introduction to computer

INTRODUCTION TO COMPUTER  

Nowadays, computers are an integral part of our lives. They are used for the reservation of
tickets for airplanes and railways, payment of telephone and electricity bills, deposit and
withdrawal of money from banks, processing of business data, forecasting of weather conditions,
diagnosis of diseases, searching for information on the Internet, etc. Computers are also used  extensively in schools, universities, organizations, music industry, movie industry, scientific
research, law firms, fashion industry, etc.

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The term computer is derived from the word compute. The word compute means to calculate. Acomputer is an electronic machine that accepts data from the user, processes the data by
performing calculations and operations on it, and generates the desired output results. Computer
performs both simple and complex operations, with speed and accuracy.
This chapter discusses the history and evolution of computer, the concept of input-process-output
and the characteristics of computer. This chapter also discusses the classification of digital
computers based on their size and type, and the application of computer in different domain
areas.  

CHARACTERISTICS OF COMPUTER  

Speed, accuracy, diligence, storage capability and versatility are some of the key characteristics
of a computer. A brief overview of these characteristics are—

1. Speed- The computer can process data very fast, at the rate of millions of instructions per second. Some calculations that would have taken hours and days to complete otherwise,can be completed in a few seconds using the computer. For example, calculation and generation of salary slips of thousands of employees of an organization, weather forecasting that requires analysis of a large amount of data related to temperature, pressure and humidity of various places, etc.

2.Accuracy - Computer provides a high degree of accuracy. For example, the computer canaccurately give the result of division of any two numbers up to 10 decimal places.

3. Diligence -When used for a longer period of time, the computer does not get tired or
fatigued. It can perform long and complex calculations with the same speed and accuracy
from the start till the end.

 4.Storage Capability - Large volumes of data and information can be stored in the computer
and also retrieved whenever required. A limited amount of data can be stored,
temporarily, in the primary memory. Secondary storage devices like floppy disk and
compact disk can store a large amount of data permanently  

 5.Versatility- Computer is versatile in nature. It can perform different types of tasks with the
same ease. At one moment you can use the computer to prepare a letter document and in
the next moment you may play music or print a document.  



Computers have several limitations too. Computer can only perform tasks that it has been
programmed to do. Computer cannot do any work without instructions from the user. It executes
instructions as specified by the user and does not take its own decisions.

 HISTORY OF COMPUTER

 Until the development of the first generation computers based on vacuum tubes, there had been
several developments in the computing technology related to the mechanical computing devices.
The key developments that took place till the first computer was developed are as follows—

Calculating Machines ABACUS was the first mechanical calculating device for counting of large numbers. The word ABACUS means calculating board. It consists of

bars in horizontal positions on which sets of beads are inserted. The horizontal bars have 10 beads each, representing units, tens, hundreds, etc. 

 Napier’s Bones was a mechanical device built for the purpose of multiplication in 1617ad. by an English mathematician John Napier. 

      Slide Rule was developed by an English mathematician Edmund Gunter in the 16th century. Using the slide rule, one could perform operations like addition, subtraction,
multiplication and division. It was used extensively till late 1970 s.  

Pascal’s Adding and Subtraction Machine was developed by Blaise Pascal. It could add and subtract. The machine consisted of wheels, gears and cylinders.

  

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

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Punch Card System was developed by Jacquard to control the power loom in 1801. He invented the punched card reader that could recognize the presence of hole in the punched card as binary one and the absence of the hole as binary zero. The Os and 1s are
the basis of the modern digital computer.

  

Babbage’s Analytical Engine An English man Charles Babbage built a mechanical machine to do complex mathematical calculations, in the year 1823. The machine was
called as difference engine. Later, Charles Babbage and Lady Ada Lovelace developed a general-purpose calculating machine, the analytical engine. Charles Babbage is also
called the father of computer.  

Hollerith’s Punched Card Tabulating Machine was invented by Herman Hollerith. The machine could read the information from a punched card and process it electronically. 

The developments discussed above and several others not discussed here, resulted in the development of the first computer in the 1940s.