Nouman Riaz has been upload this file.. thanks you regards to you alll!!!!!!!!

1. -1-
Submitted by: NOUMAN RIAZ
Submitted to: MISS: AYESHA ATTA
Roll No: 0147-BH-BAF-2011
TOPIC….
Date: May 18, 2012
INTRODUCTION OF COMPUTER

2. -2-
Computer technology has two branches .Computer Engineering and Computer Science.
Computer Engineering concerned with the manufacture of the physical components of a
computer. In computer technology these components are collectively called Computer
Hardware or simply Hardware. Computer Science is concerned with the use of computer
to perform various function is called Software Engineering and the instruction themselves
called Computer Software or simply Software’s. Software being a very important part of
the computer technology is that is a general purpose machine. It can perform a multitude
of tasks and it is the software which controls a computer in all tasks.
HISTORY AND DEVELOPMENT OF COMPUPTER
The history of computing is very old. It goes back to some 500 B.C., when Chinese used
to calculate with the help of an abacus.
However, it was not the year 1812 when an English mathematicians from Cambridge
University. Charles Babbage designed a machine which he named as different Engine.
This machine would be capable of calculating powers of numbers. Babbage also gave the
idea of an analytical Engine, which was supposed to be general purpose machine having
the ability to calculate a wide variety of arithmetic and algebraic formulae. Store data and
print results. He never converted his dreams into realities. However, his son was able to
build a part of arithmetic unit. The analytical was to be composed of:
1. input in the form of punch card
2. A memory where arithmetic values could be stored
3. An arithmetic unit to perform calculations
4. A control section which could hold. Execute and modify stored instruction
5. Automatic output of answers
The Analytical Engine was not a successful machine but it gave birth to the research in
the field of computers. In 1946 John Mauchly and J. P Eckert developed an Electronic
Numerical Integrator and Computer (ENIAC) at the Moore School of Engineering and
Technology Pennsylvania USA. This was the first truly successful computers after
Mark-1 developed at Manchester University. There were three major backs in the
ENIAC.
1. It used serial lines for processing
2. No storage facility was available

3. -3-
3. it used decimal numbers instead of binary number system
These problems were successfully overcomes in John von Neumann Electronic
Discrete Automatic Computer (EDVAC) development of these machines materialized
the existence of computers and they became commercial entity used in many
Government organization.
GENERATION OF COMPUTERS
It is quiet obvious that the development of computer is continuous process.
However, the development of computers could be categorized into the following
generation based on the technology used for the machine.
1. FIRST GENERATION
All computers developed in the initial phase of computer
development (ENIEL, EDVAL, BINAC, UNIVAC and Mark 1) belong to the First
Generation of computers .These computers were mostly made between 1945 and
1950 . Computers develop in this generation used the electrical devices like vacuum
tubes, capacitors and resisters.
2. SECOND GENERATION
The first generations computers opened the gateway to the
commercial development and sale of computers. Attempts were made to reduce the
size and costs increase the speed and reliability of computers. A breakthrough was the
invention of an electronic device called transistor.
Transistors replaced vacuum tubes and gave birth to the second generation of
computers like (UNIVAC II. IBM 1401 AND CDC 1604).Which improved the
storage and processing capabilities of computers.
3. THIRD GENERATION
In early 1960 the electronic technology of solid state was
introduced. The development of integrated circuits is referred to as solid state
technology. The integrated circuits are the collection of many electronic devices, like
transistors, on a single chip (small piece) of silicon. The computer using this

4. -4-
challenging electronic era of competition for speed and accuracy. The IBM 360. PDP
11 and HP 3000 are the computers developed in this generation.
4. FORTH GENERATION
In 1970s integrated circuit technology was developed
sufficiently to integrate all main function of a computer on a single chip called
microprocessors. The introduction of microprocessors brought the computer age into
Fourth Generation. A direct result in the development of microcomputers like IBM
PC and Apple Macintosh which brought computer down from the organizational level
to the personal level.
5. THE WAY FORWARD0
The progress in computer technology is still continued and active
research is going in difficult fields of computer technology but there is no well
categorization after the Forth Generation. The reason may be that now the
developments are taking place in a variety of fields of Computer Hardware and
Software as compared to the previous developments which mostly took place in the
field of Electronics. As a result of that further grouping of computer developments is
difficult.
TYPES OF COMPUTERS

5. -5-
Computers can be classified into three types. This classification is based on the
hardware structure and the way physical quantities are represented in a computer.
 Analog Computer
 Digital Computer
 Hybrid Computer
1- Analog Computers
These computers represent physical quantities like speed, weight etc
through an analogy with the electrical properties of current and voltage. Analog
computers are the first computer being developed and provided the bases for the
development of modern digital computers. These computers are mainly made of
electrical devices like resisters, amplifiers and transistors. They are computers used
for the calculation of observation of physical quantities or their measurement such as
temperature, speed and height etc. In general Analog computers are very fast in
processing and are used for real time simulation.
2-DIGITAL COMPUTERS
Digital Computers represent physical quantities with the help of
digits and numbers. These numbers are used to perform arithmetic calculations and

6. -6-
also make logical decisions to each conclusion depending on the data they receive
from the user. In general Digital Computers are easy to program and are general
purpose in use. The IBM PC and others personal computers belong to this category.
3-HYBRID COMPUTERS
There is another type of computer called the hybrids computer. A
hybrid computer is the combination of Analog or Digital Computers. These
computers consist partly of the components of a Digital Computer and partly of an
Analog Computer to combine the characteristics of the two types.
Although Analog Computers are still used in some defense and other real time
applications the fast development and versatility of Digital Computers have almost
eliminated the need and use of Analog computers. Now a day’s term computer, in
general, means a Digital computer. Therefore, in rest of this book we will be
discussing the Digital computer and the name, “Computer” will refer to a digital
computer.
Ref: Computer Science (professor Mehmood
Ali Anjam)
Ref: www.wikipedia.com

7. -7-