Computer Fundamentals & Programming

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Computer Fundamentals & Programming


Computer Fundamentals


1.

Introduction To Computer System

1.1.

Introduction

Computer is most important device for this era. The computer technology has almost changed the world in
short times. It becomes very essential tool in

every walk of human life. The word computer is developed from
the Latin word ‘
coputare’
which means “To
calculate

or to
compute”
.
Roughly we can say

the machine which
calculates is called a computer; but it is incomplete, In

fact

a computer is a programmable electronic
calculating machine. It received data through it input devices, process it and produce output as our
requirement with in a second. With help of computer technology a person can communicate to other people
from one p
lace to another place of the world through telephone, telex, fax, e
-
mail etc within a minute. A
computer accepts data from an input device and processes it into useful information which it displays on its
output device. It operates under the control of a
set of instructions that is stored in its memory unit.


Definition of computer


A computer is an electronic device that accepts data; process it according to a set command and then gives
results. In other words a computer is an electronic machine that is used for data processing to produce
information.


With viewpoints of this defi
nition computer
is said to

be Electronic

calculating
machine, Programmable

machine, Data

processing
device, Networking

device, Automatic system etc
...




The computer has following basic system and components devices to process data and gets the outp
ut. It
has optional

components

too.


A)


System device

i)

Input device

-

keyboard, mouse

ii)

Processing device



Central Processing Unit (CPU)

iii)

Output device



Monitor and Printer


CPU Consists motherboard, hard disk, floppy disk drive, sound card, power supply, modem, etc.


B)



Basic and optional component device


(i)

Basic Components

Capacity & functions

1

Processor

-

600 MHz, 1200 MHz, 1700 MHz

2.

Hard Disk

-

40 GB, 100 GB, 160

GB, 200 GB, 2000 GB

3

RAM

-

1
28
MB
, 256 MB, 512 MB, 1GB, 2GB

2


4

Display /Video Card

-

64 MB, 128MB, 512 MB, 1 GB

5

Keyboard

-

84 keys , 104 Keys, 124 Keys

6.

Hard disk drive

-

reads, writes on HD

7

Floppy disk drive

-

reads, writes on floppy

8

CD
-
ROM/DVD drive

-

reads, writes on CD
-
ROM, DVD
-
ROM

9

Mouse

-

pointing & clicking device

10

Monitor

-

Displaying device


A complete basic components set of these devices is called a computer. Computer may have optional


devices
too.


ii)

Optional
Components

Capacity & functions

1

Printer

450ch/sec, 1
-
18 Pg/min, 4
-
24 Pg/min

2

Scanner

Flat bed type & Handheld type

3

DVD drive

Reads/writes on DVD

4.

Zip drive

Reads/writes on Zip disk

5

Pen drive

Reads/writes on Pen drive

6

Modem

Internal &
External type

7.

Speakers

Throws sounds


1.2.

Features

(Characteristics of computer)

Computer is
very important and useful device for everywhere of a

human being of this century. This is due to
its

major capa
city

or
features. There are some important features
.


i)


Automatic


Computer is an automatic

calculating machine
; any given a job it performs independently without
assistance of

human being.

ii)


High processing speed

A computer is a very fast processing device .It can perform in a few seconds, the amount of work that a
human being can do in an entire year. It can perform data processing job very fast usually measure in micro
second (
10
-
6
), nano
second (
10
-
9
)
and Pico

s
econd (10
-
12
).

iii)


Accuracy (100%)


Computer is working its job very accurate. A computer performs every calculation with the same accuracy.
However the mistake may occur; if any mistake found in it is not due to the mistake of computer but the
mistake of
programmer. It works consistently and accurately throughout the time.

iv)

Reliability

Individual components of computer have a very high life and degree of reliability. Computer is only a
machine and it does not make errors on its own. So computer is reliable
device.

v)


Diligence (Stay constant)

3


Computer is a machine .It is free from monotony, tiredness and lack of concentration. It can continuously
work for hours without creating any error and without grumbling

vi)


Versatility (Simple to complicated jobs)

Versatile is one of the most wonderful things for a computer. It is capable to performing almost any task if the
task is reduced to the finite series of logical steps .Once moment it is preparing result of an examination next
it is busy to prepare electric
ity bills and in between it help to type a business letter.

vii)


Huge storing device

Computer
has huge

storing capacity. It can store a large number of data in it. The secondary storage device is
used for it. Thousands of books can be store in a small chip.

Fo
r instant


1 Kilobyte

= 1024 characters/symbol = 10
3
bytes around

1 Megabyte

= 1024x1024 ʺ = 10
6

ʺ

1 Gigabyte

= 1024x1024x1024 ʺ


= 10
9

ʺ

1
Terabyte =

1024x1024x1024x1024 ʺ


= 10
12

ʺ

In accordance the computer has huge storage capacity.

viii)


World Wide Networking

Computers are connected to word wide. Through internet a person from any place to the other person in any
place of the world

can talk, share picture etc .in a moment, a person get any kind of information through
computer .This is all with the help of computer and its word wide network.

ix)


No I.Q. and Feeling

Computer is a machine. It is free from any kind of emotion and feeling
. It is not a magical device also.
Though it perform the task as human being
does but

it has no brain as like a human
brain.


1.3.


Impact of the Computer Technology in the Society


1.3.1.


Background:

In the world today, computer awareness, use and its impact is
increasing in a very high speed day by day.
Compared to other technologies, it is developing and changing very frequently. It is a multi
-
dimensional
technology, which can create a multidimensional effect in the all round development of the person, the
soci
ety and the country. It can help the society providing quality service cost effectively. That is why people
are adapting this technology very fast. At present, we have seen that people from different sectors like
doctors, engineers, managers, teachers, res
earchers, businessmen, industrialists and students etc. are using the
computers. Using this technology, they are increasing their living standards, economic status, and personal
working capacity and so on.

It can bring rapid progress and prosperity in the
country. Singapore, Japan, South Korea, Taiwan and others
are good examples. To develop the country and society, the revolution of agriculture had taken more than
thousand years and the industrial revolution had taken about a century. But the revolution of

technology has
taken only about 25 years to change the society and country. It is a very fast changing technology, which can
accelerate the developing speed of the nation. It can bring fast economical revolution to the country. It can
quickly change the l
ife style to bring prosperity. Therefore, it can impact the society in multiple ways.
Advantage and disadvantage of the technology are as follows.


4


1.3.2.

Positive Impact
:

i.

Employment benefit

ii.

Greater efficiency

iii.

Higher Quality Product

iv.

Better Service

v.

Recreational
and educational benefit

vi.

Aid to handicapped

vii.

Improved Safety

viii.

Better Information retrieval

ix.

Educational benefits

x.

Personal finance benefits

xi.

Benefit of greater personal efficiency.


1.3.3.

Negative Impact:

i.

Employment problem

ii.

System Security problem

iii.

The privacy issue

iv.

Fr
eedom restrictions

v.

Privacy control

vi.

The threat to access by the hackers

vii.

The threat to the system security, etc.


1.4.

Application

of Computer in the society

Realizing the above social impact, the people of the world are endeavoring to provide computer education

to
their children from an early age. Most of the developed countries have made Computer Education compulsory
from grade one to Ph.D. level. They had prepared the curriculums to use it according to the level and
requirements. Most of the countries are inve
sting lots of money on the computer education for better quality
of life and speedy development. Due to the development of computer technology, India, South Korea,
Taiwan, Singapore and Malaysia have upgraded the living standards of their people within the

last two
decades. But Nepal could not develop much compared to what they had done. In fact, Nepal had also started
using this technology since 1970 AD but, because we did not care about the quality Computer Education in
the right time. We have not yet bee
n able to frame proper national policy of IT (Information Technology)
development and human resource development on IT. Anyway, in Nepal also people had started computer
Education from class 3 to the Ph. D. level at present. They are using computers in dif
ferent sectors. There are
good impacts of this technology. At present, people in Nepal are using this technology in the following fields
for the personal and social benefits.


1.4.1.


Education Sector:


i.

Result Processing in Schools, 10+2, Colleges and Universitie
s.

ii.

School Information System Processing in Ministry of Education.

iii.

Students & Teacher's Record Keeping.

iv.

As a teaching tool for Science, Health, Geography, etc.

v.

As a learning tool in the practical class of Schools, Colleges and Universities.

vi.

Account
keeping, Payroll System and others.

vii.

Statistical record keeping, etc.


5


1.4.2.

Health

and

Sector:

i.

CT scanning

ii.

Ultra Sound

iii.

Patient Record Keeping

iv.

Account Keeping

v.

Statistical Report

vi.

Medical Store Inventory Control

vii.

Research and Development.


1.4.3.

Banking Sector:

(i)



Bank Account Keeping

(ii)

Electronic Money Transfer

(iii)

General ledger

(iv)

Note
conciliation

(v)

Monthly/Yearly Income & Expenditure Record Keeping

(vi)

Monthly/Yearly Money Transaction

(vii)

Research and Development

(viii)

Reconciliation.


1.4.4.

Hotel

Management:

(i)


Front Desk Management System

(ii)

Manpower Management

(iii)

Account keeping

(iv)

Store and kitchen Inventory Control System

(v)

Hotel Management System

(vi)

Hotel Booking

(vii)

Record Keeping.


1.4.5.

Airlines Management:

(i)


Ticket
Booking

(ii)

Ticket Reconciliation

(iii)

Billing & Ticketing

(iv)

Spare parts Inventory Control System

(v)

Account Keeping

(vi)

Commission Agents’ record keeping

(vii)

Personnel Management System.


1.4.6.

Agriculture Sector:

(i)

National Agriculture Census

(ii)

Research and Development

(iii)

Personnel Management

(iv)

Production Control Management System

6


(v)

Manpower Training

(vi)

Store and Inventory Control System.


1.4.7.

Industrial Sector
:

(i)



National Industrial census

(ii)

Research and Development

(iii)

Production Control

(iv)

Quality Control

(v)

Inventory Control System

(vi)

Demand and Supply System

(vii)

Manpower Management System

(viii) Property Management System

(ix)

Spare parts Inventory Control System.


1.4.8.

Communication Sector:

(i)


Internat
ional News Collection, Dissemination & Control

(ii)

National News Collection, Dissemination & control

(iii)

Dissemination of news, in terms of text, voice and views

(iv)

Research and Development

(v)

Store Inventory Control System

(vi)

Record

Keeping System, etc.


There are other sector
also
where the application of computer
is
very important
these are
E
-
Governance,
Office, Intelligence Machine, Weather Forecasting, Decision Making, Distance Education, Film
recording, Traffic Control, Playing
games, Publication

etc.

1.5.

History And Development Of Computers

A computer is an invention of human beings to enhance their capabilities to accomplish tasks. Modern
computers are developed after a gradual change over a long period of time. In another word,
it was not
developed in one day. Hence it has its own history.

Tribal life in ancient time required man to remember a lot of information, so an early man felt the need to
count the things. Then he started counting using his own fingers. However, the limite
d number of fingers had
made it difficult for him to remember more facts. Thus, he started different methods to count using stones,
sticks, scratches on a rock or wall or knots in a string. As a result, during fifth century Hindu philosophers
were able to
develop a new method of counting using the numbers (digits) 0 to 9. Since there are ten digits,
the Arabic Number System method was called Decimal Number System of counting. Hence, the history of
computer implies the gradual change in the concept over a lo
ng period of time. In the following section, we
will explain the history of computing machines from their early forms to the most modern high
-
speed
electronic computers.

(a) BC 5000 to 2000 Abacus

In early days, people used pebbles or beads on a counting
board to carry out simple calculations. This tool is
called the Abacus. Its exact origin is unknown. It may have originated in China, Egypt and Greece during
5000 B.C. to 2000 B.C. An abacus can be used to add, subtract, multiply and divide. Even today the

abacus is
used in many parts of the world (e.g. China).


(b) A.D. 1614: Napier’s Bone

7


In 1614 John Napier, a Scottish Mathematician, first published the first table of logarithms. It was very
helpful in simplifying multiplication of large numbers. In
1614, Napier also developed a numbered rod in
order to multiply, divide and extract roots, known as Napier’s bone. It was called so because it was made up
of strips of bones on which numbers were painted. By the combination of these bones, direct multiplic
ation
could be done.


(c) A.D. 1620: Slide Rule

In 1620, Slide Rule was developed by William Oughtred, UK which is an analog device. It used the principle
of logarithms. It has two graduated scales. One scale slides or slips upon the other. With the proper

alignment
of the two scales, it is easy to find the product, quotient or any other function simply by viewing on the
scales.


(d)
A.D. 1642: Pascal’s adding machine

The first real calculating machine that could add and subtract was a mechanical calculator

called Pascal’s
Adding Machine or Pascaline, invented by a French scientist Blaise Pascal in 1642. Pascal’s Adding machine
consisted of ten toothed wheels. The addition or subtraction was performed by turning these wheels.


(
e) A.D. 1694: Leibnitz’s Calc
ulator

The first calculator that could perform automatic addition, subtraction as well as multiplication and division
was developed by a German philosopher Gottfried
Wilhelm

Von Leibniz. In 16
71
, Leibnitz modified his
calculator. It was also known as. Step
ped Reck
no
r.

(f) A.D. 1801: Jacquard’s Loom
and
Punched Card

At the beginning of the nineteenth century (i.e. A. D. 1801), Joseph Marie Jacquard of France invented a
punched card as an accessory to the loom. The punched card could automate the loom for th
e weaving of
intricate patterns. Thus, he could control the weaving loom through the set of holes in a card, which could
store the instruction for the loom.



(g) A.D. 1822 and 1833: Babbage’s Differential Engine

In 1822, another interesting development t
ook place in the history of computers. Charles Babbage, an English
Mathematician, invented a calculating device called Differential Engine . Babbage wanted to calculate
Polynomial functions using the method of differences.

Babbage, also wanted to design
a bigger machine, called an Analytical Engine. The idea of an Analytical
Engine developed in 1833 AD was considered as a most significant step in the history of computers, because
of his idea only, the dream of modern computer has come true. That is why he

is famous as “Father of
Computer”.

Babbage intended to have his machine to have a mechanism to input data and output the results. He wanted to
input data with the help of punched cards and the output to be printed on copper plates. Babbage’s analytical
en
gine and modern day computers are similar in their structure. This engine had four major units.

1.

Store: A memory or store which could store data and intermediate results.

2.

Mill: An arithmetic unit which was called a ‘Mill’. It could perform calculati
ons.

3.

His machine had mechanism having gears and shafts by which data and results were transferred between
the store and the mill which is similar to the control unit of today’s computer.

4.

Input and Output devices


(h) A.D. 1848 Lady
Ada
Agusta

In 1848 AD, a British mathematician Lady Agusta wrote a first program to run an analytical engine made by
Prof. Charles Babbage. Hence she is called a first programmer.


8


(i) A.D. 1850 George Boole

George Boole, a British mathematician, introduced mathema
tics of logic known as Boolean algebra. It laid
the foundation of digital computers. Boolean considered two
-
valued binary notation (i.e. 0 and 1) to represent
any form of data.


(j) A.D. 1890: Dr. Herman Hollerith

The first card machine which was electri
cally activated was used by Dr. Herman Hollerith to compute the
statistics of the 1890 AD United States population census. Hollerith was an American mechanical engineer
and statistician, working for the Census Bureau. He used the punched cards to store dat
a, with the holes
representing data values. He developed an electromechanical tabulating machine for punched cards. Because
of his sincere efforts, the population census of 1890 could be processed in one
-
third of the time allotted.


(k) A.D 1937: Electrom
echanical Computers

(Mark I)

In the early part of the twentieth century, tabulating machines were growing rapidly. In 1937, next important
event occurred in history. The first electromechanical computer with the development of MARK I was
invented by Howard

Aiken and other was constructed MARK I at Harvard University under the sponsorship
of IBM (International Business Machine).The MARK

I

also known as the Automatic Sequence Controlled
Calculator. It was 50ft. long and 8 ft. high. It used electronic tubes an
d electrical relays. MARK I took 4½
seconds to multiply two 23
-
digit numbers. It was able to produce
ballistics

tables that were used in
connection with Second World War. The input device used was the punched paper tape.


(l) A.D. 1939: Electronic Comput
ers

(ABC computer).

The age of electronic computer began when vacuum tubes were introduced. Such tubes were thousands of
times faster than the earlier electromechanical devices. The first electronic digital computer was developed in
1939 AD by John V. Atan
asoft and his student Clifford Berry It was called Atanasoft
-
Berry Computer (ABC
computer).


(m) A.D 1940: ENIAC (Electronic Numerical Integrator And Computer)

In the true sense, the first electronic computer was developed by John W. Mauchly and John Presp
er Eckert.
It was developed at the university of Pennsylvania and called ENIAC (Electronic Numerical Integrator And
Computer), based Decimal Number System.

ENIAC used high
-
speed vacuum tubes (switching devices). The high speed operation of the computer in
the
world was first experienced with ENIAC. It could add two numbers in 200 microseconds and multiply two
numbers in 2800 microseconds. Number of vacuum tubes used was 19,000. It occupied an area of 150 square
meters and was 1,000 times faster than Mark
-
1.


(n) A.D. 1949: EDSAC (Electronic Delay Storage Automated Computer)

In 1945, a noticeable improvement in the development of the computer took place when John Von Neumann,
the Hungarian mathematician genius developed the idea of Stored Program Concept, whi
ch was a very
important technique to design today's Computer. According Neumann, it would use Binary Number system
instead of Decimal Number System used in ENIAC. Then Prof. Maurie Wilkes used the I.V Neumann’s
stored program concept to design the computer

called EDSAC (Electronic Delay Storage Automatic
Computer). EDSAC was called the first stored program electronic computer developed completely in 1949.


(o) A.D. 1951: UNIVAC (Universal Automatic Computer)

After developing ENIAC, Mauchly and Eckert formed

their own company in 1946. This company built a new
computer called UNIVAC
-
I (Universal Automatic Computer
-
I) in 1951. UNIVAC was delivered to the
9


Census Bureau. Business organizations too started using UNIVAC. Hence, it was called the first
commercially
used electronic computer in the world.


(p) A.D. 1970: Microprocessor

The first Microprocessor was built at Intel Co
-
operation, USA in 1970. It was used to build minicomputer and
micro computer at the beginning.


(q) A.D 1972: Minicomputer

The first minicomputer was developed by Digital Equipment Corporation (DEC) in 1972 A.D. Within 1977
AD different computers started developing varieties of Minicomputers.


(r) A.D. 1974: Microcomputer

The first microcomputer called ALT AIR 8800 was
manufactured in 1974. It used an 8
-
bit Intel
microprocessor. The Apple personal computer and IBM pc was first introduced in 1976 and 1981 AD
respectively.


(s) A.D. 1994: Pentium Series

IBM Company launched PCXT (Extended Technology) and PCAT (Advanced Tec
hnology) microcomputers
were developed first time in 1983 and 1984 AD respectively. Then in 1994 AD Pentium series of
Microprocessor Chips were launched.

In the same year, US vice President Mr. Algor announced about “Internet for all”. Then most of the
de
veloped and developing countries tried to use Information Technology (IT), where people could use
Internet, Intranet, extranet and email. With the help of this technology they also started using Website, Digital
Library, E
-
commerce, E
-
shopping, E
-
Banking a
nd Telemedicine, etc.


(t) AD 1995: Multimedia Technology (MMX)

Pentium I with Multimedia Technology (MMX) computer was built and released. In the same year, Windows
95 and Graphical User Interface (GUI) were launched by Microsoft.


(u) A.D.1996: Linux Ope
rating system

This year different individual software developers developed Linux Operating System.


(v) A.D. 1997: MS
-
Office 97

Microsoft Company Launched MS
-
Office 97 (Office Application) for Windows 95. Similarly in the same
year private individuals also

designed and sold a special type of Operating System named LINUX in the
world market.


(w) A.D. 1998: Windows 98

Microsoft Company released advanced Windows 98 Operating System, which was the corrected and
advanced version of Windows 95 and windows 97.


(
x) AD: 2000: Windows 2000

Microsoft Company again developed and released advanced version of windows 2000 Operating System,
which are being used worldwide even today.

1.6.

History and Development of Computer in Nepal:

10


Although the first electronic digital computer was built in mid 1940’s, computer was introduced in Nepal in
the year 1972 only. It was introduced by Government for the population census of 1972 (2028 B.S). This was
the second generation computer of IBM Com
pany called IBM 1401. The Government had paid Rs One lakh
twenty five thousand per month as rent for this computer.

The Census Department at Thapathali Kathmandu had used IBM 1401 computer for the first time to process 1
corer 12.5 lakhs population census
taking 1 year, 7 months and 15 days. Later, it became essential to operate
the computer for day and night, for this reason a separate branch office called Yantric Sarinikaran Kendra
(Electronic Data Processing Centre), was established in 1974 (15th Paush 2
031 B.S.), which, after six years,
was converted to National Computer Centre (NCC).

For the population census of 1981 (B.S. 2038), a British computer ICL 2950/10 (International Computer
Limited 2900 Series) which had 64 terminals was added from the aid of
UNDP and UNFPA at two million
American dollar from the British ICL Company. By the help of this fourth generation computer, the 1981
population census was completed within one year and 3 months.

Microcomputer such as Apple, Vector and Sirus were introduced

in Kathmandu for the first time in 1982
(B.S. 2039). New companies such as Computer consultancy (CC), Management Information Processing
System (MIPS) and Data System International (DSI) were established.

Since 1983 (BS. 2040) National Computer Center, on

the other hand, also started giving training on
programming, data entry, data processing, and development of software packages. As a result, many people
from various sectors started showing their interest in the field of computers.

Since 1977 (B.S. 2034)
His Majesty’s Government employed IBM 1401 computer in tourist statistical data
processing, industrial data processing, statistical and loan account keeping of Agricultural Development
Bank, Provident fund, SLC result processing and TU result processing, e
tc. After a few years, new computer
ICL 2950/10 was brought in use, which was more efficient for data processing in some other corporations
such as Telecommunication, Electricity Authority, Janakpur Cigarette factory, Hetauda Cement Factory,
Tribhuwan Univ
ersity, etc. Many others like travel agencies, hotels, factories, printing presses also started
using computer for better & faster work. At present, not only Kathmandu is using microcomputers but also
Lalitpur, Bhaktapur, Pokhara, Nepalgunj, Bhairhawa, But
wal, Hetauda, Birgunj, Biratnagar, Janakpur, Jhapa
etc. are using computer for different purposes. Nowadays, computers have been used in different areas like,
travel agencies, hotels, Airlines, Government offices, Banks, Colleges, Schools, Hospitals, etc.
in Nepal.
People are using computer even at home for day
-
to
-
day use for their personal convenience.

Now there are more than 1000 private computer
-
training centers all over Nepal. About 50 software
development centers are working in the Nepali market. At p
resent, in Nepal more than 1250 schools, 107
higher secondary schools, 50 general colleges, 42 IT related colleges and 4 Universities are teaching and
using computer technology. More than one hundred thousand computers are busy in Nepal. More than 28
priva
te Internet Service Provider (ISP) are providing services in the Nepali market. Nepal had started using e
-
mail, Internet, e
-
Banking and Websites since 1996 AD.

The purpose of using the computers is for word processing, keeping accounts, keeping the record
s and details
of employees, inventory control, etc. A few software houses are involved in software development and in
exporting the software to the international market (i.e. in Japan, Germany, USA, UK etc) also. Some of the
private institutes and companie
s are involved in computer assembling, selling and distributing like in other
developed countries. The scope of computer in our country is increasing rapidly day by day. In May 2000
AD, Ministry of Science and Technology, HMG had announced the national pol
icy on IT. Similarly, HMG
had announced the Cyber Law and copyright Law in Sept 2004 etc.



1.7.

Generations

The "Generations of computer" refers to the development step of technology of computer. It provides a
framework for growth of computer industry. Initially it was classified according to the use various hardware
11


technologies but it has now been extended to
include both hardware and software. Up to now there are five
computer generations. They are classified with their hardware and software technologies, characteristics and
working speed which are shown by the following table.


Generation

(period)&
working
s
peed

Key hardware
technologies

Key software

technologies

Key characteristics

Some
representative

System

1
st

Generation

1942 to
1954
Second



Vacuum tubes;



electromagnetic
relay memory;




punched cards



secondary storage



Machine and
assembly
languages;



Stored program
concept;




mostly scientific
applications



Bulky in size



Highly unreliable



Limited commercial
use and costly




Difficult
commercial
production



Difficult to use



ENIAC




EDVAC




EDSAC




UNIVAC I



IBM 701

2
nd
Generatio
n 1955 to
1964 Mile
Second



Transistors;




magnetic core
memory;




magnetic tapes




Disks for
secondary storage



Batch operating
system;



High
-
level
programming
languages;



Scientific and
commercial
applications



Faster, smaller, more
reliable and easier to
program than
previous generation
system



commercial
production was still
difficult and costly



Honeywell
400



IBM 7030




CDC 1604



UNIVACLA
RC

3
rd

Generation
1965 to
1974 Micro
Second



ICs with SSI and
MSI technologies;




larger magnetic
core memory;




larger capacity
magnetic disks and
tapes secondary
storage;



Minicomputers
upward compatible
family of computer



Timesharing
operating
system;



standardization
of high
-
level
programming
languages;



Unbundling of
software from
hardware




Faster, smaller, more

reliable, easier and
cheaper to produce



Commercially,
easier to use, and
easier to upgrade
than previous
generation systems



Scientific,
commercial and
interactive on
-
line
applications



IBM
360/370



PDP
-
8



PDP
-
11




CDC 6600

4
th

Generation
1975 to
1789 Nano

Second



ICs with VLSI
technology;



microprocessors;
semiconductor
memory;




larger capacity
hard disks as in
-
built secondary
storage;




magnetic tapes and
floppy disks as
portable storage


Operating
systems for PCs;
GUI; multiple
windows on a
single terminal
screen;




UNIX operating
system; C
programming
language;



Object oriented
design and


Small, affordable,
reliable, and easy to
use PCs;



More powerful and
reliable mainframe
systems and super
computers



Totally general
purpose machines;



Easier to produce
commercially



Easier to upgrade



IBM
notebook



Pentium PC



SUN
Workstation



IBMSP/2



SGI Origin
2000




Apple II,
TRS
-
80,
VAX 9000,
CRAY
-
I,
12


media;



Supercomputer
based on parallel
vector processing
and symmetri
c
multiprocessing




personal
computers;




spread of high
-
speed computer
networks

programming




PC, network
-
based, and
supercomputing
applications;



Rapid software
development
possible

CRAY
-
2,
CRAY
-
X/MP

5
th

Generation
1990 to now
Pico Second



ICs with ULSI
technology;




larger capacity
main memory hard
disk with RAID
support larger



Ooptical disks as
portable read
-
only
storage media;



Notebook
computers;
powerful desktop
PCs and
workstations;



Powerful servers,
supercomputers




The Internet



Cluster computing



Micro
-
kernel
ba
sed,
multithreading,
distributed OS



Parallel
programming
libraries like
MPI and PVM



JAVA



World Wide
Web




multimedia,
Internet
applications



Portable computers



Powerful, cheaper,
reliable, and easier
to use desktop
machines;




Powerful
supercomputers
mainf
rames



High uptime due to
hot
-
pluggable
components



Totally general
purpose machines



Easier to produce
commercially easier
to upgrade



Rapid software
development
possible

IB notebooks,
Pentium PCs,
SUN
Workstations,
IBM SP/2, SGI
Origin 2000,
PARAM 10000




1.8.

Types of computer

There are various Types of computer they are classified as follows

i)

Volume wise

-
Super, Mainframe
, Mini, Micro computer, Laptop,
Palmtop

ii)

Job wise

-
Digital, Analog, Hydride

iii)

Brand wise

-

IBM,
IBM Compatible,

Apple
/Macintosh

iv)

Assemble wise

-

Branded and Assembled



1.9.

Computer Architecture

(
CPU, ALU,CU, Memory
)


The computer architecture means the
physical and
functional design of computer. This
means the design of
any part of the computer system or of an entire system including
hardware and software.

There

are five
basic
operation of computer system

.These are

13


i.

Inputting
:
-
The process of entering data and instruction to the computer system is inputting.

ii.

Storing:
-

Saving data and instruction to the computer to make them readily
available for initial or
additional processing whenever required is storing

iii.

Processing
:
-

performing arithmetic
operation (
add, subtract, multiply, divide, etc.) or logical operation
(comparison
like equal

to, less than, greater then, etc
.)
on

data to conve
rt them into useful information is
processing.

iv.

Out putting
:
-

The process of producing useful information or result user such a printed report or visual
display is
out
putting

v.

Controlling
:
-
Directing the manner and sequence in which all of the above operation

are perform is
controlling.


















To perform above function there are corresponding functional unit.

i)

Input
Unit
:

The computer hardware that
accept or r
eceive
data and instruction from the
user. It
performs following function
.



1.

Accepts (or reads) instruction and data
from the user
outside world
.


2.

Converts these instruction data in computer acceptable form
.

3.

Supplies the converted instruction an
d data to the computer system for further processing
.

Keyboard and mouse are the examples of input device

ii)

Output Unit
:

The hardware of the computer
system which display or give result which is generated by
processing of data. It performs following functio
n.

1.

Accept the results produce by the internal devices and software, which are in coded form and hence,
cannot be easily

understood.


2.

Convert these coded results to human
acceptable (readable)

form
.

3.

Supplies the converted results to the user.



Monitor
and printer are the examples of output device.

iii)

Storage

Unit
:
The hardware of the computer system which holds(or stores) the following:

CPU
UUU
UUU
UU

Arithmetic Logic
Unit (ALU)

Control Unit

Memory

Output

Input

14


1.

Data and instructions required for processing time which are received from input device.

2.

Intermediate results
of processing.

3.

Final result processing, before they are released to an output device.


There are
p
rimary
and secondary

storage(memory)

units. Primary

memory is also known as main
memory.

Primary storage

i.

Use to hold running program
instructions.

ii.

Used to hold data ,intermediate results ,and result of ongoing processing of job(s)

iii.

Fast in operation

iv.

Small capacity

v.

Expensive

vi.

Volatile (looses data on power dissipation)

Secondary storage

i.

Use to hold stored program instructions.

ii.

Used to hol
d data
and information of stored jobs

iii.

Slower than primary storage

iv.

Large

capacity

v.

Lot cheaper than primary storage

vi.

Non
Volatile (
retains data even without
)

Registers
-

They are additional storage locations to store data during processing time. They appear

in between ALU and CU of CPU

Address
-

Character storage locations numbers in the main memory like a mail box numbers.
Location numbers remains the same but the contents changes continuously.

iv)

ALU
:

The device inside CPU Box which performs Arithmetical & log
ical calculations. It is the place
where the actual execution of
instruction takes

place

during processing/operation.


v)

Control Unit (CU):

The control unit of a computer system manages and coordinates the operation of all

other component of the computer sy
stem. It is

like a nerves system of the body; the whole system sending
signal of data program and tells

to process data and to store in the right place.

vi)

Central Processing Unit (CPU):

The CU and ALU together constitute a processing
unit; It

is like brain
o
f a computer
system. It

is responsible for controlling the operation of all other units
of a computer system. It
is also

called micro processor.


Note:


I.

ALU+CU=CPU



It is a brain of the computer system



It is responsible for controlling the operation of
all other units of a computer system

II.

A system has following three characteristics



It has more than one element



All element of a system are logically related



All elements of a system are controlled in a manner to achieve the system goal

15



A computer is a
system as it comprises of integrated components (input unit, output unit, storage unit,
and CPU
) that

work together to perform the steps called for in the executing program.



1.10.

RISC, CISC
, EPIC

The architecture of CPUs with the small instruction set, fixed length instruction and reduce references to
memory to retrieve operands is known as RISC. It is called
reduce instruction set computer.


The architecture of CPUs with the large instruction set,

variable length instruction and a variety of addressing
mode is known as CISC. It
is called

complex instruction set computer
.

The architecture of CPUs with
the emerging technology which includes three key features, explicit
parallelism, prediction and sp
eculation
is known as

EPIC
. It is
called
Explicitly

Parallel Instruction
Computing
.



1.11.

Working Speed

Units Of The
Computer:




The working

speed of a computer means the speed
of its

processors. The

CU and ALU perform operation at
incredible speed. The
se

operations

are usually
synchronized
by the built
-
in electronic
clock (known as system
clock) that emits

millions of regularly spa
ced electric pulse per second (known as clock cycles). It is
measured in hertz .Hertz means one cycle per
second. Normally, several clock
cycles

required to
obtain,
decode

and execute single program
instruction. Hence
,

the

speed at

which an instruction is
execute
d

is

related
directly

to
a
computers built
-
in clock speed

which is the number of pulse produce per second.

This cock
speed is

measured

in mega hertz, giga
hertz. Some examples are


Class

CPU Speed

Approx year (1970
starting)

INTEL 4004

108 KHz

1970

INTEL 8080

2 MHz

1974

INTEL 8086/87

5 MHz, 8 MHz and 10 MHz

1976

INTEL 8088

4.77 MHz and 8MHz

1979

INTEL 20286/87

8 MHz, 10 MHz and 12 MHz

1982

INTEL 20386 DX

16 MHz, 20MHz and 25 MHz, 33
MHz

1985

INTEL 20386 SX/SL

16 MHz, 20MHz and 25 MHz,
33MHz

1989

INTEL 20486
DX/SX

25 MHz, 33 MHz and 50 MHz

1991

INTEL 20486 DX2

33 MHz and 66 MHz

1992

INTEL PENTIUM

60 MHz to 200 MHz

1993

INTEL PENTIUM
MMX

166 200,233 MHz and 266 MHz

1997

INTEL PENTIUM
PRO

166 and higher

1997

16


INTEL PENTIUM II

233 MHz to
450 MHz

1997

INTEL PENTIUM III

500 MHz, 750 MHz

1999

INTEL PENTIUM
IV

More than 1.1 GHz up to 2.0
GHz

2000
-
2007

INTEL Dual Core

2.0 GHz

2008

INTEL Core 2 Duo

3.4 GHz

2008



2.


Memory Units


A device or a media that can accept data holds them and deliver as per demand at a later time is called
memory. Every computer has a temporary storage built into the computer hardware. It stores instruction and
data of a program mainly when the program is
being executed by the CPU.The
temporary

storage memory is
known as main memory or primary memory or simply memory.

Physically, it
consists

of some chips either on
the motherboard or on the small circuit board
attached to

the mother board of a
computer.
It
is volatile and
random access property.


Types of main memory:

i)

Random Access Memory
(
RAM):

The memory in which time to retrieve stored information is independent of
the address where it is stored. It is
v
olatile

and random access memory.

Types of RAM

a.


Dynamic RAM
:

Very commonly used RAM. They are refreshed thousa
nd times per sec. They are used

everywhere like in printer.

b.


Static RAM
-

Special RAM. They are less often refreshed. They are costly than dynamic RAM.


(Computer writes on COMPASS offer
reading ROM)

ii)

Read Only Memory (
ROM
):

It is non volatile memories chips in which data are stored permanently, and
cannot be
alerted

by programmers .It holds

small amount data and displays it
during to start computer.

iii)

PROM
:

A program strong empty memory chip. Once stored a program, it is permanent. Therefore
PROM is non
-
volatile memory.

iv)

EPROM (Erasable PROM)

-

A chip, where the program can be erased by exposing it to ultraviolet
light.

v)

EEPROM (Electrically Erasable PROM
)
:
It

is
special

type

of EPROM

that is Electrically Erasable
PROM. It is a chip in which stored information

erased by
using high voltage of electrical pulse .it is also
known as
flash memory
.


3.




S
torage Devices:(
Auxiliary or Secondary Storage Device
)

The
devices that store data supplements main memory of a computer are called auxiliary or secondary
memory. It is

generally

non volatile memory and
used in computer to overcome the limitations of primary
storage memory. The operating speed in it is very slow a
nd cost of per
bit of storage very low than that of the

primary
memory. There are two types of secondary storage device
.


17


Types of Auxiliary Storage Device:

i)

Sequential Access

Device

(Tape)
:

It is a device where the data con only be
retrieved

in the same sequence
in which it is stored. The access time
varies accorting to the storage location of the information being accessed. The example of this type of device
is
Tape


Tape (Sequential Type)

60 MB
-
24 GB


ii)

Random Access
Device:

The storage device in
which access

to any
stored information is direct, and
approximately equal access time is required for accessing any information irrespective of its location.
Magnetic, Optical and Magneto Optical disks are the the typical examples of
such a storage device.


A.

Magnetic Disk

a.

Floppy Disk

Floppy (Random Access Type)

720 KB
-
1.44 MB


b.
Hard Disk(

Zip Disk, Super Disk
)

i.

Zip Disk

100 MB
-

250 MB

ii.

Jaz Disk (A cartridge)

2GB

iii.

Super Disk (A cartridge)

120 MB


B.

Optical Disk (
CD
-
ROM,

CD
-
R , CD
-
RW
,

DVD

Drive)

i.

CD
-
ROM

(A cartridge)

(630 MB
-
1GB) (About 700
floppy;
3,000,000 page texts)

ii.

CD
-
R(Recordable)(A cartridge)

It creates CD
-
ROM or Audio CDs to
publish.

It needs a CD
-
R software package.

It can read CD
-
R and play Audio CDs.

iii.


CD
-
RW
(A cartridge)

It is

a Re
-
Writable CD. (Many times
rewrite)

It is like a floppy disk of high storage
capacity

iv.

Digital
Video
/Versatile

It

looks same as

CD
-
ROM but has capacity
of 4.7 or 8.5 GB

It is also two types DVD
-
R and DVD
-
RW


C.

Magneto
-
Optical Drive

Magneto
-
Optical Drive

(A cartridge)

It is a special type of disk drive.

It can read and write MO
-
Disk.

It stores 200 MB faster than CD
-
ROM.


D.

Pen drive

18


It is a compact device of the size of a
pen. It

plugs into a USB(Universal
Serial Bus)

Port of the

computer

8 MB to 8 GB








































Memory

Prime

Memory

Storage

Memory

Secondary Storage

Backup Storage

RAM

ROM

Semi
-
random
Access

Serial Access

Erasable

Memory

Permanent

Memory



SRAM



Zero Power



Non
-
volatile
RAM



DRAM



Zero Power



Non
-
volatile
RAM

Disks



Floppy



Hard



CD
-
ROM



Zip Disk



Pen Drive



Magnetic Tapes



CCD



EPROM



EE
-
PROM



Flash Memory



Masked ROM



PROM

19




4.


Input Devices:

4.1.

Key Board, Mouse

a.

Keyboard


-

101 keys, Alphanumeric key, Punctuation keys, Special keys, Arrow keys, etc.

b.
Mouse


-

Curser or Pointer controller, developed in 1963 USA.


4.2.

Track Balls, Joystick

a.


Track Ball

-

Pointer mover by your palm, or thumb press.

b.

Joystick


-


Pointer mover leaver with two buttons (Triggers).


4.3.

Scanner

-

It can read text and pictures to convert it into digitals form and store to print them. It can print
600 dots per inch quality text or Images. There is single color or multiple colored sca
nners. There are half or
full page scanner.


4.4.
Digital Camera

-

It can manipulate, save, delete, and rotate the images. It sends as digitals input files to the
computer.


4.5.

OMR,

MICR,
OCR, Bar Code Reader

a.

Optical Mark Reader (OMR):

OMR is also called mark sensing, which is a technology. It can sense the
presence or absence of the pencil mark. OMR is used in the aptitude texts.


b.

Optical character Reader (OCR)
:

It reads the page of text and converts images into ASC II codes to store
into the computer. In the future it can print ditto for the user. All OCR system includes an optical scanner. It
enables to take a book and save into a computer file.

c.

Bar code Reader
:

Bar code reader is a photoelectric scanner that reads the bar code (Vertical Zebra
Striped marks,) printed on the product. In the supermarket, you can find bar codes in ever items.


d.
Magnetic ink character Reader (MICR)
:


MICR is direct entry method used in the banks. It is a special
type of input device used in ATM.



4.6.

Speech Input Devices
:

It is a type of device that allow a person to input data to a computer system by
speaking to it.



4.7.

Touch Screen, Touch Pad

a.


Touch Screen
:

-

It is a type of display screen that has the touch sensitive transparent panel covering the
screen. As a mouse

pointer, you can use your finger on screen.

b.

Touch Pad
:

-

On a portable PC you can find a small touch pad where you can u
se your finger along the
pad.


20


4.8.

Light Pen, Digitizing tablet

a.


L
ight Pen
:

-

It is special pen, which uses light sensitive defector too select object on the screen display.
This pen is also similar to

mouse.

b.

Digitizing tablet

-

It is an electronic tablet. A

stylus pen is used here to draw pictures and to
operate computer. They are called touch tablet


5.


Output Devices
:

There are two types of output device

Soft
-

copy Output and Hard
-
copy Output device. Monitor and printer
are
the

major soft
-
copy and hard
-
copy output device.

A)

Monitor and Its Type
s



The classification of monitor is as follows:

(a) Color wise


(i) colored monitor


(ii) Monochrome monitor

(b) Signal wise


(i) Digital monitor


(ii)
Analog monitor

(c)
Design wise

(i) Box type monitor

(CRT): Cathode
-
ray
-
tube



(ii) Flat type
monitors (LCD): Liquid Crystal Display


a.


Characteristics, Size, Bandwidth of a Monitor:
-

i)

Size
=
14", 15", 17", 24"

ii)

Resolution
=
how

densely pixels are packed?

For example:
-

VGA monitor

= 640x480 pixels = 300,000 pixels

SVA monitor

= 1024x 768 pixels = 800,000 pixels

Colored monitor

= 24 bits per pixels = 16 million color

High and monitor

= 1600x1200 pixels = 2,000,000 pixels


B)

Printer

and its Types:

The most

common output device for producing hard
-
copy
output is a printer
. They can also classified as

a.

Impact
printer
: uses letter headed hammer, ink ribbon, paper :

Dot matrix & Line printer,
Drum, Chain

/Band

printer

b.


Non
-

impact printer
-

Ink
-
jet, Laser, LCD printer, Thermal printer



i)

Ink jet printer
-

Ionized ink spray, qualify print, diff. fonts.

ii)

Laser printer

-

Utilizes a laser beam to produce image on the drum. 1200
-
2400 dpi quality.

iii)

LCD

& Led printer

-

Uses liquid crystal to produce im
age. Uses light emitting diodes produce image.

iv)

Line printers

-

It is a high speed printer 3000 lines/min. It can print only font. No pictures.

v)

Thermal printer

-

Produces images by trashing electrically heated pins against special paper.

vi)

Plotters

-

It draws

only pictures using pen with continuous lines. Multi color plotters use different colored
pens. They are used in the engineering applications.

vii)

Sound cards & speakers

-

Sound card is compulsory in the modem computers where speakers are used.
Sound card e
nables the computer to output sound, to record input from a microphone connected to the
computer and manipulate sound stored on a disk. Sound card translate digital data into analog sounds.


21



6.


Computer Software:

6.1


Introduction,


Software is the computer program. A program is the set of logical instructions given to a computer to
perform a certain task. All the logical components and the programs are called the software. So software is an
instruction that given to the computer. Co
mputer software means instructions or data, which are electronically
stored on the storage device. Software is mainly classified into two types.

A)


System software
:

The software required executing users program is known as system software. It
helps to impro
ve the interface between the user and the computer. It includes operating system and utilities
software that enables computer to functions. Computer cannot be operated without system software. The
system software includes;


-

Operating system


-

Language p
rocessors (assemblers, compilers, debugged) and


-

Utility programs

B)

Application software
:

The software, which is used to perform specific job, is called application
software. This software is available for applications, which are common to many users and organizations. It
includes programs, which do real job for the user. An application progra
m is a computer program which
installed on computers to give users ability to do specific task. For examples word processing, spreadsheet,
DBMS and other end user made programs. There various types of application software/program.







i)

Operating System
(OS
):
-

It

is a must to run a computer. OS performs basic tasks like
recognizing impact from keyboard, sending output to display screen, keeping tracks o files and directories on
22


the disk. Most commonly used OS are MS
-
Windows, DOS, XENIX, Mac OS, OS/2, UNIX
, MVS etc. There
are single user and multi
-
user operating systems.



ii)


Language processors:


the program translated by the language processor is understood by the
hardware of the computer. It translates the program written in a programming language into an executable
program. These are




Compilers
:
Compiler

is a program which converts source code into object code after looking whole part of
the source code all at a time
.



Interpreters:

Interpreter is a program which converts source code into object code line by line. The
advantage of the interpreters is
that they can execute a program immediately.


Some time compiler and interpreters are called language translator programs.



Debugged:


Debugged is a program which helps to find the error/mistake to the program
when the

source
code or
program is

compi
ling

or
execute by

the compiler.


iii)

Utilities
:

-

the software that provides additional facilities to the user is called utility program. It
performs very specific tasks, usually related to managing disk drives, printers and other devices, sorting or
margin is done. A call up programs by OS. Transferring

data from one I/O devices to another. Disk repair,
data copy, data move, virus scan etc are utility program


Some examples of

application software/
package
:

i)

Word processing
:
-

Creating, editing, formatting, previewing coloring line text, designing, tabula
ting
saving, deleting and coping line text. Users do disk top publishing using it.

ii)

Spreadsheet
:

-

Creating, editing, formatting line mathematical tables in rows and columns. Using
arithmetical, algebraically, statistical, logical and graphical text documen
ts. Users are the facilities here.

iii)

Database Management System (DBMS
):
-

It is a collection of record programs. Inserting, deleting,
copying, updating and saving the records are the facilities here.

iv)

Image processing
:
-

It is a set of programs, which performs graphical pictures and animations. It has
different facilities like enlarging rotating, coloring, zooming and many more.

v)

Engineering Designing Software
:
-

CAL, CAI, CAD, et
c
. Computer Aided Designing (CAD) is a set
o
programs, which performs engineering calculations, picture designs, simulations and others.

vi)

Accounting software
:
-

It helps to solve the problems of the accountant. It is use to account keeping
properly having many facilities. Accounting package, Repacka
ge and Tally are the examples of the
accounting software.

vii)

Statistical software
:
-

It is a collection of programs which performs the statistical activities. It is a kind of
powerful statistical tool. SPSS and microstate are the good examples.

viii)

Any other
tailor made software
:

-

Locally made any type of software for any type of local institutes.


C)

Human

ware:
-

23



To run above computer hardware and software and the whole computer system in the big organization, the
different types of the technical personals are

needed. Their types and post names are as given below. It is
called human ware.

i.


Data Entry Operator


-

Non officer

ii.


Data Coder



-

Non officer

iii.


Data Supervisor



-

Non officer

iv.


Data Administrator


-

Officer

v.


Programmer



-

Officer

vi.


System An
alyst




-

Officer

vii.


System Designer




-

Officer

viii.


Computer System Engineer

-

Officer

ix.


Hardware Engineer


-

Officer

x.


Maintenance Engineer


-

Officer

xi.


Networking Engineer


-

Officer

xii.


Computer Operator


-

Non officer

xiii.


Computer Instructor


-

Officer

xiv.


Computer Consultants


-

Officer


6.

Operating System(OS):

7.1.


Introduction OS

Operating System is the base program on a computer.


It tells the computer how to work or operate.


The
operating system also
allows us to load other programs that do specialized tasks on to our computer. It is
an organized set of programs that control the overall operation of the computer system. It can interact
between the computer hardware and software, and the user. The opera
ting system is the core software
component of our computer. It performs many functions and is, in very basic term, and interface
between computer and the outside world. In the section about hardware, a computer is described as
consisting of several compone
nt parts including monitor, keyboard, mouse, and other parts. The
operating system provides an interface to these parts using what is referred to as “drivers”. This is why
sometimes when you install a new printer or other piece of hardware, your system wil
l ask you to install
more software called a driver.

7.2.

What does a driver do?


A driver is a specially written program which understands the operation of the device it interfaces to, such as
printer, video card sound card or CD ROM drive. It translates
commands from the operating system or user
into commands understood by the component computer part it interfaces with. It also translates responses
from the component computer part back to responses that can be understood by the operating system,
applicati
on program, or user. The below diagram gives a graphical depiction of the interfaces between the
operating system and the computer component;



24
















7.3.

Functions Of The OS



i)

Job Management


To keep processing jobs in sequence, determining main memory, secondary storage
capability and their timing.

ii)

Batch Processing
-
Any big jobs are classified and grouped in some order, Batch wise they can be
processed. For example number wise or alphabetical

wise or VDC wise or district wise, etc.

iii)

Data Management



Data can be edited, updated and saved in any storage device. It can be retrieved and
stored at any time any data.

iv)

Virtual Storage



Some OS have a feature called virtual storage. Such OS can increa
se the capacity of
the main memory without increasing its size, during processing time, when it is necessary.

v)

I/O Management


For the smooth input data flow to the CPU and output data flow from the CPU, it can
manage. In the big computer system also OS ca
n handle very carefully and accurately. It can stop to handle
the data to the unauthorized persons, so it can save data from the less.


7.4.

Classification of the OS:


Classifications of the OS are as follows



i)


Multi user
:

-

Any OS, at the same time if more than user can use the OS that is called multi user OS.
Some OS permits hundreds or thousands o your to use concurrently. The OS called MVS for the main frame
and UNIX for the minicomputer are the multi user OS.

ii)


Multi proc
essing
:

-

Multi processing OS permits many users to use different programs at the same time.
MVS and UNIX are two examples used as multi processing OS. Multi processing OS is more complicated
than single process systems. Multi processing also refers to the

utilizing of multiple CPU in a single computer
system called parallel processing.

iii)


Multi tasking:
-

Multi tasking permits more than one program to run currently. In multi tasking, only one
CPU is involved, but it switches from one program to another so th
at it gives the appearance. Executing all
the programs concurrently. There are two types of multi tasking

i)


Preemptive
-

CPU time slices to each program.

25


ii)


Co
-
operative

-

Each program controls CPU as needed.


If the program is not using CPU, however, it c
an allow another program to us it temporally. OS/2, Windows
95, Windows NT, Amiga and UNIX use preemptive multi tasking. But

MS
-
Windows 3.x and the Multi Finder use co
-
operative multitasking.


iv)

Multi threading:
-

Multi threading allows different parts of a single program to run currently. If is a
ability of an operating system to execute different parts of a program called threads simultaneously, without
interfering with each other.

v)


Real time:
-

Real time syste
m is an interactive processing system with severe time limitation. Several
stations (PC's) can operate a database at the same time. The central input file are updated each time and
inquires are answered correctly. Hotel reservation, Air lines ticket reserv
ation and Car rental are the examples
of real time system. But DOS and UNIX is not the examples real time system.


7.


Programming Languages:

7.1.

Introduction

The language which is used to

expressed algorithm in computer understandable form or to make

a
program
i
n

computer is called programming
language. In brief Programming language means a computer
language.
The
broad classifications of programming languages are Machine

Language, Assembly Language,
and
High
-
Level Language.


7.2.

Machine Language:
The

language which is written as strings of binary 1s and 0s.It understood by
the computer without
using a translator. This is basically

based at binary system like (On/OF), (Yes/No),
(True/False), (Right/ wrong) and (1,0) etc. About 50/60 years back, the comp
uters like ENIAC had used the
language only by many switches ON/OFF. There were about 6000 switches for a single program. For the
next program the switches had to reset. A process that might take weeks. Thus the programming were like
11110101, 11010011 000
11010 etc.
This was very tedious s
uch language is called machine language.

Note: Machine language is also kwon as 1
st

generation language.


7.3.

Assembly
Language:

The

language that using alph
anumeric mnemonic codes instead of numeric
codes for the instructions in the instruction set e.g using ADD instead of 1110(binary) or 14(decimal) for
instruction to add.

T
o reduce programming complexity and provide some standardization, assembly
languages
were

developed

in

1950.

It

is known as

assembly or symbolic

language use abbreviation or
mnemonic code
like. PACK

210(8, 13), O2B (4, 7)

When we provide such assembly language command to
the compute, it converts into machine language then it performs the
job.


Note: 1.

Assembly language is also kwon as 2
nd

generation language.



2. The

Machine language and assembly language are known as low
-
level language.


7.4.

High
-
Level Language
:

26


The language
which

is similar

to broken English language

and independ
ent to the machine language

is
called High
-
Level language. In this language the programmer need not know anything about the internal
structure of computer on which high
-
level language program will be execute.

It is

written in high
-
level
coding or
writing

instructions

by

using English words and familiar mathematical symbol and expression.

COBOL
, C, C
++
, C
#,
Pascal,

FORTRAN

are some examples

of high level language.

Note:

High level language

are classified as
third, fourth

and
fifth generation

language.


7.4.1.


Types
of High
-
Level Language
:


a)


Procedural


oriented


-

3
rd

generation computer language

b)


Problem
-

oriented


-

4
th

generation computer language

c)


Nature



-

5
th

generation computer language


a)

Procedural
-
oriented language
:
-

General
-
purpose

programming lang
uage like BASIC, PASCAL, COBOL
and

FOTRAN are called procedural
-
oriented language. They are designed to express the logic and procedure of the
problem. All of them are called high level programming language or third generation language.


A
dvantages of the procedural oriented language

i)

Program statements are very similarly to English language

ii)

Very easy to write program.

iii)

Less time consuming to write program.

iv)

Easier to understand and edit.

v)

The programming languages are machine independents.


Disadvantages

i)

Program takes

long time to execute.

ii)

The programming language does not look active.


a)

Problem oriented language:
-

The fourth generation languages are called
problem oriented language
.
They are high level language, which are used designed to solve specific problems like
word processing
,
spreadsheet
,
database
management system package program, etc.


The fourth generation languages also are used to
develop

application tools as fo
llows.

i.

Personal computer application software

ii.

Query language and report generator

iii.

Design support systems and financial planning language

iv.

Application generators.


i)

Personal

computer application software
:


It means word processor, spreadsheet, DBMS, graphics, integrated packages,
P
owerPoint and other tailor
-
made

ii)

Query language an
d report generator:


It means query language allows people who are non programmer to search database using certain selection
comman
ds.
For e
xample, Airlines ticket reservation, Room booking in hostel, MIS, School information system etc.
27


Report generators are designed for people needing to prepare their reports easily, e.g.
-
QBE, SQL, HAL,
Answer/Database, Data retrieve etc.

iii)

Design

support systems a
nd financial planning language:


Decision support system (DSS) is made for managers or chief Execution officers to take decisions. Financial
planning
languages are

also a kind of decision support system, that are employed or mathematical
statistical and
forecasting procedures.

Example
:
-

Macro Stat, SPSS, Accounting packages, Metaphor, STRATAGEM, etc.

iii)


A
pplica
tion generators:


Application generators are a collection of set of program modules, preprogrammed for different jobs. A
non
programmer

uses this required report. Example the user inters his pass word and unique account code numbers,
presenters as in ATM machine to get money.


There are other examples of application generators as: FOCUS, FUSION, SAS, SYSTEM, LINE II,
RADID/3000
etc.

Different between
3GLs and

4GLs.


S.N
o

Third
-
generation language

Fourth generation language

1.

Use by programmer.

Use by non
-
programmer.

2.

Requires specification of how to perform
task.

Requires specification of what task is to be performs.

3.

All

alternatives must be specified

Default alternatives are built in.

4.

Requires large number of procedural
instructions.

Requires few instructions.

5.

Code is difficult to read, understand and
maintain.

Code is easy to understand because of English
-
like
commands.

6.

Language for batch operation.

Language developed for on
-
line use.

7.

Difficult to learn.

Easy to learn.

8.

Difficult to debug.

Easy to debug.

9.

Typically file oriented.

Typically database oriented.




v)

Natural Languages:


There are
still in developing stage. They will be using in AI and expert systems.
They have two characteristics.



i)

More human like speaking



ii)

More smarter with remembering capacity.



There popular natural
languages are

LISP and PROLOG.


7.4.2.
Assembler, Translato
rs
, Complier,
Interpreters, Linker

:

A.

Assembler

A computer program that translates an assembly language program to its machine language equivalent is
called assembler.

B.

Translator

28


High level programming language to work on the computer it must be translated
into machine language.
There are two types of translators like.

i.

Compiler
:

A translator program (software package) that translates a high
-
level language program into its
equivalent machine language program is called
compiler. In brief it reads whole program
and converts it
into machine language.

Complier translates the whole program into machine language all at a time.

The translation processor is called
compilation.


The programmer’s

program is called
source code
b
ut its machine language code is called
object code.


ii.

Interpreters
:

A language processor that translates a statement of high
-
level language, and immediately
executes it before translating the next source language statement is called interpreter. In brief it

reads
a line
and converts into machine language; one statement at a time.

Interpreters translate each program statement
into machine code just before the program statement is to be executed. This process continues till whole
process completes. But compile
r language is better than interpreted language as they can be executed later.
Complier is used in COBOL, C, C++ and FORTRAN. On the other hand interpreter language in BASIC
programming. Interpreter do not need object code and so usually easier to develop.
(i.e. to code &test).
Thus, there are code complier, C compiler and BASIC Interpreter.

C.

Linker
:

A program

that is used to properly combine all objects program files (modules) of a software,
and to convert them

into software’s final executable form is called linker.



The Compilation Process:

Source files are complied into object files, then through linkers object files using routine libraries it produces
executable programs. Thus object codes pass through
linkers. The linker combines modules and gives real values
to all symbolic address.

Hence, the linker translates object files into executables program files.




8.


General Software Features &Trends:

9.1


Introduction

We know the series of instructions that
performs a particular task in the computer is called a program. There
are two categories of programs like system software and application software.

29



A system software means combination of operating system, control program, database management
and communica
tion software. An application, software means any program that processes the data for the
user. In short, the software tells hardware how to process the data.


At present, in the world software projects are becoming more and more complex in size,
sophistic
ation, and technologies used. Now most software products manage to millions of users in different
shape and size. For example word processors, ERP packages and SCM tools, which run mainframes and
client server systems; different versions of web browsers fo
r the PC and MAC; we have DBMS that run on
MVS, UNIX, Windows NT, Linux and so on. The competition and the advancements in technology are
driving software.


Now computer and communication are becoming integral part of our lives. The driving force behind
a
ll these advancement is the computer software. They are becoming more and more complex. For example,
the software is being used in controlling satellites, operating. Intercontinental
,

Ballistic Missiles, running
banks, hospitals, airlines, hostels, etc, in
cluding door locking system and robotics.



Software may communicate via internet, using e
-
mail or videoconferencing technologies. Thus its
development is in advance and changing very fast. Now the general software features are given below.


i)

Easy to

Use:



Presently, most of the software companies are producing more and more user’s friendly, software's.