EduProz provides free classroom facilities for distance learning courses

Introduction to Information Technology
E-528-529, sector-7,
Dwarka, New delhi-110075
(Nr. Ramphal chowk and Sector 9 metro station)
Ph. 011-47350606,
(M) 7838010301-04
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"Greetings For The Day"

About Eduproz

We, at EduProz, started our voyage with a dream of making higher education available for everyone. Since
its inception, EduProz has been working as a stepping-stone for the students coming from varied
backgrounds. The best part is – the classroom for distance learning or correspondence courses for both
management (MBA and BBA) and Information Technology (MCA and BCA) streams are free of cost.

Experienced faculty-members, a state-of-the-art infrastructure and a congenial environment for learning -
are the few things that we offer to our students. Our panel of industrial experts, coming from various
industrial domains, lead students not only to secure good marks in examination, but also to get an edge over
others in their professional lives. Our study materials are sufficient to keep students abreast of the present
nuances of the industry. In addition, we give importance to regular tests and sessions to evaluate our
students’ progress.

Students can attend regular classes of distance learning MBA, BBA, MCA and BCA courses at EduProz
without paying anything extra. Our centrally air-conditioned classrooms, well-maintained library and well-
equipped laboratory facilities provide a comfortable environment for learning.

Honing specific skills is inevitable to get success in an interview. Keeping this in mind, EduProz has a career
counselling and career development cell where we help student to prepare for interviews. Our dedicated
placement cell has been helping students to land in their dream jobs on completion of the course.

EduProz is strategically located in Dwarka, West Delhi (walking distance from Dwarka Sector 9 Metro
Station and 4-minutes drive from the national highway); students can easily come to our centre from
anywhere Delhi and neighbouring Gurgaon, Haryana and avail of a quality-oriented education facility at
apparently no extra cost.

Why Choose Edu Proz for distance learning?

• Edu Proz provides class room facilities free of cost.
• In EduProz Class room teaching is conducted through experienced faculty.
• Class rooms are spacious fully air-conditioned ensuring comfortable ambience.
• Course free is not wearily expensive.
• Placement assistance and student counseling facilities.
• Edu Proz unlike several other distance learning courses strives to help and motivate pupils to get

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high grades thus ensuring that they are well placed in life.
• Students are groomed and prepared to face interview boards.
• Mock tests, unit tests and examinations are held to evaluate progress.
• Special care is taken in the personality development department.

"HAVE A GOOD DAY"

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Karnataka State Open University

(KSOU) was established on 1st June 1996 with the assent of H.E. Governor of
Karnataka
as a full fledged University in the academic year 1996 vide Government
notification
No/EDI/UOV/dated 12th February 1996 (Karnataka State Open University
Act – 1992).
The act was promulgated with the object to incorporate an Open University at the
State level for the introduction and promotion of Open University and Distance
Education systems in the
education pattern of the State and the country for the Co-ordination and
determination of standard of such systems. Keeping in view the educational
needs of our country, in general, and state in particular the policies and
programmes have been geared to cater to the needy.

Karnataka State Open University is a UGC recognised University of Distance
Education Council (DEC), New Delhi, regular member of the Association of
Indian Universities (AIU), Delhi, permanent member of Association of
Commonwealth Universities (ACU), London, UK, Asian Association of Open
Universities (AAOU), Beijing, China, and also has association with
Commonwealth of Learning (COL).

Karnataka State Open University is situated at the North–Western end of the
Manasagangotri campus, Mysore. The campus, which is about 5 kms, from the
city centre, has a serene atmosphere ideally suited for academic pursuits. The
University houses at present the Administrative Office, Academic Block, Lecture
Halls, a well-equipped Library, Guest House
Cottages, a Moderate Canteen, Girls Hostel and a few cottages providing limited
accommodation to students coming to Mysore for attending the Contact
Programmes or Term-end examinations.

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Unit1 Computer Fundamentals

• This unit deals with Generations of Computers. This unit also includes
Classification of Computers according to their size and capabilities, the different
Input-Output devices used with the computers. It deals with Central Processing
Unit, Memory Unit, terms Hardware, Software, computer languages. The
Advantages and Disadvantages of Computers are also discussed in this Unit.

Today computers have become part of our life. Usage of computers in different fields has
become a necessity in the present competitive world. Lot of work and evolutions has
transpired from the initial computer systems to the present day computer systems.
Computers are made up of Electrical, Electronic and Mechanical components. Computers
are just the machines and you must specify the work that is to be carried out by the
computer. Thus to carry out a specific task series of instructions must be given to the
Computer in a particular order.

Objectives

To Understand

· Generations of Computers

· Classification of Computers

· Organization of Computers

· Input-Output devices

· Central Processing Unit

· Memory Unit- Primary and Secondary Memory

· The terms Hardware and Software

· Computer Languages

· Application of Computers

· Advantages and Disadvantages of Computers

History

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The tool known as ABACUS was the age-old tool used by man to count and calculate
was designed and developed by Chinese some 5000 years ago.

Blaise Pascal designed a working mechanical calculator in 1642. These devices were able
to add and subtract directly, whereas multiplication and division were performed through
repeated addition and subtraction respectively.

Gottfried Von Leibnitz a German, modified Pascal’s calculating machine which could
multiply numbers directly.

In 1833 Charles Babbage an English scientist, designed Analytical Engine using tooth
wheels so that it could perform all mathematical operations in a predetermined sequence
using a set of operational instructions, so he is called as Father of modern computers.

Lady Ada Lovelace is considered as the first lady Computer Programmer as she has
developed the concept of writing systematic operational instructions for the analytical
engine.

In 1850 George Boole an English mathematician proposed logic theory of using the
binary (two) number system. This number system had only two numbers 0 and 1. In this
procedures all the quantities are represented in terms of o and 1 for example 9 is
represented as 00001001.

Bool proposed a logic popularly known as Boolean algebra. Computer processors are
designed on this system of logic.

A statistician Dr. Herman Hollerith, developed a punched card that would contain data
coded in form of punched holes.

Self Assessment Questions:

1) Who is the first lady Computer Programmer?

2) What is logic proposed by an English mathematician George Bool?

Generations of Computers

Evolution of modern computer is commonly considered in terms of Generation of
Computers.

First Generation (1940-1956): Vacuum Tubes

The computers of this generation were made of vacuum tubes for circuitry and magnetic
drums for memory. This made computers bulky and heavy. Punched cards were used to
feed the information. Magnetic tapes were used as external storage devices. They were
very expensive to operate and in addition to using a great deal of electricity, generated a

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lot of heat and occupied a large amount of space. These machines used machine and
assembly level language.

The UNIVAC and ENIAC computers are examples of first-generation computing
devices.

Second Generation (1956-1963): Transistors

The computers of this generation made up of transistors replacing vacuum tubes. These
are small in size so the machines occupied a less amount of space. The use transistors
made the computers work much faster. The transistor was far superior to the vacuum
tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and
more reliable than their first-generation predecessors. Though the transistor still
generated a great deal of heat that subjected the computer to damage, it was a vast
improvement over the vacuum tube. Second-generation computers still relied on punched
cards for input and printouts for output. The development of higher-level languages like
FORTRAN, COBOL and BASIC was possible.

Third Generation (1965-1971): Integrated Circuits

The computers of these generations were made up of IC (Integrated Circuits). Integrated
circuits mean incorporation of hundred of transistors on a single silicon chip. These were
still smaller than the computers of second-generation machines. Heat generated was also
less and occupied less space.

Instead of punched cards and printouts, users interacted with third generation computers
through keyboards and monitors and interfaced with an operating system, which allowed
the device to run many different applications at one time with a central program that
monitored the memory. Computers for the first time became accessible to a mass
audience because they were smaller and cheaper than their predecessors.

Fourth Generation (1971- ): Microprocessors

The computers of this generation saw the advent of Large Scale Integration (LSI) and
Very Large Scale Integration (VLSI), which incorporated several thousands transistors in
a single chip. The main characteristic of this generation computers is the evolution of the
use of Microprocessors. Microprocessors had thousands of integrated circuits were built
onto a single silicon chip.

The Intel 4004 chip, developed in 1971, located all the components of the computer –
from the central processing unit and memory to input/output controls – on a single chip.

Self Assessment questions

1) What are the components used in second and third generation computers

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2) Give example for first generation computers

Classification of Computers

Computers are classified according to their sizes and their capabilities. Broadly, they may
be categorized as personal computers, lap top computers, minicomputers, mainframes
and supercomputers.

Personal Computers: A microcomputer is the smallest general purpose processing
system. Functionally it is similar to any other large system. Microcomputers are self-
contained units and usually designed for use by one person at a time.

Minicomputers: A minicomputer is medium sized computer that is more powerful than a
microcomputer. An important distinction between a microcomputer and a minicomputer
is that a minicomputer is usually to serve multiple users simultaneously.

Mainframes computers: Computers with large storage capacities and very high speed of
processing are known as mainframes. They support a large number of terminals for
simultaneous use by a number of users.

Super computers: These have extremely large storage area and computing speeds,
which are many times faster than earlier discussed machines. While the speed of earlier
discussed computers measured in turns of million instructions per second whereas in
supercomputers speed is measured as tens of millions of operations per second; an
operation is made of many instruction. These have more than one processor in it and the
processing is carried out in parallel. The super computers are used in applications include
large scale numerical problems in scientific and engineering disciplines like weather
forecasting, atomic research, space research etc.

Lap Top/ Note Book Computers:

These are the computers, which are small in size and weigh few Kgs. These computers
can be carried from one place to another easily. The people who are always on the move
mostly use these. This has all the capabilities of a Personal Computer. It has an LCD
screen and has rechargeable batteries.

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Now you can even get computers which can be placed on you palm hence the name Palm
Top Computers.

Self Assessment Questions:

1) Classify the computers according to their size and capabilities

Organization of a Computer

A computer is a fast and accurate device, which can accept data, store data, process them
and give, desired results as output. The computer is organized into four units as shown in
the following diagram.

1.4.1 Input Unit:

Any device designed to assist in the entry of data into a computer is known as Input
device. Input devices convert data from any convenient external format into binary codes
that a computer can store and manipulate internally. Some of the most common, most
popularly used devices are discussed below.

Mouse:

This Input device is categorized as an pointing device because it
is used to point and select an option on the monitor. It is small boxlike object that is
connected to the computer by a cable and can be rolled around on the table. A pointer on

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the screen follows the movements of the mouse; rolling the mouse left moves the pointer
left by an equipment amount, rolling the mouse in the right direction moves the pointer in
the right direction, rolling the mouse in the up direction moves the pointer in the up
direction, rolling the mouse in the down direction moves the pointer in the down
direction and you can roll the mouse in a angular direction also. In order to select an
option on the computer screen, the user should move the pointer at the desired position
and press the button on the mouse. The mouse can be used to open menus, select texts for
editing, move objects on the screen, draw images or diagrams etc.

A mouse can be classified on the basis of the number of buttons it has, the technology it
uses, and the kind of interface it shares with the computer. A mouse may have one, two
or three buttons. The program that uses the mouse determines the function of each button.
A mouse may be classified as a Mechanical mouse and an Optical mouse, on the basis of
the technology it uses. In a Mechanical mouse, the rubber-coated ball that projects
through the bottom surface rotates as the mouse is moved along a flat surface and sends
electrical signals to the system unit by means of switches inside the mouse. This causes
the cursor, or pointer, to move in a corresponding fashion. An Optical mouse uses diodes
to emit light beam instead of a rotating ball to detect movement across a specially
patterned metal pad.

Light Pen:

This is also categorized into a pointing device, which can be used only with video
displays. It can be used to select an option by simply pointing at it, or drawing figures
directly on the screen. An electron beam that repeatedly scans the display screen from left
to right and from top to bottom produce a video display. Because of this scanning action,
each point on the display is illuminated at a slightly different time. The light pen, which
is a pen like device, has a photo detector at its tip. The detector can detect changes in the
brightness of the screen. The light pen is connected to the computer by a cable. When the
pen is pointed at a particular spot on the screen, the point is scanned and the photo
detector records changes in the brightness and sends electrical pulses to the computer.
The computer can find out the exact spot with this information. Light pens are useful for
menu-based applications. It is also useful for drawing graphics in Computer Aided
Design software.

Touch Screen:

Touch screens are normally used when information has to be accessed with minimum
effort. The user need to only touch the appropriate point on the display to point out an
item to the computer. This is again a kind of pointing devices.

Joy Stick:

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This is another kind of Input device used to play computer games, which
is connected to game port.

Keyboard:

Keyboards are the most widely used input devices. The most popular keyboards are those
that look, feel, and possibly sound like an ordinary typewriter keyboard. Alternatives are
Membrane keyboards, whose keys are merely printed on a plastic membrane. A pressure
sensitive two-dimensional keyboard covered with a dust proofed and dirt proofed plastic
sheet are useful in dirty environments. Keyboards are of different varieties. Generally a
keyboard has 105 keys. It features 12 function keys arranged at the top of the keyboard,
and larger Backspace key, a numeric keypad, a cursor movement keypad, toggle lights,
Shift keys, Alt keys, Ctrl keys, Caps Lock key, Num Lock key, Spacebar key, Enter key,
Alphabetical keys etc.

Scanners:

These are the eyes of your computer. They can see images or printed text and translate
them into binary code. Most scanners collect data from a page by recording, which areas
are light and which areas are dark. They contain a camera, which is made up of thousands
of tiny cells, called charge coupled devices (CCD). Each CCD detects whether a small
part of the image is either light or dark. It transmits this data to the CPU, which then
creates the image. Some scanners are sensitive enough to tell the difference between
colors.

Many scanners available nowadays are capable of not only scanning texts and graphics,
but also integrated text and graphic files. Scanners are used to reproduce photographs on
the computer screen. Businesses use scanners fro storing documents on the computer.

Optical Character Readers (OCR): These are another kind of input devices that are
used to read any printed text. They can interpret hand made marks, handwritten
characters, machine printed characters and special symbols and codes. Optical character
readers scan text character-by-character converts them into machine-readable codes and
store it in the memory. Since they read characters at the rate of around 2600 characters
per second this reduces the organizations the data inputting time.

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Magnetic Ink Character Reader (MICR): This is a device that identifies a character
that is written with the ink that contains particles of magnetic material. This device is
mainly used to read the Bank cheque.

Mark Sense Reader: This device is used to recognize the marks made by a pencil or pen
on a specially designed paper. These devices are also known as Optical Mark Readers
(OMR). These devices are used in competitive exams, to carry out the survey work etc.

Bar Code Reader: This is used to read different kind of vertical lines known as bars
which signify some information.

1.4.2 Output Unit:

Any peripheral device that converts the stored binary coded data into convenient external
forms as text and pictures are known as Output devices. Some of the most popularly used
Output devices are discussed below.

Visual Display Unit:

The Visual Display Unit is an output device that gives visual
representation of data. They are also known as Monitors. They are television screen like
devices used for displaying the output of computers. Computer monitors are often called
Cathode Ray Tubes (CRT). Computer users may select from monochrome (black and
white) or color/graphics monitors. CRT monitors are too bulky for portable computers.
Instead they have flat screen monitors. Many of these use Liquid Crystal Display (LCD)
screens. An LCD screen is filled with molecules (tiny particles) of a liquid, which reflects
the light. When the computer scans the screen, some molecules twist to shut out light.
The off molecules cause a pixel to go dark, and so form part of image. LCDs are similar
to the display those found in calculators and digital watches are widely used in Laptop
computers and pocket computers.

Printer:

The Printer is another output device used to store the output for later reference. Using
Printers, output can be obtained on paper.

The Printers can be divided into two categories

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1) Impact Printers 2) Non Impact Printers

Impact Printers:

These printers print by striking the type against the ribbon and the printer. The example
for this kind of printers is Dot Matrix Printers, Daisy wheel Printers and Line Printers.
They can produce carbon copies, if necessary.

Dot Matrix Printer: The print head comprises a matrix of tiny needles, usually of seven
rows and five columns. They are electrically driven and punch characters in the form of
patterns of tiny dots. The pattern of dots for each character is dictated by the information
held electronically in the printer.

Daisy wheel printer: It is a character printer and derives it’s name from the shape of the
print wheel. The daisy shape wheel is made of metal or plastic and holds the characters
on its petal. The wheel rotates at a high speed and when the required character is
positioned over the ribbon, a tinny hammer strikes it against the ribbon thus transferring
the character symbol to the paper.

Dot matrix and Daisy wheel printers are called as character printers as they can print only
one character at a time.

Line Printers: It prints an entire line at a time and is the fastest printer. It is the fastest
printer as it prints all the characters in the line simultaneously.

Non-Impact Printers: These create the images without striking the type against the
ribbon and paper instead they are practically noiseless and create images only on one
copy. The example for these kind of printers is Ink-jet printers, Laser Printers and
Thermal printers.

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Ink-jet Printers: These printers print characters by spraying electrically charged ink
onto the paper. They are capable of producing characters of various shapes and sizes. We
can take colored output.

Laser Printer: These are high speed, high quality printers. A laser beam is used to burn
characters images on the rotating drum and the heated surface area picks up the toner
particles, which is sprinkled on the paper.

Thermal Printer: These kind of printers use heated dot matrix wires to print the output
on a specially treated paper. The output on a thermal paper fades quickly when exposed
to light.

Plotters:

This is an output device used to create high quality visuals on papers, which cannot be
obtained using a printer. It is used to create presentation visuals, charts, graphs, table, and
engineering plans. A plotter consists of an arm that moves across the paper on which the
diagram or graph needs to be drawn. A pen moves along the arm, and the arm itself
moves relative to the paper. A combination of the two thus provides movement along the
horizontal and vertical axes. To draw clear, high quality designs, a plotter needs high
quality pens with special inks of different colors. A plotter is more software dependent
than any other peripheral and needs much more instructions that the printer for producing
output.

1.4.3 Central Processing Unit:

The Central Processing Unit (CPU) is the heart of the computer combined with the
processing system of a computer. The CPU carries out actions with help of Arithmetic-
Logic Unit (ALU). This is done following a detailed set of instructions written in the
main memory. It also uses the main memory for temporary storage of information.
Through the channels of information “Bus”, the CPU instructs various parts called device
controllers to transfer data between secondary memory and the main memory. The CPU
accepts the data from the Input unit processes it and gives the result/output to the output
device. The data/result can be stored for the use by storing it in the secondary memory.
The total operations of the computer is synchronized and controlled by the CPU.

The processing capacity of a computer is measured in terms the amount of data processed
by the CPU in one operation. The CPU has three important sub units.

1) Arithmetic-Logic unit

2) Control Unit

3) Memory Unit

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Arithmetic-Logic Unit (ALU): The ALU is an electronic circuit used to carry out the
arithmetic operations like addition, subtraction, multiplication and division. This unit
carries out logical operations like greater than, less than, equal to etc. It performs the
operation on the data provided by the input devices. A comparison operation allows a
program to make decisions based on its data input and results of the previous
calculations.

Logical operations can be used to determine whether particular statement is TRUE or
FALSE.

The ALU operates on the data available in the main memory and sends them back after
processing again to main memory.

Control Unit: The control unit coordinates the activities of all the other units in the
system. Its main functions are to control the transfer of data and information between
various units and to initiate appropriate actions by the arithmetic-logic unit.
Conceptually, the control unit fetches instructions from the memory, decodes them, and
directs them to various units to perform the specified tasks.

Memory Unit: The main memory is also called primary memory, is used to store data
temporarily. Although, the CPU is the brain behind all the operations in the computer, it
needs to be supplied with the data to be processed and the instructions to tell it what to
do. Once the CPU has carried out an instruction, it needs the result to be stored. This
storage space is provided by the computer’s memory. Data provided by the input device,
and the result of that processed data is also stored in the memory nit. This main memory
is like a scratch pad. The storage capacity of the memory is generally measured in
megabytes.

8 Bits = 1 Byte

1024 Bytes= 1 Kilobyte (KB)

1024 Kilobytes= 1 Megabyte (MB)

1024 Megabytes= 1 Gigabyte (GB)

Different kinds of primary memory are Random Access Memory (RAM) and Read Only
Memory (ROM). You can read and write data in RAM but the data is volatile or
temporary that is whenever the power is switched off the contents of RAM is lost so its is
required to store the data in the secondary memory if the data is required for the future
use. But you can only read the data from ROM and you can not write any thing into it and
the data is permanent. The manufacturer himself has written the data in it initially.

Secondary Memory:

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This is the permanent memory. The data stored in it is permanent. But you can delete the
data if you want. There are different kinds of secondary storage devices available. Few of
them are Floppy disks, Fixed (hard) disks and Optical disks etc.

Floppy disk:

This is one of the most common storage medium used today
in computers. It is flexible circular plastic disk coated with magnetic material. The disk
has two surfaces and data will be stored/retrieved from both the surfaces. Circular tracks
are recorded on each of the surfaces. A track is further subdivided into sectors. These
tracks, sectors and surfaces of disks are used to identify the place where the data will be
written/retrieved.

The information can be stored or retrieved by inserting the floppy disk in the disk drive
present in the computer. The above shown floppy disk is 3.5-inch floppy disk, which has
the capacity of 1.44 MB.

Fixed (hard) disk:

These are smooth metal plates coated with a thin film of magnetic material. A set of such
magnetic plates is fixed to a spindle one below the other to make up a set of disks. This
disk pack is sealed and mounted on a disk drive. The disk drive consists of a motor to
rotate the disk pack around its axis at the speed of about 7200 rotations per minute
(RPM). The drive also has a set of magnetic heads mounted on arms. The arm assembly
is capable of moving in and out in radial direction. Information is recorded on the surface
of a disk as it rotates about its axis. Circular tracks are recorded on each of the surfaces.
A set of corresponding tracks in all surfaces of disks is called a cylinder. A track is
further subdivided into sectors. These cylinders, sectors and surfaces of disks are used to
identify the place where the data will be written/read.

These have the capacities in 40 Giga Bytes (GB), 80 GB etc.

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Optical disks:

These disks are different from the magnetic disks by the way the data is recorded and
retrieved. In optical disks, a laser beam is used to write and read data on these reflective
disks. Optical disk have storage capacity much more higher than the magnetic disks.
These optical disks are popularly known as Compact disks (CD). To read the contents of
the CD you are required to place the CD in the CD drive of your computer. But to record
data on your CD you are required to have CD-Writer drive in your computer. This CD-
Writer drive can be used to Read and Record the data on CD.

Different forms of CD’s are available they are basically CD, CD-R and
CD-RW.

CD-ROM: Compact Disk Read Only Memory. On these the data is already recorded and
you are going to use this CD_ROM.

CD-R: Compact Disk Recordable. In this the data can be written only once.

CD-RW: Compact Disk ReWritable. In this the once stored data can be erased and new
data can be stored.

Compact disks with different capacities are available they are 650 MB, 700 MB etc.

Digital Versatile Disk Read Only Memory (DVDROM):

This uses the same principle as CD-ROM for reading and writing. But in this the data is
stored two layers. On each layer the data is recorded. The distance between successive
tracks is less. Thus the capacity can be doubled. The total capacity of DVDROM is 8.5
GB. In double-sided DVD two such disks are placed back to back so the recording can be
done at both the sides. Since each side can hold 8.5 GB of data, both sides in total can
store 17GB of data.

Magnetic Tape Drives:

Magnetic tape memories are similar to the commonly used audio tape recorders. A
magnetic tape drive is made up of spool on which a magnetic tape is wound. The tape is

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transported across a set of magnetic heads and is taken up on another spool. Between the
spools heads are mounted which are used store and retrieve the data from the tape. The
standard size of width of the tape is half an inch. The data is recorded and retrieved
sequentially. So the access time in case of tape is large compared to disks.

Self Assessment Question:

1) Explain different kinds of Input devices

2) Differentiate between Impact and Non Impact printers

3) List out different kinds Optical Disks

4) List out different kinds Optical Disks

Two important Computer terminologies:

1. Hardware

2. Software

Hardware: This comprises the Electronic, Electrical and mechanical components of the
machine. The physical parts, which can be seen, touched and felt about.

Software: These are the programs. Program means the set of meaningful instructions
written in a particular order so as to carry out some task. The program is fed into or
stored in the computer. A computer is said to be running or executing a program when it
is carrying out programs instructions. Without the software the hardware is of no use. As
computers are dumb machines they can work only with the help of software, which tell
them what the machine is required to do. Writing instructions for a computer is known as
programming, and the persons who writes programs is called as a Programmer. There are
different languages and packages to write these instructions.

Computer Languages

A language is a system of communication. A programming language consists of all the
syntaxes (grammar or usage rules) and semantics (meaning) that permit people to
communicate with the computer. The computer languages must have instructions to
manipulate input/output, text etc. They should have instructions to calculate, do logical
operations like comparison, storing and retrieval of information etc.

These languages are broadly classified as

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· Machine level language

· Assembly level language

· High level language

· Fourth generation languages

Machine level language: A program written using binary numbers i.e. 0’s and 1’s
specified for the processor’s operation and absolute binary address is known as the
machine language of the computer. The instruction prepared in machine level language
comprises of two parts. The first part makes the operation code or op code or command
which species the function required to be carried out by the processor. The second part of
the instruction specifies the operand on which the operation is required to be performed.
Operand can be data or the location of the data.

Assembly level language: This language uses mnemonics or abbreviations to represent a
particular operation. Again the instruction in this language has two parts, first parts
representing the operation required to be performed (mnemonic for a operation) and the
second part representing the operand on which the operation specified in the first part will
be performed. The operand can be data, location for data retrieval/store or label etc. The
operation code (mnemonic) and operand varies from processor to processor.

Ex: Assembly level language instruction for 8086 processor is

ADC BX, AX

Ex: Assembly level language instruction for 8085 processor is

ACI 65H

A program written in Assembly level language is converted to its machine level language
by translator software called as Assembler.

High-level language: In this language the instructions are written in simple English. But
again you should use certain specified English words of the particular language, which
represent a particular operation. These languages are machine independent and procedure
oriented. These languages are easy to understand and write programs. The example for
the higher-level languages is BASIC, COBOL, FORTRAN, PASCAL, C, C++ and Java
etc.

BASIC: Beginners All-purpose Symbolic Instruction Code.

COBOL: Common Business Oriented Language designed specially for business data
processing.

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FORTRAN: Formula Translation, this language is more suited for science, engineering
and mathematical calculations.

Pascal: This language is named after Blaise Pascal an eminent scientist who developed
mechanical calculator.

C: This is a more efficient general-purpose language.

Ex:

main()

{

float i,j,k;

i=3.5;

j=8.5;

k=j-i;

printf(“Entered values are i=%f, j=%f, The result of subtraction is k=%f”,i,j,k); }

In the above program three variables named as i, j and k are declared to hold real values.
Then two values are assigned to variables i and j. Then value of i is subtracted from the
value of j and the result is stored in k. Then the values of i, j and k are printed with
appropriate messages.

C++: This language is the extension of C language. This language is object oriented.

Java: This language is another general purpose and object oriented language.

A program written in Higher-level language is converted to its machine level language
equivalent by translator software. Two different types are translator software are
available they are Interpreter and Compiler

Interpreter: This translator software converts program, one statement at time, and
executes it immediately.

Compiler: This translator software converts entire program at a time and then executes it.

Fourth Generation languages: These are the application development tools, which
improve the efficiency and productivity. A number of tools from different vendors are
available in the market and these tools are collectively referred to as fourth generation
languages (4GL). A 4GL tools interacts with Database Management System (DBMS) or

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Relational Database Management System (RDBMS) to store, retrieve, manipulate and to
generate reports according to the user requirement.


1) Explain different categories of Programming languages

Two kinds of software present are

1. System Software: The computer uses this software. This software control and direct
the operation of the computer. It coordinates and synchronizes operations of different
units of the computer. It helps carrying out Input-Output operations, implementing the
instructions given by the user, converting the instructions, which are in higher-level
language to machine level language equivalent etc. The examples for the System
software are Operating System, Compiler, and Interpreter etc.

2. Application Software: These are the software used for specific applications such as
letter typing, accounting, billing and inventory etc. It acts as an interface between the user
and system software. This application software takes the help of system software to
process the needs of the users.

Operating System

This is the system software, which acts as an interface between the user and computer.
All the computers require operating system without which one cannot work with the
computer. This control, co-ordinates, synchronizes all the operations of the computer.
Whatever the user wants to do with the computer with the help of the application
software, the operating system will assist the application software to carry out the job. Or
even the user can directly interact with the operating system to get his work done.
Different operating systems are available they are Microsoft Disk Operating System
(MS-DOS), Microsoft-Windows 98, Microsoft-Windows XP, Microsoft-Windows 2003
Server, UNIX, LINUX etc.

This operating system resides in the secondary memory and if you want to work with the
computer it is required to be loaded in the primary memory.

Booting

The process of loading the operating system from the secondary memory to primary
memory is called as booting. This is the process carried out first when the computer is
turned on. A program called as bootstrap loader, which is stored in the Read Only
Memory present in the computer, carries out the process of booting.

Basically two different kinds of operating system exist they are :

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· Single User: Only one user can access the machine at a time on which this kind of
operating system is loaded. Example is Microsoft Disk Operating System (MS-DOS).

· Multi User/Multi tasking Operating System: Many users can access the machine on
which this kind of operating system is loaded simultaneously i.e. through the network.
Example: Microsoft-Windows 98, Microsoft-Windows XP, Microsoft Windows-NT,
Microsoft Windows 2003 Server, UNIX, LINUX etc.

Port

We have discussed different input and output units earlier and these units are required to
be connected to the computer before they are used and these units are connected to the
connector or socket present at the back of a computer. This connector or socket is called
as a port. Instructions and data are allowed to flow between devices and computer.
Different kinds of ports are available they are Parallel Port, Serial Port, Keyboard Port,
Game Port, Universal Serial Bus (USB), PS2 Port and Monitor Port.

Universal Serial Bus is a new type of port that can be used to connect up to 27 different
peripheral devices with single connector. Using this, different devices can be connected
to a unit, which is out side the system unit.

Applications of Computers

Computers have a very big impact on our day-to-day life. They can be used for a number
of applications like Business, Education, Research, Office, Accounting, Military, Space,
Entertainment, Medical etc. You can use it for any of the applications. Computers are
becoming the integral part of our life, which enhances our efficiency and productivity. In
this competitive world the usage of computers to carry out day-to-day work will give you
an edge over the others.

Following are the broad application areas where computers are used extensively

· Entertainment: It can be used to make cartoon movies, animation and special effects in
movies, games etc.

· Day to day life: It can be used in institution like Collages, Hospitals, Railway and
Airline Booking Systems, Shops, Bank etc. to carry out day to day work. For example
train ticket bookings can be done with help of computer. If you want to book a ticket to a
particular destination instead of a human being searching for the availability of the tickets
in books or by calling a respective station the computers can do that job as computers of
different station are connected in a network

The computer without using paper does most of the jobs done by the human beings with
the help of paper. if an entry is to be made in many place in the case of not using the
computers humane being are required to make entrees in all the places whereas the
computers are used than the human beings are required to do entries in our place in all the

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other place computers will do not entries atomically. For example when a sale bill is
made in shop the entry is made in the Ledger, Cash/Bank book, Stock book etc.
automatically.

· Communication: Nowadays Internet is becoming integral part of life to gather
information about different topics or to send and receive emails etc.

· Scientist: It can be used for research purposes, space programs, nuclear programs etc.


1) Explain the application area of computers

Disadvantages

· Computers cannot think by themselves and they require human direction to perform
specific tasks.

· If the data given is wrong then it gives the wrong result. For example if you want to add
two numbers say 900 and 760, (here 900 and 760 are data) instead of typing 900 and 760
if you give the data as 900 and 780 then the result what you get will be wrong.

· Instructions given also should be correct that is instead of addition if you ask it to
multiply it will multiply.

· It will not work without electricity.

· Investment and maintenance in this equipment is also required.

Summary

Charles Babbage is known as the Father of modern computers. Lady Ada Lovelace is
considered as first lady computer programmer. George Boole proposed the binary
numbers system. The First generation computers are made of Vacuum tubes, the Second
generation computers made of Transistors, the Third generation machines are made up of
IC’s and Fourth generation machines are made up of VLSI technology. Computers are
classified according to their sizes and capacities. Computers are organized into four parts
and they are Input Unit, Output Unit, Central Processing Unit and Memory Unit.
Hardware is nothing but the combination of Electrical, Mechanical and Electronic
components. Software is nothing but the series of instruction written in a particular order
to carry out a specific task. Computers have application in all the walks of life that is in
Business, Education, Research, Science, Entertainment etc.

Terminal Questions

1) Explain different generations of Computers

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2) With the block diagram explain the organization of Computers

3) Discuss the Advantages and Disadvantages of Computers

Unit 2 Number Systems

• This unit deals with Generations of Computers. This unit also includes
Classification of Computers according to their size and capabilities, the different
Input-Output devices used with the computers. It deals with Central Processing
Unit, Memory Unit, terms Hardware, Software, computer languages. The
Advantages and Disadvantages of Computers are also discussed in this Unit.

Introduction

Any quantity is measured in some system. The quantity measured is represented in some
numbers. There are different number systems. In each number system different symbols
are used to represent the numbers. The different number systems are Decimal, Octal,
Binary etc.

Objectives:

To understand

· Decimal Number System

· Binary Number System

· Binary Addition and Subtraction

· Binary Multiplication And Division

· Conversion From Decimal Numbers To Binary

· Negative Numbers

· Representing Negative Numbers Using Complements

· Complements In Binary Number System

· Gates: OR, AND, NOT

Decimal Number System

In this ten symbols are used to represent the numbers hence it is Decimal number system.
The ten symbols are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. These are called Arabic numerals.

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It is necessary to learn only the 10 basic numerals and the positional notational system in
order to measure any desired quantity or to count any required figure. After memorizing
the addition and multiplication tables and learning a few simple rules, we can perform all
arithmetic operations.

For example let us represent the quantity 127. The actual meaning of the number 127 can
be seen more clearly if we notice that it is said as “one hundred and twenty seven”
Basically, the number is a contraction of 1 x 100 + 2 x 10 + 7. The important point is that
the value of each digit is determined by its position. For example, the 3 in 300 has a
different value than the 3 in 30. We show this verbally by saying “three hundred” and
‘thirty” Different verbal representations have been invented for numbers from 10 to 20
(eleven, twelve, . .), but from 20 upward we break only at powers of 10 (hundreds,
thousands, lakhs, crores etc.). Written numbers are always contracted, however, and only
the basic 10 numerals are used, regardless of the size of the integer written.

The base, or radix, of a number system is defined as the number of different digits which
can occur in each position in the number system. The decimal number system has a base,
or radix, of 10. Thus the system has 10 different digits (0, 1, 2, 3, 4 , …9), any one of
which may be used in each position in a number.

Binary Number System

In this number system two symbols are used to represent the numbers hence it is binary
number system. The two symbols are 0 and 1.The same type of positional notation is
used in the binary number system as in the decimal system.

Although the same positional notation system is used, the instead of powers of 10 as used
in decimal number system the binary system uses powers of 2. As was previously
explained, the number 127 actually means 1 ×102 + 2 × 101 + 7 × 100. In the binary
system, the same number (127) is represented as 1111111, meaning 1 × 26 + 1× 25+ l ×
24+1×23+ l × 22 + l × 21 + l × 20.

Binary Addition and Subtraction

In the same manner as decimal addition is performed Binary addition is also carried out.
The table for binary addition is as follows:

“Carry-overs” are performed in the same manner as in decimal arithmetic. Since 1 is the
largest digit in the binary system, any sum greater than 1 requires that a digit be carried
over. For example, 010 plus 010 binary requires the addition of the two 1’s in the second
position to the left, with a carry-over. Since 1 + 1 = 0 plus a carry-over of 1, the sum of
010 and 010 is 100. Here are three more examples of binary addition:

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It is necessary to establish a procedure for subtracting a larger digit from a smaller digit
in subtraction. The only case in which this occurs with binary numbers is when 1 is
subtracted from 0. The remainder is 1, but it is necessary to borrow 1 from the next
column to the left. This is the binary subtraction table.

0–0=0

1–0=1

1–1=0

0 – 1 = 1 with a borrow of 1

A few examples will make the procedure for binary subtraction clear:

Binary Multiplication and Division

Binary Multiplication:

The table for binary multiplication is also given below.

0x0=0

1x0=0

0x1=0

1xl=1

The following examples of binary multiplication show the simplicity of each operation. It
is only necessary to copy the multiplicand if the digit in the multiplier is 1 and to copy all
0s if the digit in the multiplier is a 0.

The following two examples of binary multiplication illustrate the simplicity of each
operation. If the digit in the multiplier is 1 then copy multiplicand and copy all 0s if the
digit in the multiplier is a 0.

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Binary Division:

Binary division is, like any number system is very simple.

0÷1=0

1÷1=1

Division by zero is not done in any number system

Following are the examples of division:

To convert the quotient obtained in the second example from binary to decimal, we
would proceed as follows:

Therefore, 10.011010101 binary equals approximately 2.416 decimal.

Self Assessment question:

1) With example explain when the Carry or a Borrow is generated

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Conversion from Decimal Numbers to Binary

Many methods are available for converting a decimal number to a binary number.

In first method simply subtract all powers of 2, which can be subtracted from the decimal
number until nothing remains. The highest power of 2 is subtracted first, then the second
highest, etc. To convert the decimal integer 14 to the binary number system, first the
highest power of 2, which can be subtracted from 14, is found. This is 23 = 8. Then 14 – 8
= 6. The highest power of 2, which can be subtracted from 6, is 22, or 4 so 6-4=2. Now
subtract 21 , that is 2 from 2 so the remainder of subtraction is 0

The binary representation for 14 is, therefore, 1110.

But this is a laborious method for converting numbers and is convenient for small
numbers, but for larger numbers it may be difficult. So in the second method, the decimal
number is repeatedly divided by 2, and the remainder after each division is used to
indicate the coefficients of the binary number to be formed. The binary number derived is
written from the bottom up.

The binary representation of 123 is, therefore,1111011. Checking this result gives

But this method will not work for mixed numbers. If similar methods are to be used, first
it is necessary to bifurcate the number into its whole and fractional parts; that is, 121.567
would be divided into 121 and 0.567. The binary representation for each part is found,
and then the two parts are added.

The conversion of decimal fractions to binary fractions may be accomplished using
several techniques. Again, the most obvious method is to subtract the highest negative
power of 2, which may be subtracted from the decimal fraction. Then the next highest
negative power of 2 is subtracted from the remainder of the first subtraction, and this
process is continued until there is no remainder or to the desired precision.

So let us consider the following example where 0.875 will be converted to it’s binary
equivalent.

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Thus 0.875 decimal is represented by 0.111 binary. A much simpler method for longer
fractions consists of repeatedly “doubling” the decimal fraction. If a 1 appears to the left
of the decimal point after a multiplication by 2 is performed, a 1 is added to the right of
the binary fraction being formed. If after a multiplication by 2, a 0 remains to the left of
the decimal point of the decimal number, a 0 is added to the right of the binary number.
This process can be continued till you get 0 after the decimal point after the
multiplication other wise for as number of precision you want. The following example
illustrates the use of this technique in converting 0.3475 decimal to the binary system:

BINARY REPRESENTATION

The binary representation of 0.3475 is, therefore, 0.01011000

Negative Numbers

For writing negative numbers a standard convention adopted and it consists of placing a
sign symbol before a number that is negative. For example, negative 27 is written as -27.
If – 27 is to be added to + 45, we write

+45 + (–27) = 18

But if a negative number is subtracted from a positive number, for example the above
expression can be written as +45 – (– 27) = + 45 + 27 = 72
(- and – becomes +).

In binary machines each of the binary digit is represented by a switch which can be used
to represent two values but one at a time either ON or OFF.

As an example, given a set of six switches, any number from 000000 to 111111 may be
represented by the switches if we define a switch with its contacts closed as representing
a 1 and a switch with open contacts as representing a 0. If we desire to increase the total
range of numbers that we can represent so that it will include the negative numbers from
000000 to – 111111, another bit (or switch) will be required. We then treat this bit as a
sign bit and place it before the magnitude of the number to be represented.

The convention is adopted generally is that when the sign bit is a 0, the number
represented is positive, and when the sign bit is a 1, the number is negative. Let us
consider the previous example where we have used six switches to represent the quantity
and now to specify the sign of the quantity whether positive or negative one more switch
will have to be used. When the contacts of this seventh switch is open, the number will be
a positive number equal to the magnitude of the number stored in the other six switches;

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and if the switch for the sign bit is closed, the number represented by the seven switches
will be a negative number with a magnitude determined by other six switches.

Let us consider the following example when seven switches are used

– 37 = 1100101

The seventh switch represents the negative sign, which is 1

+37 = 0100101

The seventh switch represents the positive sign, which is 0

Representing Negative Numbers Using Complements

The negative numbers can be represented in complement form so that a machine can be
made to add and subtract, using only circuitry for adding.

2.5.1 Complements in Binary Number System

There are two types of complements in this and they are 2’s complement and 1’s
complement.

The 2s complement of a binary number is formed by simply subtracting each bit of the
number from the radix minus one and adding a 1 to the least significant bit. Since the
radix in the binary number system is 2, each bit of the binary number is subtracted from
1. The application of this rule is actually very simple; every 1 in the number is changed to
a 0 and every 0 to a 1. Then a 1 is added to the least significant bit of the number formed.
The 2’s complement of 10110 is formed by the following steps

So the 2s complement of 10010 is 01010.

Similarly the 2s complement of 10010 is 01110. Subtraction using the 2s complement
system involves forming the 2s complement of the subtrahend and then adding this
complement to the minuend. For instance,

Example 1:

11001 11001

– 10100 = + 01100

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00101 1 00101

Carry is dropped

Example 2

10110 10110

– 01110 = + 10010

01000 1 01000

Carry is dropped

Subtraction using the 1s complement system is also straightforward. The 1s complement
of a binary number is formed by changing each 1 in the number to a 0 and each 0 in the
number to a 1. For instance, the 1s complement of 11101 is 00010, and the 1s
complement of 00011 is 11100.

When subtraction is performed in the 1s complement system, any end-around carry is
added to the least significant bit. For instance,

Note: Observe the difference in 2’s and 1’s complement subtraction for the same
quantity.


1) Explain the concept of 1’s and 2’s complement

2.6 Gates

A gate is an electronic circuit which operates on one or more input signal to produce an
output signal. There are different gates like OR, AND, NOT etc.

OR Gate:

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The following table gives the combinations of input and the output for each of the
combinations. This table is also called as truth table of OR gate.

Inputs Output

XY Z
0 0 0
1 0 1
0 1 1
1 1 1

In the above table X and Y are the Inputs and Z is the Output. As shown in the table
when both the Inputs are 0 then the Output is 0. If any one of the Input or both the Inputs
are 1 then the Output is 1.

Logical addition table

0+0 0
0+1 1
1+0 1
1+1 1

OR gate is used to realize the logical addition operation.

AND Gate:

The following table gives the combinations of input and the output for each of the
combinations. This table is also called as truth table AND gate.

Inputs Output

XY Z
0 0 0
1 0 0

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0 1 0
1 1 1

In the above table X and Y are the Inputs and Z is the Output. As shown in the above
table the Output is 1 only when both the Inputs are 1 and in all other cases the output is 0.

Logical multiplication table

0.0 0
0.1 0
1.0 0
1.1 1

AND gate is used to realize the logical multiplication operation

NOT Gate

Singular or unary operations define an operation on a single variable. The familiar
example of unary operation is -, so we can write -7, -9 or –Z, that means we are to take
the negative of these values. The operation complementation means inversion of a
quantity and this operation is defined by the following table.

Input Output

X Z
0 1
1 0

The above table gives the output for each input. This table is also called as truth table
NOT gate. The operation complementation or inversion of a quantity can be realized by
the help of NOT gate


1) Differentiate between OR, AND and NOT gate

Summary

In Binary number system two symbols are used to represent the numbers hence it is
binary number system. The two symbols are 0 and 1.The same type of positional notation

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is used in the binary number system as in the decimal system. In the same manner as
decimal arithmetic is performed Binary addition, subtraction, multiplication and division
is also carried out. The negative numbers are represented in complement form so that a
machine can be made to add and subtract, using only circuitry for adding. There are two
types of complements in this and they are 2’s complement and 1’s complement.

A gate is an electronic circuit which operates on one or more input signal to produce an
output signal. There are different gates like OR, AND, NOT et

Terminal Questions

1) Convert the following from Binary to Decimal

a) 11111

b) 10110

c) 11001

d) 00101

2) Perform the following Arithmetic operations in Binary

a) 11011 + 11110

b) 11.01 + 101.11

c) 1110 – 1100

d) 1001 – 0101

e) 1011 * 110

f) 111* 101

g) 1111÷ 111

h) 111 ÷ 11

3) Perform the following subtraction using 1’s and 2’s complement system

a) 11101 – 11110

b) 11001 – 10011

4) Write the truth table of OR, AND, NOT gates

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Unit 3 Introduction to Operating Systems

• In this unit we deal with different terminologies with reference to Operating
System and various flavors of Operating System. This unit also includes the main
functions of Operating system. We discuss various features of Windows XP in
specific in this unit.

Introduction

Operating System is systems software. This software acts as an Interface between the
user and the computer. It also controls and coordinates different operations of computer.

As computer understands machine language and it is difficult for us to understand the
machine language, we issue commands in our language say in English. But the computer
does not understand our language as it knows only machine language so this software
accepts the commands given by us in the language known to us say in English and
converts that command into equivalent machine level language command for the
execution by the computer.

So without operating system we can not work with the computer. It is similar to a
situation where two people of different languages speaking to each other with the help of
an interpreter who knows both the languages.

To work with any of the software it has to be present in the Primary memory i.e. Random
Access Memory (RAM) of the computer. But we know that when we switch off the
machine whatever is present in the RAM will be lost. So how the OS will be brought to
the RAM? When we switch on the machine after Power On Self Test (POST) process the
operating system will be loaded into the computer’s memory with the help of certain
instructions (Bootstrap program) present in the ROM. The process of loading the
Operating System into computer’s memory is known as Booting. Once the Operating
System is loaded into the memory of the computer we can work with the computer.

Thus the main functions of Operating System are

1) To act as an interface between the user and the computer

2) To monitor the use of the resources of computers (Resources can be hardware or
Software)

3) To control and coordinate Input and Output devices

4) To manage the program and data files i.e. to store, to retrieve, to delete files

5) To help the application programs execute commands given by the user

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Examples for operating systems are Microsoft Windows 98, Microsoft Windows XP,
Microsoft Windows 2000, Microsoft Windows 2003, UNIX, Linux, Novell Netware,
Solaris etc.

Operating system is a general term and the above mentioned examples are the names for
the product given by different Organizations which have developed this Operating system
software.

Objectives:

To understand

· Different types of operating systems

· Features of Windows XP

· Options available in the Start button after Windows XP Installation

· Copying of files/Folders

· Restoring the deled files/folders

· Windows media player

Different types of Operating Systems

Let us categorize the Operating System as follows

1) Single User

2) Multi User

3) Batch Processing

4) Multi Processing

5) On Line and Real Time

Single user

a) Single user, Single Task: As the name implies, this operating system is designed to
manage the computer so that one user can effectively do one thing at a time. The Palm
OS for Palm handheld computers is a good example of a modern single-user, single-task
operating system. When you are using MS-DOS it is a single user single task operating
system.

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b) Single user, Multi-tasking: This is the type of operating system most people use on
their desktop and laptop computers today. Microsoft’s Windows and Apple’s MacOS
platforms are both examples of operating systems that will let a single user have several
programs in operation at the same time. For example, it’s entirely possible for a Windows
user to write a letter and at the same time the printing of another letter can be done or at
the same Internet browsing can be done.

So in Single user operating systems there is one keyboard and one monitor that you
interact with.

Consider a typical home computer. There is a single keyboard and mouse that accept
input commands, and a single monitor to display information output. There may also be a
printer for the printing of documents and images.

In essence, a single-user operating system provides access to the computer system by a
single user at a time. If another user needs access to the computer system, they must wait
till the current user finishes what they are doing and leaves.

Multi-user

A multi-user operating system allows many different users to take advantage of the
computer’s resources simultaneously. The operating system must make sure that the
requirements of the various users are balanced, and that each of the programs they are
using has sufficient and separate resources so that a problem with one user doesn’t affect
the entire community of users. Unix, VMS and mainframe operating systems are
examples of multi-user operating systems.

A multi-user operating system lets more than one user access the computer system at one
time. Access to the computer system is normally provided via a network, so that users
access the computer remotely using a terminal or other computer.

These terminals nowadays are generally personal computers and use a network to send
and receive information to the multi-user computer system. Examples of multi-user
operating systems are UNIX, Linux and mainframes such as the IBM AS400.

The multi user operating systems must manage and run all user requests, ensuring they do
not interfere with each other. Devices which can only be used by one user at a time, like
printers and disks must be shared amongst all those requesting them so that all the output
documents are not jumbled up. If each user tried to send their document to the printer at
the same time, the end result would be garbage. Instead, documents sent are placed in a
queue, and each document is printed in its entirety before the next document to be printed
is retrieved from the queue. It is similar to a situation where in you are waiting for your
turn in a ticket counter to get a ticket. The ticket issuer issues the ticket when your turn
comes. Here also all the printing jobs wait in a queue and jobs are printed one after the

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other. Some priority can also be set to some jobs so that they can be taken up early
according to some priority.

Batch Processing Systems:

In these kinds of systems the user feeds his job into the computer and waits for the
completion of his job. New job can not be started until the old job is not completed. Thus
the jobs required to be processed are kept in ready state and whenever one job is
completed the next job is automatically taken and executed.

Multi Processing:

We are considering the system with more than one processor. When we are having more
than one processor in the system then different tasks can be actually run simultaneously
on different processors. For example if we have two processors in a system and two tasks
to run then these two different tasks can be run on two different processors
simultaneously. The operating systems used in such systems are called Multi Processing
operating systems. Multi Processing is achieved in different ways.

On Line and Real Time Systems:

In these kinds of systems the information should be retrieved quickly whenever needed
and updated immediately once a transaction is complete. There should not be any delay
in the process. Such systems are called On Line Systems. The example for these kinds of
systems are ticket reservation systems may it be Air line or Railway. In such system, the
response time should be very short because a customer’s reservation is to be done while
he waits. So the information about a particular route and status about the reservation
should be obtained without any delay and similarly when ticket is issued that information
is also be updated immediately.

In few of the applications computers are used to control the operations of physical
system. A factory floor in which, the machines are controlled by the computers. For
example the rotation speed of lathe, controlling the temperature of furnace, controlling
the placement of space crafts in the correct orbits etc. In such an application the operation
is in real time that is the control has to be exercised during the actual functioning of the
system. Real time operating systems have to work within strict limits of a critical job.


1) Differentiate between Multi tasking in single processor system and Multi processing

Introduction to Windows-XP

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This is another operating system brought out by Microsoft for desktop machines.
Windows XP features friendly new screens, simplified menus, and a whole lot more.
Discover the fresh, streamlined design of Windows XP.

Following are the features of Windows XP

Safe and Easy personal computing: Windows XP makes personal computing easy and
enjoyable. Power, performance, a bright new look, and plenty of help when you need it.
Windows XP has it all, along with unmatched dependability and security.

World of Digital media: A lot of working with digital media at home, at work, and on
the Internet. Enjoy photography, music, videos, computer games, and more.

Connected Home and Office: Share files, photos, music, even a printer and Internet
connection – all on a network that is private and secure.
Best for Business: With Windows XP, you get the proven dependability of Microsoft
Windows 2000, enhanced for high-speed performance and even greater reliability.

Installation of Windows XP

Once Windows XP is installed on your computer you will get a desktop as shown in fig.
1.

Now you can click on to start button available at the left hand corner of the screen. You
will get menu as shown in Fig. 2.

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In this menu you will get different options which are discussed below.

3.5.1 My Documents

Clicking on this item opens the folder named as My Documents as
shown in Fig. 3 and you can store a file in this or you can open an already existing file.

Fig. 3

3.5.2 My Recent Documents

This folder contains the recently opened documents as
shown in figure 4. When you move the cursor on this you will get another menu which
contains the recently opened documents.

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Fig. 4

3.5.3 My Pictures

Clicking on this item opens the folder named as My Pictures as shown
in Fig. 5 and you can store digital photos, images and graphic files or retrieve that kind of
file from this folder.

Fig. 5

3.5.4 My Music

Clicking on this item opens the folder named as My Music as shown in
Figure 6 and one can store and retrieve music and audio files.

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Fig. 6

3.5.5 My Computer

Clicking on this gives you access to, and information about the disk
drives, cameras, scanners and other hardware devices connected to your computer as
shown in figure 7.

Fig. 7

From the menu of figure 7 you can go to any of the secondary devices installed. For
example if you want to work with C drive double click on that drive and the drive is
opened and you can get the contents of the drive as shown in figure 8.

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Fig. 8

Fig. 9

Now you can go to the required folder or can create a new folder. To create a new folder,
follow the steps given below.

1) Bring the mouse pointer to the blank area of desk-top then right click the mouse
pointer you will get a menu as shown in figure 9.

2) Now click on the folder icon the new folder is created with name of the folder as New
Folder.

3) Later you can change the name of the folder. To do this, right click on the folder of
which you want to change the name. From the resulting menu click on to Rename option.
Now it allows you to change the name of the folder and you can type the new name for
the folder.

3.5.6 Control Panel

Clicking on this item provides option for you to customize the
appearance and functionality of your computer, Add or Remove programs and set up net
work connections and user accounts. The menu is shown in figure 10.

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Fig. 10

Depending on the kind of set up you want to do select the required option. For example if
you want to change the desktop of your computer, follow the steps given below.

1) Click on to Appearance and Themes you will get a menu as shown in figure 11.

2) Now click on to Change the desktop background. You will get a menu as shown in
figure 12. Now you can select the required background as shown in figure 13 and click
on to Apply and then on OK. The new desktop will be applied. You can even have
desktop designed by you. To do that click on to Customize Desktop option and follow the
steps shown in the resulting menu.

Fig. 11

Fig. 12

3.5.7 Printers and Faxes

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Clicking on this displays installed printers and faxes. Also helps in
adding new ones. This menu is shown in figure 13. To add a printer you can click on to
Add a printer option and follow the steps shown in menus.

Fig. 13

3.5.8 Help and Support

Clicking on this item opens a central location as shown in figure 14
for help topics, tutorials, troubleshooting and other support services. For example if you
are not able to copy a file from your hard disk to your floppy disk there may be some
problems and you want to know what the problem is and want to fix the problem. You
click on to the option Fixing a problem and in the resulting menu as shown in figure 15
type the text My floppy drive is not working and click on to . You will get a menu as
shown in figure 16 which shows the search result. Now you can click on to any of the
option available for example click on to search result Copy a file or folder to floppy disk.
You will get menu as shown in figure 17 and follow the steps given.

Note: You can even type the searching text in the menu shown in figure 14 also.

Fig. 14

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Fig. 15

Fig. 16

Fig. 17

3.5.9 Search

Clicking on this opens a window as shown in figure 18 where you can
pick search options and work with search results.

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Fig. 18

For example if you want to search a particular file you can click on to All files and
folders option and you will get a menu as shown in figure 19.

Fig. 19

Here you have different criteria using which you can search. Following are the different
criteria’s.

All or part of the file name: Here you can type the complete name of the file name or
partial name with the help of wild card characters.

Ex: test.doc or te*.doc ( this will search for all the files which starts with te and has
extension as doc) or t*.* (this will search for all the files which starts with t and having
any type of extension). Using wild card characters will be useful when you don’t know
the exact name of the file.

A word or phrase in a file: You can type in a particular word or phrase which you know
is present in the file which you are searching for.

Look in: Here you can specify the place (drives or folders) where you think file is
present. Default is all drives.

When was it modified: Here you can specify the tentative date of modification of the
file which you want to search? Default is Don’t remember.

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What size it is: Here you can specify the approximate size of the file. Default is Don’t
remember.

You can make use of the advanced options also.

3.5.10 Run

Clicking on this opens a window as shown in figure 20 where you can
type the name of the folder, program, document or Internet resource, it will be opened.

Fig. 20

Here you can type the name of the program which you want to execute. You can use the
Browse option to select the file which you want to execute. Then click on to OK.

For example you want to got to DOS prompt you can type in command and click on to
OK. You will get a menu as shown in figure 21. Now to go back to Windows XP again
you can type in exit at the prompt and press Enter key.

Fig. 21

3.5.11 All Programs

Moving the cursor on this gets you a menu which shows the programs
installed in the computer which is shown in figure 22. From this menu you can select the
program which you want to execute. Move the mouse pointer over the program which
you want to execute and click on that. Some of the options shown in figure may have sub
menu also, so it will be displayed and you can select the required program from that

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menu also. For example the Accessories option has sub menu which is shown in figure
23. Presence of sub menus is identified by the symbol in front of the option.

Fig. 22

Fig. 23

3.5.12 Log Off

Clicking on this provides option for closing your programs and logging off
or for leaving your programs running and switching to another user.

If different users are created you can switch between the users. Click on to Log off you
will get a menu as shown in figure 24. Then to know the different users click on to
Switch User you will get a menu as shown in figure 25. Here you can select the user to
which you want to switch to or you can come back to the same user by clicking on that
user.

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Fig. 24

Fig. 25

3.5.13 Turn Off Computer

Clicking on this provides the option for turning off or restarting the
computer, or for activating standby or Hibernate modes as shown in figure 26.

Fig. 26

If you want to switch off the computer you can click on to Turn Off option. If you want
restart the computer you can click on to Restart option.


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1) In Windows XP why control Panel is used?

2) Explain the different options available in Search tool of Windows XP?

Copying of Files/Folders

Files/Folders can be copied/moved from one location to another location. To do this
follow the steps given below.

For example you want to copy a file named Internet from mahalasa subdirectory of which
is in D drive to a folder named swarnalakshmi in C drive.

1) Click on to Start, from the resulting menu click on to My Computer (figure 29).

2) Double click on to D drive, in the resulting menu double click on to mahalasa folder it
will display the contents of the folder.

3) Right click on to the file named Internet. From the resulting menu as shown in figure
27, click on to Copy option if you want to copy this file to another location. Click on to
Cut option if you want to move this file to another location.

Fig. 27

Fig. 28

Note: if you want to copy this file to floppy disk, click on to Send option and you will get
another sub menu as shown in figure 28, then click on to 3 ½ Floppy (A:) option. Make
sure that floppy disk is inserted in the floppy drive.

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4) Now click on to this icon twice you will reach a menu which displays you with
all the drive option as shown in figure 29. Double click on to the drive C and in the
resulting menu double click on to swarnalakshmi folder and now right click the mouse
pointer. You will get a menu; click on to Paste option. The file will be copied or moved
depending on the option which you had selected in step 2.

Fig. 29

Recycle Bin

When ever you deleted a file or folder it will be stored in Recycle Bin. You can even
restore the deleted file or permanently delete the file or empty the Recycle Bin.

To restore or permanently delete a file/folder:

Right click on to Recycle Bin icon from the resulting menu click on to Explore option. In
the resulting menu right click on to file which you want to restore or permanently delete.
From the resulting menu click on to Restore if you want to restore the file or click on to
Delete if you want permanently delete it.

To empty the Recycle Bin:

Right click on to Recycle Bin icon from the resulting menu click on to Empty Recycle
Bin option.

Windows Media Player

This tool is used to play the digital media like music, Video, CD, DVD and Internet
radio. To start this tool Click on to Start, from the resulting menu click on to Windows
Media Player icon. Using the resulting menu you can select the files which you want to
play.

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Summary

Operating system is system software which acts as an Interface between the user and
computer. There are different types of Operating systems like Single User, Multi user,
Batch Processing, Multi Processing, On Line and Real Time. Windows XP is the
Operating System for the Desktop machines brought out by Microsoft. Windows XP is
Safe and Easy for personal computing, can be used to connect to the Network easily.

Terminal Questions

1) Discuss different types of Operating systems

2) Explain different features of Windows XP

Unit 4 MS-WORD-I

• This Unit deals with most widely used Microsoft tool Word, which is used to
create and edit document. This unit deals with the basic parts of Word. How you
can create, save and close a new document. It also deals with formatting of the
document. Working with table is also discussed. The header, footers and Page
setup is also discussed in this.

Introduction

In an organization lot of documents to be prepared, for example letters to be written to
suppliers, customers, banks, authorities. Similar letters may have to be written again and
again. For all these, the letter may be typed once and it can be stored in the computer.
When the same or similar letter is needed then it can be retrieved and changes can be
made to it if needed. Thus lot of time is saved in typing and the efficiency is increased.
So Microsoft Word is such software which can be used to create, format, store, retrieve,
edit and print the document.

Microsoft Corporation developed this software. This software is used to create, edit, lay
out, save, print, mail merge etc. a document.

Objectives

To Understand

· The steps to start Microsoft Word

· Basic units of Microsoft Word

· The creation of a document

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· The saving of the document

· The opening of an existing document

· The formatting of a document

· Editing of a document

· Numbering

· Inserting of symbols, pictures, tables in the document

· The printing of document

4.2 Starting MS-WORD

Following steps are undertaken to start Microsoft Word

1. Move the mouse pointer over the Start button present on the extreme left of the task
bar and then click the left mouse button. A push up menu appears.

2. Place the Mouse pointer over the Program option inside the push up menu. A second
menu gets displayed immediately.

3. Move the mouse pointer over Microsoft Word option and click the left mouse button
as shown in Fig.1. A blank document file named Document1 gets displayed on the
screen instantly Fig. 2. Now the text/data can be entered in the file Document1 appeared.

Fig. 1

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Fig. 2

Basic Units of MS Word

1. Title Bar – Displays the application name, file name and various window controls like
minimize button, maximize button and close button.

2. Menu Bar – Different options for selection.

3. Standard tool bar – Displayed by default, allows to give common commands like
saving the file, opening a file, printing etc.

4. Formatting toolbar – Allows the user to give commands related to formatting
text/data like Bold, Underline, Font Style, Font Size, Color etc.

5. Editing area - Here you can type and edit the text.

6. Scroll Bars – Used to scroll through different parts of current document.

7. Drawing Tool Bar – This is used to draw different shapes, arrows, etc.

8. Status Bar –

The Status bar, which is a horizontal area at the bottom of the document window in
Microsoft Word, provides information about the current state of what you are viewing in
the window and any other contextual information.

To display the status bar, click on the tools menu then click on to Options then click the
View tab, and then select the Status bar check box under Show

Note: Toolbar

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To display a toolbar, point to Toolbars on the View menu, and then click the toolbar you
want. If the button you want doesn’t appear, click More Buttons on that toolbar. For Help
on an option, press SHIFT + F1, and then click the option.

Now let us discuss in detail each of these units.

Title Bar:

Fig. 3

1. Title Bar: Displays the application name, file name and various window controlled
like minimize button, maximize button and close button.

a. Minimize button : This is used for changing a window/ document into a button

b. Maximize button : This is used for enlarging window/ document after it has been
minimized or restored. When a document is maximized then to bring it back to the
original size use Restore button.

c. Close button : This is used to close a window/document

Menu Bar:

This has different options for selections (which is discussed in detail below). In addition
to minimize and close button(described above) it has a restore button which is used for
bringing a window/sheet to its original size and adjusting the size of a
window/Document.

Fig. 4

File: This helps in creating a new file; opening an existing file; saving a file; printing;
print preview; setting up of print area; page setup; sending the page to MS-PowerPoint
etc; closing the Document; exiting MS Word etc.

Edit: This helps in copying, cutting, deleting a range of text. Pasting a text which has
been copied or cut from some other location. Clearing the content at a particular location.
Finding the particular text and Replacing it with new text in the Document etc.

View: This helps in enabling and disabling certain tools in the word window. This is also
used to add Header and Footer to the document.

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Insert: This can be used to insert page numbers, page breaks, pictures etc.

Format: This helps in changing the Font of the text

Tools: This helps with the spell checker, protection of documents by providing the
password The document can be customized according to one’s specification etc.

Table: This is used to insert, delete, select, and draw table.

Window: This is used to hide/unhide the work book. To create new window, to split the
pane etc.

Help: This can be used to get any help about MS Word.

Standard tool bar:

Fig. 5

New: This is used to create a new Document

Open: This is used to open an existing file

Save: This is used to save the file

Print: This is used to take the print out of the file

Preview : This is used to see the printing document before printing

Spelling checker: This is used to check the spelling and grammatical errors in the
file

Cut: This is used to move a selected block from one location to another.

Copy: This is used to copy a selected block we want from one location to another

Paste: This is used to make appear the block selected during the copy or cut
operation at a certain location.

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Format Painter: This is used to copy character and paragraph formats. Follow the
steps given below to use Format painter.

To copy paragraph formatting, select the paragraph – including the paragraph mark – that
has the formatting you want to copy.

To copy character formatting, select the text that has the formatting you want to copy.

On the standard tool bar, click Format Painter and then select the paragraph or text
you want to apply the formatting to.

To copy the selected formatting to several locations, double click Format Painter. Click
the button again when you’re finished, or press ESC.

Undo: This is used to retain any modifications made to a file

Redo: This is used to repeat the last action.

Insert Hyperlink: Hyperlink can be used to move to a specific location in the same
document or other document.

Tables and Borders: This is used to draw a table with the drawing tool. The border
of the table can also be set to required design.

Insert Table: This is used to insert a table with required number of Rows and
Columns. The border of the table can also be set to required design.

Insert Worksheet: A work sheet with required number of cells can be inserted in
your document and you can work with that work sheet.

Columns: Changing the pages into columns.

Drawing: This is used to toggle between enable/disable of Drawing tool bar.

Document Map: The Document Map is a separate pane that displays a list of
headings in the document and keeps track of your location on it. When you click a
heading in the Document Map, Word jumps to the corresponding heading in the
document, displays it at the top of the window, and highlights the heading in the
Document.

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Zoom: You can “zoom in” to get a close-up view of your document or “zoom
out” to see more of the page at a reduced size.

Close: To close all open documents without exiting the program.

Find: This is used to find a text or find a text and replace it by the required text.

Formatting Tool Bar

Fig. 6

Font: This helps in changing the style of the text typed in the documents. You can select
a required font from the available font list and change the style of the text which is inside
the selected block.

Font Size: This helps in changing the size of the text. You can select a required size for
the font from the available list and change the size of the text which is inside the selected
block.

Bold: This helps in make the selected block look bolder than the other text

Italic: This helps to make the text in the selected block look tilted or slanted.

Underline: This helps in getting an underline to the selected text.

Align Left: This helps in aligning the contents in the selected block to the left edge of the
page.

Center: This helps in aligning the contents of the selected block to the center of the page.

Align Right: This helps in aligning the contents of the selected block to the right edge of
the page.

Justify: The contents of the document can be aligned from the left edge to the right edge
of the page.

Numbering: Automatic numbering can be generated when you want number certain
points that you are typing.

Increase Indent and Decrease Indent: These can be used to set the position of Text in
relation to the left and right margins and spacing is used to set the amount of space
between lines and paragraphs.

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Highlight Color: Particular portion of the document can be highlighted using this icon.

Font Color: The color of the text can be changed to the required color by using this icon.

Vertical Scroll Bar: The vertical scroll bar consists of two buttons Up Arrow Scroll
button and the Down Arrow Scroll button. Clicking of any of these buttons allows you to
see those lines of a document, which are not visible on the screen.

Horizontal Scroll Bar: The horizontal scroll bar consists of two buttons Right Arrow
Scroll button and the Left Arrow Scroll button. Clicking of any of these buttons allows
you to move the contents of the document to the left or right of the screen respectively.

Closing the MS Word document

There are two ways in closing the Document.

1. Closing the document without saving it

2. Closing the document with saving it

1) Closing the document without saving it: In this your work/latest update is not saved.
To do this follow the steps mentioned below.

1. Move the mouse pointer over the File option on Menu bar and click the left
mouse button. A pull down menu gets displayed immediately as shown in Fig 7.

Fig. 7

2. Inside this pull down menu move the mouse pointer to the Close option and click the
left mouse button. A message box gets displayed immediately asking you whether you
want save this sheet with three options Yes, No and Cancel. Move the mouse pointer
over No and click the left mouse button this will close the sheet without saving it.

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