operations and integrity
constraints. In such a database the data and relations between them are organized in tables.
A table is a collection of records and each record in a table contains the same fields.
Relational databases (RDBMS) are entirely unique when compared to the aforementioned
models as the design of the records is organized around a set of tables (with unique
identifiers) to represent both the data and their relationships. The fields to be used for
83
matching are often indexed in order to speed up the process and the data can be retrieved
and manipulated in a number of ways without the need to reorganize the original database
tables. Working under the assumption that file systems (which often use the hierarchical or
network models) are not considered databases, the relational database model is the most
commonly used system today. While the concepts behind hierarchical and network
database models are older than that of the relational model, the latter was in fact the first
one to be formally defined.
Properties of Relational Tables:
¾ Values Are Atomic
¾ Each Row is Unique
¾ Column Values Are of the Same Kind
¾ The Sequence of Columns is Insignificant
¾ The Sequence of Rows is Insignificant
¾ Each Column Has a Unique Name
Fig 4.10 Relational Model
4.3.4.4 Object-Oriented Model
After the relational DBMS soared to popularity, the most recent development in DMBS
technology came in the form of the object-oriented database model, which offers more
flexibility than the hierarchical, network and relational models put together. Under this
84
model, data exists in the form of objects, which include both the data and the data’s
behavior. Certain modern information systems contain such convoluted combinations of
information that traditional data models (including the RDBMS) remain too restrictive to
adequately model this complex data. The object-oriented model also exhibits better
cohesion and coupling than prior models, resulting in a database which is not only more
flexible and more manageable but also the most able when it comes to modeling real-life
processes. A major benefit of this approach is the unification of the application and
database development into a seamless data model and language environment. As a result,
applications require less code, use more natural data modeling, and code bases are easier to
maintain. Object developers can write complete database applications with a modest
amount of additional effort.
However, due to the immaturity of this model, certain problems are bound to arise, some
major ones being the lack of an SQL equivalent as well as lack of standardization.
Furthermore, the most common use of the object oriented model is to have an object point
to the child or parent OID (object I.D.) to be retrieved; leaving many programmers with the
impression that the object oriented model is simply a reincarnation of the network model at
best. That is, however, an attempt at the over-simplification of an innovative technology.
In contrast to a relational DBMS where a complex data structure must be flattened out to fit
into tables or joined together from those tables to form the in-memory structure, object
DBMSs have no performance overhead to store or retrieve a web or hierarchy of
interrelated objects. This one-to-one mapping of object programming language objects to
database objects has two benefits over other storage approaches: it provides higher
performance management of objects, and it enables better management of the complex
interrelationships between objects. This makes object DBMSs better suited to support
applications such as financial portfolio risk analysis systems, telecommunications service
applications, World Wide Web document structures, design and manufacturing systems,
and hospital patient record systems, which have complex relationships between data.
These applications include computer aided design (CAD), computer-aided engineering
(CAE), computer-aided manufacturing (CAM), computer-aided software engineering
(CASE), expert systems, and multimedia systems. Some key features required for effective
modeling of these applications, that are absent in conventional database models, are:
1. Ability to model complex nested entities, such as design and engineering objects, and
multimedia documents. Conventional database models do not provide mechanisms, such as
configuration management, to represent and manage such entities.
2. Support for general data types found in object-oriented programming languages.
Database management systems based on conventional database models support only a
limited set of atomic data types, such as integer, string, etc. They do not even allow storage
and retrieval of long unstructured data, such as images, audio, and textual documents.
3. Support for proper match between object-oriented programming languages and database
languages. A database application is normally implemented by using some conventional
programming language (such as COBOL, PASCAL, C, or C++), and some database
85
languages (data definition language, data manipulation language, query language) that are
part of database management system. With popularity of object-oriented paradigm, use of
object-oriented programming languages for implementing applications has become a
common practice. However, database languages used in database management systems for
conventional database models do not use object-oriented concepts for implementing
applications. This mismatch between object-oriented programming languages and database
languages used in database management systems for conventional database models makes
database implementation of many applications inconvenient.
Object-oriented database model was introduced to overcome these shortcomings of
conventional database models. An object-oriented database is a collection of objects
whose behavior, state, and relationships are defined in accordance with object-oriented
concepts (such as object, class, class hierarchy, etc.). An object-oriented database
management system allows definition and manipulation of an object-oriented database.
Figure 4.11 shows an example of an object-oriented database structure. Class Vehicle is
root of a class composition hierarchy including classes Vehiclespecs, Company, and
Employee. Class Vehicle is also root of a class hierarchy involving classes Two Wheeler
and Four Wheeler. Class Company is, in turn, root of a class hierarchy with subclasses
Domestic Company and Foreign Company. It is also root of a class-composition hierarchy
involving class Employee.
Fig 4.11 An example of an object-oriented database structure
86
Class/subclass link
Attribute/domain link
--------------------------------------------------------------------------------------------------------TW
Two Wheeler
FW
Four Wheeler
DC
Domestic Company
FC
Foreign Company
Com
Company
Emp
Employee
---------------------------------------------------------------------------------------------------------
4.3.5 Main Components of a DBMS
A DBMS allows users to organize, process, and retrieve selected data from a database,
without any need to know about underlying database structure (organization and location of
data). Four major components of a DBMS are:
1. Data Definition Language (DDL)
2. Data Manipulation Language (DML)
3. Query Language
4. Report Generator
These are described below.
4.3.5.1 Data Definition Language (DDL)
Data definition language (DDL) is used to define the structure of a database. Database
structure definition (also known as database schema) typically includes the following:
1. Definition of all data elements to be included in the database.
2. Organization of data elements (fields) into records (or tuples), tables, etc.
3. Definition of field name, field length, and field type for each data element. Field
name is used to refer to a data element while accessing it. Field length is used to
define maximum size of a data element (such as employee-name field may have a
maximum size of 30 characters). Common field types are:
•
Numeric: Can contain numbers formed with digits 0 to 9, a decimal point, and a +
or – sign
•
Alphanumeric: Can contain a combination of alphabetic characters, special
symbols, and digits
•
Logical: Can contain one of two possible values - Yes/No or True/False
•
Date/time: Can contain a single date, time, or date-time value
•
Memo: Can contain any type of data that user might like to type Binary: Can
contain binary data
4. Definition of controls for fields that can have selective values only. For example, in
an employee database, sex field can have controls to accept values M or F only.
Similarly, age field can have controls to accept values 18 or more and less than 70
only. Such controls ensure correctness of entered data to some extent.
5. Definition of access controls to various tables, records, and fields for different
87
categories of users to protect sensitive data items from unauthorized users.
6. Definition of logical relationships among various data elements of database.
In short, virtually everything about a database structure is included in its schema. It is
possible to generate a complete description of a database from its schema. Systems analysts
use this description for defining new applications on the database
Database systems are installed and coordinated normally by individuals called database
administrators. They are responsible for following aspects of database administration
1. Establish and control data definitions and standards.
2. Determine relationships among data elements.
3. Design database security system to guard against unauthorized use of data in the
database.
4. Train and assist applications programmers in use of database.
A data dictionary is developed and used in a database to document and maintain data
definitions. It is created/updated automatically by DDL module of DBMS as database
schema is defined / changed.
4.3.5.2 Data Manipulation Language (DML)
Once structure of a database (database schema) has been defined, it is ready for entry and
manipulation of data. Data manipulation language (DML) includes commands to enable
users to enter and manipulate data. With these commands, users can add new records to
database, navigate through existing records, view contents of various fields of a record,
modify contents of one or more fields of a record, delete an existing record, and sort
records in desired sequence.
In some DBMS, data definition language and data manipulation language are combined
together, while in others, they are supported as separate DBMS components.
Query Language
Although it is possible to navigate through a database one record at a time to extract
desired information from the database, this approach can be very inefficient and frustrating
when there are thousands of records and several files in the database. Hence, all database
management systems provide a query language enabling users to define their requirements
as queries for extracting desired information from a database. For example, for an
inventory database, a user may be interested in such information as "list item description
and vendor name for all items whose current inventory level is less than 20 units", or "list
stock number and item description for all items with a profit margin greater than 25%". A
query language enables proper formulation of queries for extraction of such information
from a database.
Earlier, each database management system had its own query language. In this approach,
queries developed for one DBMS could not be used with other DBMSs. However,
eventually one query language, called SQL (pronounced "S-Q-L"), emerged as an industry
standard. It was originally developed by IBM and was based on an earlier query language
called SEQUEL, an acronym for "Structured English QUEry Language". Today, SQL is
88
the standard Structured Query Language used in many DBMSs.
A query language can be easily learnt by a non-programmer. This enables normal users of a
database to obtain desired information from the database without the help of any
programmer
Report Generator
A report is presentation of information extracted from a database. Report generators
enable users of a database to design the layout of a report in desired format. This means
that that users can specify proper spacing between data items to be presented in a report,
and can also include suitable report titles and subtitles, column heading, page numbers,
separation lines, and other elements making a report more readable and presentable. Report
generators can also be instructed to perform arithmetic operations (such as calculating
subtotals and totals) on data found in numeric fields to make a report more meaningful and
useful.
4.3.6 Creating and Using a Database
In this section, we will take a closer look at how a database is created and used. Large
databases on large computer systems are created and maintained normally by professional
programmers. Users of these databases, however, need not be programmers. They can be
used easily by non-programmers to access data and produce reports. On the other hand,
many database management systems, designed for personal computer systems, enable
nonprogrammers to not only use, but even tolerate their own databases. These databases
normally are simple in structure and small in size.
4.3.6.1 Creating a Database
Creation of a database is a three steps process:
1. Defining its structure (schema)
2. Designing forms (custom screens) for displaying and entering data
3. Entering data into it
These steps are described below
Schema Definition
First thing we do to set up a database is to define its structure (schema definition). This is
done by identifying characteristics of each field in it. A good way to begin defining schema
of a database is to list down on paper all fields to be included in the database, and then to
determine the name, type, and size of each field. This information is then captured into the
system by using a tool called schema builder. Schema builder enables a user to define a
database schema interactively by prompting the user to enter name, type, size, etc. for each
field.
While defining the schema of a database, it is important to consider possible future needs
and needs of all types of users of the database. That is, all possible fields that may be
needed should be included in database structure while defining it. Although it is possible to
modify database structure at any time, making such modifications is a time-consuming
process. Hence, it is always better to carefully design a database in first instance, and
minimize need to modify its structure later.
89
EMPLOYEE DATABASE DATA ENTRY FORM
EMPLOYEE
ID:
856392
EMPLOYEE NAME:
SEX:
M
LAST NAME:
FIRST NAME:
MIDDLE NAME:
CONTACT ADDRESS:
ADDRESS1:
ADDRESS2:
CITY:
STATE:
POSTAL CODE:
-
TELEPHONE
NO.:
AGE:
48
SINHA
PUNIT
KUMAR
F/8, ANAND PARK
SOCIETY, AUNDH
PUNE
MH
411007
(020) 5680-4892
ANY OTHER INFORMATION:
IS FLUENT IN JAPANESE LANGUAGE
Fig 4.12 A typical database form used for data entry
90
Designing Forms
After defining the structure of a database, next step is to design forms (custom screens) for
convenient data entry. Each form displays a set of fields of database structure with
appropriate amount of blank spaces against each to enable data entry in those fields. Figure
4.12 shows such a form.
To facilitate easier data entry, often forms are designed with several fancy features, such
as:
l. A list-box for a field listing the options from which users can select a choice. For
example, in Figure 4.10, SEX field may have a list-box listing options "Male" and
"Female," and users simply select appropriate option for an employee. Depending on a
user's selected option, system enters "M" or "F" automatically in SEX field. Similarly,
STATE field may have a list-box listing all states, from which users can select appropriate
option for an employee's address.
2. Simple validation checks defined for a field to ensure correctness of entered data to some
extent. For example, in Figure 4.10, a validation check may be defined for POSTAL CODE
field to accept only six numeric characters. With this, the field will not accept less than or
more than six characters, and will also not accept alphabetic or special characters.
Similarly, a validation check may be defined for AGE field-to accept values in the range 18
to 70 only (both inclusive). Validation checks can be used also to force a certain character
position of a field to be a letter or numeral.
3. Automatic conversion of typed characters to upper-or lower-case. For example, in Figure
4.10, this feature may be used with STATE field. Hence, the system will accept
"mh","Mh";"mH" or "MH'; for state code of Maharashtra, and will convert the entry to
"MH" automatically. This feature greatly eases data entry and ensures uniformity of data.
4. Automatic formatting of certain fields. For example, in Figure 4.10, this feature can be
used with TELEPHONE NO field to display the value of this field automatically in
specified format (with parentheses, space, and hyphen). That is, to enter telephone number
"(020) 5680-4892", user only needs to type "02056804892", and the system displays "(020)
5680-4892" in that field automatically.
Entering Data
After forms have been designed, the database is ready for entry of data. Data is entered one
record at a time. To enter data, a user issues a command that calls up and displays
appropriate form with blank fields. The user then keys in data for each field in appropriate
spaces. In this manner, the user enters data for first record, then for second record, and so
on. In most database systems, records are assigned a number automatically as they are
entered.
While entering data into fields, the Tab or Enter key is used usually to move to next field.
Pressing Enter or Tab key in last field of the form saves the record in database and moves
to a new, blank form for next record's data entry. In addition to using the Tab or Enter key
91
to move forward through fields one can call directly go to any field on the form by c1icking
on it with mouse.
4.3.6.2 Viewing, Modifying, Deleting and Adding Records
All database systems provide commands to add, delete, view, or modify records of a
database. Command for viewing a record only enables users to display data in various
fields of a record in same screen format as that used for data entry. Users can specify a
record to be displayed by specifying its key field value. Database systems usually also
provide flexibility to users to move between records for viewing different records, such as
"go to first record", "go to previous record", "go to next record", and "go to last record".
Many database systems also provide facility to set up filters, which allow users to browse
through and view those records only that meet some criterion. For example, in employee
database created by using the form of Figure 4.10 if a user wants to view records of female
employees only, the user can set a filter for "Sex" field, and only records containing "F" in
that field will be displayed. Note that while a filter is set, the user cannot access records
that do not meet the filter criteria. Filters provide a quick and convenient way to narrow
down the number of records with which users have to work.
Command for modifying a record enables users to not only view, but also update data in
various fields of a record. To modify contents of a particular field of a record, the record is
displayed first, then cursor is positioned in the field at appropriate character position
where change is to be made by clicking mouse there, and then contents of the field is
edited appropriately. Data in any other field of the record can be edited similarly. Finally,
Enter key has to be pressed for changes to take effect. Some database systems may prompt
the user to confirm the changes made, before effecting the changes and allowing the user
to move to another record.
Command for deleting a record enables users to remove records from a database. To delete
a record, a user first selects the record, either by specifying its key field value, or by using
the facility to move between records just as is done in case of viewing a record. The user
then uses delete command, to delete the record. Most database systems prompt the user to
confirm deletion of the selected record before deleting it. This feature prevents deletion of a
record by mistake.
Command for adding a record enables users to add new records to a database. When this
command is enabled, the system displays a blank form and waits for a user to enter data.
The user then keys in data for each field in appropriate spaces, and finally presses Enter or
Tab key, after keying data in last field to save the record. On doing this, the system
displays a new blank form for next record's data entry. If no more records are to be added,
the user uses mouse to select the option to terminate the process for adding new records.
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4.3.6.3 Searching for Desired Information
A database management system enables its users to quickly search for desired information
from large volume of data stored in a database with great ease. Features supported
commonly in modem database systems for this are:
1. Find command
2. Query language
3. Query by Example (QBE)
These features are described below.
Find Command
Find command is used for simple database queries, like searching for records having a
particular string pattern in a field. For example, in employee database created by using the
form .of figure 4.10, Find command may be used to list records of all employees whose last
name is "SINHA". Similarly, it may be used to list records of all employees who belong to
the city of "PUNE".
To use Find, a user has to type the string pattern to be searched and then has to indicate
which field to search in. For instance, in the example above, user has to type "SINHA" and
indicate that this string has to be searched in the "LAST NAME" field. User can specify
either a single field or all fields.
Find command cannot be used for creating an elaborate set of criteria for complex queries.
Furthermore, it can operate only on one table at a time, and a user cannot save a specified
criterion for future use.
Query Language
For handling complex queries, all database systems support a query language. Most of
these query languages conform to the SQL standard. In SQL, a user has to specify criteria
for search along with the fields and table (or tables) with which to work with. Criteria for
search can be built by using relational operators (= [equal to], > [greater than], < [less
than], and combinations of these operators), and logical operators (AND, OR, and NOT).
For example, to list names of all employees whose last name starts with letter "S", who
belong to "PUNE", and whose age is more than 40 years, SQL query looks as follows:
SELECT [LAST NAME], [FIRST NAME], [MIDDLE NAME]
FROM Employee
WHERE ([LAST NAME] = "S...”) AND (CITY = "PUNE") AND ([AGE> 40))
Keywords SELECT, FROM, and WHERE tell SQL engine how to interpret each part of
the query statement. SELECT keyword tells SQL which fields are to be displayed for
records that match the criteria. FROM keyword tells SQL which table(s) to work with.
WHERE keyword tells SQL the criteria for selecting records (search criteria). Brackets [...]
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around some field names are needed in the example above because these field names
contain spaces, and brackets help the database to interpret each field name correctly.
A query language can be learnt and used easily even by a non-programmer, because
complexity of a query language statement is more or less of same order as given in the SQL
statement above. Furthermore, a query language uses a few keywords only that are easy to
remember and use. In fact, SQL has a few dozen or so basic keywords only.
Other advantages of using a query language are that a query statement can be used for
creating an elaborate set of criteria for complex queries, it can operate on multiple tables at
a time, and specified criteria can be saved for future use.
Query By Example (QBE)
Although query languages are easy to learn and use, many database developers further
simplify the job of specifying search criteria. For this, they provide a simpler user interface
(called front end) to query language. A database user specifies facts about a query by using
this interface and a query language builder composes query language statements
automatically from the facts. Front end usually consists of a form (called QBE form), and a
user specifies a search criteria simply by inputting values into the fields of this form. Again
values may be input either by typing them or by selecting an option from a set of options
provided for a particular field, depending on how the front end has been designed to work.
QBE form is designed to collect all necessary information from a user for composing query
language statement(s) for search criteria. Once the user completes the QBE form, QBE
engine converts user inputs automatically into suitable query language statement(s) for
search processing. Hence, the user is relieved of remembering query language keywords
and using them with correct syntax to. Form queries. This front-end feature is called query
by example (QBE). It is very useful for many database users, especially beginners.
Creating Reports
Users of a database system can use report generator to assemble output of a database query
in desired format. For this, a user creates a report specifying the layout of display (or
printout) of fields requested by the user in the query. Users can also specify titles and
subtitles for a report, column headings for various fields, and other elements, to make the
output appear more presentable. Furthermore, users can even specify sorting parameters to
obtain sorted output with respect to one or more fields in the output. When sorting is on
more than one field, a user has to specify the primary, secondary, and tertiary key fields. A
user can save a created report and use it later for generating similar reports whenever
required.
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4.4 REVIEW QUESTIONS
--------------------------------------------------------------------------------------------------------1. Differentiate between various data processing systems?
2. What is a file management system?
3. Write a short notes on:
a) Hierarchical database mode;
b) lNetwork database model;
c) Object-oriented database model.
4. What is query by example (QBE)? How does it make the job of querying a database
simpler?
5. What is SQL? How it is useful?
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DATA COMMUNICATIONS
---------------------------------------------------------------------------------------------------------
Structure
5.1 Introduction
5.2 Basic Elements of a Communication System
5.2.1 Data Transmission Modes
5.2.2 Transmission Basics
5.3 Types of Data Transmission Media
5.3.1 Bounded Media
5.3.2 Unbounded Media
5.4 Modulation Techniques
5.4.1 Modems
5.4.2 Analog versus Digital Transmission
5.5 Multiplexing
5.5.1 Time Division Multiplexing (TDM)
5.5.2 Frequency Division Multiplexing (FDM)
6.6 Review Questions
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5.1 INTRODUCTION
--------------------------------------------------------------------------------------------------------The term Communication has a history as old as the existence of life on earth. The
telegraph revolutionized long-distance communications almost everywhere, reducing the
time taken to communicate across a country from days to hours or minutes, or from months
to days between continents. The early telegraph was a very simple device; it used a direct
current cell to operate an electromagnet.
At the time of the invention of the telephone, most effort was directed towards the
development of a 'multiple' telegraph: one that could signal more than one code at a time.
Despite digital communication getting a head start, voice telephony rapidly came to
dominate the wide-are a communications arena. It is only the last few decades that have
seen the development of wide-area networks exclusively for data, and only in the last few
years that this technology, in the form of ISDN, has become available to home subscribers.
Until very recently, if one wished to communicate between a home computer and a remote
site, one had no choice but to use a modem to convert the computer signals into a form
suitable for a voice communications medium.
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Frequently, however, data must be sent beyond the local circuitry that constitutes a
computer. In many cases, the distances involved may be enormous. Unfortunately, as the
distance between the source of a message and its destination increases, accurate
transmission becomes increasingly difficult. This results from the electrical distortion of
signals traveling through long conductors, and from noise added to the signal as it
propagates through a transmission medium. Although some precautions must be taken for
data exchange within a computer, the biggest problems occur when data is transferred to
devices outside the computer's circuitry. In this case, distortion and noise can become so
severe that information is lost.
Data Communications concerns the transmission of digital messages to devices external to
the message source. "External" devices are generally thought of as being independently
powered circuitry that exists beyond the chassis of a computer or other digital message
source. As a rule, the maximum permissible transmission rate of a message is directly
proportional to signal power and inversely proportional to channel noise. It is the aim of
any communications system to provide the highest possible transmission rate at the lowest
possible power and with the least possible noise.
---------------------------------------------------------------------------------------------------------
5.2 BASIC ELEMENTS OF A COMMUNICATION SYSTEM
--------------------------------------------------------------------------------------------------------Communication is the process of transferring messages and data from one point to another.
The three basic elements of any communication process are:
1) A sender (source) which creates the message to be transmitted.
2) A medium which carries the message.
3) A receiver (Sink) which receives the message.
For example when we speak to our friend over telephone we are sender, the telephone line
through which our voice is transmitted is a medium and our friend is a receiver. This is a
simple example of voice communication. The same concept holds for the data
communication also.
Medium
Sender
(Source)
Receiver
(Sink)
Fig 5.1 Basic Elements of a Communication System
5.2.1 Data Transmission Modes
Data transmission, whether analog or digital, may also be characterized by the direction in
which the signals travel over the media.
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Fig 5.2 Means of communication
1. Simplex:
In cases where signals may travel in only one direction, the transmission is considered
simplex.
For example,
A football coach calling out orders to his team through a megaphone is using simplex
communication. In this example, the coach’s voice is the signal, and it travels in only one
direction—away from the megaphone’s mouthpiece and toward the team. Simplex is
sometimes called one-way, or unidirectional, communication.
2. Half Duplex
In half-duplex transmission signals may travel in both directions over a medium but in only
one direction at a time. Half-duplex systems contain only one channel for communication,
and that channel must be shared for multiple nodes to exchange information. For example,
an apartment’s intercom system that requires you to press a “talk” button in order to allow
your voice to be transmitted over the wire uses half-duplex transmission. If you visit a
friend’s apartment building, you press the “talk” button to send your voice signals to their
apartment. When your friend responds, he presses the “talk” button in his apartment to send
his voice signal in the opposite direction over the wire to the speaker in the lobby where
you wait. If you press the “talk” button while he’s talking, you will not be able to hear his
voice transmission. In a similar manner, some networks operate with only half-duplex
capability over their wires.
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3. Full-Duplex
When signals are free to travel in both directions over a medium simultaneously, the
transmission is considered full duplex. Full duplex may also be called bi-directional
transmission or sometimes, simply duplex. When you call a friend on the telephone, your
connection is an example of a full-duplex transmission, because your voice signals can be
transmitted to your friend at the same time your friend’s voice signals are transmitted in the
opposite direction to you. In other words, both of you can talk and hear each other
simultaneously.
Full-duplex transmission is also used on data networks. For example, modern Ethernet
networks use full-duplex. In this situation, full-duplex transmission uses multiple channels
on the same medium. A channel is a distinct communication path between two or more
nodes, much as a lane is a distinct transportation path on a freeway. Channels may be
separated either logically or physically.
An example of physically separate channels occurs when one wire within a network cable
is be used for transmission while another wire is used for reception. In this example, while
each separate wire in the medium allows half-duplex transmission, when combined in a
cable they form a medium that provides full-duplex transmission. Full-duplex capability
increases the speed with which data can travel over a network. In some cases—for
example, telephone service over the Internet—full-duplex data networks are a requirement.
Many network devices, such as modems and NICs, allow you to specify whether the device
should use half- or full-duplex communication. It’s important to know what type of
transmission a network supports before installing network devices on that network. If you
configure a computer’s NIC to use full duplex while the rest of the network is using halfduplex,
For example, computer will not be able to communicate on the network.
Fig 5.3 Modes of Data Transmission
5.2.2 Transmission Basics
In data networking, the term transmission has two meanings. First, it can refer to the
process of issuing data signals on a medium. It can also refer to the progress of data signals
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over a medium from one point to another. Long ago, people transmitted information across
distances via smoke or fire signals. Needless to say, many different types of data
transmission have evolved since that time. The transmission techniques in use on today’s
networks are complex and varied.
Analog and Digital Signaling
One important characteristic of data transmission is the type of signaling involved. On a
data network, information can be transmitted via one of two signaling methods:
i.
ii.
Analog
Digital
Both types of signals are generated by electrical current, the pressure of which is measured
in volts. The strength of an electrical signal is directly proportional to its voltage. Thus,
when network engineers talk about the strength of an analog or digital signal, they often
refer to the signal’s voltage. The essential difference between analog and digital signals is
the way voltage creates and sustains the signal.
1. Analog Signaling
In analog signals, voltage varies continuously. In digital signals, voltage turns off and on
repeatedly, pulsing from zero voltage to a specific positive voltage. An analog signal’s
voltage appears as a continuous wave when graphed over time, because voltage is varied
and imprecise in analog signals, analog transmission is more susceptible to transmission
flaws such as noise than digital signals. To understand this concept, think of two tin cans
connected by a wire. When you speak into one of the tin cans, you produce analog sound
waves that vibrate over the wire until they reach the tin can at the other end. These sound
waves are merely approximations of your voice, and they are significantly affected by the
quality of the wire.
For example,
If you try the tin can experiment with a pure copper wire, your voice will arrive at the other
end sounding clearer than if you used fishing line, because copper conducts sound better
than plastic. Regardless of which medium you use, however, the sound waves will become
distorted as they traverse the wire, arriving at the second tin can at least a little muddled.
This vulnerability makes analog transmission less precise than digital transmission.
2. Digital Signaling
Unlike analog signals where there is a smooth curve, digital signals jump directly to the
next value.
For example,
If the voltage changed from -5 V to 0 V, it would change instantly, not drop off with a
curve. When digital signals can exist in only one of two values, they go directly to the next
value, typically changing between 0 and 1. The jump from one value to another is known
as a transition. In digital signaling, transitions give a notched appearance to the graph.
Digital signals are synchronized in bits which can be clocked by either sending a separate
clocking scheme across the network with the bits, or by using a guaranteed state-change
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clocking scheme. Data rate is measured in bits per second (bps). Also known as hertz or
baud, this rate is sometimes called baud rate. Encoding data in a digital signal can be
done using several encoding types. The different encoding types can be described as either
state-transition encoding or current-state encoding. State-transition encoding uses a change
(or lack of a change) in a signal to represent a data value. One way this is done is to let a
change in voltage represent a 1. Whenever the voltage changes this is translated to a 1; if
the voltage remains the same, the value is a 0. State-transition could also allow that a
change in voltage represents a specific value. When the voltages changes from high to low
this represents a 1, while a change from low to high represents a 0.
Fig 5.4 Analog Signal
Fig 5.5 Digital Signal
Data rate: This is the rate, in bits per second (bps), at which data can be communicated.
Bandwidth: This is the maximum bandwidth of the transmitted signal as constrained by
the nature of the transmission medium or transmission channel, expressed in cycles per
second, or hertz (Hz).
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Noise: The average level of noise over the communications path.
Error rate: The rate at which errors occur, where an error is the reception of a 1 when a 0
was transmitted or the reception of a 0 when a 1 was transmitted.
The problem we are addressing is this communications facilities are expensive, and, in
general, the greater the bandwidth of the transmission facility, the greater the cost.
Furthermore, all transmission channels of any practical interest are of limited bandwidth.
The limitations arise from the physical properties of the transmission medium or from
deliberate limitations at the transmitter on the bandwidth to prevent interference from other
sources. Accordingly, we would like to make as efficient use as possible of a given
bandwidth. For digital data, this means that we would like to get as high a data rate as
possible at a particular limit of error rate for a given bandwidth. The main constraint on
achieving this efficiency is noise.
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5.3 TYPES OF DATA TRANSMISSION MEDIA
-----------------------------------------------------------------------------------------Data Transmission Media is divided into two types
1) Bounded Media
2) Unbounded Media
5.3.1 Bounded Media
It is also known as guided media. Bounded transmission media constrain and guide
communication signals. These are made up of a central conductor (usually copper)
surrounded by a jacket material. Bounded media are great for LANs because they offer
high speed, good security, and low cost. However, sometimes they cannot be used due to
distance limitations.
Cables differ by their properties. Depending on your needs, you may opt for one cable type
over another because it has some characteristics that are more important to you.
For example, coaxial cable is fairly resistant to outside interference but cannot be used for
some high-speed LANs. Some of the characteristics you will look at for each cable type
include the following:
Cost: Cost can be an important consideration when deciding on a network cable. Only a
few years ago, fiber-optic cable was extremely expensive, and almost no one could justify
the cost to use it.
Installation: Using the example above, one reason fiber-optic cable was so expensive was
due to the installation. Only highly skilled technicians were capable of installing this cable
correctly. Obviously the best situation is having someone on staff that can install the cable.
If you need to get an outside contractor, the installation cost may outweigh the actual cable
cost.
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Capacity: So you have gotten past the cost and installation issues, and now the question is,
“How fast will it go?” Normally, cable speed is referred to as bandwidth and is an
important characteristic of a media type. Bandwidth is usually measured in bits per
second. For example, standard Ethernet cable is usually up to 10 Mbps, which is 10 mega
bits per second (note the small b for bits, not B for Bytes).
Attenuation (Maximum Distance): Depending on what you need to network together, the
maximum cable distance may also be another consideration.
Immunity to Interference: The last property is how well the cable holds up against
interference, normally electromagnetic interference, or EMI. EMI could play a big part in
which cable type you use, depending on the location. Suppose you needed to run a network
into a manufacturing facility with a lot of heavy machinery that used electrical motors. An
unshielded type of cable may not be the best choice in that situation.
Three common types of bounded media are in use out in the world they are
a) Coaxial
b) Twisted pair
c) Fiber optic
a) Coaxial Cable
Coaxial cable, called “coax” for short, was the foundation for Ethernet networks in the
1980s and remained a popular transmission medium for many years. Over time, however,
twisted-pair cabling has replaced coax in most modern LANs. Coaxial cable consists of a
central copper core surrounded by an insulator, a braided metal shielding, called braiding,
and an outer cover, and called the sheath or jacket. The copper core carries the
electromagnetic signal, and the braided metal shielding acts as both a shield against noise
and a ground for the signal. The insulator layer usually consists of a plastic material such as
polyvinyl chloride (PVC) or Teflon. It protects the copper core from the metal shielding,
because if the two made contact, the wire would short-circuit. The jacket, which protects
the cable from physical damage, may be PVC or a more expensive, fire-resistant plastic
Because of its insulation and protective braiding, coaxial cable has a high resistance to
interference from noise. It can also carry signals farther than twisted-pair cabling before
amplification of the signals becomes necessary, although not as far as fiber-optic cabling.
On the other hand, coaxial cable is more expensive than twisted-pair cable because it
requires significantly more raw materials (such as copper for the core, Teflon for the
insulation, and so on) to manufacture. Coaxial cable is also less desirable than twisted-pair
because it supports lower throughput.
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Fig 5.6 Coaxial Cable
b) Twisted-Pair Cable
The most popular network cabling right now is twisted pair. It is lightweight, easy to
install, inexpensive, and supports many different types of networks. It can also supports
speeds of up to 100Mbps.
Twisted-pair cabling is made up of pairs of solid or stranded copper twisted around each
other. The twists are done to reduce the vulnerability to EMI and cross talk. The number of
pairs in the cable depends on the type. The copper core of the cable is usually 22-AWG or
24-AWG, as measured on the American Wire Gauge standard.
Twisted-pair (TP) cable is similar to telephone wiring and consists of color-coded pairs of
insulated copper wires, each with a diameter of 0.4 to 0.8 mm, or 22-24 AWG (American
Wire Gauge) standard copper wires. The wires are twisted around each other to form pairs
and all the pairs are encased in a plastic sheath, The twists in the wire help to reduce the
effects of crosstalk. Crosstalk, which is measured in decibels (dB), occurs when signals
traveling on nearby wire pairs infringe on another pair’s signal. If you envision the wire
pairs in a single cable as couples in an elevator, you can imagine how one couple speaking
very loudly might impair the other couple’s ability to converse. Because they are twisted
around each other, the release of current from one wire cancels out the release of current
from the adjacent wire. Another form of crosstalk, called alien crosstalk, can occur when
signals from an adjacent cable (as opposed to adjacent wires) interfere with another cable’s
transmission. Alien crosstalk becomes a real threat when network administrators bundle
more cables into smaller conduits.
Fig 5.7 Twisted-pair cable
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The more twists per inch in a pair of wires, the more resistant the pair will be to all forms
of noise. Higher-quality, more expensive twisted-pair cable contains more twists per foot.
The number of twists per meter or foot is known as the twist ratio. Because twisting the
wire pairs more tightly requires more cable, however, a high twist ratio can result in greater
attenuation. For optimal performance, cable manufacturers must strike a balance between
crosstalk and attenuation reduction. Because twisted-pair is used in such a wide variety of
environments and for a variety of purposes, it comes in hundreds of different designs.
iii. Fiber-Optic Cable
Fiber-optic cable, or simply fiber, contains one or several glass fibers at its center, or core.
Data are transmitted via pulsing light sent from a laser or light-emitting diode (LED)
through the central fibers. Surrounding the fibers is a layer of glass called cladding. The
cladding glass is a different density from the glass in the strands. It acts as a mirror,
reflecting light back to the core in patterns that vary depending on the transmission mode.
This reflection allows the fiber to bend around corners without diminishing the integrity of
the light-based signal. Outside the cladding, a plastic buffer protects the glass cladding and
core. Since it is opaque, it also absorbs any light that might escape. To prevent the cable
from stretching, and to further protect the inner core, strands of Kevlar (an advanced
polymeric fiber) surround the plastic buffer. Finally, plastic sheath covers the strands of
Kevlar.
Fig 5.8 A fiber-optic cable
Like twisted-pair cable, fiber comes in a number of different types. Fiber cable variations
fall into two categories: single-mode and multimode. Single-mode fiber uses a narrow core
(less than 10 microns in diameter) through which light generated by a laser travels over one
path, reflecting very little. Because it reflects little, the light does not disperse as the signal
travels along the fiber. This continuity allows single mode fiber to accommodate high
bandwidths and long distances (without requiring repeaters).
Single-mode fiber may be used to connect a carrier’s two facilities. However, it costs too
much to be considered for use on typical data networks. Multimode fiber contains a core
with a larger diameter than single mode fiber (between 50 and 100 microns in diameter)
over which many pulses of light generated by a light emitting diode (LED) travel at
different angles. Because light is being reflected many different ways in a multimode fiber
cable, the waves become less easily distinguishable the longer they travel. Thus, multimode
fiber is best suited for shorter distances than single-mode fiber. It is commonly found on
cables that connect a router to a switch or a server on the backbone of a network. Because
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of its reliability, fiber is currently used primarily as a cable that connects the many
segments of a network. Experts predict, however, that it will replace UTP as the primary
means of bringing data to the desktop within the next decade. Fiber-optic cable provides
the benefits of nearly unlimited throughput, very high resistance to noise, and excellent
security. Because fiber does not conduct electricity like copper wire, it does not emit a
current. As a result, the signals it carries stay within the fiber and cannot easily be picked
up except at the destination node. Copper, on the other hand, generates signal that can be
monitored by taps into the network. Fiber can also carry signals for longer distances than
can coax or twisted-pair cable. In addition, you can use longer lengths of fiber with fewer
repeaters than on a copper-based network. Finally, fiber is widely accepted by the highspeed networking industry. Thus, industry groups are establishing standards to ensure that
fiber-networking equipment from multiple manufacturers can be integrated without
difficulty.
Fig 5.9 Single-mode and multimode fiber-optic cables
The most significant drawback to the use of fiber is its high cost. Another disadvantage is
that fiber can transmit data in only one direction at a time; to overcome this drawback, each
cable must contain two strands—one to send data and one to receive it. Finally, unlike
copper wiring, fiber is difficult to splice, which means quickly repairing a cable in the field
(given little time or resources) is difficult if not impossible.
5.3.2 Unbounded Media
Unbounded, or wireless, media does not use any physical connectors between the two
devices communicating. Usually the transmission is sent through the atmosphere, but
sometimes it can be just across a room. Wireless media is used when a physical obstruction
or distance blocks the use of normal cable media. Following are the types of unbounded
media:
1. Radio Waves
i. Short-wave
ii. Very-high frequency (VHF) television and radio
iii. Ultra-high frequency (UHF) television and radio Micro waves
2. Microwaves
i. Terrestrial Microwaves
ii. Satellite Microwaves
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3. Infrared
i. Point-to-point
ii. Broadcast
1. Radio Waves
Radio waves have frequencies between 10 KHz and 1GHz. Radio waves include the
following types:
i.Short-wave
ii.Very-high frequency (VHF) television and radio
iii.Ultra-high frequency (UHF) television and radio
Most radio frequencies in the US and Canada are regulated. To gain permission to use a
regulated frequency can take a long time and a large amount of money. The good news is
that there are some frequencies that are not regulated and anyone can use.
The problem with unregulated frequencies is that they can get saturated. To ease this, there
have been limits set on the amount of power that devices can broadcast in these
frequencies. While letting more people use the frequencies, this cuts down on the usable
range.
2. Microwaves
Microwaves travel at higher frequencies than radio waves and provide better throughput as
a wireless network media. Microwave transmissions require the sender to be within sight of
the receiver. These systems use licensed frequencies, which makes them more costly than
radio wave systems. Microwaves are utilized on the following two types of communication
systems:
i. Terrestrial Microwaves
Terrestrial microwave transmissions are used to transmit wireless signals across a few
miles. These systems are often used to cross roads or other barriers that make cable
connections difficult. Terrestrial systems require that direct parabolic antennas be pointed
at each other. Relay towers can be used as repeaters to extend the distance of the
transmission. These systems operate in the low giga hertz range and require licensed
frequencies. Installation can be difficult because terrestrial microwave transmissions
require that the antennas have a clear line of sight.
ii. Satellite Microwaves
Satellite microwave transmissions are used to transmit signals throughout the world. These
systems use satellites in orbit about 50,000 kilometers (km) above the earth. Satellite dishes
are used to send the signal to the satellite where it is then sent back down to the receiver’s
satellite. These transmissions also use directional parabolic antennas within line-of-site.
The large distances the signals travel can cause propagation delays. These delays vary from
under a second to several seconds. These delays are roughly the same for transmissions
down the street as for transmissions across the world. This equipment is expensive and
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quite complicated. Launching a satellite into orbit is a task beyond many organizations.
These systems can provide average bandwidth but lack advanced security and protection
from interference. These systems can provide a good bandwidth connection to link LANs
across the world, but this capability comes with (literally) a hefty price.
3. Infrared
Infrared frequencies are just below visible light. These high frequencies allow high-speed
data transmissions. This technology is similar to the use of a remote control for a television.
Infrared transmissions can be affected by objects obstructing the sender or receiver and by
interference from light sources. These systems are immune to electromagnetic interference
and can be used successfully where certain types of cable media fail. These transmissions
fall into the following two categories:
i. Point-to-point Infrared
Point-to-point infrared transmissions utilize highly focused beams to transfer signals
directly between two systems. Many laptop systems and PDAs (personal data assistants)
use point-to-point transmissions. Point-to-point systems require direct alignment between
devices. Point-to-point can provide an alternative to terrestrial microwave as well. If two
buildings have direct line-of-site availability, point-to-point can utilize high-power infrared
beams. This does not require an FCC license and is immune to EMI. These systems are
susceptible to interference from anything that can block the path of the beam. This provides
a high level of security, as any attempt to interfere with the beam would be noticeable. One
must be careful when working with high-power laser beams, as they can cause damage to
eye and skin tissue.
ii. Broadcast
Broadcast infrared transmissions use a spread signal, one broadcast in all directions,
instead of a direct beam. This helps to reduce the problems of proper alignment and
obstructions. It also allows multiple receivers of a signal. Some systems utilize a single
broadcast transceiver to communicate with many devices. This type of system is easy to
install. Broadcast infrared transmissions operate in the same frequencies as point-to-point
infrared and are susceptible to interference from light sources. The drawback of this system
is that the diffused signal reduces transmission rates to 1Mbps. This system overcomes
some of the problems of point-to-point transmissions, but the trade-off is a decrease in
speed.
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5.4 MODULATION TECHNIQUES
--------------------------------------------------------------------------------------------------------Data modulation is a technology used to modify analog signals in order to make them
suitable for carrying data over a communication path. In modulation, a simple wave, called
a carrier wave, is combined with another analog signal to produce a unique signal that gets
transmitted from one node to another. The carrier wave has preset properties (including
frequency, amplitude, and phase). Its purpose is merely to help convey information; in
other words, it does not represent information. Another signal, known as the information or
data wave, is added to the carrier wave. When the information wave is added, it modifies
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one property of the carrier wave (for example, the frequency, amplitude, or phase).The
result is a new, blended signal that contains properties of both the carrier wave and added
data. When the signal reaches its destination, the receiver separates the data from the
carrier wave.
Modulation can be used to make a signal conform to a specific pathway, as in the case of
frequency modulation (FM) radio, in which the data must travel along a particular
frequency. Modulation may also be used to issue multiple signals to the same
communications channel and prevent the signals from interfering with one another. In
frequency modulation, the frequency of the carrier signal is modified by the application of
the data signal.
There are three forms of modulation- amplitude, frequency and phase modulation. They are
described below:
1) Amplitude modulation (AM) is a technique used in electronic communication, most
commonly for transmitting information via a radio carrier wave. AM works by varying the
strength of the transmitted signal in relation to the information being sent. It is a method of
impressing data onto an alternating-current (AC) carrier waveform. The highest frequency
of the modulating data is normally less than 10 percent of the carrier frequency. The
instantaneous amplitude (overall signal power) varies depending on the instantaneous
amplitude of the modulating data. For example, changes in the signal strength can be used
to reflect the sounds to be reproduced by a speaker, or to specify the light intensity of
television pixels.
2) Frequency Modulation (FM) In telecommunications, frequency modulation (FM)
conveys information over a carrier wave by varying its frequency (contrast this with
amplitude modulation, in which the amplitude of the carrier is varied while its frequency
remains constant). In analog applications, the instantaneous frequency of the carrier is
directly proportional to the instantaneous value of the input signal. Digital data can be sent
by shifting the carrier's frequency among a set of discrete values, a technique known as
frequency-shift keying.
It is a method of impressing data onto an alternating-current (AC) wave by varying the
instantaneous frequency of the wave. This scheme can be used with analog or digital data.
Examples; FM is also used at audio frequencies to synthesize sound. This technique,
known as FM synthesis, was popularized by early digital synthesizers and became a
standard feature for several generations of personal computer sound cards.
3) Phase modulation (PM) It is a form of modulation that represents information as
variations in the instantaneous phase of a carrier wave.
Unlike its more popular counterpart, frequency modulation (FM), PM is not very widely
used. This is because it tends to require more complex receiving hardware and there can be
ambiguity problems in determining whether, for example, the signal has changed phase by
+180° or -180°. This scheme can be used with analog or digital data.
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Fig 5.10 (a) Analog Source signal (b ) FM (c) PM
5.4.1 Modems
The word "modem" is a contraction of the words modulator-demodulator. A modem is
typically used to send digital data over a phone line.
The sending modem modulates the data into a signal that is compatible with the phone
line, and the receiving modem demodulates the signal back into digital data. Wireless
modems convert digital data into radio signals and back.
Fig 5.11 Modem
A modem is the peripheral used to transfer information between several computers over a
wire transmission medium (e.g. telephone lines). Computers operate digitally using binary
language (a series of zeros and ones), but modems are analogue. The digital signals pass
from one value to another. There is no middle or half-way point. It is "All or Nothing"
(one or zero). On the other hand, analogue signals do not move "in steps", but rather
continuously.
110
Modems came into existence in the 1960s as a way to allow terminals to connect to
computers over the phone lines. A typical arrangement is shown in Fig. 5.11.
(a)
(b)
Fig 5.12 An Architecture of Modem
5.4.2 Analog versus Digital Transmission
As a technology, analog is the process of taking an audio or video signal (the human voice)
and translating it into electronic pulses. Digital on the other hand is breaking the signal into
a binary format where the audio or video data is represented by a series of "1"s and "0"s.
Analog is a transmission standard that uses electrical impulses to emulate the audio
waveform of sound. When you use a phone, the variations in your voice are transformed by
a microphone into similar variations in an electrical signal and carried down the line to the
exchange.
A method of storing, processing and transmitting information through the use of distinct
electronic or optical pulses that represent the binary digits 0 and 1 is known as Digital
Signal
111
Advantages of Analog
1. Uses less bandwidth
2. More accurate
Disadvantages of Analog
1. The effects of random noise can make signal loss and distortion impossible to recover
Advantages of Digital
1. Less expensive
2. More reliable
3. Easy to manipulate
4. Flexible
5. Compatibility with other digital systems
6. Only digitized information can be transported through a noisy channel without
degradation
7. Integrated networks
Disadvantages of Digital
1. Sampling Error
2. Digital communications require greater bandwidth than analogue to transmit the same
information.
3. The detection of digital signals requires the communications system to be synchronized,
whereas generally speaking this is not the case with analogue systems.
---------------------------------------------------------------------------------------------------------
5.5 MULTIPLEXING
--------------------------------------------------------------------------------------------------------A form of transmission that allows multiple signals to travel simultaneously over one
medium is known as multiplexing. In order to accommodate multiple signals, the single
medium is logically separated into multiple channels, or sub channels.In
telecommunications and computer networks, multiplexing (also known as mixing) is a
process where multiple analog message signals or digital data streams are combined into
one signal over a shared medium. There are many different types of multiplexing, and the
type used in any given situation depends on what the media, transmission and reception
equipment can handle.The aim is to share an expensive resource. For each type of
multiplexing, a device that can combine many signals on a channel, a multiplexer (mux), is
required at the sending end of the channel. At the receiving end, a demultiplexer (demux)
separates the combined signals and regenerates them in their original form.
Multiplexing is commonly used on networks to increase the amount of data that can be
transmitted in a given time span.
5.5.1 Time division multiplexing (TDM)
Time-Division Multiplexing (TDM) is a type of digital or (rarely) analog multiplexing in
which two or more signals or bit streams are transferred apparently simultaneously as sub112
channels in one communication channel, but are physically taking turns on the channel.
The time domain is divided into several recurrent timeslots of fixed length, one for each
sub-channel divides a channel into multiple intervals of time, or time slots. It then assigns a
separate time slot to every node on the network and in that time slot, carries data from that
node.
For example, if five stations are connected to a network over one wire, five different time
slots would be established in the communications channel. Workstation A may be assigned
time slot 1, workstation B time slot 2, workstation C time slot 3, and so on. Time slots are
reserved for their designated nodes no matter whether the node has data to transmit or not.
If a node does not have data to send, nothing will be sent during its time slot. This
arrangement can be inefficient if some nodes on the network rarely send data.
Fig 5.13 Time division multiplexing
5.5.2 Frequency Division Multiplexing (FDM)
In FDM, available bandwidth of a physical medium is divided into several smaller, disjoint
logical bandwidths. Each component bandwidth is used as a separate communication line
(channel). Figure 5.14 illustrates FDM process.
The best example of FDM is the manner in which multiple radio stations are supported
simultaneously. Each radio station is assigned a frequency range within a bandwidth of
radiofrequencies. Several radio stations may be transmitted speech signals simultaneously
over physical channel “ether”. Note that the concept of “ether” an invisible, ever present,
and un-provable medium was proposed to explain the theory of transmission of waves in
space. The electromagnetic propagation of wave in space is now a more acceptable and
proven concepts but the term “ether” has come to stay. A radio receiver antenna receives
signals transmitted by all stations. Finally tuning dial in a radio set is used to isolate signals
of the station tuned. In FDM, signals to be transmitted must be analog signals. Hence,
digital signals must be converted to analog form, if they are to use FDM
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40 KHz
40 KHz
Sig-1
Sig-1
50 KHz
Sig-2
50 KHz
SENDER
Sig-3
RECEIVER
Sig-5
60 KHz
Sig-3
60 KHz
Channel
Sig-4
Sig-2
70 KHz
Sig-4
70 KHz
80 KHz
80 KHz
Sig-5
Figure 5.14 Illustrates FDM Process
---------------------------------------------------------------------------------------------------------
5.6 REVIEW QUESTIONS
--------------------------------------------------------------------------------------------------------1. Differentiate among simplex, half-duplex, and full-duplex modes of data
transmission.
2. Explain the term bandwidth and baud.
3. What is an optical fiber? How it is used for data communication.
4. List the difference between FDM and TDM. Which method is suitable for
communication between computers and why?
5. Write short note on:
a)
Microwave system;
b)
Coaxial cable; and
c)
Modem.
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COMPUTER NETWORKS
--------------------------------------------------------------------------------------------------------------
Structure
6.1 Need for Computer Communication Networks
6.1.1 Advantages of Networking
6.2 Types of Network
6.3 Network Topologies
6.4 Network Protocol
6.4.1 Key Features of Protocols
6.4.2 Roles of Protocol
6.4.3 Need for Protocol Architecture
6.5 OSI and TCP/IP Model
6.5.1 ISO and Other Models
6.5.2 How the OSI Model Works
6.5.3 Key Words and Concepts from the OSI Model
6.5.4 The TCP/IP Model
6.5.5 Internetworking With TCP/IP
6.6 The Future of Internet Technology
6.7 Internet Protocols
6.7.1 Low Level Protocols
6.7.2 High Level Protocols
6.8 World Wide Web
6.9 E-Mail
6.10 Search Engines
6.10.1 Types of Search Engines
6.11 Review Questions
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6.1 NEED FOR COMPUTER COMMUNICATION NETWORKS
--------------------------------------------------------------------------------------------------------Definition: A computer network is a collection of computers and devices connected to
each other. The network allows computers to communicate with each other and share
resources and information
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Need: If your business has more than one computer, chances are you could benefit from
networking them. A local area network (LAN) connects your company's computers,
allowing them to share and exchange a variety of information. While one computer can be
useful on its own, several networked computers can be much more useful. Resource
sharing and communication are two principal reasons of building and using computer
networks.
Here are some of the ways a computer network can help your business:
o File sharing: Have you ever needed to access a file stored on another computer? A
network makes it easy for everyone to access the same file and prevents people
from accidentally creating different versions.
o Printer sharing: If you use a computer, chances are you also use a printer. With a
network, several computers can share the same printer. Although you might need a
more expensive printer to handle the added workload, it's still cheaper to use a
network printer than to connect a separate printer to every computer in your office.
o Communication and collaboration: It's hard for people to work together if no
one knows what anyone else is doing. A network allows employees to share files,
view other people's work, and exchange ideas more efficiently. In a larger office,
you can use e-mail and instant messaging tools to communicate quickly and to
store messages for future reference.
o Organization: A variety of scheduling software is available that makes it possible
to arrange meetings without constantly checking everyone's schedules. This
software usually includes other helpful features, such as shared address books and
to-do lists.
o Remote access: Having your own network allows greater mobility while
maintaining the same level of productivity. With remote access in place, users are
able to access the same files, data, and messages even when they're not in the
office. This access can even be given to mobile handheld devices.
o Data protection: You should know by now that it's vital to back up your computer
data regularly. A network makes it easier to back up all of your company's data on
an offsite server, a set of tapes, CDs, or other backup systems. Of course, another
aspect of data protection is data security.
6.1.1 Advantages of Networking
Speed: Networks provide a very rapid method for sharing and transferring files. Without a
network, files are shared by copying them to floppy disks, then carrying or sending the disks
from one computer to another. This method of transferring files in this manner is very timeconsuming.
Cost: The network version of most software programs are available at considerable savings
when compared to buying individually licensed copies. Besides monetary savings, sharing a
program on a network allows for easier upgrading of the program. The changes have to be
done only once, on the file server, instead of on all the individual workstations.
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Centralized Software Management: One of the greatest benefits of installing a network is the
fact that all of the software can be loaded on one computer (the file server). This eliminates
that need to spend time and energy installing updates and tracking files on independent
computers throughout the building.
Resource Sharing: Sharing resources is another area in which a network exceeds stand-alone
computers. Most companies cannot afford enough laser printers, fax machines, modems,
scanners, and CD-ROM players for each computer. However, if these or similar peripherals are
added to a network, they can be shared by many users.
Flexible Access: Networks allow employees/students to access their files from computers
throughout the company/college. Students can begin an assignment in their classroom, save
part of it on a public access area of the network, and then go to the media center after college to
finish their work.
Security: Files and programs on a network can be designated as "copy inhibit," so that you do
not have to worry about illegal copying of programs. Also, passwords can be established for
specific directories to restrict access to authorized users.
Requires Administrative Time: Proper maintenance of a network requires considerable time
and expertise. Many companies have installed a network, only to find that they did not budget
for the necessary administrative support.
File Server May Fail: Although a file server is no more susceptible to failure than any other
computer, when the files server "goes down," the entire network may come to a halt. When this
happens, the entire school may lose access to necessary programs and files.
--------------------------------------------------------------------------------------------------------------
6.2 TYPES OF NETWORK
-------------------------------------------------------------------------------------------------------------When we talk about computer networks apart from the communication media we are
concerned with how computers are connected with each other. In the sense we are having
basically following types of networks:
•
•
•
LAN (Local Area Network)
WAN (Wide Area Network)
MAN (Metropolitan Area Network)
Local Area Network (LAN)
LAN stands for Local Area Network. It's a group of computers which all belong to the
same organization, and which are linked within a small geographic area using a network,
and often the same technology (the most widespread being Ethernet). This is a computer
network covering a small physical area, like a home, office, or small group of buildings,
such as a school, or an airport.
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Fig 6.1 Three most popular LAN implementations
A local area network is a network in its simplest form. Data transfer speeds over a local
area network can reach up to 10 Mbps (such as for an Ethernet network) and 1 Gbps (as
with FDDI or Gigabit Ethernet). A local area network can reach as many as 100, or even
1000, users. By expanding the definition of a LAN to the services that it provides, two
different operating modes can be defined:
•
•
In a "peer-to-peer" network, in which communication is carried out from one
computer to another, without a central computer, and where each computer has the
same role.
In a "client/server" environment, in which a central computer provides network
services to users.
Fig 6.2 LAN
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Metropolitan Area Network (MAN)
A Metropolitan Area Network is a system of LANs connected throughout a city or
metropolitan area. A metropolitan area network (MAN) is a network that connects two or
more local area networks or campus area networks together but does not extend beyond the
boundaries of the immediate town/city. Routers, switches and hubs are connected to create
a metropolitan area network. MANs have the requirement of using telecommunication
media such as voice channels or data channels. Branch offices are connected to head
offices through MANs. Examples of organizations that use MANs are universities and
colleges, grocery chains, and banks.
Location: Separate buildings distributed throughout a city. MAN takes over the rein in
hand where LAN is not optimal feasible both technical and financially.
Fig 6.3 MAN
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The main criterion for a MAN is that the connection between LANs is through a local
exchange carrier (the local phone company).
WAN (Wide Area Network)
As the term implies, a WAN spans a large physical distance. The Internet is the largest
WAN, spanning the Earth. A WAN is a geographically-dispersed collection of LANs. A
network device called a router connects LANs to a WAN. In IP networking, the router
maintains both a LAN address and a WAN address.
A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are
not owned by any one organization but rather exist under collective or distributed
ownership and management.
A Wide Area Network is a network system connecting cities, countries, or continents
together. WANs are connected together using one of the telecommunications media.
The main difference between a MAN and a WAN is that the WAN uses Long Distance
Carriers. Otherwise the same protocols and equipment are used a MAN.
Fig. 6.4 WANs use Long Distance Carriers
(a)
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(b)
Fig 6.5 Examples of WAN
They may link the computers by means of cables, optical fibers, or satellites, but their users
commonly access the networks via a modem (a device that allows computers to
communicate over telephone lines). The largest wide – area network is the Internet, a
collection of networks and gateways linking millions of computer users on every continent.
---------------------------------------------------------------------------------------------------------
6.3 NETWORK TOPOLOGIES
--------------------------------------------------------------------------------------------------------------------------------------------------------------
Topology of a network refers to the way in which the network’s nodes (computers or other
devices that need to communicate) are linked together. It determines the various data paths
available between any pair of nodes in the network. Choice of a topology for a computer
network depends on a combination of factors such as:
1. Desired performance of the system
2. Desired reliability of the system
3. Size (number of nodes and their geographical distribution) of the system.
4. Expandability of the system
5. Cost of components and services required to implement the network.
6. Availability of communication lines.
7. Delays involved in routing information from one node to another.
121
Network topologies are categorized into the following basic types:
1.
2.
3.
4.
5.
Bus Topology;
Ring Topology;
Star Topology;
Tree Topology;
Mesh Topology.
Bus Topology: Bus networks (not to be confused with the system bus of a computer) use a
common backbone to connect all devices. A single cable, the backbone functions as a
shared communication medium that devices attach or tap into with an interface connector.
A device wanting to communicate with another device on the network sends a broadcast
message onto the wire that all other devices see, but only the intended recipient actually
accepts and processes the message. Ethernet bus topologies are relatively easy to install and
don't require much cabling compared to the alternatives
Benefits of Bus Topology
1. Cabling costs are minimized because of the common trunk.
2. Failure of a node does not affect communication among other nodes in the network
3. Addition of new nodes to the network is easy.
Disadvantages of Bus topology
1. Difficult to trouble shoot because no central distribution points exist.
2. Cable breaks can disable the entire segment because they remove the required
termination from each of the two cable fragments.
Fig 6.6 Bus Topology
Ring Topology: In a ring network, every device has exactly two neighbors for
communication purposes. All messages travel through a ring in the same direction (either
"clockwise" or "counterclockwise"). A failure in any cable or device breaks the loop and
can take down the entire network.
Ring topologies are found in some office buildings or school campuses.
122
Benefits of Ring Topology
1. Each repeater duplicates the data signals so that very little signal degradation occurs.
2. Ring network works well where there is no central node for making routing decisions.
3. It is more reliable because communication is not dependant on a single central node. If a
link between any two nodes fails, or if one of the nodes fails, alternate routing is possible.
Disadvantages of Ring topology
1. A break in the ring can disable the entire network. Many ring designs incorporate extra
cabling that can be switched in if a primary cable fails.
2. Because each node must have the capability of functioning as a repeater, the networking
devices tend to be more expensive.
3. It requires more complicated control software
Fig 6.7 Ring Topology
Star Topology: Many home networks use the star topology. A star network features a
central connection point called a "hub" that may be a hub, switch or router. Devices
typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet. The star
topology is a popular method of connecting the cabling in a computer network. In a star,
each device connects to a central point via a point-to-point link. Depending on the logical
architecture used, several names are used for the central point including the following:
•
•
•
•
Hub
Multipoint Repeater
Concentrator
Multi-Access Unit (MAU)
Compared to the bus topology, a star network generally requires more cable, but a failure in
any star network cable will only take down one computer's network access and not the
entire LAN. (If the hub fails, however, the entire network also fails).
Benefits of Star Topology
1. Each device is isolated on its own cable. This makes it easy to isolate individual devices
from the network by disconnecting them from the wiring hub.
2. All data goes through the central point, which can be equipped with diagnostic devices
that make it easy to trouble shoot and manage the network.
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3. Hierarchical organization allows isolation of traffic on the channel. This is beneficial
when several, but not all, computers place a heavy load on the network. Traffic from those
heavily used computers can be separated from the rest or dispersed throughout for a more
even flow of traffic.
4. It has minimal line cost because only n-1 lines are required for connecting n nodes.
Fig 6.8 Star Topology
Disadvantages of Star topology
1. Because point-to-point wiring is utilized for each node, more cable is required.
2. Hub failures can disable large segments of the network.
Tree Topology: Tree topologies integrate multiple star topologies together onto a bus. In
its simplest form, only hub devices connect directly to the tree bus and each hub functions
as the "root" of a tree of devices. This bus/star hybrid approach supports future
expandability of the network much better than a bus (limited in the number of devices due
to the broadcast traffic it generates) or a star (limited by the number of hub connection
points) alone.
Benefits of Tree Network topology
1. A Tree Topology is supported by many network vendors and even hardware vendors.
2. A point to point connection is possible with Tree Networks.
3. All the computers have access to the larger and their immediate networks.
4. Best topology for branched out networks.
124
Fig 6.9 Tree Topology
Disadvantages of Tree Topology
1. In a Network Topology the length of the network depends on the type of cable that is
being used.
2. The Tree Topology network is entirely dependant on the trunk which is the main
backbone of the network. If that has to fail then the entire network would fail.
3. Since the Tree Topology network is big it is difficult to configure and can get
complicated after a certain point.
Mesh Topology: Mesh topologies involve the concept of routes. Unlike each of the
previous topologies, messages sent on a mesh network can take any of several possible
paths from source to destination. (Recall that even in a ring, although two cable paths exist,
messages can only travel in one direction.) Some WANs, most notably the Internet, employ
mesh routing.
A mesh network in which every device connects to every other is called a full mesh. As
shown in the Fig 6.10 below, partial mesh networks also exist in which some devices
connect only indirectly to others.
Benefits of Mesh Topology
1. Provides redundant paths between devices.
2. The network can be expanded without disruption to current users.
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3. It is fault tolerant; since there is no gateway, nodes can connect to each other with no
regard to the state of the rest of the network. In addition, nodes can create their own paths
through the network because there is no gateway computer.
Disadvantages of Mesh Topology
1. Requires more cable than the other LAN topologies
2. Complicated implementation
3. Setup time can be quite time consuming.
Fig 6.10 Mesh Topology
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6.4 NETWORK PROTOCOL
--------------------------------------------------------------------------------------------------------A protocol is the formal code of behavior for a system, or to be more precise the set form
in which data must be presented for handling by a particular computer configuration. A
protocol defines the set of rules governing the exchange of data between two entities such
as user application programs, file transfer packages, email etc.
6.4.1 Key Features of Protocols
a) Syntax. This is concerned with the format of the data blocks;
b) Semantics. This includes control data for co-ordination and error handling;
126
c) Timing. This allows for speed matching and sequencing.
6.4.2 Roles of Protocol
In any computer network, data communication software normally performs the following
functions for the efficient and error free transmission of data:
i.
Data sequencing: It refers to breaking a long transmission into blocks and
maintaining control that is along message is split up into smaller packets of fixed
size. These packets are further fragmented into data frames, this techniques is
widely used in conjunction with error control techniques to reduce the amount of
data that must be retransmitted in case of a detected error.
ii.
Data routing: Routing algorithms are designed to find the most efficient paths
between sources and destinations. They can handle varying degree of traffic on the
present network configuration with optimum time utilization. Normally, they are
dynamic enough to accommodate network changes and growth.
iii.
Flow control: A communication protocol also prevents a fast sender from
overwhelming a slow receiver. It ensures resources sharing and protection against
congestion by regulating the flow of data on the communication lines.
iv.
Error control: Error detecting and recovering routines are also important elements
of communication protocols. The most common methods for correcting errors are to
retransmit a block. This method requires coordination of the two stations that the
block having error is discarded by the receiving station and is repeated by the
transmitting station.
v.
Precedence and order of transmission: There are well defined rules to condition
all stations about when to transmit their data and when to receive data from other
stations. It is ensured that all stations get a chance to use the communication lines
and other resources of the network depending upon the priorities assigned to them.
vi.
Connection establishment: When two stations of a network want to communicate
with each other, the communication protocol establishes and verifies a connection
between the two.
vii.
Data security: Providing data security and privacy is also built into most
communication software packages it prevents access of data by unauthorized users
because it is relatively easy to tap a data communication line.
viii.
Log information: Data communications software’s can also develop log
information which consists of all jobs and data communications tasks that taken
place. Such information is normally used for financial purposes and the various
users of the network are charged accordingly.
127
6.4.3 Need for Protocol Architecture
When any two computer based entities wish to exchange data there must exist more than
just a physical data path between the two communicating devices. There has to be some
amount of co-operation between the two devices to enable the data transfer to take place.
Some typical tasks that need to be performed for the data transfer to take place are:
i.
The source system must set up the communication path or inform a remote network
of the identity of the system it wishes to communicate with.
ii.
The source system must determine whether the remote system is ready to accept
data.
iii.
The file transfer application on the source system must make sure that the file
management program within the remote system is ready to accept the data from the
source.
iv.
If there is any incompatibility between the two system's file formats, one of the
systems must perform a format translation.
v.
If data are lost, there must be some recovery system.
vi.
When the data transfer is complete, the systems must inform each other of their
readiness to break the connection.
vii.
The tasks described above are a highly simplified view of the process that actually
takes place and the logic to implement this co-operation is too complex to be
installed as a single module. Instead, this logic is broken down into a set of subtasks, each of which is implemented separately.
viii.
In protocol architecture, the logic modules are arranged in a vertical stack. Each
layer of this stack performs a subset of the entire logic necessary to communicate
with a remote system. Layers should be designed so that changes in one layer do
not affect any higher or lower layers.
ix.
This stack of logic modules must be implemented in both of the machines that wish
to communicate. Communication is achieved by corresponding, or peer levels in
both machines communicating with each other. Each of these peer levels
communicate according to a set of rules or conventions that are known as a
protocol.
128
--------------------------------------------------------------------------------------------------------------
6.5 OSI AND TCP/IP MODEL
--------------------------------------------------------------------------------------------------------------
6.5.1 ISO and Other Models
Figure 6.11 shows the reference model of the Open Systems Interconnection (OSI), which
has been developed by the International Standards Organization (ISO). We will briefly
define the functions and operation of each layer of this architecture in turn.
Layer 1: the Physical Layer
This layer is concerned with transmitting an electrical signal representation of data over a
communication link. Typical conventions would be: voltage levels used to represent a “1”
and a “0”, duration of each bit, transmission rate, mode of transmission, and functions of
pins in a connector. An example of a physical layer protocol is the RS-232 standard.
Layer 2: the Data Link Layer
This layer is concerned with error-free transmission of data units. The data unit is an
abbreviation of the official name of data-link-service-data-units; it is sometimes called the
data frame. The function of the data link layer is to break the input data stream into data
frames, transmit the frames sequentially, and process the acknowledgement frame sent
back by the receiver. Data frames from this level when transferred to layer 3 are assumed to
be error free.
Layer 3: the Network Layer
This layer is the network control layer, and is sometimes called the communication subnet
layer. It is concerned with intra-network operation such as addressing and routing within
the subnet. Basically, messages from the source host are converted to packets. The packets
are then routed to their proper destinations.
Layer 4: the Transport Layer
This layer is a transport end-to-end control layer (i.e. source-to-destination). A program on
the source computer communicates with a similar program on the destination computer
using the message headers and control messages, whereas all the lower layers are only
concerned with communication between a computer and its immediate neighbors, not the
ultimate source and destination computers. The transport layer is often implemented as part
of the operating system. The data link and physical layers are normally implemented in
hardware.
Layer 5: the Session Layer
The session layer is the user’s interface into the network. This layer supports the dialogue
through session control, if services can be allocated. A connection between users is usually
called a session. A session might be used to allow a user to log into a system or to transfer
files between two computers. A session can only be established if the user provides the
remote addresses to be connected. The difference between session addresses and transport
addresses is that session addresses are intended for users and their programs, whereas
transport addresses are intended for transport stations.
129
Layer 6: the Presentation Layer
This layer is concerned with transformation of transferred information. The controls
include message compression, encryption, and peripheral device coding and formatting.
Layer 7: the Application Layer
This layer is concerned with the application and system activities. The content of the
application layer is up to the individual user.
Fig 6.11 Layers, Protocols & interfaces
130
Fig. 6.12 The OSI model
6.5.2 How the OSI Model Works
At the top of the model in the application layer are the actual programs operated by the
computer users, such as email clients or web browsers. On the bottom is the physical layer
comprised of the network media that makes the actual physical connection between
computers. In between lie all the layers that make the actual communication occur.
Each computer on a network needs to have a protocol stack, sometimes called a protocol
suite, which provides the software necessary for the computer to communicate on the
network. TCP/IP is the most common protocol suite. These stacks are comprised of
131
several different protocols that perform the functions of the various layers of the OSI
Reference Model.
When an application sends information from one computer to another, the data is passed
down through the protocol stack on the sending computer, across the network, and then up
through the protocol stack on the receiving computer. At each level of the process,
information is attached to the data as it is sent. On the receiving end, this information is
stripped off until the original data is finally available to the receiving application.
6.5.3 Key words and concepts from the OSI model
Application – Layer 7
E-mail
FTP
Client/Server
TCP
Presentation – Layer 6
Encryption/decryption
ASCII to EBCDIC
TCP
Session – Layer 5
Traffic Light or mediator
Maintains order
TCP
Transport – Layer 4
Checks for lost or incomplete transmissions
End to end validity
TCP
Network – Layer 3
WAN
Node to node transmission
CSU/DSU
Switching functions
IP, IPX, SNA, AppleTalk
Data Link – Layer 2
LAN
Checks integrity of transmissions
Router functions
LAN types:
Bus- Ethernet
Ring-Token Ring, Sonet, FDDI
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Star-Mainframe, Switched Ethernet
MAC addressing
CSMA/CD
ATM
Physical – Layer 1
Plugs and connectors (RJ-11: telephone use; RJ-45: Ethernet use)
Sonet
Wiring
Unshielded vs. Shielded Twisted Pair (Cat 3, Cat 5, 10baseT)
Thin-net vs. thick-net Coax (Ethernet)
Single-mode Vs Multimode Fiber
6.5.4 The TCP/IP model
TCP/IP is based on a four-layer reference model. All protocols that belong to the TCP/IP
protocol suite are located in the top three layers of this model.
As shown in the following figure, each layer of the TCP/IP model corresponds to one or
more layers of the seven-layer Open Systems Interconnection (OSI) reference model
proposed by the International Standards Organization (ISO).
Fig 6.13 TCP/IP Model
The types of services performed and protocols used at each layer within the TCP/IP model
are described in more detail in the following table.
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Layer
Description
Protocols
Application
Defines TCP/IP application protocols and how
host programs interface with transport layer
services to use the network.
HTTP, Telnet,
FTP, TFTP,
SNMP, DNS,
SMTP,
X Windows,
other application
protocols
Transport
Provides communication session management
between host computers. Defines the level of
service and status of the connection used when
transporting data.
TCP, UDP, RTP
Internet
Packages data into IP datagram, which contain
source and destination address information that
is used to forward the datagram between hosts
and across networks. Performs routing of IP
datagram.
IP, ICMP, ARP,
RARP
Network
interface
Specifies details of how data is physically sent
through the network, including how bits are
electrically signaled by hardware devices that
interface directly with a network medium, such
as coaxial cable, optical fiber, or twisted-pair
copper wire.
Ethernet, Token
Ring, FDDI,
X.25, Frame
Relay, RS-232,
v.35
Note
•
The OSI reference model is not specific to TCP/IP. It was developed by the ISO in
the late 1970s as a framework for describing all functions required of an open
interconnected network. It is a widely known and accepted reference model in the
data communications field and is used here only for comparison purposes.
6.5.5 Internetworking with TCP/IP
In today's computing environment, the hierarchical, terminal-based networks of the past are
becoming less important. Modern computer networking technologies allow organizations
to construct flexible enterprise inter networks that permit intelligent computing devices of
all types to be interconnected to solve business problems. TCP/IP, which is an acronym for
Transmission Control Protocol/Internet Protocol, represents a particularly important
form of internetworking technology that allows organizations to extend the reach of their
computing systems.
The term TCP/IP refers to a set of protocols, or a protocol suite, that defines the rules
governing how messages are exchanged in a computer network. The TCP/IP protocol suite
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grew out of a research project that began in 1969 and was funded by the U. S. Department
of Defense. The TCP/IP protocols are based on the packet-switching ideas developed for an
early research computer network called the ARPANET, whose acronym was based on the
name of the Advanced Research Projects Agency (ARPA) that funded its development.
ARPA is now known as the Defense Advanced Research Projects Agency (DARPA). The
early ARPANET tied together a number of research computers using conventional leased
telecommunications lines.
The original idea behind the TCP/IP protocol suite was to define a standard set of
procedures to allow individual computer networks to be connected to the ARPANET.
Today, the main purpose of the TCP/IP protocol suite is to allow diverse types of physical
networks to be tied together so that any networked computer can talk to any other
computer. The TCP/IP protocols allow the interconnected individual networks to give the
appearance of a single, unified network-called an internet-in which all computers can freely
exchange data as if they were all directly connected. The TCP/IP protocols make it appear
to a system that there is a simple point-to-point connection to any other system in the
internet, even though data might have to follow a quite complex path in traveling from one
system to another.
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6.6 THE FUTURE OF INTERNET TECHNOLOGY
--------------------------------------------------------------------------------------------------------------------------------------------------------------
From the humble beginning in the late 60s, today internet spans the whole world with
hundreds of millions of computers connected to it (500 million in 2004 estimated). The
remarkable achievement of the internet technology is that it has been able to accommodate
exponential growth (i.e., doubling each year) of the number of computers connected to it.
Also the speed of computers has been doubling every year and there are a variety of
computers connected to the internet. Individual LANs in an organization may use one of a
variety of interconnections and local protocols for communication. The physical connection
between computers may range from fast gigabit fiber optics to slower wireless. In spite of
this variety of technologies and speeds internet still works effectively. The reason for this is
the universal adoption of TCP/IP as the standard protocol which has proved very robust in
spite of rapid changes in technology. TCP/IP protocol emerged as a result of cooperative
effort in which a large number of persons participated and experimented before accepting
any version. The internet protocol accommodates a variety of hardware and a variety of
network speeds as it makes no assumptions regarding the underlying network hardware.
Packet switching ensures efficient and fault tolerant routings of packets. TCP ensures
reliable receipt of all packets sent by a sender to a receiver. It continuously monitors traffic
conditions on the internet and automatically adapts when there is congestion in the
network.
The only major problems currently faced by the internet are:
1. IP addresses are limited to 32 bits and the number of requests for addresses will
exceed this limit soon.
2. Originally the major traffic on the internet was e-mail and character files. Now
multimedia use has increased and one expects to send audio and video files in real
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time for which internet was not designed.
To meet these demands a new generation internet protocol called IPv6 has been proposed
which is expected to replace IPv4, the current protocol. Currently extensive research and
experiments are in progress to test IPv6. Thus IPv6 may slowly replace the current protocol
(IPv4) over the next few years. The major new features proposed in IPv6 are:
1. 128 bit addresses for source and destination in place of 32 bits which is the current
address size. This address size will allow a huge increase in allowed devices to be
connected to the internet.
2. The packet lengths can go upto 64 KB. This will allow easy transfer of multimedia
data, particularly voice.
3. The protocol has a feature to specify the kind of data being transmitted and will
permit real-time multimedia data to be given priority in transmission.
4. The proposed protocol improves security of data being sent over the internet.
It is thus clear that internet has come to stay and will continue to grow in the coming years.
With increasing use of wireless and mobile systems one may see even ordinary household
systems such as refrigerators, ovens, etc., connected to the internet and controlled remotely.
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6.7 INTERNET PROTOCOLS
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
Let us try to find the meaning of protocols in real life. In our day-to-day life, protocols are
a set of procedures and customs that aid in communication and relationships between
people. Many times the term is used in governmental foreign relations and other similar
human dialogue. When used in the context of computer networking, a protocol has a
similar meaning, but is more specific. A network protocol is the set of very detailed rules,
sequences, message formats, and procedures that computer systems use and understand
when exchanging data with each other.
In other words, a network protocol (which includes all of the Internet protocols) is the term
used to describe how computer systems communicate with each other at the bit and byte
level. Network protocols are layered on top of each other, with each layer providing
additional capabilities, but using the facilities provided by the lower layer.
Depending upon their capabilities, we can divide the Internet Protocols in two categories:
6.7.1 Low Level Protocols
Let's start with the lowest-level Internet protocol, and gradually move upwards to the
higher levels.
IP: The most fundamental protocol is called IP, i.e. 'Internet Protocol'. IP is responsible
only for transmitting each chunk of data from one system to another. It needs to know only
the network location of source and destination computer in which data is to be sent back
and forth.
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The common term for a network location is 'address', and each system on the Internet has
an address. This address is called an IP address, and there are two formats for an IP
address.
Internally, each computer system uses an IP address that is composed of four numbers,
usually written for humans with dots between each number. An example IP numeric
address is ‘178.127.201.1’. However, since it's easier for humans to remember names
instead of numbers, most IP addresses have corresponding English-like names, also
separated with dots. The previous address can be written as a name as 'halcon.com'.
Scattered throughout the Internet are systems with the responsibility of translating Internet
name addresses into the IP address numeric form. These systems are called 'name servers'.
In general, it is better to use an Internet name address rather than the IP numeric address.
This is because IP numeric addresses can sometimes change for a given location, and the
change will be transparent if you are using the Internet name address rather than the IP
numeric address. However, the name servers have to be updated.
Occasionally you do need to use the numeric form of an Internet address, and most Internet
applications allow you to enter either format. Another term used in conjunction with
Internet name addresses is 'host name', because every Internet address must correspond to a
computer system (a 'host') somewhere on the Internet. The systems that provide IP name to
number translation are called 'Domain Name Servers', or DNS.
TCP and UDP: We have just seen how systems communicate at a very low level, using IP
addresses in either a numeric or name form to identify each other. The IP layer doesn't
provide many capabilities other than sending chunks of data back and forth. Much more is
needed than that, which is where TCP and UDP come in.
TCP, which is an abbreviation for 'Transmission Control Protocol', is very common on
the Internet, and is almost always mentioned together with IP, making the acronym TCP/IP
(TCP running on top of IP).
The TCP protocol provides a virtual connection between two systems, along with certain
guarantees on the data chunks (called 'packets') that are passed between the systems. Two
guarantees are retransmission of packets that are dropped (because of some network
problem), and ensuring that the packets are received in the same order that they are sent
(there can be multiple routes that a packet can take while traversing the Internet).
A third guarantee is that each packet received by the application has exactly the same
content as when it was sent. If a bit has changed or been dropped for some reason, TCP
will detect it and cause the packet to be re-transmitted.
Some applications use a different protocol running on top of IP called UDP ('User
Datagram Protocol'). UDP sends data one chunk at a time (called a 'datagram') to the
other system and doesn't provide a virtual connection like TCP does. UDP also doesn't
provide the same guarantees that TCP does, which means that datagram may be lost or
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arrive out of sequence. Each received datagram is checked for internal integrity (like TCP),
but if it has been corrupted it is dropped, rather than re-transmitted (as TCP does).
You might be wondering why UDP is used instead of TCP since UDP is not as reliable as
TCP. To provide the extra guarantees, TCP has a lot of overhead compared to UDP, which
makes TCP slower than UDP. For applications where performance is more important than
reliability, UDP makes more sense. Some examples include audio and video streaming
over the Internet, and Internet phone applications.
SLIP and PPP: Many people are now connecting to the Internet (through an Internet
Service Provider, commonly abbreviated as ISP) by dialing up through a modem. Since IP
wasn't designed to be used over dial-up lines, this requires yet another protocol.
SLIP and PPP both allow IP data to be sent over dial-up lines. SLIP is an abbreviation for
'Serial Line IP' and PPP is short for 'Point-to-Point Protocol'. Both take IP data and
package it up so that it can be sent over modem dial-up lines. PPP is considered to be
newer and better than SLIP, although many Internet providers continue to support SLIP
dial-up access.
While connected to an ISP using SLIP or PPP, your system is now another location on the
Internet, with its own IP address. Your account with the ISP may assign you a permanent,
fixed IP address and name, or it may provide what is called a 'dynamic' IP address. Since at
any given time only a subset of dial-up lines are in use for an ISP, the provider may assign
an IP number (and also typically an IP name) from a pool of available addresses.
6.7.2 High Level Protocols
At this point we know a little bit about how different systems communicate with each other
on the Internet at the lower protocol levels. Your workstation or PC is most likely on a
LAN that is connected to the Internet, or using PPP or SLIP to dial-up to an ISP. TCP/IP or
UDP/IP is used to send packets of information back and forth from your system to a remote
system somewhere on the Internet. Now let's discuss the higher-level applications that are
using a client / server relationship to send information back and forth. These higher-level
applications are actually the things used on the Internet. That is why high-level protocols
are also known as Internet Application Protocols.
FTP and Telnet: FTP ('File Transfer Protocol') is a way to upload and download files on
the Internet. Downloading and uploading are two basic processes used on the Internet.
Downloading is the process of transferring the data from the Internet to the local computer,
while uploading is the reverse process i.e. transferring the data from the local computer to
the Internet.
Typically a site on the Internet stores a number of files (they could be application
executables, graphics, or audio clips, for example), and runs an FTP server application that
waits for transfer requests. To download a file to your own system, you run an FTP client
application that connects to the FTP server, and request a file from a particular directory or
folder. Files can be uploaded to the FTP server, if appropriate access is granted. FTP
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differentiates between text files usually ASCII (American Standard Code for Information
Interchange), and binary files (such as images and application executables), so care must be
taken in specifying the appropriate type of transfer.
When an Internet site makes files available to the general public, this is called 'anonymous'
FTP. A password does not need to be supplied, although the user e-mail address is typically
requested. Some sites have confidential files or directories, and an FTP login and password
is needed to download or upload.
Telnet is a way to remotely login to another system on the Internet. The Telnet allows you
to remotely connect into other computers and access them just as if you were sitting
directly in front of them. A telnet server must be running on the remote system, and a telnet
client application is run on the local system. When you are logged in to a system using
telnet, it is as if you were logged in locally and using the operating system command line
interface on the telnet server system. Typical operating systems for telnet servers are
UNIX, Windows NT, and VMS.
HTTP: HTTP stands for 'HyperText Transfer Protocol'. It is the primary protocol of the
World Wide Web (WWW). When a Web browser (such as Internet Explorer or Netscape)
connects to a Web server, it uses HTTP to request Web pages. A Web browser is an
Internet client application, and the Web server is an Internet server application.
HTTP has the ability to transfer Web pages, graphics, and any other type of media that is
used on the Web. HyperText Markup Language (HTML) the internal format of Web pages.
HTML consists of a set of tags and internal commands that are embedded inside Web
pages to control the appearance and layout of Web pages, as well as links to other Web
pages.
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6.8 WORLD WIDE WEB
-------------------------------------------------------------------------------------------------------------Since we have learnt about the Internet advantages and the famous tools available with the
Internet, it is the time now to look at a very interesting topic i.e. World Wide Web
(WWW). World Wide Web is a system of Internet servers that uses HTTP to transfer
specially formatted documents. The documents are formatted in a language called HTML
(HyperText Mark-up Language) that supports links to other documents, as well as graphics,
audio, and video files.
Hypertext refers to a computer-based document in which words or phrases are crossreferenced and a user can easily jump between these cross-references by selecting the
highlighted word. For example, the word web here is highlighted, indicating that it is a
hypertext link to another document.
A related term is hypermedia, which means that graphics, audio and video are also used as
cross-referenced items. One can jump from one document to another simply by clicking on
hyperlinks.
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Here are some of the advantages of WWW:
•
•
Standard Interface: Because the web presents a standard interface to FTP, News,
e-mail, gopher and other Internet tools, as well as a standard way of accessing
information through web pages and databases through forms, the web has become
an invaluable tool for simple access to the net.
Formatted Output: The Web supports formatted text. You can have:
™ Headings of a number of sizes...
while normal text can be formatted in a number of ways, including: bold,
italicized, super or sub-scripted. You can also have lists and tables.
™ Hypertext: As mentioned above, web pages use hypertext links to provide a
very easy and straightforward way to navigate around the net. Hypertext links
can be within a document, between web pages on the same computer or
between web pages on different computers. Hypertext links can also be between
graphics, audio and video.
™ Multimedia: One of the big advantages the web over earlier systems such as
telnet-based programs and gopher is that it is multimedia capable.
Any of the graphical browsers (like Internet Explorer and Netscape Navigator)
can display formatted text, as well as GIF images. Some browsers can also
handle JPEG images. You can also have images embedded in your web page,
like this structure:
If you want to view a file that your browser can't read, then you can easily
configure your browser to call up another program to view the file. This means
that you can send any type of data file across the web: MPEG or QuickTime
movies, WAV sound files, Excel spreadsheets, PhotoCD photos, postscript
files... the list is endless. The best solution of this type is a plug-in, which is
installed as part of your browser. We will study about browsers and plug-ins in
more details later in the chapter. However you can configure your browser to
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feed files with a specific extension to a particular program. Excel files, for
example, with a .xls extension would open up MS Excel.
™ Interactive Pages: With forms, users can interact with web pages to obtain
dynamic or customized information. A typical example of form is the
registration form that you have to fill up while registering for an email account.
Fig 6.14 Registration Form for an email account
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6.9 E-Mail
-------------------------------------------------------------------------------------------------------------
E-mail is an abbreviation for Electronic Mail. It is a way of sending messages from one
computer user to another computer user. The mail could be sent between two people using
the same computer or between two people on different sides of the world.
Advantages of E-Mail
™ Speed: Because e-mail is based around computer networks, it is fast - much
faster than standard mail (otherwise known as snail mail). An e-mail message
that you send to someone in Finland or Brazil could take only a few seconds to
reach them.
™ Cost: Depending on how you have obtained your Internet access, e-mail is free
or very cheap, much cheaper than the 45 cents it takes to send a standard letter
within Australia.
™ Flexibility: With the new MIME e-mail system being used today, you aren't
limited to text in your e-mail messages. You can include pictures, sound files,
movies, data files from your favorite spreadsheet program, etc.
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6.10 SEARCH ENGINES
-------------------------------------------------------------------------------------------------------------Search engines are automated computers owned by companies such as Google, AltaVista,
Yahoo etc that spend all of their time day and night surfing the Internet.
A search engine helps you find information on the Internet. To use a search engine, you
must enter a word (or words) that you expect will be in the Web pages or newsgroup
messages you're looking for, then click a Search button. The search engine will look
through its collection of documents for Web pages and newsgroup messages containing
these keywords.
Search engines can be used to find Web sites in many languages. Your computer's ability to
process accented letters and other characters will determine whether you can search for
French sites, or sites in any other language.
Advantages of using a search engine
• They are very comprehensive
• The flexibility of indexing every word gives users complete search control
Disadvantage
• Submitting queries to search engines can result in millions of results
6.10.1 Types of Search Engines
•
Crawler-Based Search Engines: Crawler-based search engines, such as Google,
create their listings automatically. They "crawl" or "spider" the web, then people
search through what they have found. If you change your web pages, crawler-based
search engines eventually find these changes, and that can affect how you are listed.
Page titles, body copy and other elements all play a role.
•
Human-Powered Directories: A human-powered directory, such as the Open
Directory, depends on humans for its listings. You submit a short description to the
directory for your entire site, or editors write one for sites they review. A search
looks for matches only in the descriptions submitted. Changing your web pages has
no effect on your listing. Things that are useful for improving a listing with a search
engine have nothing to do with improving a listing in a directory. The only
exception is that a good site, with good content, might be more likely to get
reviewed for free than a poor site.
•
Hybrid Search Engines: In the web's early days, it used to be that a search engine
either presented crawler-based results or human-powered listings. Today, it is
extremely common for both types of results to be presented. Usually, a hybrid
search engine will favor one type of listings over another. For example, MSN
Search is more likely to present human-powered listings from LookSmart.
However, it does also present crawler-based results, especially for more obscure
queries.
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6.11 REVIEW QUESTIONS
-------------------------------------------------------------------------------------------------------------1. What is a LAN? What are its main objectives?
2. Describe layering concepts in the OSI model of network architecture with functions
of each layer.
3. Who actually controls the internet?
4. What are the advantages and disadvantages of Internet?
5. Why High-level protocols are called Application protocols?
6. What are the differences between Low-level and high-level Internet Protocols?
7. What are E-Mail Etiquettes? Discuss.
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OFFICE AUTOMATION SYSTEMS - PART I
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Structure
7.1 MS Word –I
7.1.1 What Is Word Processor
7.1.2 Starting Microsoft Word
7.1.3 Key Terminologies
7.1.4 Opening and Formatting Documents
7.1.5 Formatting Page
7.1.6 Inserting a Table
7.1.7 Inserting a Picture
7.1.8 Inserting Page Numbers and Date/Time
7.2 MS Word – II
7.2.1 Autocorrect Facility
7.2.2 Spelling and Grammar
7.2.3 Macros
7.2.4 Mail-Merge in Microsoft Word 2000
7.2.5 Create a Template
7.2.6 Style
7.3 MS-Excel-I
7.3.1 Working with Worksheet
7.4 MS Excel-II
7.4.1 Using Excel's Built-In Functions
7.4.2 What-if Analysis
7.4.3 Data Table sorting
7.5 MS-Excel-III
7.5.1 Graphs and Charts
7.6 Review Questions
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7.1 MS WORD – I
-------------------------------------------------------------------------------------------------------------Over the centuries, we as human beings have always felt the need to communicate and
share our ideas and thoughts. The written word has always remained the best and the most
effective way of interaction irrespective of the place and nature of job of the person.
Sometimes, writing a note comes more easily to us than conveying it verbally. We often
prefer to talk to our distant friends and relatives by way of writing only. At times, it is far
144
easier to express our feelings by setting them down on paper rather than saying them orally.
Any kind of formal or informal message can be best sent across by penning it down.
Once the whole work of writing is done, you would be very anxious to read it through to
check for any grammatical errors or spelling mistakes. If there are any, then imagine the
disappointment you will have to face because then it will demand the pains of writing the
whole document again. Similar kinds of problems are faced with our old conventional
typewriter also. A small change in the typewritten text would involve retyping the entire
text again. Now, as and when the work of writing the whole document is over, we must
concentrate our attention at the final look of the document. The document has to be made
attractive with text neatly and properly organized within margins. Paragraphs are required
to be indented with reasonable spacing between lines. Finally, the document should be free
from all kinds of spelling mistakes and grammatical errors. This is a universal truth that a
neatly organized and well formatted document is definitely more appealing to the reader's
eye.
The following things are to be kept in mind while giving a neat and formal look to your
document.
™ A long document should be broken down into small paragraphs. Proper line spacing
should be given.
™ The words at the end of the line should not be incomplete.
™ The important words and headings should be highlighted either by way of
underlining them or by putting them in different font and size.
™ There should not be any grammatical and spelling mistakes. The text should be
placed properly between margins.
™ Inspite of taking all the efforts and precautions, we cannot keep track of all the
above mentioned requirements. Now, for easing our job, software called 'Word
Processor' has come to our rescue. A Word Processor can do all of these things
without any hassle.
7.1.1 What Is Word Processor
Word processing includes typing in text and manipulating it so as to give a very
systematic and organized look to your document, which enables easy reading. The
application software or program, which helps us in processing the text, is called ’Word
Processing Software' or simply a 'Word Processor’.
So, you can say that a word processor is nothing but a computer program that helps you to:
type your text, correct spelling mistakes and grammatical errors align text within margins
offer a variety of font styles and font sizes see a preview of the text that you have typed in.
The commonly used word processing packages are:
145
•
•
•
•
MS-WORD,
Word Star
Word Perfect
Professional Write
Normally, a word processor can accomplish the following tasks:
™
™
™
™
™
™
™
™
Brochures
Newsletters
Reports
Advertisements
Resumes and Cover letters
Books
Directories
World Wide Web Pages
There is absolutely no end to what a word processor can do. By now you must have
realized that the word processing applications have become much more sophisticated than
before.
7.1.2 Starting Microsoft Word
1. Double click on the Microsoft Word icon on the desktop.
2. Click on Start --> Programs --> Microsoft Word
Fig 7.1
146
Fig 7.2
7.1.3 Key Terminologies
Fig 7.3 (a)
147
Fig 7.3 (b)
Fig 7.3 (c)
148
Fig 7.3
(d)
Fig 7.3 (e)
Fig 7.3 Key Terminologies
149
Viewing the toolbars
The toolbars in Microsoft Word provide easy access and functionality to the user. There are
many shortcuts that can be taken by using the toolbar. First, make sure that the proper
toolbars are visible on the screen.
1.
2.
3.
4.
Click View
Select Toolbars
Select Standard, Formatting, and Drawing
Other toolbars can be selected if you wish
Fig 7.4
Name
Icon
Description
New Blank Document
Creates a new, blank file based on the default
template.
Open (File menu)
Opens or finds a file.
Save (File menu)
Saves the active file with its current file name,
location, and file format.
Mail Recipient
Sends the contents of the document as the body of
the e-mail message.
Print (File menu)
Prints the active file or selected items. To select print
options, on the File menu, click Print.
Print Preview (File menu)
Shows how a file will look when you print it.
150
Spelling and Grammar
(Tools menu)
Checks the active document for possible spelling,
grammar, and writing style errors, and displays
suggestions for correcting them. To set spelling and
grammar checking options, click Options on the
Tools menu, and then click the Spelling and
Grammar tab.
Cut (Edit menu)
Removes the selection from the active document and
places it on the Clipboard.
Copy (Edit menu)
Copies the selection to the Clipboard.
Paste (Edit menu)
Inserts the contents of the Clipboard at the insertion
point, and replaces any selection. This command is
available only if you have cut or copied an object,
text, or contents of a cell.
Copies the format from a selected object or text and
applies it to the object or text you click. To copy the
Format Painter (Standard
toolbar)
formatting to more than one item, double-click
,
and then click each item you want to format. When
you are finished, press ESC or click
off the Format Painter.
again to turn
Undo (Edit menu)
Reverses the last command or deletes the last entry
you typed.
Redo (Edit menu)
Reverses the action of the Undo command.
Hyperlink
Inserts a new hyperlink or edits the selected
hyperlink.
Tables and Borders
Displays the Tables and Borders toolbar, which
contains tools for creating, editing, and sorting a
table and for adding or changing borders to selected
text, paragraphs, cells, or objects.
Zoom
Enter a magnification between 10 and 400 percent to
reduce or enlarge the display of the active document.
Office Assistant
The Office Assistant provides Help topics and tips to
help you accomplish your tasks.
Table 7.1 Basic Terminologies of Tool Bar
7.1.4 Opening and Formatting Documents
Opening a document: If your document is stored on any of the storage devices like hard
disk or floppy disk, then it becomes possible to retrieve that document and the user can
manipulate it the way he/ she wants. WORD offers a variety of ways to open your
documents which are discussed below:
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Method 1: Opening a document from desktop
Click at the Start button. Point at 'Open Office Document and click it . Alternatively, click
at the option 'Open Office Document’ of the Office shortcut bar available on the desktop.
Method 2: Opening a document from Word’s startup screen
Click at the 'File' menu and select the option 'Open'
Alternatively, for opening a document, just double-click at the 'Open' button from the
standard toolbar. This icon looks exactly similar to a file folder.
One very important thing to observe here is that - an 'Open' dialog box appears on the
screen after employing any of the above mentioned methods of opening a document. In
this 'Open' dialog box you would notice a 'look in' box which is used for selecting the drive
as well as the folder where your required document is resident in. Then, there is 'Files of
Type' box which helps you to select the kind of file that you want to open. Suppose you
want that only the WORD documents should be shown in the file list, then click at the pull
down arrow and from the drop down list, select 'Word Documents' option. In case you
want to see all the files in the selected drive, then select 'All Files' option from the drop
down list. Finally click the filename in the file list and click at the <Open> button or
double click the filename to open up the file.
Creating a New Document
1. Click on File
2. Select New
o To create a blank document, simply select Blank Document. To create a
document based on one of the templates provided in Microsoft Word, select
which one you would like to create and select OK
Saving a document
For future retrieval of the document, it needs to be saved on hard disk or floppy disk. Once
all the text is entered, save the document with any of the following methods:
Method 1: Click at the 'File' menu and then select 'Save' option. When the file is being
saved for the very first time, the 'Save as' dialog box comes up because WORD needs some
additional information from you.
Firstly, WORD wants you to give a name to your file. This has to be given in the
'Filename' box. Secondly, the kind of file you are trying to save, should be given in the
'Save as type' box. Thirdly, the place where you want to save your document should be
given in the 'Save in' box. After giving all this information, click at the <Save> button.
Your file is finally saved onto the disk.
The 'Save as' dialog box is displayed only once till the time you don't give a name to your
document. Once the document has a name, next time if you try to save your file after
making a few changes in it, then the 'Save as' dialog box will not appear on the screen.
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Method 2: The other way of saving you r files is by clicking at the 'Save' button available
on the standard toolbar. It's a good idea to keep saving your documents after every few
minutes. The reason is if the computer goes down or a power failure occurs, then the
chances of recovering something in the document are high. Unsaved new documents are
the most vulnerable.
Closing a document
WORD offers a very handy method of closing documents. Like, you would prefer to close
and remove the office files that are no more required on your table, in the similar manner
you may want to close WORD documents too. So, for closing a file, click at the 'File'
menu and select the 'Close' option. This will close the file that is recently opened. As many
documents are opened in WORD, you are required to issue 'File - Close' commands for
those many times to close all the files one by one.
Exiting Word
To quit WORD or to close the WORD application program, click at 'File\Exit' option. With
this command, all the currently opened documents are also closed automatically. WORD
will again prompt you to save your files before quitting.
Formatting Text
1. Highlight the text that you want to format by dragging your mouse over while
holding down the left mouse button
2. Change the text to your desire
3.
o
Formatting Documents
Each one of us have a hidden desire that the reader should feel interested in whatever we
are trying to convey. So, for achieving this, a special effort on our front is required. We
must give a refined look to the document. The formatting features like fonts, bullets and
numbering, font type etc. can be used very intelligently to create the whole impact. Now,
let us proceed further learning about these special features smartly.
Defining Font Type and Size of Text
A font can be defined as a set of letters that have a common or the same typeface.
Different font types and sizes can be applied using the formatting toolbar or the Format
menu. Let's discuss them one by one.
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Using Formatting Toolbar: The formatting toolbar is designed very artistically.
It contains most of the tools that need to be used to give a complete and wholesome look to
your document. The toolbar also shows you the font type and size as applied to your text.
It also displays the effects (Bold, Italic or Underline) as given to the text. For applying a
font type and size to your text, use the formatting toolbar in following steps:
1. Select the text.
2. Click at the arrow beside the font type box and select a font type of your choice
from the drop down list.
3. Again, click at the arrow beside the font size box and select an appropriate font size
from the drop down list.
Using Format Menu: The required font type and size can also be applied to the text by
using 'Format Menu’ as described in the following steps:
1. Select the text.
2. From the 'Format' menu, select the 'Font' option. The 'Font' dialog box appears on
the screen.
Fig 7.5 Font Dialog Box
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3. Choose appropriate font type from the 'font' box. You can move up or down in the
'Font' box with the help of up and down arrow keys.
4. Similarly, choose the required font style and size for your text from the 'Font style'
and 'Size' boxes respectively.
5. The preview of the selected text can be seen in the 'Preview' window with the
applied formatting features.
6. Click <OK> button.
You will find the look of your text changing with the application of new font type, style
and size.
Making Text Bold, Italic & Underlined Using Formatting Toolbar: If you
have
given a keen look at the formatting toolbar, then you must have observed three buttons
showing the letters B, I and U. The letter 'B' stands for Bold, '1' for Italic and 'U' for
Underline. In order to make your text look a bit darker then the rest of the document,
concentrate on the following steps:
1.
2.
Select the text.
Click at the 'B' button.
On carrying out these steps, the 'B' button becomes depressed or lightened. If you do not
want the text to be bold, select the text again and click at the 'B' button. This button on the
toolbar again becomes prominent and your text is not bold anymore.
At times you would like to see your text in italics or would like to underline it. To do this,
do the following steps:
1.
2.
Select the text.
Click at 'U' button to underline and ‘I’ button to italicize it.
Alternatively, the same work can also be done using the 'Format' menu by following steps:
1. Select the text.
2. Click at the 'Font' option of the 'Format' menu.
3. In the 'Font' dialog box, activate the 'Bold' option or 'italic' option from the 'Font
style' box to show your text in bold or italics.
4. In order to underline the text, select the required option from the 'Underline' box
drop down list.
If you are a keyboard person, you can also use one or more of the following key sequences
to achieve the same, after selecting the text:
Press <Ctrl + B> keys to bold the text
Press <Ctrl + 1> keys to italics the text
Press <Ctrl+ U> keys to underline the text
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Fig 7.6
Changing Case of Text: WORD offers a quick and handy way to change the case of your
text. Lowercase characters can easily be changed to uppercase by hitting <Shift + F3>
keys. To achieve the contrary effect, press the <Shift + F3> keys again. This would
convert uppercase characters to lowercase.
Alignment of Text: Text alignment means placement of text between the margins. Your
text can be left, right, centre aligned or it can be justified within the margins. Left
alignment of text would mean the arrangement of text evenly in a straight line at the left
side of the document but with uneven edges on the right side.
Right aligned text is just the opposite of left aligned text with text evenly arranged at the
right edge of the document but uneven from the left side. Justified text would involve even
edges of text along both margins. Centre aligned text means that the text is placed exactly
in the centre of the page. Centre aligned text is most suitable for giving titles, headings etc.
Generally and most frequently the text is left aligned because then the text becomes easily
readable and understandable. Now, let us find out how text can be aligned using the
formatting toolbar.
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1. Select the text (it could be a single line or a paragraph or the whole document).
2. Click at any of the alignment buttons from the formatting toolbar to get the desired
result.
If you are more in the habit of using keyboard, then give the following keyboard shortcuts
after selecting the text:
Press <Ctrl + L> keys to left align the text Press <Ctrl + R> keys to right align the text
Press <Ctrl + E> keys to show the text in the center.
Formatting Paragraphs: Formatting means deciding alignment of the paragraph. It also
includes the spacing that is to be put in between the lines. In order to carry out formatting
on paragraph, it needs to be selected first. Then go to the 'Format' menu and do the
following steps:
1. From the 'Format' menu, select 'Paragraph' option. A 'Paragraph' dialog box shoots
up on the screen.
Fig 7.7 Paragraph
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2. You can set the alignment i.e. decide the placement of text on the screen by clicking
on the dropdown arrow of the 'Alignment' box. Your whole of the paragraph can be
left, right or center aligned.
3. Go to the 'Line Spacing' box and click at the drop down arrow to make a choice.
Finally click at the <OK> button. In the 'Line Spacing' box there are many options
that need a bit of elaboration. Let us find them. For the options 'At least', 'Exactly'
and 'Multiple', a number has to be given in the 'At' box. In these cases, the space is
measured (between the lines) in terms of print size. The 'At least' option uses the
space as given in point size but it can also use some extra space in a case where it
needs to accommodate some text. 'Exactly' option gives exactly the same space as
defined in the 'At' box. If word needs extra space to adjust some more text, then it
cannot get it. 'Multiple' option allows you to specify the line spacing of your own
choice. If you want the lines to be triple spaced then type '3' in the 'At' box.
EXERCISE
Create a First-line Indent
1. Place your cursor anywhere within the first paragraph of the sample text you
created in Exercise 2.
2. Choose the Home tab.
3. In the Paragraphs group, click the launcher. The Paragraph dialog box appears.
4. Choose the Indents and Spacing tab.
5. Click to open the drop-down menu on the Special field.
6. Click First Line.
7. Enter 0.5" in the By field.
8. Click OK. The first line of your paragraph is now indented half an inch.
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Bullets and Numbering: It is always advisable to put the text entries, which are separated
by commas in the bulleted or the numbered form. Adding bullets to the text makes it easy
to read and understand. Major points can be very well emphasized through this technique.
Points put in the order of preference are long remembered by the reader.
Moreover, in our day to day life, we prefer to make our daily list in the numbered manner
rather than putting it in a paragraph. The only idea is that the chances of forgetting are
turned low and visibility of important points is clearer. You can put bullets or numbers in
an existing list by using either the formatting toolbar or the 'Format' menu.
Using Formatting Toolbar
1. Select the text.
2. Click at either the 'Bullets' button or the 'Numbers' button on the formatting toolbar.
In case you decide that you don't require 'numbers' or ‘bullets’, you can very easily put
them off by repeating the above steps. This method perhaps offers a wider choice of
symbols other than the typical black circle. Let us discuss this method:
1.
2.
Select the text.
Select the 'Format-Bullets and Numbering' option.
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A 'Bullets and Numbering' dialog box appears on the screen(see figure below) . Select the
'Bulleted' tab in case you want bullets in your document. If you wish to put numbers then
select the 'Numbered' tab. Choose any of the bullets or numbers and apply it onto your
document by clicking <OK> button. You see how easy it is to place bullets and numbers in
your document.
Fig 7.8
7.1.5 Formatting Page
Page Setting: Page setting includes putting your text neatly between margins. Margins are
nothing but an invisible frame within which the whole text appears. When a blank new
document is opened, a default margin is always there. This margin is laid for sides, top and
bottom of the page. You can always fiddle with the default settings of WORD according to
your demand and requirements. We will learn to set margins by two methods:
Margin Setting through File / Page Setup
The default setting of the top and bottom margin is 1 inch and in the sides, it is 1.25 inches.
To modify the default margin setting, follow the steps given below:
1. Select 'Page Setup' option of 'File' menu. A 'Page Setup' dialog box appears on the
screen.
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Fig 7.9
2. Click in the 'Top' box and erase off the current setting by using either the <Del> key
or the <Backspace> key from the keyboard. Type in the desired number.
Alternatively, you can use the top arrow to increase the margin and down arrow to
decrease it.
3. Similarly, change the settings in the Bottom, Left and Right boxes as well.
At times, you might want that the changes that have been made recently should apply to the
current document only, and then click at <OK> button. But in case, you want that the
current document as well as any other new document that you open should have these page
settings, then click at the <Default> button. The next step would be to click at the <Yes>
button in which case WORD is trying to seek your permission in changing the default
settings for page setup.
Setting Margins using Ruler Line: Ruler line is very frequently used to change margins.
It is a quick and easy way to set margins but needs some amount of practice also. To set
margin using the ruler line, carry out the steps discussed below:
1. Place your mouse pointer on the left side of the horizontal ruler line. Slowly, move
the mo use pointer towards your right side till the place where your mouse pointer
acquires the shape of a double-headed arrow. A 'Left Margin' tool tip appears on
the screen.
2. Click at that location and drag the mouse towards right side to increase the margin
or on the left side to reduce it.
3. Release the mouse button when suitable margin is attained.
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In order to set right margin, the method is just the same as discussed in the above three
steps. If you observe closely, you will find a thin gray line above the 'Right Indent' button
which is in the extreme right of the Ruler Line. This is the Right Margin Line. Place the
mouse pointer at this line and click on it. Drag the pointer in either direction to increase or
decrease the right margin. Finally, release your mouse button.
Now, let us learn how to set the top and bottom margins using the vertical ruler line. This
vertical ruler line appears only in the Page Layout view. So, in a case if your vertical ruler
line is not apparent on the screen, then first switch yourself to Page Layout view by
selecting 'Page Layout' option from the 'View' menu. To set the top margin:
1. Take your mouse pointer on the thin gray line that appears between the darkened
and white areas on the top side of the vertical ruler line.
2. As soon as your mouse pointer takes the shape of a double headed arrow, click and
drag it either upwards or downwards to attain the desired top margin.
3. Release the mouse button.
When you are trying to play with the margins, a line is shown across the page which keeps
moving up or down according to the movement of your mouse pointer. This gives you the
exact location of your margin on the page.
7.1.6 Inserting a Table
1.
2.
3.
4.
5.
6.
Click where you want your table to go.
To create a four-column, five-row table
Choose Table > Insert > Table from the menu. The Insert Table dialog box opens.
Type 4 in the Number of Columns field.
Type 5 in the Number of Rows field.
Select Auto in the Column Width field. Selecting Auto allows Microsoft Word to
determine the size of your column widths. Alternatively, you can enter the column
width you desire.
7. Click OK. Your table should look like the one shown here, with four columns and
five rows
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Fig 7.10 Table
Alternate Method -- Creating a Table by Using the Insert Table Icon:
You can also create a table by clicking on the Insert Table icon on the Standard toolbar.
1. Click the Insert Table icon.
2. Highlight the number of rows and columns you need. The maximum table size you can
create by this method is a four-row by five-column table.
3. Press Enter (or click) to create the table.
Note: Microsoft Word has a Tables and Borders toolbar. This lesson does not cover the
Tables and Borders toolbar.
163
Moving Around a Table: Each block in a table is called a cell. Use the Tab key to move
from cell to cell from left to right. Use Shift-Tab to move from cell to cell from right to left.
The following exercise demonstrates.
1. Click in the first cell in the first column.
2. Press the Tab key nine times. The cursor moves forward nine cells.
3. Press Shift-Tab six times. The cursor moves backward six cells.
Note: You can also move to a cell by clicking in the cell. In addition, you can move around
the table by using the left, right, up, and down arrow keys.
Entering Text into a Table: To enter text into a table, simply type as you normally
would. Press Tab to move to the next cell. Enter the text shown below into your table.
1. Type Salesperson in the first cell in the first column. Press the Tab key.
2. Type Dolls in the first cell in the second column. Press the Tab key.
3. Continue until you have entered all of the text.
Salesperson
Kennedy, Sally
White, Pete
York, George
Banks, Jennifer
Dolls
1327
1421
2190
1201
Trucks
1423
3863
1278
2528
Puzzles
1193
2934
1928
1203
Selecting a Row and Bolding the Text: You learned about bolding in Lesson Three. In
this exercise, you will select the first row of the table and bold all of the text on the row.
Click anywhere on the first row of your table.
Choose Table > Select > Row from the menu.
Press Ctrl-b to bold the row.
Right-Aligning Text: You learned about alignment in Lesson Five. In this exercise, you
will right-align the second (Dolls), third (Trucks), and fourth (Puzzles) columns of the table
you created.
You need to highlight "Dolls," "Trucks," and "Puzzles." Place the cursor before the "D" in
"Dolls." Press the F8 key to anchor the cursor. Then press the right arrow key until you
have highlighted "Dolls," "Trucks," and "Puzzles."
Choose Table > Select > Column from the menu.
Press Ctrl-r to right-align the cells.
Your table should look like the one shown here. Make any needed corrections before
continuing.
Note: All of the formatting options you learned about in previous lessons can be applied to
cells in a table.
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Adding a New Row to the End of the Table
You can add additional rows to your table. The simplest way to add a new row is to move
to the last column of the last row and press the Tab key. You can then type any additional
text you need to add.
1. Move to the last column of the last row of your table.
2. Press the Tab key.
3. Type the text shown here.
Atwater, Kelly 4098
3079
2067
Adding a Row within the Table
You can add a new row anywhere in the table. The exercise that follows demonstrates.
To add a row just above York, George:
1. Place the cursor anywhere in the fourth row (the row with York, George as the
salesperson).
2. Choose Table > Insert > Rows Above from the menu.
3. Add the information shown here to the new row.
Pillar, James
5214
3247
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5467
Resizing the Columns
You can easily change the size of your column widths. In this exercise, you will select the
entire table and adjust all the column widths.
1. Click anywhere in your table.
2. Choose Table > Select > Table from the menu. Your table is selected.
3. Choose Table > Table Properties from the menu.
4. Choose the Column tab.
5. Type 1" in the Preferred Width field. This will cause Microsoft Word to set all the
columns to a width of one inch.
6. Click OK.
Depending on your font, the first column of your table might not be wide enough and the
text might be wrapping.
To widen the first column:
1.
2.
3.
4.
5.
6.
Place the cursor anywhere in the first column.
Choose Table > Select > Column from the menu.
Choose Table > Table Properties from the menu.
Choose the Column tab.
Type 1.5 in the Preferred Width field.
Click OK.
Alternate Method -- Resizing Your Column Widths by Using the Width Indicator
You can resize your column widths by placing the cursor on the line that separates two
columns. This causes the width indicator to appear. After the width indicator appears, leftclick and drag with the mouse to adjust the column width.
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Adding a New Column to a Table
You can add new columns to your table. To add a new column between the Salesperson
and Dolls columns:
1. Place the cursor anywhere in the Dolls column.
2. Choose Table > Insert > Columns to the Left from the menu.
3. Label the new column Region and add the text shown in the table below.
Salesperson
Kennedy, Sally
White, Pete
Pillar, James
York, George
Banks, Jennifer
Atwater, Kelly
Region
S
N
N
S
S
S
Dolls
1327
1421
5214
2190
1201
4098
Trucks
1423
3863
3247
1278
2528
3079
Puzzles
1193
2934
5467
1928
1203
2067
Sorting a Table
With Microsoft Word, it is easy to sort the data in your table. To sort your table data by
Region and within Region by Salesperson in ascending order:
1. Click anywhere on your table.
2. Choose Table > Sort from the menu.
3. Select Region in the Sort By field.
4. Select Text in the Type field (because you are sorting text).
5. Select Ascending.
6. Select Salesperson in the Then By field.
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7. Select Text in the Type field (because you are sorting text).
8. Select Ascending.
9. Select Header Row (because your table has titles across the top of the table).
10. Click OK.
Microsoft Word should have sorted your table like the one shown here:
Salesperson
Pillar, James
White, Pete
Atwater, Kelly
Banks, Jennifer
Kennedy, Sally
York, George
Region
N
N
S
S
S
S
Dolls
5214
1421
4098
1201
1327
2190
Trucks
3247
3863
3079
2528
1423
1278
Puzzles
5467
2934
2067
1203
1193
1928
Deleting a Column
You can delete columns from your table. To delete the Trucks column:
1. Place your cursor anywhere in the Trucks column.
2. Choose Table > Delete> Columns from the menu.
Deleting a Row
You can delete rows from your table. To delete the York, George row:
1. Place your cursor anywhere in the York, George row.
2. Choose Table > Delete > Rows from the menu.
Merge Cell
Using Microsoft Word, you can merge cells -- turn two or more cells into one cell. In this
exercise, you are going to create a new row at the top of your table, merge the cells, and
add a title to the table.
1. Move to the cell located on the first row of the first column of your table (the
Salesperson cell).
2. Choose Table > Insert > Rows Above from the menu.
3. Choose Table > Merge Cells from the menu.
4. Type Toy Sales in the new cell.
5. Press Ctrl-e to center the title.
Table Headings
If Microsoft Word splits your table with a page break, the table heading will display on the
first page but not on subsequent pages. To correct this problem, you can designate rows as
headings. Heading rows are repeated on the top of your table at the top of each page. To
designate a row as a heading:
1. Place your cursor on the row.
2. Choose Table > Heading Rows Repeat from the menu.
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Converting Text to a Table
You can convert text to a table; however, a delimiter such as a comma, paragraph marker,
or tab must separate columns of text. In the exercise that follows, you will convert commadelimited text into a table.
1. Type the following as shown (do not bold).
Color, Style, Item
Blue, A980, Van
Red, X023, Car
Green, YL724, Truck
Name, Age, Sex
Bob, 23, M
Linda, 46, F
Tom, 29, M
2. Highlight the text.
3. Choose Table > Convert > Text to Table from the menu.
4. Type 3 in the Number of Columns field.
5. Select Auto in the Column Width field.
6. Select the Commas radio button in the Separate Text At frame.
7. Click OK.
Microsoft Word should have converted your text to a table and your table should look like
the one shown here.
169
Splitting a Table
With Microsoft Word, splitting a single table into two tables is easy. To separate the table
you just created into two tables:
1. Place your cursor anywhere on the row that reads "Name, Age, Sex."
2. Choose Table > Split Table from the menu.
You should now have two tables.
Table AutoFormat
You can use AutoFormats to apply borders, shading, special fonts, and color to your table.
Microsoft Word lists all Formats in the Table AutoFormat dialog box. While in the Table
AutoFormat dialog box, click a format to see that format displayed in the Preview box. You
can customize how the format is applied. Check the features you want in the Formats to
Apply and the Apply Special Formats To frames. Microsoft Word comes with a long list of
AutoFormats.
To apply an AutoFormat to your Name, Age, and Sex table:
1. Click anywhere in the table.
2. Choose Table > Table AutoFormat from the menu.
3. Click Table Colorful 1 in the Table Styles box.
4. Select Heading Rows and First Column in the Apply Special Formats To frame. Do
not select Last Row and Last Column.
5. Click Apply.
Your table should look like the one shown here.
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Table Properties
Use the Table Properties dialog box to modify the alignment of the table with the body
text and the text within the table. Access the box by selecting Tables|Table Properties.
ƒ
Size - Check the Preferred width box and enter a value if the table should be an
exact width.
ƒ
Alignment - Highlight the illustration that represents the alignment of the table in
relation to the text of the document.
ƒ
Text wrapping - Highlight "None" if the table should appear on a separate line
from the text or choose "Around" if the text should wrap around the table.
ƒ
Borders and Shading - Select from a number of border styles, colors, and widths.
Click the Shading tab to change the background color and pattern.
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ƒ
Options - Click the Options button on the Table Properties window. To change
the spacing between the document text and the table borders under Default cell
margins. Check the Allow spacing between cells box and enter a value to add
space between the table cells.
Save File
Save your file by following these instructions:
1. Choose File > Save As from the menu.
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2.
3.
4.
5.
Specify the correct folder in the Look In field.
Name your file by typing lesson7.doc in the File Name field.
Click Save.
Choose File > Exit from the menu to close Microsoft Word.
7.1.7 Inserting a Picture
When choosing a clip to add to your document, keep in mind that just about anything can
be adjusted. You can size, crop, add lines and fill effects, use a layout that lets you type
text over the clip and more. To insert clipart:
1. Place the insertion point in the location where clipart is to be added.
2. From the Insert menu, choose Picture and Clipart. The Insert Clipart dialog box
displays as below.
Fig 7.11 Clip Art
Note the Favorites category that you can add often used clips to for easy access. You'll
find out how below. Also note, that there is a Search for clips field available for your use.
Clipart in Word is categorized and related to keywords. By typing a keyword in this box
and pressing Enter, Word will search for all clips associated with that word regardless of
the category.
3. Click on a category that suits your needs. In our example, we've chosen
"Entertainment". The first page of clips immediately displays.
4. To navigate through the clipart pages, use the arrows outlined in yellow below, or
click on Keep Looking to go to the next page.
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5. Click on the image you want to insert. A shortcut menu appears. This little
shortcut menu can be a valuable tool - see the explanations in the graphic below.
The last tool, which finds clipart that is similar, can be great if you need more than one clip
to insert with the same theme or if you like the look of one and want to see other clipart
with the same artistic effect.
6. Once you are sure have located the right clip, click and choose the Insert Clip
button or right-click on the clip and choose Insert Clip.
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The clipart is inserted in your document, but it probably needs some adjusting to fit your
needs.
Modifying Clipart
The first thing you should know about modifying clipart, is how to adjust the size. When
you single-click on clipart, the clipart is selected and square "nodes" appear on the corners
and sides, as below.
To resize:
A double arrow is displayed when hovering the mouse over one of these nodes. Holding
the mouse button down, drag to reduce or enlarge the image.
To have more control over adjusting the size, hold down the Alt key while dragging. This
allows for more precise adjustments.
Note: The nodes on the corners adjust the size proportionally, and do not distort the
image. More than likely, you will want to use the corner nodes to adjust size. The nodes
on the bottom and top adjust the height only, and the nodes on the sides adjust the only the
width. Take a look at the following comparison.
Size adjusted with corner node.
Size adjusted with side node.
(no distortion)
(distortion)
To crop:
You can also use the Picture toolbar to adjust brightness, crop, change the layout, etc. To
use the picture toolbar, select the clipart, then right-click on the existing toolbars at the top
of your screen and choose Picture. The toolbar is displayed.
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This same toolbar is used when you insert a picture from a file - like a family photo. If you
crop a picture, you cut out part of the picture along one of the sides. So, let's pretend our
clipart is a family photo and cut out our mother-in-law!
1. Choose the Crop tool, as above.
2. Move your mouse over one of the top, bottom, or side nodes. The crop tool appears
along with your mouse.
3. Hold the mouse button down and drag to crop. Note that you can also press the Alt
key here while dragging for greater control.
Other useful Picture toolbar tools:
If tools or selection options are grayed out, it is because the tool is only available when
inserting a picture file such as a JPEG or GIF.
The first button on the toolbar inserts a picture from a file into your document. You
will not use this tool when working with clipart.
The second tool is Image Control. You can use this tool to grayscale your clipart
or make it black and white. We'll discuss a watermark later on.
Following image control, are buttons that can be used to increase or decrease the
contrast and brightness of the clipart.
The Text Wrapping tool tells word how you want to treat text that surrounds the
clipart. For example, you might want to type text over the clipart and use it as a
background.
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The Format Picture tool (paint bucket) opens the Format Picture dialog box,
which is discussed in the next section of this tutorial.
And last but not least, if you are not satisfied with the adjustments you have made,
the Reset Picture button on the end of the toolbar resets the clipart to its original
state.
The Format Picture Dialog Box
The methods discussed so far, are ones that I find are the easiest to use. However, you can
also make modifications with the Format Picture dialog box. It allows you to make many
changes at one time, and has a few additional features.
The easiest way to access the Format Picture dialog box is to double-click on the clipart.
The Picture tab is displayed first by default. As you can see, there are fields for cropping
and image control. Exact measurements and percentages can be used here to adjust
cropping, brightness, and contrast. However, I find the Picture toolbar discussed earlier to
be more "friendly". Personally, I could spend all day going to this box and adjusting
measurements, etc. - but if I use the Picture toolbar, I can see my changes immediately and
modify accordingly.
In the following example, some of the more useful features are demonstrated by creating a
watermark of our clipart that we can type text over for a newsletter title.
1. Select Watermark from the Color field.
2. Move to the Colors and Lines tab of the dialog box and select Patterned Lines
from the Line, Color field.
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The Patterned Lines dialog box appears as below.
3. Select a pattern and choose Foreground and Background colors to match your
clipart. A preview is shown in the Sample field.
4. Choose OK.
5. Next, move to the Layout tab.
6. Use the picture examples and choose a Wrapping style. In our example, we need
Behind text.
7. Choose OK on the Format Picture dialog box. Our clipart now looks like the
example below.
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8. Move your insertion point and type text as you would in any document.
When you choose to have Behind text as the layout, you are allowed to move the image
around on your screen. In this case, we want to move the image down and a bit to the right.
9. Select the image. Move your mouse to the middle of the image, hold the button
down, and drag the clipart to the proper location. Remember, you can press and
hold the Alt key for more precise movement.
Voila! We're finished. Clipart can be an amazing addition to your documents. It takes a
little time and practice, but is well worth the effort!
7.1.8 Inserting Page Numbers and Date/Time
1. Click Insert at top of screen
2. Select Page Numbers and/or Date & Time
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--------------------------------------------------------------------------------------------------------------
7.2 MS WORD – II
-------------------------------------------------------------------------------------------------------------7.2.1 Autocorrect facility
Microsoft Word's AutoCorrect facility can automatically correct common spelling mistakes
and often-used acronyms, initialisms etc. AutoCorrect can be turned on and off from the
Tools menu:
1. Go to the Tools menu and select Options.
2. Click the Spelling & Grammar tab.
3. In the Spelling area, check (on) or uncheck (off) the Check spelling as you type
checkbox.
Adding entries to AutoCorrect
To manually add entries to AutoCorrect:
Go to the Tools menu and select AutoCorrect (Word 2000) or AutoCorrect Options (Word
XP/2003).
In the AutoCorrect: English (Australia) dialog, go to the Replace field and enter the
incorrect word or acronym/initialism (eg. organize, ATO).
In the with field, enter the correct word or full text of the acronym/initialism (eg. organize,
Australian Taxation Office).
• Click the Add button.
• Click the OK button.
Now, if you were to type: 'The ATO site can tell you how to organize your records', Word
would automatically change the sentence to read: 'The Australian Taxation Office site can
tell you how to organize your records, as you type.
Fig 7.12 Autocorrect dialog box
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If you're using spell checking as you type, you can also add entries through the right-click
menu:
1. Right-click the underlined word and select AutoCorrect.
2. From the sub-menu list of options, select the replacement word.
Note: AutoCorrect can be used for phrases as well as single words. If you find yourself
constantly using phrases such as 'give consideration to' instead of 'consider', or 'in the near
future' instead of 'soon', you can tell MS Word to automatically correct the phrase as you
type.
AutoCorrect Options buttons
In Word XP/2003, you can also manage auto-corrections using AutoCorrect Options
buttons. To turn on AutoCorrect Options buttons:
Go to the Tools menu and select AutoCorrect Options.
Tick the Show AutoCorrect Options buttons checkbox.
Click the OK button.
Now, whenever Word makes an auto-correction, you can backspace (or move your mouse)
to the correction to display the auto-correction underline:
However over the underline to show the AutoCorrect Options button, and then click the
button to display options:
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Change back
: Undoes the correction for this one instance.
Stop Automatically Correcting
: Undoes the correction for this one instance, and then
deletes the auto-correction so it will not happen again.
AutoCorrect Options buttons remain available for each correction until the document is
closed. If you change your mind about changing an auto-correction, open the button again
and select Redo AutoCorrect.
Deleting entries from AutoCorrect
To delete entries from AutoCorrect:
1. Go to the Tools menu and select AutoCorrect (Word 2000) or AutoCorrect Options
(Word XP/2003).
2. Click the Spelling & Grammar tab.
3. Scroll through the list at the bottom of the tab and click on the entry to be deleted.
4. Click the Delete button.
5. Click the OK button.
7.2.2 Spelling and Grammar
Word will automatically check for spelling and grammar errors as you type unless you turn
this feature off. Spelling errors are noted in the document with a red underline. Grammar
errors are indicated by a green underline. To disable this feature, select Tools|Options from
the menu bar and click the Spelling and Grammar tab on the dialog box. Uncheck
"Check spelling as you type" and "Check grammar as you type", and click OK.
To use the spelling and grammar checker, follow these steps:
•
•
•
•
•
Select Tools / Spelling and Grammar from the menu bar.
The Spelling and Grammar dialog box will notify you of the first mistake in the
document and misspelled words will be highlighted in red.
If the word is spelled correctly, click the Ignore button or click the Ignore All
button if the word appears more than once in the document.
If the word is spelled incorrectly, choose one of the suggested spellings in the
Suggestions box and click the Change button or Change All button to correct all
occurrences of the word in the document. If the correct spelling is not suggested,
enter the correct spelling in the Not In Dictionary box and click the Change
button.
If the word is spelled correctly and will appear in many documents you type (such
as your name), click the Add button to add the word to the dictionary so it will no
longer appear as a misspelled word.
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As long as the Check Grammar box is checked in the Spelling and Grammar dialog
box, Word will check the grammar of the document in addition to the spelling. If you do
not want the grammar checked, remove the checkmark from this box. Otherwise, follow
these steps for correcting grammar:
ƒ
If Word finds a grammar mistake, it will be shown in the box as the spelling errors.
The mistake is highlighted in green text.
ƒ
Several suggestions may be given in the Suggestions box. Select the correction that
best applies and click Change.
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ƒ
If no correction is needed (Word is often wrong more than it is right), click the
Ignore button.
Synonyms
Word 2000 has a new feature for finding synonyms. Simply right-click on the word and
select Synonyms from the shortcut menu. From the list of suggested words, highlight the
word you would like to use or click Thesaurus... for more options.
Thesaurus
To use the thesaurus, select Tools | Language |Thesaurus from the menu bar or select it
from the Synonyms shortcut menu as detailed above.
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A list of meanings and synonyms are given on the windows. Double-click on the words in
the Meanings box or click the Look Up button to view similar words. Double-click words
in the Replace with Synonym box to view synonyms of those words. Highlight the word
you would like to add and click the Replace button.
7.2.3 Macros
Do you always perform repeated tasks in Microsoft Word? Repeated tasks, if not
automated are prone to human errors. If you perform a task repeatedly in Microsoft Word,
you can automate the task by using a macro.
A macro is a series of Word commands and instructions that you group together as a single
command to accomplish a task automatically. Since not all of us are programmers who can
write code in Visual Basic, I will show you a way to create macros without even writing
code.
First open up your Word document then click Tools > Macro > Record New Macro
Fig 7.13 Selecting Macros
According to the help document the macro recorder in Word acts like a tape recorder. It
records your deliberate keystrokes and mouse button clicks … when you record a macro,
you can use the mouse to click commands and options, but not to select text.
You must use the keyboard to record these actions. For example, you can use F8 to select
text and press END to move the cursor to the end of the line. Remember that it records
keystrokes and mouse clicks only.
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When you record a macro it will ask for a macro name so assign it a descriptive macro
name. After that, click the OK button to record the macro.
Once you see the recording toolbar, enter the keystrokes that you want to record. In the
example below I indented the first line of the paragraph (TAB) then I selected all (ControlA) then I applied the bold format (Control-B). After this I stopped the recording of macro
by clicking the stop button.
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The macro will be saved and you can run it by clicking the run macro command (or Alt-F8)
from the Tools menu.
Before the macro run:
After the macro run:
Now that you know how to make macros by recording keystrokes and mouse clicks, apply
this tip on your own repeated tasks. This will increase your productivity and also you
quality of work.
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7.2.4 Mail-Merge in Microsoft Word 2000
Click Tools > Mail Merge
The Mail Merge Helper opens. Mail Merge is a three step process.
Fig 7.14 Mail Merge
Step 1:
Click Create to choose the document type. Click on the document type that you will be
creating. On the next screen choose to use the current document as the Merge Document.
Click Edit to edit the current document.
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Step 2:
Click Get Data. This gets enabled once Step 1 is completed. Choose from the Get Data list
where the contacts are stored.
When the data source is chosen, a message will warn that no Merge Fields are in the
current document and will ask to insert Merge Fields in the document. Click "Edit Main
Document" on this message to enter Merge Fields in the document.
Merge Fields are placeholders for where the Contact's real information will be inserted by
the wizard.
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Click in the appropriate place in the document that you want to insert Merge Fields.
From the Mail Merge toolbar Click "Insert Merge Field" and Click the Merge Field to
insert into the document. The Merge Field will appear as "<<Company>>" in the
document.
Click "ABC" to view the document with the merged data.
Click "Mail Merge Helper" button on the Mail Merge Toolbar.
Step 3:
Click Merge on the Mail Merge Helper screen.
On the next screen Click Merge.
Separate documents with the Merge Fields replaced by the actual contact details will be
created.
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The Mail Merge process is complete. Use this Mail Merged document to send faxes to
multiple
recipients
using
the
Fax
Merge
feature
in
Fax4Word.
How to Fax Merge
Once you have created a Mail Merge document, all you need to do is...
Click "Fax Merge" on the Fax4Word toolbar in MSWord.
In the Fax Merge screen, fill the details from the drop down list and choose the appropriate
fields
from
the
list
for
Name,
Company
and
Number.
Note: Number is required.
Click "Fax Only" to send the fax.
Select a printer from the drop down list for "Use this printer to print a paper copy for
filing".
To send fax and print a copy of the sent fax click "Fax and Copy" on the Fax Merge screen.
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The fax will be sent when "Fax only" or "Fax and Print" is clicked. To view the status of
the faxes being sent, go to Fax Console. (Click Start > All Programs > Accessories >
Communications > Fax > Fax Console).
The Fax Merge is completed and multiple faxes are sent with just a few clicks.
7.2.5 Create a Template
Templates are a special type of Word document that can hold text, styles, macros, keyboard
shortcuts, custom toolbars and AutoText entries. A document created using a template will
have access to all of these features and a large part of your job in creating a new document
will be done for you if your templates are well thought out. You don't need to use all (or
even any) of these features for templates to help you and those with whom you work.
Using Templates
• A template sets what text, formatting and graphics will automatically appear in the
new document. The template is a base pattern of content for a document.
• Templates can be created for expense reports, status reports — any document that
is used repetitively.
• Templates not only save you time, they allow for a custom editing environment,
store tools to edit a document effectively, store Styles, store automated macro
procedures, and store AutoText boilerplate
Accessing Library Templates
™ The built-in Template Library gives you access to more than 40 preset templates
from within Word.
™ From the main menu, choose File > New to open the New Document pane, and
click on General Templates to open the Templates dialog box:
To select a Template from the Templates dialog box:
™ From the main menu, choose File > New to open the New Document panel
™ Click on General Templates to open the Templates dialog box.
™ Select the required template. The Preview area will show a thumbnail image of the
template.
™ Select the Template option in the Create New options area.
™ This will create the item as a template rather than a one-time document.
™ Click OK.
™ The new template will open. Make any adjustments if needed, and save with a
different name under a different folder.
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Modifying a Template
™ The templates in the Template Library and on the Microsoft.com Website cannot
be altered until they have been saved in an alternate folder on the hard drive with a
different name.
™ Once saved, open the template, and make any alterations required.
To save a modified Template:
™ From the main menu, choose File > Save As to save the template as a template file.
™ Confirm that Document Template is selected in the Save as type field.
™ Once all selections are set and confirmed, click Save.
™ The various template tabs allow you to select and use templates to create Letters,
Faxes and Memos, do a Mail Merge, etc.
™ Most of the templates have built-in directions that cover where to enter information
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Fig 7.15 Templates
7.2.6 Style
When working with Word, you can use styles to quickly format your documents. A style is
a set of formats consisting of such things as fonts, font colors, font sizes, and paragraph
formats. Word 2007 supplies you with pre-designed style sets that contain styles for titles,
subtitles, quotes, headings, lists and more. The sections that follow all show you how to
work with styles. Click Save Target As from the menu that appears, and save the linked file
to a directory on your computer. Then open the file.
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EXERCISE:
Choose a Style Set
1. Choose the Home tab.
2. Click Change Styles in the Styles group. A menu appears.
3. Click Style Set. A menu appears. You can choose from any of the styles listed on
the menu.
4. Click Simple. Word 2007 reformats all of the paragraphs into the Simple style by
applying the Normal format to each paragraph.
Apply a Style
You can see of all the styles available to you in the style set by clicking the launcher in the
Styles group and opening the Styles pane. You can leave the Styles pane open and
available for use by docking it. To dock the Styles pane, click the top of the pane and drag
it to the left or right edge of the Word window.
You do not need to select an entire paragraph to apply a style. If the cursor is anywhere in
the paragraph, when you click on the style, Word formats the entire paragraph.
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EXERCISE:
Apply the Title Style
1. Choose the Home tab.
2. Click the launcher in the Styles Group. The Styles pane appears. You can drag it to
the side of the Word window to dock it. To close the Styles pane, click the Close
button in the upper right corner of the pane .
3. Click anywhere in the paragraph "Single-Parent Family—Career Help."
4. Click Title in the Styles pane. Word 2007 applies the Title style to the paragraph.
Headings and subheadings mark major topics within your document. With Word 2007, you
can easily format the headings and subheadings in your document.
Apply Headings
1. Click anywhere in the paragraph "The Nature of Single Parenthood."
2. In the Style box, click Heading 1. Word reformats the paragraph.
3. Repeat steps 1 and 2 in the following paragraphs:
•
•
•
Types of Single Parents
Career Development Needs of Single Parents
Career Development Programs
Apply Subheadings
1. Click anywhere in the paragraph "Displaced Homemakers"
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2. In the Style box, click Heading 2. Word reformats the paragraph.
3. Repeat steps 1 and 2 for the following paragraphs:
•
•
•
•
•
Displaced Homemakers
Adolescent Mothers
Single Fathers
High School Dropout Prevention
Established Education Sites
Alternate Method -- Apply Styles with the Ribbon
You can also choose styles by selecting the option you want from the Styles group on the
Ribbon. First you must place your cursor in the paragraph to which you want to apply the
style. Then you click the More button in the Styles group to see all of the styles in the
currently selected set. As you roll your cursor over each of the styles listed, Word 2007
provides you with a live preview of how the style will appear when applied.
1. Select the paragraphs "Emotional Support" through "Parenthood Education" (they
are probably on page two).
2. Click the More button in the Styles group.
3. Locate and click the List Paragraph style. Word applies the List Paragraph style to
the paragraphs you selected.
Change Style Sets
Once you have applied styles, changing to another style set is easy. You simply open the
Style Set gallery. As you move your cursor down the menu, Word 2007 provides you with
a live preview of the effect of applying the style set. To choose a style set, you click it.
EXERCISE:
Change Style Sets
1. Click Change Styles in the Styles group. A menu appears.
2. Click Style Set. A menu appears. As you move your cursor down the menu Word
2007 provides you with a live preview of the effect of applying the Style set to your
document.
3. Click Formal. Word 2007 reformats all of the paragraphs into the Formal style
applying the appropriate format to each paragraph.
--------------------------------------------------------------------------------------------------------------
7.3 MS-EXCEL-I
-------------------------------------------------------------------------------------------------------------Microsoft Excel is an electronic spreadsheet. You can use it to organize your data into rows
and columns. You can also use it to perform mathematical calculations quickly. This
tutorial teaches Microsoft Excel basics. Although knowledge of how to navigate in a
Windows environment is helpful, this tutorial was created for the computer novice. This
lesson will introduce you to the Excel window. You use the window to interact with Excel.
To begin this lesson, start Microsoft Excel 2007. The Microsoft Excel window appears and
your screen looks similar to the one shown here.
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Note: Your screen will probably not look exactly like the screen shown. In Excel 2007,
how a window displays depends on the size of your window, the size of your monitor, and
the resolution to which your monitor is set. Resolution determines how much information
your computer monitor can display. If you use a low resolution, less information fits on
your screen, but the size of your text and images are larger. If you use a high resolution,
more information fits on your screen, but the size of the text and images are smaller. Also,
settings in Excel 2007, Windows Vista, and Windows XP allow you to change the color
and style of your windows.
The Microsoft Office Button
In the upper-left corner of the Excel 2007 window is the Microsoft Office button. When
you click the button, a menu appears. You can use the menu to create a new file, open an
existing file, save a file, and perform many other tasks.
The Quick Access Toolbar
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Next to the Microsoft Office button is the Quick Access toolbar. The Quick Access toolbar
gives you with access to commands you frequently use. By default, Save, Undo, and Redo
appear on the Quick Access toolbar. You can use Save to save your file, Undo to roll back
an action you have taken, and Redo to reapply an action you have rolled back.
The Title Bar
Next to the Quick Access toolbar is the Title bar. On the Title bar, Microsoft Excel displays
the name of the workbook you are currently using. At the top of the Excel window, you
should see "Microsoft Excel - Book1" or a similar name.
The Ribbon
You use commands to tell Microsoft Excel what to do. In Microsoft Excel 2007, you use
the Ribbon to issue commands. The Ribbon is located near the top of the Excel window,
below the Quick Access toolbar. At the top of the Ribbon are several tabs; clicking a tab
displays several related command groups. Within each group are related command buttons.
You click buttons to issue commands or to access menus and dialog boxes. You may also
find a dialog box launcher in the bottom-right corner of a group. When you click the dialog
box launcher, a dialog box makes additional commands available.
7.3.1 Working with Worksheet
Microsoft Excel consists of worksheets. Each worksheet contains columns and rows. The
columns are lettered A to Z and then continuing with AA, AB, AC and so on; the rows are
numbered 1 to 1,048,576. The number of columns and rows you can have in a worksheet is
limited by your computer memory and your system resources.
The combination of a column coordinate and a row coordinate make up a cell address. For
example, the cell located in the upper-left corner of the worksheet is cell A1, meaning
column A, and row 1. Cell E10 is located under column E on row 10. You enter your data
into the cells on the worksheet.
199
Fig 7.16 Worksheet
The Formula Bar
If the Formula bar is turned on, the cell address of the cell you are in displays in the Name
box which is located on the left side of the Formula bar. Cell entries display on the right
side of the Formula bar. If you do not see the Formula bar in your window, perform the
following steps:
1. Choose the View tab.
2. Click Formula Bar in the Show/Hide group. The Formula bar appears.
Note: The current cell address displays on the left side of the Formula bar.
The Status Bar
The Status bar appears at the very bottom of the Excel window and provides such
information as the sum, average, minimum, and maximum value of selected numbers. You
can change what displays on the Status bar by right-clicking on the Status bar and selecting
the options you want from the Customize Status Bar menu. You click a menu item to select
it. You click it again to deselect it. A check mark next to an item means the item is
selected.
200
Move around a Worksheet
By using the arrow keys, you can move around your worksheet. You can use the down
arrow key to move downward one cell at a time. You can use the up arrow key to move
upward one cell at a time. You can use the Tab key to move across the page to the right,
one cell at a time. You can hold down the Shift key and then press the Tab key to move to
the left, one cell at a time. You can use the right and left arrow keys to move right or left
one cell at a time. The Page Up and Page Down keys move up and down one page at a
time. If you hold down the Ctrl key and then press the Home key, you move to the
beginning of the worksheet.
EXERCISE:
Move around the Worksheet
The Down Arrow Key
• Press the down arrow key several times. Note that the cursor moves downward one
cell at a time.
The Up Arrow Key
• Press the up arrow key several times. Note that the cursor moves upward one cell at
a time.
The Tab Key
1. Move to cell A1.
2. Press the Tab key several times. Note that the cursor moves to the right one cell at a
time.
201
The Shift +Tab Keys
• Hold down the Shift key and then press Tab. Note that the cursor moves to the left
one cell at a time.
The Right and Left Arrow Keys
1. Press the right arrow key several times. Note that the cursor moves to the right.
2. Press the left arrow key several times. Note that the cursor moves to the left.
Page Up and Page Down
1. Press the Page Down key. Note that the cursor moves down one page.
2. Press the Page Up key. Note that the cursor moves up one page.
The Ctrl-Home Key
1. Move the cursor to column J.
2. Stay in column J and move the cursor to row 20.
3. Hold down the Ctrl key while you press the Home key. Excel moves to cell A1.
Go To Cells Quickly
The following are shortcuts for moving quickly from one cell in a worksheet to a cell in a
different part of the worksheet.
EXERCISE
The Name Box
You can also use the Name box to go to a specific cell. Just type the cell you want to go to
in the Name box and then press Enter.
1. Type B10 in the Name box.
2. Press Enter. Excel moves to cell B10.
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Select Cells
If you wish to perform a function on a group of cells, you must first select those cells by
highlighting them. The exercises that follow teach you how to select.
Alternative Method: Select Cells by Dragging
You can also select an area by holding down the left mouse button and dragging the mouse
over the area. In addition, you can select noncontiguous areas of the worksheet by doing
the following:
1. Go to cell A1.
2. Hold down the Ctrl key. You won't release it until step 9. Holding down the Ctrl
key enables you to select noncontiguous areas of the worksheet.
203
3. Press the left mouse button.
4. While holding down the left mouse button, use the mouse to move from cell A1 to
C5.
5. Continue to hold down the Ctrl key, but release the left mouse button.
6. Using the mouse, place the cursor in cell D7.
7. Press the left mouse button.
8. While holding down the left mouse button, move to cell F10. Release the left mouse
button.
9. Release the Ctrl key. Cells A1 to C5 and cells D7 to F10 are selected.
10. Press Esc and click anywhere on the worksheet to remove the highlighting.
Enter Data
In this section, you will learn how to enter data into your worksheet. First, place the cursor
in the cell in which you want to start entering data. Type some data, and then press Enter. If
you need to delete, press the Backspace key to delete one character at a time.
EXERCISE:
Enter Data
1. Place the cursor in cell A1.
2. Type John Jordan. Do not press Enter at this time.
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Delete Data
The Backspace key erases one character at a time.
1. Press the Backspace key until Jordan is erased.
2. Press Enter. The name "John" appears in cell A1.
Edit a Cell
After you enter data into a cell, you can edit the data by pressing F2 while you are in the
cell you wish to edit.
Alternate Method: Editing a Cell by Using the Formula Bar
You can also edit the cell by using the Formula bar. You change "Jones" to "Joker" in the
following exercise.
1. Move the cursor to cell A1.
2. Click in the formula area of the Formula bar.
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3. Use the backspace key to erase the "s," "e," and "n."
4. Type ker.
5. Press Enter.
Alternate Method: Edit a Cell by Double-Clicking in the Cell
You can change "Joker" to "Johnson" as follows:
1. Move to cell A1.
2. Double-click in cell A1.
3. Press the End key. Your cursor is now at the end of your text.
206
4. Use the Backspace key to erase "r," "e," and "k."
5. Type hnson.
6. Press Enter.
Change a Cell Entry
Typing in a cell replaces the old cell entry with the new information you type.
1. Move the cursor to cell A1.
2. Type Cathy.
3. Press Enter. The name "Cathy" replaces "Johnson."
Wrap Text
When you type text that is too long to fit in the cell, the text overlaps the next cell. If you
do not want it to overlap the next cell, you can wrap the text.
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EXERCISE:
Wrap Text
1. Move to cell A2.
2. Type Text too long to fit.
3. Press Enter.
4. Return to cell A2.
5. Choose the Home tab.
6. Click the Wrap Text button
. Excel wraps the text in the cell.
Delete a Cell Entry
To delete an entry in a cell or a group of cells, you place the cursor in the cell or select the
group of cells and press Delete.
EXERCISE:
Delete a Cell Entry
1. Select cells A1 to A2.
2. Press the Delete key.
3. Save a File
4. This is the end of Lesson1. To save your file:
5. Click the Office button. A menu appears.
6. Click Save. The Save As dialog box appears.
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7. Go to the directory in which you want to save your file.
8. Type Lesson1 in the File Name field.
9. Click Save. Excel saves your file.
10. Close Excel
11. Close Microsoft Excel.
12. Click the Office button. A menu appears.
13. Click Close. Excel closes.
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7.4 MS EXCEL - II
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7.4.1 Using Excel's Built-in Functions
The following activity shows you how to use Excel's built-in functions in your calculations.
If you have access to the program, you should do the activities as you read. This will
enhance your understanding of each step.
1. Employing the SUM function to compute sales totals.
As our first example illustrating the use of an Excel built-in function, we will modify the
Example1 worksheet. One of the Excel built-in functions is the function SUM which, as its
name suggests, computes sums of values in a range of cells.
To do this, we delete the formula in cell B10, type an = sign, then select the function
selection dialog box (the symbol fx) from the tool bar (see the cursor position in the figure
below). The dialog box shown in the figure is then displayed and we can choose from
among the many Excel built-in functions. In the figure, we have selected the SUM function
from the Most Recently Used function list. Once we make this selection we click to close
the function selection dialog box.
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Fig 7.17 Built-in Functions
2. Setting the argument -- a range of cells.
When we close the function selection dialog box, a second dialog box appears, as shown
below. The purpose of this dialog box is to help us set the arguments for the function we've
chosen. In this example, the spreadsheet "guesses" that we wish to sum the cells (starting
with the first one from the top with numerical data in it) immediately above the formula
cell. In other words it selects for us the range of cells B3:B9. This is almost correct. We
probably don't care to include the empty cell B9, so we edit the range to read B3:B8, then
click OK.
Notice before going on that the dialog box also has a brief explanation of what the function
we've selected does and what its arguments stand for. And it even tells us what the result
would be for the arguments it has pre-selected for us.
3. Completing the formula.
Once we adjust the arguments to be the range B3:B8 and click OK, we get the result shown
in the figure below. In a moment we will replicate the SUM function across the row to cells
C10, D10, E10. But first, let's see how the SUM calculation differs from the previous
calculation we made with the addition formula.
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4. Comparing the SUM function and a formula using the + operator.
The SUM function is a convenient way to compute sums when we expect the amount of
data in our spreadsheet to expand or contract in the future. The reason is that the SUM
function automatically accounts for inserting and deleting data within the range of cells in
its argument. The formula constructed with the + operator will not adjust for this
accommodation.
Let's modify our spreadsheet to illustrate. Suppose for a moment we had a special
promotion sale at the end of February and we want to now include these sales figures as a
separate row in our data. It is easy to add more data in a spreadsheet by inserting rows (or
columns) into the worksheet.
The figure below shows how we would add a row after the February sales figure row. First
you select the row before which you wish to insert a new row. Do this by clicking the row
number at the right of the worksheet -- the entire row will be highlighted. Next you select
the Rows choice from the Insert menu as shown in the figure. A new blank row will be
inserted before the selected row.
To complete our modification we add appropriate data to new row 5, as shown in the figure
below.
Now notice (compare totals with those in the previous figure in Step 3) that the total for
Region 1 is automatically updated to include the additional $10,000 we just entered in cell
B5. However, the total for Region 2 does not include the new amount in cell C5.
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The formula in cell C11, as you can see from the figure, changes to keep exactly the same
values in the sum as were there before the insertion of the new row. The new value is
omitted altogether. The SUM function incorporates the new row as part of its new range.
Hence the SUM function and the + operator are adjusted in different ways for the insertion
of new data. We added the new row just for the purpose of making this point. Let's delete it
before proceeding. To do this we select row 5 again (remember, click the row number on
the left side) and then select Delete from the Edit menu.
As a final adjustment to the worksheet in this step, replicate the SUM function formula in
cell B10 to cells C10, D10, and E10.
5. Computing average sales per month for each region.
Next, we'll add formulas to calculate the average monthly sales for all three regions. The
following figure illustrates entering the appropriate formula for computing the Region 1
monthly average. Note that we're employing a built-in function AVERAGE. If we know
the function's name and purpose already, we can simply type the formula. Or we could
consult the function selection dialog box as we did for the SUM function earlier.
In the figure below, we're entering the formula directly. The figure illustrates also that
instead of typing in the range B3:B8, we can drag over that range of cells (note the dotted
box surrounding the selected range) to indicate the range when the time comes for the
function's argument to be entered in the formula. We would complete the formula shown
below by typing in the closing right parenthesis and then clicking the green check mark to
the left of the formula bar.
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Once the average is computed for Region 1, you should replicate the formula to cells C12,
D12, and E12 to compute monthly averages for the other regions and for the total monthly
sales.
6. Computing the standard deviation of the averages.
As a final illustration, let's suppose we wish to compute the standard deviation of the
averages we just calculated. Mimic the procedure given in Step 5 and enter a formula
employing the built-in function STDEV for computing the standard deviation for the
Region 1 monthly average. Consult the figure below for help if you need it. Now replicate
the standard deviation calculation to cells C13, D13, and E13.
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The completed worksheet should have the following figures in it. Check your work against
these numbers and locate and correct any errors.
7. An Exercise -- Computing Car Payments.
In this exercise you will get a chance to practice employing an Excel built-in function on
your own. Suppose you wish to compute the monthly payments you would have on a car
you'd like to buy. Suppose the car costs $10,000 and you know you can secure a 10%
annual interest rate loan for this amount. You'd like to do an analysis to decide what term
(pay-back time) you should try to get. Of course the longer the term, the lower your
monthly payments -- but the more interest you pay over the life of the loan. You want the
shortest term for which you can still swing the monthly payments.
Set up a worksheet like the one in the figure to calculate the various payments for different
terms. Note that you can type a long text string (like the one shown here in C2) and it will
overflow to adjacent cells to the right as long as there is no date in those cells.
Excel has a built-in function for computing loan payments. It is called PMT and can be
found in the financial function list as shown below.
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The arguments for the PMT function hold the interest rate (Rate) for the period in which
you're interested -- a month in this case, the number of periods (Nper) you expect to pay,
the present value (Pv) or amount of the loan, the future value (Fv) of the loan (this will be
0 if you intend to pay the loan off), and the type (Type) of payment to be made (this is 0 if
your payments begin at the end of the month you get the loan; 1 if the payments begin
immediately when you get the loan -- 0 is the most common option here).
Convince yourself that the arguments for your function should be those shown below.
The completed worksheet should have the following figures in it. Check your work against
these numbers and correct any errors. The parentheses and red type face indicates that these
numbers represent a payment (negative).
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7.4.2 What - if Analysis
What-if analysis is the process of changing the values in cells to see how those changes
will affect the outcome of formulas on the worksheet.
Three kinds of what-if analysis tools come with Excel: scenarios, data tables, and Goal
Seek. Scenarios and data tables take sets of input values and determine possible results. A
data table works only with one or two variables, but it can accept many different values for
those variables. A scenario can have multiple variables, but it can accommodate only up to
32 values. Goal Seek works differently from scenarios and data tables in that it takes a
result and determines possible input values that produce that result.
In addition to these three tools, you can install add-ins that help you perform what-if
analysis, such as the Solver add-in. The Solver add-in is similar to Goal Seek, but it can
accommodate more variables. You can also create forecasts by using the fill handle and
various commands that are built into Excel. For more advanced models, you can use the
Analysis Pack add-in.
Use scenarios to consider many different variables
A scenario is a set of values that Excel saves and can substitute automatically in cells on a
worksheet. You can create and save different groups of values on a worksheet and then
switch to any of these new scenarios to view different results. For example, suppose you
have two budget scenarios: a worst case and a best case. You can use the Scenario Manager
to create both scenarios on the same worksheet, and then switch between them. For each
scenario, you specify the cells that change and the values to use for that scenario. When
you switch between scenarios the result cell changes to reflect the different changing cell
values.
Worst case scenario
Changing cells
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Result cell
Best case scenario
Changing cells
Result cell
If several people have specific information in separate workbooks that you want to use in
scenarios, you can collect those workbooks and merge their scenarios.
After you have created or gathered all the scenarios that you need, you can create a
scenario summary report that incorporates information from those scenarios. A scenario
report displays all the scenario information in one table on a new worksheet.
Scenario summary report
NOTE Scenario reports are not automatically recalculated. If you change the values of a
scenario, those changes will not show up in an existing summary report. Instead, you must
create a new summary report.
Use Goal Seek to find out how to get a desired result
If you know the result that you want from a formula, but you are not sure what input value
the formula requires to get that result, you can use the Goal Seek feature. For example,
suppose that you need to borrow some money. You know how much money you want, how
long a period you want in which to pay off the loan, and how much you can afford to pay
each month. You can use Goal Seek to determine what interest rate you must secure in
order to meet your loan goal.
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NOTE Goal Seek works with only one variable input value. If you want to determine
more than one input value, for example, the loan amount and the monthly payment amount
for a loan, you should instead use the Solver add-in.
Use data tables to see the effects of one or two variables on a formula
If you have a formula that uses one or two variables, or multiple formulas that all use one
common variable, you can use a data table to see all the outcomes in one place. Using data
tables makes it easy to examine a range of possibilities at a glance. Because you focus on
only one or two variables, results are easy to read and share in tabular form. If automatic
recalculation is enabled for the workbook, the data in data tables immediately recalculates;
as a result, you always have fresh data.
A one-variable data table
A data table cannot accommodate more than two variables. If you want to analyze more
than two variables, you can use scenarios. Although it is limited to only one or two
variables, a data table can use as many different variable values as you want. A scenario
can have a maximum of 32 different values, but you can create as many scenarios as you
want.
7.4.3 Data Table sorting
Microsoft Office Excel 2007 introduces significant changes to sorting table data. You can
now sort up to 64 columns of data. You can also sort based on colors and custom lists. In
my previous Office Talk column about table filtering in Microsoft Office Excel 2007, I
briefly discuss changes to sorting features. One of the more important changes in sorting is
the elimination of the three-condition limit. You can now sort up to 64 columns. Office
Excel 2007 introduces updates to the Sort dialog box. Figure7.18 show sorting a table by
five columns.
More Sorting Options
The Sort dialog box is similar in behavior to the Conditional Formatting Rules Manager
dialog box that I discuss in the series of Office Talk columns on conditional formatting. For
more information, see Additional Resources. To create sort conditions, on the Data tab,
click Sort, and in the Sort dialog box, click Add Level. Like filters, sort levels change
based on data types. Office Excel 2007 uses that information to offer settings that are more
descriptive and easier to understand than "ascending" and "descending." For example, for
text columns, you have A to Z and Z to A sorting; for numeric columns, you can sort from
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Smallest to Largest and Largest to Smallest; and for date columns, you have Newest to
Oldest and Oldest to Newest sorts. You can reorder sort conditions by using the buttons at
the top of the Sort dialog box. You can also copy sort levels to save time. The Options
button opens the Sort Options dialog box, which allows you to specify whether the sort
should be case-sensitive and allows you to specify the sort orientation. Both of these
features existed in Microsoft Office Excel 2003 but are more discoverable in Office Excel
2007.
Figure 7.18 Sort Options dialog box
Sorting by Colors
The following example illustrates additional sort functionality introduced in Office Excel
2007. Assume you have the following table of formatted data.
Figure7.19 Sample table with formatted data
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One of the common requests from Excel users is the ability to sort by color, either
manually applied or applied by conditional formatting. In Office Excel 2007, you can sort
by:
• Background color (however applied)
• Font color (however applied)
• Cell icon (applied by using conditional formatting)
For example, you can set up several conditions on the table data as seen in Figure 7.20.
Figure 7.20 You can easily set up multiple sort conditions
When you click OK, Office Excel 2007 applies the sort starting from the top. Notice the
buttons at the top of each column indicate that the column is being sorted. The filter state is
displayed here if a filter is applied.
Figure 7.21 Buttons at the top of each column provide sorting and filtering status
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In addition to sorting by built-in values and color, you can specify a custom sort order by
selecting Custom List at each level of sorting. You can create a custom list from the Sort
dialog box.
Figure 7.22 You can specify a custom list to sort by
Sorting by Cell Color
In Office Excel 2007, you can sort by color or cell icon by using in-grid filter capabilities
(also known as AutoFilter). For example, assume that you have the table shown in Figure
7.23
Figure 7.23 Sorting by Cell Color
To sort the table data so that all of the yellow and green items appear at the top of the
column, use the sort button to sort first by the green background.
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Figure 7.24 Sort first by green background
This organizes all of the green values at the top of the column.
Figure 7.25 Result of sorting on the color green
Next, repeat the procedure for the yellow items. This results in the following table.
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Figure 7.26 Result of sorting on two colors sequentially
Sorting by color moves all rows that meet the criteria to the top of the table. This capability
is also added to the context menu in a table or filtered range. For example, in the table
shown in Figure 6, you can right-click a cell with a green background and select Put
Selected Cell Color on Top in the Sort submenu.
Figure 7.27 Sorting by using the context menu
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Sorting with Custom Lists
Next, consider an example that illustrates how to sort on a custom list of values. Assume
you have a table with a column of modes of transportation.
Figure 7.28 Column of text values
First, in the Sort dialog box, specify the column name and then, in the Order list, select
Custom List. Click OK.
Figure 7.29 Select Custom List in the Order drop-down
In the Custom List dialog box, select NEW LIST and then type in the data values
separated by commas. Click OK when you are finished.
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Figure 7.30 Resulting table after sorting on a custom list
The table is now sorted by the custom list of values you specified.
Figure 7.31 Sorted column
Conclusion: The ability to sort up to 64 columns of data gives you greater control over
how your data appears. Likewise, sorting by cell color or font color enables you to put the
data that is important to you at the top of the table column or a range. The ability to sort
user-defined lists of values allows you to customize tables in a way that is relevant to your
needs.
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7.5 MS-EXCEL-III
-------------------------------------------------------------------------------------------------------------7.5.1 Graphs and Charts: A graph is a chart or drawing that shows the relationship
between changing things. They are a diagram displaying the relationship between numbers
or amounts. Common graphs use bars, lines, or parts of a circle to display data. Below are
the steps given to insert Graphs and charts. They are:
Step 1 - Enter the data to be graphed. For the purpose of this lesson you will use data from
a Favorite Fruit Survey. Enter it as you see below:
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Step 2 - Highlight data to be graphed. Do not include the row with heading titles, only the
names of fruit and the numbers. If your worksheet looks like the one above; put your cursor
in call A2, click hold the mouse button down and drag to cell B7. Highlighted data should
look like the image below:
Note: Cell A2 is selected; the select color extends around the cell
Step 3 - Select the Chart Wizard. That is done by going to the Insert menu and selecting
Chart. You can also click on the Chart Wizard button on the Standard toolbar.
Step 4 - From the Chart Wizard box that opens select Chart type. For this activity, I
selected pie.
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After you have selected the Chart type, click and hold your mouse pointer down on the
Press and Hold... button to see what your data looks like in the chart type you selected. If
you do not like the look, select another chart type. After you have selected the chart type
you will have two options:
• Select Next and let Chart Wizard show you a series of options to make changes to
your chart.
• Select Finish and Chart Wizard puts your completed chart on the spreadsheet. You
can see the finished product below.
The first step taken by Chart Wizard is to verify the range of data being used for this chart.
The Data range displayed below is read "all cells from A2 to B7."
Notice where the cursor is located in the dialog box above. It is pointing to the small box at
the end of the line where the Data range is displayed. If the data range should be changed,
click on the box the cursor is pointing to.
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The dialog box shrinks allowing you to see your entire spreadsheet. You can edit the data
range in this small window. When you are finished, click the same box at the end to restore
the window.
Select Next to go to the dialog box below. This box allows you to add a title to the chart,
make changes on the legend, or make changes on the data labels.
Select Next to move to the final dialog box which allows you to see the chart as a new
sheet or place it on one of the sheets in your workbook.
If you let the Chart Wizard finish your chart after the first dialog box, or work through
each of the four steps, your chart will look something like the one below.
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--------------------------------------------------------------------------------------------------------------
7.6 REVIEW QUESTIONS
-------------------------------------------------------------------------------------------------------------1. State whether the following statement True (T) or False (F) :
a) MS-Word has the facility of Macros.
b) Mouse setting can be changed from control panel.
c) Print preview option is in edit menu
d) In MS-Word a table consists of rows and columns.
e) Using the Edit option you can switch over from Normal mod to outline
mode.
f) The tool bar allows you to format the vertical alignment to text.
g) Mail merge option is in table menu.
h) Del key removes the one character form the left position. A byte is equal to
8 bits.
2. Answer the following Questions briefly:
a) Write the steps to insert a page break
b) Write the steps to insert table
c) How will you move a paragraph in MS-word?
d) Write any four features of Word Processing.
e) How to insert rows and columns in a table?
f) What is the Auto Correct feature used for?
g) Write the steps in creating a chart in Ms Excel
h) Distinguish between the following:
• save and save as; and
• cut past and copy past.
i) How to convert text in to a column?
j) Explain how to create a MS-Excel work sheet to calculate the employee
pay. Find out the gross pay, detection and net pay.
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--------------------------------------------------------------------------------------------------------------
OFFICE AUTOMATION SYSTEMS - PART II
--------------------------------------------------------------------------------------------------------------
Structure
8.1 Ms PowerPoint-I
8.1.1 Starting Microsoft PowerPoint
8.1.2 Auto Layout
8.1.3 Toolbars
8.1.4 Insertion of New Slides
8.2 MS PowerPoint-II
8.2.1 Apply a Design Template
8.2.2 Presentation Using Chart Wizards
8.2.3 Frame Movements of The Above
8.3 Review Questions
--------------------------------------------------------------------------------------------------------------
8.1 MS POWERPOINT-I
-------------------------------------------------------------------------------------------------------------Microsoft PowerPoint is a powerful tool to create professional looking presentations and
slide shows. PowerPoint allows you to construct presentations from scratch or by using the
easy to use wizard.
8.1.1 Starting Microsoft PowerPoint
Two Ways
Double click on the Microsoft PowerPoint icon on the desktop.
Click on Start --> Programs --> Microsoft PowerPoint
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Creating & Opening a Presentation: After you open up Microsoft PowerPoint, a screen
pops up asking if you would like to create a New Presentation or Open an Existing
Presentation.
•
AutoContent Wizard
o Creates a new presentation by prompting you for information about content,
purpose, style, handouts, and output. The new presentation contains sample
text that you can replace with your own information. Simply follow the
directions and prompts that are given by Microsoft PowerPoint.
•
Design Template
o Creates a new presentation based on one of the PowerPoint design templates
supplied by Microsoft. Use what is already supplied by Microsoft
PowerPoint and change the information to your own.
•
Blank Presentation
o Creates a new, blank presentation using the default settings for text and
colors.
8.1.2 Auto Layout
After you have opened a new presentation, PowerPoint displays the New Slide dialog box
containing several Auto Layouts. Auto Layouts provide a pre-determined layout for each
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specific type of slide. They provide consistency throughout the presentation. Each layout
depicted is described in the lower right corner when you click the layout. This sample New
Slide dialog box shows the Title Slide selected (denoted with the thick border).
After you select Blank Presentation a window pops up asking you to select the layout of the
first slide.
Pre-Designed Slide Layouts (Left to Right)
• Title Slide
• Bulleted List
• Two Column Text
• Table
• Text & Chart
• Chart & Text
• Organizational Chart
• Chart
• Text & Clip Art
• Clip Art & Text
• Title Only
• Blank Slide
NOTE: If you already know what you want in your next slide, it is a very good idea to
choose one of the pre-designed layouts from above. However if you do not, then you
can still insert what you want in throughout your Presentation anytime you desire.
Just choose Blank Slide and insert items as you see fit.
Different Views That PowerPoint Demonstrates:
There are different views within Microsoft PowerPoint that allow you to look at your
presentation from different perspectives.
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Normal View
Outline View
Slide View
Slide Sorter View Slide Show View
Switches to
normal view,
where you can
work on one slide
at a time or
organize the
structure of all the
slides in your
presentation
Switches to
outline view,
where you can
work with the
structure of your
file in outline
form. Work in
outline view when
you need to
organize the
structure of your
file.
Switches to slide
view, where you
can work on one
slide at a time
Displays
Runs your slide
miniature versions show in a full
of all slides in a screen, beginning
presentation,
with the current
complete with
slide if you are in
text and graphics. slide view or the
In slide sorter
selected slide if
view, you can
you are in slide
reorder slides; add sorter view. If you
transitions, and
simply want to
animation effects. view your show
You can also set from the first
the timings for
slide:
electronic slide
Click Slide Show
shows.
at the top of the
screen
Select View
Show
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8.1.3 Toolbars
Toolbars include important components for developing a presentation. A toolbar is an
onscreen bar which contains shortcut buttons. These allow easy access to frequently used
commands. You can easily get to the toolbars you need by telling PowerPoint which ones
to display.
PowerPoint includes 13 toolbars including commonly used ones such as the Standard,
Formatting, Drawing, Picture, and E-mail toolbars. You don't need all of them at once, and
some you may seldom use so you don't want them taking up space on your screen. You can
pick and choose which toolbars are visible, and once you know how to turn toolbars on and
off, you can always get to the toolbar you need.
Display and Hide PowerPoint Toolbars
Click View. Then click on Toolbars. A fly-out menu will appear with a list of all of the
Windows toolbars and any others that you may have installed from other applications on
your computer.
In the list of PowerPoint toolbars, the ones with the check mark next them are visible.
The ones without a checkmark are hidden.
To make a toolbars visible, simply click on its name in the list, a checkmark will appear
next to the toolbar name in the list and the toolbar will become visible in your PowerPoint
workplace. Check the toolbar you want to be visible and repeat as necessary.
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You can also right-click on any existing toolbar and check or uncheck any entry in the
shortcut menu.
You can also right-click your mouse anywhere in a toolbar area and the list of PowerPoint
toolbars will appear. From here you can turn toolbars on or off.
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Moving and Changing the Toolbars:
You can reposition toolbars on the presentation you are working on. You can also resize
toolbars so that all or only a few of the buttons contained in them are visible.
Each toolbar has four vertical dots that help you move them to a fixed position on the
screen or to floating positions on the screen. To move a toolbar, click the four dots that are
found on the left end of each toolbar.
Note that when you choose to view a toolbar, it appears in the position in which it was most
recently used. It was last docked at the bottom of the screen, then that's where it will appear
again when it is turned back on. You may need to experiment with various toolbar
locations until you find the arrangement that works best for you.
Creating Your Own Toolbar:
You can create your own customized toolbar. Right click any toolbar and hit Customize. In
the Customize dialog box. Select the toolbars tab and click New. Name the toolbar and
allocate a template.
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In the Toolbars list, click the toolbars you want to display. Click Close, and the toolbars
you selected appear on the workspace.
8.1.4 Insertion of new slides
To create a new slide:
1. Do one of the following:
• Choose Insert > New Slide from the menu.
• Click the New Slide button
.
• Press Ctrl-M.
The Apply Slide Layout pane will appear on the right side of the screen. The Apply Slide
Layout pane provides you with slide templates you can use when creating your PowerPoint
presentation. There are four types of Text Layout templates.
Title Slide - The Title Slide contains two text placeholders that you can use to display a
title and a subtitle of your presentation.
Title Only - The Title Only slide contains a single placeholder. You can use it to display a
title.
Title and Text - The Title and Text template provides a placeholder for a title and a
placeholder for text.
Title and 2 Column Text - The Title and Text template provides a placeholder for a title
and two placeholders for text.
2. To select a layout, click the layout you want in the Apply Slide Layout pane. The
layout will then appear in the Slide pane.
3.
4.
To add text, click inside the placeholder and type.
To add an additional slide to your presentation do one of the following:
• Right-click on the slide layout. A menu will appear. Choose Insert New Slide.
• Click the down arrow next to the slide layout. A menu will appear). Choose Insert
New Slide.
Change Your Slides
After creating a slide, if you want to add text:
1. Place the cursor at the point at which you would like to add text.
2. Type the information you want to add.
If you would like to change text:
1. Highlight the text you want to change.
2. Type the new text.
You can use the backspace key to delete text. You can also delete text by highlighting the
text and pressing the Delete key.
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--------------------------------------------------------------------------------------------------------------
8.2 MS POWERPOINT-II
-------------------------------------------------------------------------------------------------------------8.2.1 Apply a Design Template
.
1. Click the design icon
2. Design templates will appear on the left side of the screen.
3. Scroll down to view the design templates.
4. Right-click the design template you want to apply. A context menu will appear. Choose
Apply to All Slides. We used the Lock and Key design template.
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Outline and Slides Tab
1.
Use the Slides tab to view thumbnails of your slide.
2.
Click the Outline tab to view the text of your presentation as an outline.
Slide Sorter View
1. Choose View > Slide Sorter from the menu to move to Slide Sorter view.
2. Double-click a slide to return to Normal view.
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Run Your Slide Show
1. Press F5 to run the Slide Show.
2. Use the arrow keys on your keyboard to move forward and backward through your
slides.
3. Use the Esc key to return to Normal view.
Print Your Outline
1. Choose File > Print Preview from the menu.
2. Click the down arrow next to the Print What icon.
3.
Select Outline view.
4. Click the Print icon.
5. Click Close.
Print Your Slides
1. Choose File > Print Preview from the menu.
2. Click the down arrow next to the Print What icon.
3. Select the slides you want to print.
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4.
5.
6.
7.
Click the down arrow next to Options. A menu will appear.
Choose Color/Grayscale > Pure Black and White.
Click the Print icon.
Click Close.
Print Your Slides as a Handout
1. Choose File > Print Preview from the menu.
2. Click the down-arrow next to the Print What icon.
3. Select Handouts (2 Slides per Page).
4. Click the Print icon.
5. Click Close.
8.2.2 Presentation using Chart Wizards
a) To animate a single object on a PowerPoint slide
1. Select the object.
2. Choose SLIDE SHOW: Preset Animation.
3. Select the animation effect you desire for the selected object.
Animated Layers or Slides you may find it useful to bring a layered object into a
presentation one layer at a time, building it on-screen. To animate a layered object or to
animate each object on a slide:
1.
2.
Choose SLIDE SHOW: Custom Animation. (You must be in Normal, Outline, or
Slide View.)
In the Custom Animation dialog box, each object is identified in the Check to
animate slide objects list.
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3.
4.
5.
6.
(If you don't remember what a particular object is), click the object's name in the list;
that object appears selected in the preview window.
Click in the object's checkbox to animate that object. It will be added to the
Animation order list.
To change the order that the animated objects appear, select the object in the
Animation order list, then click the up or down arrow to move the object through the
list.
Choose whether the object appears only on a mouse click or after a specified number
of seconds.
To choose other effects such as sound effects and how the object appears on the slide
during the on-screen presentation, click on the Effects tab.
To animate text:
1. Click on the Effects tab.
2. In the Introduce Text section, from the drop-down box, choose whether the text is
introduced all at once, by word, or by letter.
To animate charts click the Chart Effects tab. You can choose to introduce the data by
series, categories, or elements.
NOTE: Be careful of using too many effects in any single presentation because they soon
become detraction to rather than an enhancement of the presentation.
b) Create a Presentation Using the AutoContent Wizard in Microsoft PowerPoint
1.
2.
In PowerPoint, click Getting Started to open the dropdown menu
Select New Presentation from the menu
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3.
4.
Click From AutoContent Wizard
The AutoContent Wizard opens. In the opening pane, click Next and you arrive
at the second pane
5.
Click a category from one of the following:
• All: Lists all slide presentations in all categories. You can scroll the window
and select a slide presentation to create from the list
• General: Displays a list of general business topics
• Corporate: Displays a list of corporate topics such as business plans,
financial reports, employee orientation, and so on
• Projects: Lists presentations that might be used in a planning process
• Sales/Marketing: Lists presentations suited for a marketing program
6. Click a presentation from within a category and click Next to move to the next pane
7. Select an output option from one of the following:
• On-Screen Presentation: Click this radio button to create a presentation that
is intended to be shown on your computer or on a projector connected to your
computer
• Web Presentation: Click this radio button for a slide presentation that you
want to show on a Web site
• Black and White Overheads: Click this radio button if you want to print
your slides on clear acetate on a black-and-white laser printer
• Color Overheads: Click this radio button if you want to print your slides on
clear acetate on a color printer
• 35mm Slides: Click this radio button if you want to print your slides on a
commercial film recorder that outputs to 35mm slides
8. Click Next to advance to the next pane
9. Type a title for your presentation in the Presentation Title text box
10. Type a footer in the Footer text box if you want a footer to appear on your slides
11. Click Next in the wizard to advance to the last pane in the wizard
12. Click Finish to complete the slide creation and open it in PowerPoint
13. Edit the presentation to customize it for your own needs.
8.2.3 Frame movements of the above
Using the Slide Sorter
The Slide Sorter shows a thumbnail of each slide in the presentation. From this
view, it is easy to rearrange the presentation, make duplicate slides, delete slides, and place
transitions into the presentation. To place your presentation in Slide Sorter View, click
the Slide Sorter Tool. The current slide is denoted by a thicker border.
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To select a different slide, click the slide you wish to become current.
To duplicate or delete the current slide, choose EDIT: Duplicate (or Delete) Slide.
PowerPoint provides visual indicators beneath each slide showing any slide transition, text
animation, or advance timing that you have applied to that slide.
Using Transitions:
Transitions determine the effects applied when you move from one slide to another during
an on-screen presentation. You must be in Slide Sorter View to access the Transition
Toolbar.
To choose only a transition effect, click the dropdown box beside the words "No
Transition" and select a transition. To have other transition choices available to you, click
the Slide Transition Tool.
When you click the Slide Transition Tool, the Slide Transition dialog box allows you to
choose not only a transition effect from a drop-down box, but also offers other choices that
affect your on-screen presentation.
TIP: Don't use a different transition on each slide because your audience's attention should
remain focused on you and the content, not the effects. If you want to use multiple
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transitions, a good rule of thumb is to apply a unique transition to each slide in a specific
module of the presentation.
Generally, you should leave the Effect Speed set to Fast. This brings in the next content
slide quickly and keeps your audience's attention focused on the presentation content.
PowerPoint contains a few built-in sounds. To play a sound as the slide is transitioning,
make a sound selection from the Sound drop-down box. Unless you have a well thought
out reason for doing so, don't choose to have the sound loop until the next sound; it can
become annoying very fast while you're giving a presentation, as well as making it difficult
for you to speak over. Also, many presentation locations don't have adequate speakers
attached to the computer to allow all of your audience to hear the sound.
Advance determines when the current slide proceeds to the next.
On mouse click advances the presentation to the next slide, or displays the next bullet
point, only when you click the mouse. (You can also use the keyboard arrow keys or the
spacebar.)
Automatically after xx seconds, makes the transition xx seconds after the preceding
transition ended.
NOTE: Make sure that if you select automatically, that you remove the check in on mouse
click.
For self-running presentations that function similar to a kiosk presentation where your
audience may stop, watch, then leave, generally you will want to set the advance to 3-5
seconds.
For a self-running presentation where you are speaking in synchronization with the
presentation, generally you will want to set the advance to 3-5 minutes.
Rehearse Timings
The Rehearse Timing Tool allows you to practice giving an on-screen presentation,
regardless of any slide advance timings you may have set previously. The tool times not
only the entire presentation, but also each individual slide, as you rehearse. Each time you
advance the slide, the time is recorded. You must be in Slide Sorter View to access the
Rehearse Timing Tool.
To use the Rehearse Timing Tool, click the Rehearse Timing Tool. When you have
completed rehearsing, PowerPoint displays the total time for the rehearsed presentation and
ask if you want to record the new timings. If you click "Yes," these new timings will
replace any slide advance timings you may have previously set for the presentation.
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Bullet Effects:
The Text Preset Animation Tool controls how bulleted points appear on the slide during an
on-screen presentation. You must be in Slide Sorter View to access the Text Preset
Animation Tool.
To animate bulleted points, the slide containing bulleted points must be the current slide.
Then click the drop-down box and choose the animation effect you desire.
Hidden Slides
You can hide slides within a presentation. Hidden slides remain available as part of the
saved presentation and are accessible to you during development or in future presentations
but do not appear as one of the consecutive presentation slides during a show.
You must be in Slide Sorter View to access the Hidden Slide Tool. To hide a slide,
make sure it is the current slide, and then click the Hide Slide Tool.
Hidden slides display in Slide Sorter View with a slash through the slide number.
Slide View does not differentiate between hidden and non-hidden slides, and all are
displayed. During presentation, however, hidden slides are passed over unless specifically
chosen by you through the Slide Show Navigator.
--------------------------------------------------------------------------------------------------------------
8.3 REVIEW QUESTIONS
-------------------------------------------------------------------------------------------------------------1. How to create 5 slides using different design templates?
2. How to make an effective presentation?
3. Explain the steps of AutoContent Wizard to create presentations.
4. What are the basic component of a slide?
5. Explain the steps to create a title slide.
6. How to create a slide show with time delay and user input?
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--------------------------------------------------------------------------------------------------------------
OFFICE AUTOMATION SYSTEMS - PART III
--------------------------------------------------------------------------------------------------------------
Structure
9.1 Introduction to Ms Outlook
9.1.1 How to Set Up Outlook Express
9.1.2 New For Outlook 2000
9.1.3 Exploring Outlook 2000
9.1.4 Exploring Inbox
9.2 Difference between Outlook Express and Microsoft Outlook
9.3 Computer in Office Automation
9.3.1 Office Automation Technologies
9.4 Computers in Engineering
9.5 Review Questions
--------------------------------------------------------------------------------------------------------------
9.1 INTRODUCTION TO MS OUTLOOK
-------------------------------------------------------------------------------------------------------------Microsoft Office Outlook or Outlook is a personal information manager from Microsoft.
The 2007 version is available both as a separate application as well as a part of the
Microsoft Office suite.
Microsoft Outlook 2000 helps you to organize, find, and view all of this information—all
in one place. It is easy to use, like the other programs in the Office suite, provides an
integrated approach to the Web. Outlook 2000 offers e-mail and collaboration features
when used with Internet-based messaging systems and even more advanced functionality
when used on an intranet with Microsoft Exchange Server.
Microsoft Outlook 2000 messaging and collaboration client provides the following
capabilities:
• Electronic mail
• Personal calendar and group scheduling
• Contact information and task list
• Custom collaboration and information-sharing programs
9.1.1 How to Set Up Outlook Express
Before you can use Outlook Express to send and receive e-mail, you need to set up an
account. You can have more than one account—for business, online shopping, and so on—
and each person who uses your computer may have their own, completely separate account.
Outlook Express gracefully handles it all.
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Start Outlook Express
There are many ways to start Outlook Express, but here's a sure-fire way to find and start it.
1. Click the Start button.
2. Point to All Programs.
3. Click Outlook Express.
These first three steps are shown in the image below:
Fig 9.1 Opening Outlook Express from the Start menu
4. If asked whether you'd like to open this particular account automatically every time you
start Outlook Express, click Yes (if you do) or No (if you don't). If you don't want to be
asked this question again, click to check the Always perform this check... box.
5. Check When Outlook Express starts, go directly to my Inbox.
Outlook Express directs all incoming mail to the Inbox, so it makes sense to bypass this
opening page.
If you don't see the list of folders and contacts on the left, click Layout on the View menu.
Click Contacts and Folder List to check them, and then click OK.
Fig 9.2 Outlook Express list of folders
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Quick start. You'll notice that when you use Outlook Express regularly, Windows XP will
put the Outlook Express icon on the Start menu (along with other programs you've used
recently). In that case, just click the Outlook Express icon in the Start menu to open the
program.
Set Up an Outlook Express E-Mail Account ; The Internet Connection Wizard makes
short work of setting up your online mailbox by walking you through each step for every email account you set up.
1. Before you get going, make sure you know your email address along with the following
information. (You may need to contact your ISP, Internet Service Provider, to get it.)
First, information about the e-mail servers:
¾ The type of e-mail server you use: POP3 (most e-mail accounts), HTTP (such as
Hotmail), or IMAP
¾ The name of the incoming e-mail server
¾ For POP3 and IMAP servers, the name of the outgoing e-mail server (generally
SMTP)
Second, information about your account:
¾ Your account name and password (For some solid advice about making a secure
password, read the Create strong passwords article.)
¾ Find out if your ISP requires you to use Secure Password Authentication (SPA) to
access your e-mail account—yes or no is all that's required.
2. Start Outlook Express, and on the Tools menu, click Accounts.
3. If the Internet Connection Wizard starts up automatically, skip ahead to step 4. Click
Add, and then click Mail to open the Internet Connection Wizard
Fig 9.3 Mail option from the Add button
4. On the Your Name page of the wizard, type your name as you want it to appear to
everyone who gets e-mail from you, and then click Next.
5. Most people use their full name, but you can use any name—even a nickname—that
people will recognize.
6. On the Internet Explorer Address page, type your e-mail address, and then click
Next.
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Fig 9.4 Internet Connection Wizard's E-mail Server Names
Note: If you chose HTTP as your incoming e-mail server—as for a Hotmail or MSN
account—this wizard page changes slightly so you can identify your HTTP mail service
provider.
7. On the Internet Mail Logon page, type your account name and password.
Fig 9.5 Internet Connection Wizard's Internet Mail Logon
Note: If you're concerned about break-ins to your e-mail, click to clear the check in the
Remember Password box. You'll then be prompted for the password each time you send
or retrieve mail.
8. Click Next, and then click Finish.
You're ready to send your first e-mail!
Unsure if your new e-mail account is working? Send an e-mail message to a friend. If
they get the message, your account is ready to roll! But if you run into problems setting up
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your account, Outlook Express offers help. Search for troubleshooting topics from
Contents and Index on the Help menu.
Set Up a Web-based E-Mail Account
The e-mail that you get in a Hotmail account and other Web-based accounts is not stored
on your hard disk, but is kept on the account-provider's computer. That's what makes it
possible to access your account from any computer in the world over the Internet. Here's
how you set yourself up.
1. Go to the Web site and follow the setup instructions—for example,
http://www.hotmail.com/ for Hotmail.
2. Set up Outlook Express to use the account, by following the instructions above in Set up
an Outlook Express e-mail account.
If you share your computer with someone else, take advantage of Fast User Switching. A
feature of Windows XP, it lives up to its name by enabling you to switch among users on a
single computer without closing any programs you are running or logging off.
¾ To turn Fast User Switching on, open User Accounts in Control Panel. Click
Change the way users log on or off. Make sure the Use Fast User Switching box
is checked.
¾ Then, to switch users, click Start, click Log off and then click Switch User. On the
Welcome screen, click the user account you want to switch to. That's it!
Close Outlook Express
In closing, Outlook Express works just as all other Windows programs do.
Ì On the File menu, click Exit.
Tip: For a fast way out, press ALT+F4.
Version
Number
Name
Release Date
Notes
Outlook for
MS-DOS
-
-
Bundled with Exchange Server 5.5
Outlook for
Windows 3.x
-
-
Bundled with Exchange Server 5.5
Outlook for
Macintosh
-
-
Bundled with Exchange Server 5.5
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Outlook 97
Outlook 98
8.0
January 16,
1997
8.5
Freely distributed with books and magazines
June 21, 1998 for coping with newest Internet standard such
as HTML mail
Outlook 2000
Outlook 2002 10
9.0
June 7, 1999
Included in Office 97 and also bundled with
Exchange Server 5.5.
Included in Office 2000 and also bundled
with Exchange 2000 Server.
May 31, 2001 Included in Office XP.
Office Outlook
11
2003
October 21,
2003
Included in Office 2003 and also bundled
with Exchange Server 2003.
Office Outlook
12
2007
November
30, 2006
Included in Office 2007, except Office Home
and Student edition.
Table 9.1 Versions of Microsoft Outlook
9.1.2 New for Outlook 2000
Whether you are a new user to a messaging and collaboration client or are already familiar
with it, you will want to discover the new features that are present in Outlook 2000:
Preview Pane: A preview window that appears in the Inbox, allowing you to view e-mail
messages quickly without opening the message. The Preview Pane is now available for
viewing items in all Outlook 2000 folders.
Automatic spell check in multiple languages: Microsoft Word 2000 can serve as an email editor, offering Language AutoDetect spell check and proofing support.
Run Rules Now: You can manually apply any of these rules to any Outlook 2000 folder at
any point of time.
Direct booking of resources: Reserve conference rooms without dedicated-resource
computers running.
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Enhanced Mail Merge: You can filter the Contacts list in Outlook 2000 as desired and
then pass the contacts to the Microsoft Word Mail Merge and merge on any Outlook fields.
Outlook Bar shortcuts: You can easily create a shortcut on the Outlook Bar to any file,
folder, or Web page.
Find Exchange Server Public Folder: Outlook 2000 can search on Microsoft Exchange
Server Public Folder properties to locate items in public folders.
Web integration: You can view a contact's personal Web page, post your calendar to a
public folder for viewing on the Web, and share information within Outlook 2000.
Folder home pages: You can associate one or more Web pages with any personal or
Exchange Server folder.
View the Web: Clicking any Outlook Bar shortcut to a Web page, displays the Web page
in the right Outlook pane. Basic Web navigation is supported and the currently displayed
page can be opened in your default Web browser.
Internet group scheduling and iCalendar support: Group scheduling is possible over
the Internet. You can publish and download free/busy information for scheduling meetings,
as well as send and receive meeting requests and responses over the Internet.
Online meetings: You can easily schedule real-time meetings and automatically start the
Microsoft NetMeeting conferencing software.
Microsoft NetShow™ Integration: You can easily schedule your time to watch
broadcasts via Microsoft NetShow services and automatically start Microsoft NetShow at
the designated time.
Save as Web page: You can save Outlook 2000 items as HTML, making it easy to save
your course calendar, schedules, and even your contacts to a Web page.
HTML Mail: Outlook 2000 fully supports sending and receiving of e-mails in HTML.
Mails can be anything from simple formatted text to a complete Web page. Outlook 2000
also includes HTML stationery with different fonts and backgrounds.
9.1.3 Exploring Outlook 2000
In Outlook 2000 you will find folders from which you can create tasks and contacts,
schedule meetings and appointments, and send and receive messages. You can also switch
easily between these folders, from the Outlook Bar or the Folders list or can create any new
Outlook item from within any Outlook folder. On using the Office toolbar, you can even
create Outlook items from other Office 2000 programs.
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Toolbars: You will find that the Standard and Web toolbar features in Outlook 2000 are
similar to those in other Office programs. For each Outlook folder, you can also display
“Advanced toolbar” that gives you ready access to more features specific to Outlook 2000.
To display toolbars, click View, point to Toolbars, and select those you want to make
visible.
Outlook Today: The Outlook Today window provides a preview of your day. By using
Outlook Today, you can see a summary of your appointments, a list of your tasks, and how
many new e-mail messages you have. You can set this page to be the first page that opens
when you start Outlook 2000, and you can customize Outlook Today to provide the
information that you need.
Click Send/Receive to send and
receive e-mail messages if you
have a dial-up connection.
Click this button to
customize the
Outlook Today
settings.
Web Toolbar
Standard Toolbar
Advanced Toolbar
Folder list
The number in
parentheses
indicates how
many unread
e-mail messages
you have.
Displays the scheduled
tasks for today, whether
the task has been
completed, and the
priority level for each
task.
Fig 9.6 MS Outlook
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Indicates how many
unread e-mail
messages are in the
Inbox folder.
9.1.4 Exploring Inbox
Electronic mail, or e-mail, is quickly becoming one of the most widely used forms of
communication in the world. It is fast, convenient, and doesn't require a stamp. Using email, you can send a simple text message, like a reminder about an assignment or you can
send a message that includes other files, such as a grade report spreadsheet or graphic file.
With a microphone, you can even send voice messages.
Using e-mail can be beneficial for students and enhance instruction in many ways, from
making it easier to ask questions to providing a forum for out-of-class discussions and
collaboration. It can provide meaningful contact outside the classroom with instructors and
peers. E-mail is easy to use and is becoming more and more accessible to students through
their home computers or an information appliance like Microsoft Web TV. A few minutes
of instruction can get most students (and instructors) up and running with e-mail.
More Inbox symbols:
Inbox symbols:
Accepted meeting request
High importance
message
Tentatively accepted meeting
request
Low importance
message
Declined meeting request
Read message
Canceled meeting
Unread message
Task request
Forwarded message
Accepted task
Replied to message
Declined task
Message is flagged for follow
up
Saved or unsent
message
Message is flagged as
complete
Sealed message
Digitally signed
message
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The following illustration shows the Inbox window in Outlook 2000. In this window you
can receive, compose, send, and organize e-mail messages.
Forwarded—
This arrow indicates that this
message has been forwarded.
Bold—
Messages displayed in bold
have not been read.
Web toolbar
Standard
toolbar
Advanced
toolbar
Folder list—
Use this list to
organize your
messages in
personal folders.
Status bar—
Displays the
number of
messages in
your Inbox and
the number of
messages
unread.
Preview pane—
Displays a preview of the
highlighted message in
your inbox.
Creating and sending e-mail messages
There are two ways to send e-mail messages using Outlook 2000: You can either open
Outlook 2000 and begin a new message there or you can open any Office 2000 program,
create a document, and send it directly to e-mail from that Office program.
To create and send an e-mail message from Outlook 2000
• Start Outlook 2000.
• On the Actions menu, click New Mail Message. Or, on the Standard toolbar, click
New Mail Message . To send a message on stationery, on the Actions menu,
point to New Mail Message Using, click More Stationery, and then select a
background. The New Message window opens.
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•
In the To field, type the e-mail address of the person to whom you are sending the
message. If you are sending to more than one person, type a semicolon (;) between
the e-mail addresses.
Or –
•
•
•
•
•
•
•
•
Click “To” to open your address books. Select an address book and double-click a
name. The address moves to the To Message Recipients field.
Repeat the above step to add more e-mail addresses to the “To” field.
To send a carbon copy (CC) to someone, click the CC field. Type the e-mail
address in the field, or click CC, choose an address from one of your address books,
and click OK. Repeat to CC other people.
To send a blind carbon copy (BCC) to someone (to CC someone without the other
message recipients knowing the person received the message), on the View menu
select Bcc Field. Type the e-mail address in the field, or click BCC, choose an
address from one of your address books, and click OK. Repeat to Blind CC other
people.
To add a subject line to the message, click in the Subject field and then type a brief
line regarding the subject of the message.
Click in the blank field below the Subject field (the message field) and type your
message.
When you are satisfied with your message, click Send. The message automatically
moves to your Outbox folder and you return to the main Inbox window.
If you are always connected to the network and Internet connection, your message
is automatically sent.
Or -
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•
•
If you are not already connected to the Internet, click Send/ Receive to connect to
the Internet and send the message.
When the message has been sent, it moves to the Sent Items folder. If the message
cannot be delivered to someone, you usually, but not always, receive an automatic
reply letting you know who could not be reached and why.
To attach a file to a message from Outlook 2000
In Outlook 2000, address and compose a text message as described in the “To create and
send an e-mail message” section of this chapter.
•
•
•
•
To attach a file to the message, position the cursor in the message field where you
want to insert the file. This can be at the beginning, at the end, or anywhere in
between.
On the Insert menu, click File. Or, click the Insert File button on the Standard
toolbar. The Insert File dialog box opens.
Locate the file you want to attach. Click the file and then click OK. An icon
representing the file labeled with the file name appears in the message field.
-OrClick on a file and drag it to the message field.
To create and send an e-mail message from another Office 2000 program
All Office 2000 programs integrate e-mail into their core functionality. You can send any
document as a message or an attached file from directly within an Office 2000 program.
•
•
•
•
•
•
Open the Office 2000 program of your choice.
Open an existing document or create a new one and save the document.
On the File menu, point to Send to. A submenu appears.
On the submenu, you have two choices for sending the document. Select one:
9 To send a copy of this document as the text of the e-mail message, click
Mail Recipient. The document becomes the body text of a new e-mail
message.
9 To send a copy of the document as an attachment to the e-mail message,
click Mail Recipient (as Attachment). The document becomes an attachment
to a new e-mail message.
If you select Mail Recipient, click Send Copy to send the message.
-OrIf you select Mail Recipient (as Attachment), click Send to send the message.
Receiving and replying to e-mail messages
•
•
When Outlook 2000 receives messages, it stores them in the Inbox folder. The
number next to the word “Inbox” in the Folder list tells you how many messages are
waiting for you. If there is no number, you have no new messages.
When you click the Inbox folder in the Folder list, the contents of the folder are
displayed on the upper, right portion of the window, which is called the Message
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List pane. The Message header shows the subject and author of the messages in the
Inbox. If a message header is bold, that message has not yet been read. If the
message header is not bold, the message has been opened.
To receive and read messages
• Open Outlook 2000.
• If you are always connected to the network and the Internet, any messages sent to
you are automatically received to the Inbox folder. If you have new messages, an
envelope icon appears in the taskbar.
Or –
•
•
•
Click Send and Receive. Your computer connects to the Internet and tries to
retrieve your messages to the Inbox folder. (It also sends any messages in the
Outbox folder.)
In the Folder list, click the Inbox folder. (If it has a number next to it, you have new
or unread messages.) New and unread messages appear in bold in the Message List
pane.
To read a new message, click it in the Message List pane. The contents of the
message are displayed in the Message Contents pane.
-Or –
•
•
•
Double-click the message in the Message List pane to open the message in its own
window.
To open an attachment, double-click its file icon. The attachment opens in the
appropriate program.
When you are finished, you can close the message and it remains in the Inbox
folder.
Using the Organize button
Outlook 2000 can automatically organize certain messages for you. Outlook 2000 can save
you time sorting through unwanted “junk” messages, highlight messages from certain
people, and even move specified messages into certain folders upon delivery.
To organize messages using the Organize button
Ì Open the Inbox folder. (For some options you will need to have messages in the
Inbox.)
Ì Click Organize on the Standard toolbar, or, on the Tools menu, click Organize. The
Ways to Organize Inbox dialog box opens at the top of the message pane.
Ì Four options are available on the left side of the dialog box: Using Folders, Using
Colors, Using Views, and Junk E-mail. You can do any of the following:
¾ Click Using Folders to create new folders, open the Rules Wizard, and move
messages to other folders. You can easily create a rule to move messages
from a certain sender into another folder upon delivery.
259
Ì
¾ Click Using Colors to color code messages by sender.
¾ Click Using Views to select how you see messages in your Inbox.
¾ Click Junk E-mail to color code junk and adult content messages, or have
them sent directly to Deleted Items or another folder. You can also add
senders to the junk or adult content filters.
When you are finished, click Organize to close the dialog box.
You can also organize messages that have already been moved to other folders by opening
that folder and then clicking Organize.
Using the Rules Wizard
• A rule is a set of conditions and actions for processing and organizing your e-mail
messages. Conditions identify messages for processing, and actions determine what
kind of processing is performed. For example, you can define a rule that tells
Outlook 2000 to forward all messages sent to you from students in Biology 101
section 3 to your lab assistants, or create a rule that tells Outlook 2000 to put all
message with “Homework” in the subject field into a certain folder in your Personal
Folders list.
• If you receive a large volume of mail from several different groups (personal mail,
mail from students, mail from colleagues, even junk mail) you can use the Outlook
Rules Wizard to create your own rules to manage your messages automatically.
Here are some examples of rules you can create:
¾ Assign categories to messages based on their contents.
¾ Set up a notification, such as a message or a sound, when important
messages arrive.
¾ Move messages to a particular folder based on who sent them.
¾ Delete messages in a conversation.
¾ Flag messages from a particular person.
¾ Assign categories to your sent messages based on their contents.
¾ Delay delivery of messages by a specified amount of time.
¾ Redirect an e-mail message to a person or distribution list.
¾ Automatically reply to a certain type of message with a specific message
you create.
To create a rule
•
Open Outlook 2000 and click the Inbox folder to display its contents.
•
On the Tools menu, click Rules Wizard. The Rules Wizard dialog box opens.
•
Click New. The Rules Wizard displays a list of the different types of rules you
can create along with a description of the rule in the Rule description box.
•
Select the type of rule you want to create and click Next.
•
Select the conditions for the rule as directed by the Rules Wizard and then click
Next.
•
Specify the action for the rule as directed by the Rules Wizard and then click
Next.
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•
•
•
Specify any exceptions to the rule as directed by the Rules Wizard and then click
Next.
Specify a name for the rule and then select the Turn on this rule check box to
activate it.
Click Finish. The rule is added to the Rules Wizard list.
There are three ways to control how rules are applied in the Rules Wizard:
• When you create a rule, you specify whether the rule is applied when the message
arrives in the Inbox or when you send a message. You set these options for each
rule.
• After you create multiple rules, you can move the rules up or down in the list in the
Rules Wizard to change the order in which they are applied. Rules are applied in the
order they appear in the list. Rules that are marked “client only” are applied after all
other rules.
• You can specify whether the rule runs automatically or manually. This is useful
when you want to apply rules manually to messages already delivered to the Inbox.
Creating an address book
• Use the Address Book dialog box to look up e-mail and fax information when you
address messages. Use the Contacts folder to store and retrieve all types of
information about others such as street addresses, telephone numbers, e-mail
addresses, fax phone numbers, and Web page addresses. To open the Address Book
on the Standard toolbar, or click Address Book
dialog box, click Address Book
on the Tools menu.
• There can be several types of address books in the Address Book dialog box
including the Global Address List, the Personal Address Book, and the Outlook
Address Book. Select these address books in the Show names from box. Contacts in
the Contacts folder that include an entry in the e-mail field or one of the fax phone
number fields automatically appear in the Outlook Address Book.
To add information to the address book
Ì
Ì
Ì
Ì
Ì
Ì
Ì
Ì
Ì
Click Address Book
on the Standard toolbar. The Address Book dialog box
opens.
In the Show Names from the drop-down box, select Personal Address Book.
Click New Entry
on the dialog box's toolbar.
In the Put this entry in the drop-down list, click Personal Address Book.
Select the type of entry you want to create (Microsoft Mail Address, Internet
Address, Other Address, and so forth) and then click OK.
Enter the person's name and e-mail address in the appropriate fields.
If you want, click the Business, Phone Numbers, or Notes tabs and enter additional
information.
Click OK to save the information.
Repeat steps 3 through 7 to add more addresses.
261
Exploring Contacts
Outlook 2000 serves as much more than just an e-mail program: you can use it to maintain
an electronic address book of your students, colleagues, and anyone else you need to
contact. Storing contacts electronically in Outlook 2000 allows you to find information
about someone quickly and easily. In the Contacts folder, you can store a wide range of
information about people, from their work and home phone numbers and physical
addresses to e-mail addresses and Web addresses, if they have them. You can link any
Outlook item or Office document to a contact to help you track activities associated with
that person or group.
Contacts symbols:
Activities have
been
automatically
recorded in
Journal for this
contact
Contact
Contact has an
attachment
Contact is flagged
for follow up
Contact is flagged
as complete
When you enter a name or address for a contact, Outlook 2000 separates the name or
address into parts and puts each part in a separate field. You can sort, group, or filter
contacts by any part of the name or any part of the address you want.
From a contact in your contact list, you can click a button or menu command to have
Outlook 2000 address a meeting request, e-mail message, or task request to the contact. If
you have a modem, you can also have Outlook 2000 dial the contact's phone number. You
can have Outlook 2000 time the call and keep a record in Journal complete with the notes
you take during the conversation.
262
Click the flag icon to mark the selected
contact so you can follow up with him or
her. Click the mail icon to send a new
e-mail message to selected contact.
Click the telephone icon to have Outlook
automatically dial the selected contact's
phone number.
Change the way Outlook
displays contacts by
selecting a new view
from this list.
Lett
Click a sy
button to
contacts b
that sym
Standard
Toolbar
Advanced
Toolbar
Outlook Bar
Status bar—
Displays the
total number
of contacts.
You can file contact information under a last name, first name, company name, nickname,
or any word that helps you find the contact quickly, for example, “Section 004” for
students in a particular class. Outlook 2000 gives you several naming choices to file the
contact under or you can enter your own choice. You can enter up to three addresses for
each contact. Designate one address as the mailing address and use it for mailing labels,
envelopes, or creating mail-merge letters.
Creating contacts
A contact is a person or organization you correspond with. You can store information
about contacts such as job titles, phone numbers, addresses, e-mail addresses, Internet email addresses, and notes. When you create a contact, you can start by entering all new
information or you can start with information from an existing contact.
263
To create a new contact
Ì
Ì
Ì
Ì
Ì
On the File menu, point to New and then click Contact. The Contact dialog box
opens.
In the Full Name box, type a name for the contact.
Enter the information you want to include for the contact. There are several tabs
on which you can enter information.
If you wish, assign the contact to a category. Click Categories and then select a
category from the list.
Click Save and Close.
Exploring Calendar
Outlook 2000's Calendar offers an easy way to keep track of appointments and schedule
your time. You can look at appointments and tasks for a given day or look at appointments
in relation to other appointments in the month. You can also post your calendar to a Web
page or print it out and make handouts so that students, parents, or others can know when
you are available.
264
Click to view calendar
entries for today or a
specific day, work week,
calendar week, or month.
The current date is marked
with a red box.
The date shown in the daily
planner panel is shaded.
Web
Toolbar
Changes how Outlook
displays your calendar.
Click the ar
show other
Standard
Toolbar
Advanced
Toolbar
Folder List
Status bar—
Displays the
total number of
calendar items.
Customize how
Outlook displays the
hours of the day.
Displays tasks scheduled for the
Color coding shows
selected date and allows you to
further information about
add a new task to Outlook without
the appointment, such as
if you will be out of the
filling out the Task dialog box.
office or if the
appointment is tentative.
To change appointment information
quickly, click the appropriate appointment
and type the new information.
To change appointment information using
the Appointment dialog box, double-click
the appointment.
265
Calendar symbols:
Appointment
Click to see calendar
items that do not fit in
the current view
Meeting
Meeting request
Recurring
appointment
Recurring meeting
Recurring meeting or
appointment
Reminder for the
appointment or
meeting
Private meeting or
appointment
Start and end times
of the appointment or
meeting
Calendar item has an
attachment
To set calendar preferences
With the Calendar folder open, on the Tools menu, click Options. The Options dialog box
opens.
•
•
•
Click the Preferences tab.
Under Calendar, select Default reminder to have Outlook 2000 remind you
automatically of all appointments. Then, in the drop-down box, select the amount of
time before appointments you want to receive the reminder. (You can change this
time for individual appointments when you create them.)
Click Calendar Options. The Calendar Options dialog box opens.
266
•
•
•
•
•
•
Select the days of the week you want to show on your calendar.
Select other options as necessary. To select a time zone, or show more than one
time zone at a time, click Time Zone.
To have Outlook 2000 automatically display holidays for different countries or
religions, click Add Holidays.
If you are responsible for coordinating resources, such as conference rooms, or
classrooms, click Resource Scheduling.
To publish your free/busy information on a Web or other server, click Free/Busy
Options.
When you are finished, click OK.
--------------------------------------------------------------------------------------------------------------
9.2 DIFFERENCE BETWEEN
MICROSOFT OUTLOOK
OUTLOOK
EXPRESS
AND
--------------------------------------------------------------------------------------------------------------
Definition
Outlook Express
Microsoft Outlook
Outlook Express is the e-mail client that
is included with Microsoft Internet
Explorer 4.x, Microsoft Internet Explorer
5.x, the Microsoft Windows 98 operating
system,
the
Microsoft
Windows
Millennium Edition (Me) operating
Outlook is Microsoft's premier
messaging and collaboration client.
It is a stand-alone application that is
integrated into Microsoft Office
and Exchange Server. Outlook also
provides
performance
and
267
Technology
Platforms
Supported
Calendars,
group
scheduling, task,
and contact
management
system, the Microsoft Windows 2000
operating systems, and Microsoft Office
98 for the Macintosh. Outlook Express is
designed for home users who gain access
to their e-mail messages by dialing in to
an Internet service provider (ISP).
Built on open Internet standards, Outlook
Express is designed for use with any
Internet standard system, for example,
Simple Mail Transfer Protocol (SMTP),
Post Office Protocol 3 (POP3), and
Internet Mail Access Protocol (IMAP). It
provides full support for today's most
important e-mail, news, and directory
standards such as Lightweight Directory
Access Protocol (LDAP), Multipurpose
Internet Mail Extension Hypertext
Markup Language (MHTML), Hypertext
Markup
Language
(HTML),
Secure/Multipurpose
Internet
Mail
Extensions (S/MIME), and Network
News Transfer Protocol (NNTP). Full
support ensures that you can take
advantage of new technologies as well as
seamlessly send and receive e-mail
Versions of Windows later than
Microsoft Windows 95, versions of
Windows earlier than Microsoft
Windows 95, Macintosh, and UNIX
platforms
Not Supported
268
integration with Internet Explorer
5.5. Complete integration of e-mail,
calendaring,
and
contact
management, makes Outlook the
perfect client for many business
users
Outlook is designed for use with
the Internet (SMTP, POP3, and
IMAP4), Exchange Server, or any
other
standards-based
communication
system
that
supports Messaging Application
Programming Interface (MAPI),
including voice mail. Outlook is
based on Internet standards and
supports today's most important email, news, and directory standards,
including LDAP, MHTML, NNTP,
MIME, and S/MIME, vCalendar,
vCard, iCalendar, and full support
for HTML mail. Outlook also
offers the same import tools that are
offered with Outlook Express. This
enables easy migration from other
e-mail clients, and offers further
migration from Microsoft Mail,
Microsoft Schedule+ 1.0, Microsoft
Schedule+ 7.0, Lotus Organizer,
NetManage
ECCO,
Starfish
SideKick, Symantec ACT, as well
as synchronization with leading
Personal Digital Assistants (PDAs),
such as the 3Com Palm Pilot.
Versions of Windows later than
Microsoft Windows 95, versions of
Windows earlier than Microsoft
Windows 95, and Macintosh
platforms
Supported By Outlook and is
widely used across organizations
Integration with
Other
Applications
Network System
Outlook Express handles not only
Internet mail but also Internet news, a
feature that Outlook does not natively
possess. But Outlook has a host of
features that Outlook Express does not
have, such as a calendar, a task list, a
journal, and automatic backup into
archive files. The address book in
Outlook is a very sophisticated contact
management system unlike the simple
address book used by Outlook Express.
Outlook can be programmed using Visual
Basic for Applications (VBA) but
Outlook Express cannot. Outlook is
highly interoperable and so can be used
in combination with Word, for example,
to perform mail-merge in e-mail or to
automate outgoing mail messages.
Outlook Express does not interact with
other programs in this way except for
creating a new mail message when a
program requests it.
Outlook Express was designed for use on
a single computer and so its message
store and settings cannot be stored on a
server.
Outlook also has a very powerful
Junk Mail feature which has
received high praise and is envied
just as highly by many Outlook
Express users. In a similar vein,
Outlook has message rules for both
incoming and outgoing mail, while
Outlook Express can only filter
incoming. Outlook rules also offer
a much wider range of actions than
do rules in Outlook Express.
Outlook however was tailor-made
for networks, and so its message
store can be on a central server that
many machines can access. If you
need to access your e-mail from
more than one machine on your
network
--------------------------------------------------------------------------------------------------------------
9.3 COMPUTER IN OFFICE AUTOMATION
-------------------------------------------------------------------------------------------------------------Office automation is defined as using computer and communications technology to help
people better use and manage information. Office automation technology includes all types
of computers, telephones, electronic mail, and office machines that use microprocessors or
other high-technology components.
People who use office automation are often called knowledge workers-senior executives,
managers, supervisors, analysts, engineers, and other white-collar office workers. In most
offices, information (often in paper form) is the end product and is essential for 'conducting
the company's business. Office automation systems keep track of the information
originating in various operations throughout the company, such as order processing,
accounting, inventory, and manufacturing. Office automation provides knowledge workers
with information-producing systems to collect, analyze, plan, and control information about
the many facets of the business, using text, voice, graphics and video display technology.
269
People
Although it takes people to complete work, it is the way people work that accounts for
productivity. In recent years, the trend has been towards people working together to
accomplish more. This is called work-group computing, which means a number of
knowledge workers, each with different tasks, jobs or duties, work together towards a
common goal. In large companies, there may be dozens or hundreds of workgroups. In
smaller companies, everyone is part of the workgroup.
Ergonomics
Business learned that "office could not be automated in the same way the factory was
automated, and the field of ergonomic began to emerge. Office tasks involve a great deal of
thinking and decision-making. As a result office systems must be flexible and versatile.
Moreover, they must be deigned so any knowledge worker, regardless of background can
easily use them. This is called ergonomics, the study of how to create safety, comfort and
ease of use for people who use machines. It is not a new field of study; in fact it has existed
for over 100 years.
With the advent of computers, ergonomics engineers became particularly interested in
office automation systems, furniture "and. environments for the knowledge worker
intensive studies determined the best ,designs for Keyboard, set. Eyes fatigue- levels for
monitors, and specified desks and seating designs that alleviate physical stress. Office
furniture companies soon introduced ergonomically designed chairs and "equipment.
Ergonomics has- played a significant role in -helping people use technology more
effectively
There are five primary technologies used in managing information in office automation:
•
•
•
•
•
Text or written words
Data, as in umbers or other non-text forms.
Graphics, including drawings, charts and photographs
Audio, as in telephone, voice mail, or voice recognition systems
Video, such as captured images, videotapes or teleconferencing.
In the past these forms of information- was created using different technologies. Text was
created using conventional typewriters' or more" recently, word processing.
9.3.1 Office Automation Technologies
Data, such as sales reports, was provided by the central computer. Charts and grabs were,either l1and-drawn or created using 35mm slide photography and videotapes were user” or
training. Audio was limited t9 the" phone or tape recording. It was not possible to combine
these various forms of information.
What made it Possible to combine them was the computer. What computer produces is
called an electronic document, which is a self-contained work, conveying information that
has been created by a knowledge worker and stored in a computer system. An electronic
document may be a simple main that may be printed on paper or transmitted via electronic
270
mail. Or it may be a more complex document, with graphics or even Video. Most computer
'systems can incorporate sound, so that an onscreen document can be annotated with
comments spoken by the document creator.
Today, the computer integrates others different media and others' as well Data, sound and
images can all -be 'entered info' a computer-, stored- and translated into the kind of output
we need. It is now common to seek knowledge worker’s in workgroups using a special type
of, software designed' specifically for them and their work. This application software’s
called groupware, lets networked PCs and workstations share information and electronic
documents from both corporate and on-line sources. At the center of this integration are
networking and communications systems...
Office Automation Systems
Office automation uses computer based systems to provide" information to help knowledge
workers make decisions that benefit the business. Office automation systems are"
comprised of many distinct subsystems: text management systems, business analysis
systems, document management systems" and Network and communications C systems.
Text Management Systems
A text management system is a completer system -c1esigned to work with the written or
typewritten word. It includes all kinds of typewriters, word processing systems, PCs with
word processing, desktop publishing and text editing systems, and even computerized
typesetting equipment. Text management systems are used for test like writing memos,
notes, letters and other short documents, - printing envelopes" and labels preparing preprinted forms such as invoices, composing complex documents such as proposals and
reports, retrieving and editing documents such as contracts, Creating display documents
like newsletters, etc.
Business Analysis Systems
Managers need solid data from which to extract the information necessary to make good
decisions for the business. In the past, these knowledge workers had to rely on their
experience and other personal factors to make decisions. A business analysis system
provides data that, when used with the proper software, helps its users - better understand
the business environment and make more effective decisions. Corporate users routinely use
spreadsheets for analyzing cost and benefits and for creating budgets.
Other software tools for performing analysis that and"-.commonly used in large companies
are decision support systems (DSS), expert systems and executive support \ systems (ESS).
A decision support system helps the knowledge worker to extract information from the
various MIS database and reporting systems, analyze it, and then formulate a decision or a
strategy for business planning. An expert system is a computer system that can. store and
retrieve data with special problem solving expertise. An executive support system is an
information system that consolidates and summarizes ongoing transactions within the
organization. It provides the management with all the information it requires at all times
from internal as well as external sources.
271
Document Management Systems
Document management systems aid in filing, tracking and managing documents, whether
they are paper, computer based, micrographic, or purely electronic. Office automation
demands that data be immediately accessible and instantaneously retrievable. For that
reason, we are slowly moving away from paper and toward. Document forms that can be
stored on the computer.
Network and Communication Management Systems
Today, knowledge workers have many ways to communicate with one another, primarily
by voice, fax, and e-mail. They can communicate in real-time, via phone or computer. They
can also communicate using computer controlled PBX telephone systems to record a digital
message and leave it in the recipient's electronic mailbox. These systems are called network
and communication management systems. The network and communication management
systems include telephone, electronic mail, voice messaging systems, and teleconferencing
and fax machines.
--------------------------------------------------------------------------------------------------------------
9.4 COMPUTERS IN ENGINEERING
-------------------------------------------------------------------------------------------------------------Introduction
In the global economy, it is absolutely necessary for an organization to keep costs as low as
possible in order to remain competitive. Since design, production, and manufacturing
consumes so -much of a manufacturing company's budget, great savings are being made by
automating these procedures as much as possible.
Electronic Data Interchange (EDI)
EDI is the computer-to-computer exchange of business documents in a standard format.
These formats look much like standard forms and are highly structured. One widely used
format is for purchase orders and consists of an outer digital 'envelope' with the addresses
of both the sender and receiver. Inside the digital envelope a series of structured codes
define the part number, cost, tax information, shipment methods, bill-to location, ship-to
location, and contacts to call. This EDI purchase order can be automatically generated by
the buyer when inventory fall below a certain point and send via networks to the supplier.
At that end it is automatically processed and creates a list of the products to be shipped
even before the normal workday begins.
Computer Aided Design/Computer Aided Manufacturing (CAD/CAM)
An increasingly, popular tool for product design is Computer-aided-Design (CAD). CAD
systems are computer programs or integrated packages for workstation hardware and
software that allow the user to draw and easily modify product designs on a computer
screen. Advanced CAD systems provide designers with at least 3 major benefits.
Graphics capabilities - CAD systems allow the designer to view a product from different
perspectives, including three-dimensional rotations, and various cross-sections. The
designer can also make proportional changes in scale, or change the angle of an arc with
the click of a computer mouse rather than having to redraw the entire product.
272
Design, storage and retrieval - Some CAD systems can store the design characteristics of
existing products and components. Then, for example, if a company needs a gear for a new
product, the designer can enter the relevant information about the gear, such as its diameter,
tooth pattern, and required hardness, into the CAD system. The CAD system determines
whether the company is already using an identical of sufficiently similar gear, in which
case a new one is unnecessary. If not, a gear that has similar properties may exist. The
designer can then use the design of this similar gear as a starting point for the new gear:
This capability not only promotes the use of common components but also reduces design
time.
Automatic evaluation of specifications - One of the most time-consuming aspects of
design for highly technical products is calculating whether or not product specifications,
such as strength, heat resistance or aerodynamic drag, are satisfied. These calculations can
be programmed into some CAD systems so that whenever the designer changes the design
(by altering the shape or material to be used), these performance characteristics are
recalculated automatically and compared to the product requirements. This is sometimes
called Computerized. -Engineering (CAE).
The overall benefits of CAD systems can be substantial. The features described above
reduce development time and cost, and they improve product quality because more design
options can be evaluated in greater detail more quickly. For example, Motorola used threedimensional CAD to produce its award-winning MicroTac pocket sized cellular phone two
years ahead of the competition. It is not uncommon for CAD systems to reduce product
cycle times by 10-50 %.
Even greater time and cost reductions have resulted from recent advances whereby CADengineered designs are converted automatically into software programs for computerized
production machines. These are called Computer-aided Design/Computer-assistedManufacturing (CAD/CAM) systems. This automatic conversion eliminates the costly and
time consuming steps of having a person convert design drawings into a computer program
for computer-controlled production equipment; such as robots or machine tools. CAD and
CAD / CAM systems are not used by large automotive or electronics companies alone.
Future Enterprises, the largest maker of wedding jewelry in the United States, reported that
its CAD / CAM system reduced the time required to design and make jewelry from five
months to one week.
Product Data Management (PDM)
One of the major manufacturing challenges is to maximize the time-to-market benefits of
concurrent engineering while maintaining control -of your data and distributing it
automatically to the people who need it, when they need it. The way PDM systems cope
with this challenge is that master data is held only once in a secure 'vault' where its
integrity can be assured and all changes to it monitored, controlled and recorded.
Duplicate reference copies of the master data, on the other hand, can be distributed freely,
to users in various departments for design, analysis and approval. The new data is then
released back into the vault. When a 'change' is made to data, what actually happens is that
273
a modified copy of the data, signed and dated, is stored in the vault alongside the old data,
which remains in its original form .as permanent record.
The following are some of the benefits of the PDM system:
•
•
•
•
•
Reduced time-to-market
Improved design productivity
Better use of creative team skills
Data integrity safeguarded
Better management of engineering change
Feature Prototyping
One of the problems with product design is getting an intimate feel for the appearance and
behavior potential of a product. Now there are software packages, which can generate
computer prototypes, which' can be distributed and tested by actual customers. Usage data
from these tests is collected automatically and used to refine product specifications until
they precisely meets customers' needs. This process helps in ensuring the market success of
the new product before costly and time-consuming investments in engineering and
manufacturing are made.
Better than communicating with customers using written specifications, static drawings,
flip charts, or multimedia authoring tools, feature prototyping 'using fully functional
prototypes provide accurate and valuable feedback to the company based on customers'
experience that can make the difference -between a resounding market winner -and an
embarrassing product failure.
Project Management
When projects from marketing campaigns to construction projects are undertaken, keeping
track of all the tasks is a big job and that. is what project management programs have been
developed to do. One concept they use is the critical path; the series of tasks that must
follow one another in order and cannot be overlapped or begun until the previous one is
completed. For example, a roof cannot be put on a house until the walls are up, and the
walls cannot be built until the foundation is completed. When these dependent tasks are
laid out end-to-end, they form the project's critical path. Any delays in the tasks on this
path delay the entire project. Tasks not on the critical path like paving the driveway do not
affect the project's completion date. Speeding up the project, called trashing the schedule
can be done only by changing the dates on the critical path, but changing some dates on the
critical path may result in another path becoming critical. Since this process is so
interactive, it lets itself to computerization. Graphics are often used to show the
complicated relationships in the timing and sequence of a project.
274
--------------------------------------------------------------------------------------------------------------
9.5 REVIEW QUESTIONS
-------------------------------------------------------------------------------------------------------------1. Explain salient features of MS-Outlook.
2. Compare Outlook Express and Ms Outlook.
3. Explain the Calendar views available in MS outlook.
4. What is the utilities available in MS outlook for E-mails? Comment on it.
5. What is the role of computers in Engineering?
275
“The lesson content has been compiled from various sources in public domain including but not limited to the
internet for the convenience of the users. The university has no proprietary right on the same.”
?
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Dhodballapur Nelmangala Road, SH -74, Off Highway 207, Dhodballapur Taluk, Bangalore - 561204
E-mail: [email protected] | Web: www.raitechuniversity.in
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