Computer Fundamental

Computer Fundamental

Contents

Computer
Evolution of Computer
Generation of Compute
Types of Computer 
Computer Organisation
Input devices
Output devices
Processing device
Storage devices
Computer Software
A Look to the Future

1. COMPUER

COMPUTER: Computer is an electronic device. That restores and accesses the data. It takes the instructions from the user. Manipulates the data and give output to users.

The term Computer is derived from the word Computer. A computer is capable of performing complex processing of information that too at a tremendous speed. Today, computer gives us the information we need, to extend our thinking power. Computer usage is bringing about far reaching qualitative changes in our lives. Through constant improvement, computers have grown into the most influential tool.

A computer is a fast and accurate electronic data manipulating system designed to accept and store data (input), process them, and produce results (output) under the direction of a stored program of instructions.

We are looking forward to a paper-less office. Nowadays all the transactions are done through Internet. Gone are the days, when you needed to wait for weeks to receive a mail from other corner of the world. Now you can receive it within seconds after the other person send it. You can check your account sitting at home, instantly. You can do on-line trading, on-line shopping through Internet.

2. EVOLUTION OF THE COMPUTER

Computing has a long history. It took over generations for early man to build mechanical devices for counting large numbers. The first calculating device called ABACUS was developed by the Egyptian and Chinese people. Abacus is a wooden frame with wire strings across it carrying colored beads. In the simple abacus each wire carries 10 beads. Shifting the beads from one side to the other does counting. Although quite old, it is still used today in some parts of the world.

Abacus

Abacus

Napier’s bones: English mathematician John Napier built a mechanical device for the purpose of multiplication in 1617 A D. The device was known as Napier’s bones.

Slide Rule : English mathematician Edmund Gunter developed the slide rule. This machine could perform operations like addition, subtraction, multiplication, and division. It was widely used in Europe in 16th century.

Pascal's Adding and Subtractory Machine: In 1642, Blaise Pascal, a Frenchman (modern language is named in his honor), developed the first mechanical calculating machine. The machine consisted of dials and toothed wheels. When one wheel moved through a complete revolution, the adjacent wheel moved through one-tenth of a revolution. One could simply dial in the numbers to be added and the result would appear in the window. It was able to perform addition and subtraction. Later, German philosopher Gottfried Leibniz improved Pascal’s invention by producing a machine that could add, subtracts, multiply, divide and extract roots.

Leibniz’s Multiplication and Dividing Machine: The German philosopher and mathematician Gottfried Leibniz built around 1673 a mechanical device that could both multiply and divide.

Babbage’s Analytical Engine: It was in the year 1823 that a famous English man Charles Babbage built a mechanical machine to do complex mathematical calculations. It was called difference engine. Later he developed a general-purpose calculating machine called analytical engine. You should know that Charles Babbage is called the father of computer.

Mechanical and Electrical Calculator : In the beginning of 19th century the mechanical calculator was developed to perform all sorts of mathematical calculations. Up to the 1960s it was widely used. Later the rotating part of mechanical calculator was replaced by electric motor. So it was called the electrical calculator.

Modern Electronic Calculator : The electronic calculator used in 1960 s was run with electron tubes, which was quite bulky. Later it was replaced with transistors and as a result the size of calculators became too small.

The modern electronic calculator can compute all kinds of mathematical computations and mathematical functions. It can also be used to store some data permanently. Some calculators have in-built programs to perform some complicated calculations.

3. Generation of Computers

The First Generation (1946-1958): First generation computers used Thermion valves. These computers were large in size and writing programs on them was difficult. Some of the computers of this generation were:

ENIAC (Electronic Numerical Integrator and Calculator) was the first general-purpose computer to be put in full operation. ENIAC used around 18,000 vacuum tubes and occupied a very large room of around 20x40 square feet. These vacuum tubes consumed more electricity and much heat was generated and so burnt out frequently. Air conditioning was required. The failure rate of these vacuum tubes was also very high. Constant maintenance was required. Due to all these problems they had limited commercial use.

EDVAC: It stands for Electronic Discrete Variable Automatic Computer and was developed in 1950. The concept of storing data and instructions inside the computer was introduced here. This allowed much faster operation since the computer had rapid access to both data and instructions. The other advantages of storing instruction was that computer could do logical decision internally.

Other Important Computers of First Generation:

EDSAC: It stands for Electronic Delay Storage Automatic Computer and was developed by M.V. Wilkes at Cambridge University in 1949.

UNIVAC-1: Ecker and Mauchly produced it in 1951 by Universal Accounting Computer setup.

Limitations of First Generation Computer

Followings are the major drawbacks of First generation computers.

1. The operating speed was quite slow.

2. Power consumption was very high.

3. It required large space for installation.

4. The programming capability was quite low.

Second Generation Computers: Around 1955 a device called Transistor replaced the bulky electric tubes in the first generation computer. Transistors are smaller than electric tubes and have higher operating speed. They have no filament and require no heating. Manufacturing cost was also very low. Thus the size of the computer got reduced considerably.
It is in the second generation that the concept of Central Processing Unit (CPU), memory, programming language and input and output units were developed. The programming languages such as COBOL, FORTRAN were developed during this period. Some of the computers of the Second Generation were
1. IBM 1620: Its size was smaller as compared to First Generation computers and mostly used for scientific purpose.
2. IBM 1401: Its size was small to medium and used for business applications.
3. CDC 3600: Its size was large and is used for scientific purposes.

Third Generation Computers: The third generation computers were introduced in 1964. They used Integrated Circuits (ICs). These ICs are popularly known as Chips. A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. So it is quite obvious that the size of the computer got further reduced. Some of the computers developed during this period were IBM-360, ICL-1900, IBM-370, and VAX-750. Higher level language such as BASIC (Beginners All purpose Symbolic Instruction Code) was developed during this period.
Computers of this generation were small in size, low cost, large memory and processing speed is very high.

Fourth Generation Computers: The present day computers that you see today are the fourth generation computers that started around 1975. It uses large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors. Due to the development of microprocessor it is possible to place computer’s central processing unit (CPU) on single chip. These computers are called microcomputers. Later very large scale Integrated Circuits (VLSIC) replaced LSICs.
Thus the computer which was occupying a very large room in earlier days can now be placed on a table. The personal computer (PC) that you see in your school is a Fourth Generation Computer.

Fifth Generation Computer: The computers of 1990s are said to be Fifth Generation computers. The speed is extremely high in fifth generation computer. Apart from this it can perform parallel processing. The concept of Artificial intelligence has been introduced to allow the computer to take its own decision. It is still in a developmental stage.