Computer System

Input operation of the computer is performed by input unit.Processing operation is performed by processing unit.Output operation is performed by output unit.And storage is performed by storage unit.All these unit of te computer combinetogether to form a computer system.The basic units in the computer system are described as below:
1.Input unit:It accepts data from the users.It includes device such as keyboard,mouse,microphone etc.
2.processing unit:it process data to form information.It include central processing unit.
3Output unit:It produces the result of the processing.it includes devices such as monitar,printer,speaker etc.
4.stoarage unit:It stores data and information for future use .It includes devices such as hard disk,optical disk etc.

Characters of computer

Computer can do lots of work but to do that work computer need user to do or operate it. There are characters of computer are:-
1.Accuracy
Computer is a 100% accurate machine. It gives the accurate result to the user. But if user gives wrong data or information to the user then it gives wrong output to the user. It is called GIGO (Garbage In Garbage Out). It performs the work according to the user. Computer is an electronic machine so it always accurate,
2.Storage:
Computer can store a huge number of data. Data can be anything like name, age, weight, music and game. It can store a file for future uses. It’s storing capacity is more and we can store anything, as we like.
3.Speed
It speed is also very fast .Due to its fast speed it’s processing speed also very fast. Speed can be measure in different ways. Speed is mostly needed for fast processing. Fast speed helps to perform a difficult task in a second.

HISTORY OF COMPUTER

arly Development Of Computer:Mechanical Calculating Device
1. Abacus
It is the first counting device, developed by Hindu philosopher, before 2500 years ago.It gives mathematical concepts and their issue, arthematical operations.It is only a memory-helping device rather than a real calculating machine.It is a rectangualr box,divided into two parts by mid bar, upper part is calles heaven, consist of two beads and each bead equal to value 5 and lower part is called earth,consist of five bead and each bead equal to value 1.While calculating beads are brought near to the mid bar.

2.Napier's Bones
Another interesting invention is Napier's bones, a cleaver multiplication tool invented in 1614 by mathematician John Napier(1550-1617), of Scotland. The
bones are a set of vertical rectangular rods, each one divided in 10 squares. The top square contains a digit and the remaining squares contains the first 9 multiples of the digit.Each multiple has its digital separated by a diagonal lines.When a number is constructed by arranging side by side the rod with the corresponding digits on the top, then its multiple can be easily obtained by reading the corresponding row of multiples from left to right while adding the digits found in the parallelograms formed by the diagonal lines. No wonderJohn Napier is also the inventor of the logarithms, a concepts used to change multiplication into addition.

3.Slide Rule
The slide rule is an analog device for performing mathematical computations.The first slide rules was created in 1620 by British mathematician William Oughtred(1574-1660). His device was based on the logarithmic scale created by British astronomer Edmud Gunter(1581-1626) in 1620. Gunter's work,in turn was based in the principle of logarithm set forth by Scottish mathematiclan John Napier(1550-1617) in1614.

4.Pascaline
Blaise Pascal(1623-1662), had a father who was an overworked and harassed tax commissioner.The young pascal devised a mechanical calculator to help him with his work. Pascal started on the project in 1642 when he was 19 and three years later he had a working machine, the Pascaline. In this machine numbers were entered by dialing a series of numbered wheels, and a series of toothed wheels transferred the movements to a result dial.Printed in wheel had the numbers from 0 to 9.It could add and subtract by the movement of wheels. The number of calculating capacity of pascaline was9,99,99,999.It is not used for division and multiplication.

5.Leibnitz Stepped Reckoner
Gottfried Willam Leibnitz(1646-1716) is perhaps best known for his work in thw calculus and his subsequent priority dispute with Newton,but he also condtructed a calculator, the Stepped Reckoner, which employed the stepped gear principle.This principle has been used in many more recent machines. The Stepped Reckiner was much more complex than Pascal's machine and could perform all four of the basic arithmetic functions.It also had a logical design fault in the carry mechanism, which was not discovered until many years later.The stepped gear or Leibnitz Eheel consists of a culinder having 9 gear teeth of varying lengths.

6.Charles Babbage
Charles Babbage(1792-1871)is an English man who is one of the creative thinkers in the field of comuputer science.He is considered to be the father of computer science.He is alsi the mathematician.He built am machine that could perform difficult calculation accurately and quickely.Now a days all computer are cased in his idea.He had the concept of usind binary digit in his machine.

7.Lady Augusta Ada Lovelace
She is the great person in the field of computer science. She is the first person to develop program by using binary system so she is cinsiderd top be the first programmer in computer science.

COMPUTER GENERATION

you know that the evolution of computer started from 16th century and resulted in the form of that we see today.The present day computer,howerever, has also undergone rapid change during the last fifty years.Computer are classified into different generation.They are:
1.First Generation Computer(1943-1958):-
First generation of computer used Thermion valves.These computer were large in size and writing programs on them was difficult..They use vaccum tubes as memory device and they have 1 to 4kb storage capacity.They use machine level programming language. Some name of 1st generation computer are:-
a.ENIAC b.EDVAC,
c.EDSAC d.UNIVAC-1

2.Second Generation Computer(1959-1965):-
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 heatinf. Manufacturing cost was also very low.Thus the size of the computer got reduced considerably.Magnetic core memory was used as internal storage. Some name of 2nd generation of computer are:-
a. IBM 1620 b.IBM 1401
c. CDC 3600

3.Third Generation Computer(1966-1973):-
The third generation computers were introduced in 1996.They used Intergrated Circuits(Ics).These are popularly known as chips.A single IC has many transitors,registers and capactiors built on a single thin slice of silicon.Magnetic disks were used as secondary memory. Some of the computer of the 3rd generation of computer are:-
a. IBM-360 b.ICL-1900
c. IBM-370 d. VAX-750

4.Fourth generation computer (1974-1990):-
The present day computers that you see today are the fourth generation computers that started around 1974.It uses large scale Intergrated Circuits(LSIC) buil 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 Intergated Circuits(VLSIC) rrplaced LSICs.Some of the computer of the 4th generation of computer are:-
a.8086 b.8088
c.80286Sx d.80386Dx
e.Pentium I f.Pentium II

5.Fifth Generation Computer(1990-upward):-
The computers having artifical intelligence and high processing capacity undergoing on the development stage from 1990 are said to be fifth generation computer. It can perform large number parallel processing.ULSI(Ultra Large Scale Integration) as CPU component and AI(Arificial Intelligence) are main features of this generation.

Disadvantage of computer

1.It cannot be used on the dusty and the rough environment.
2.Computer is very expensive eo each and every people cannot afford the computer.
3.Repairs and maintenance is required frequently.
4.Skilled user is required to work inside the computer.
5.Computer is the non-intelligebt machine.It cannot think and give the decisions.
6.Electricity is needed to operate but may be destroyed by electric shock and other physical destruction.

Advantage of computer

1.It can perform a difficult task within a second.
2.It is a parallel processing.
3.It can store a large number of data for future use.
4.We can get entertainment by playing games.
5.Design and Implementation of an audio.
6.It is use to count the population of a country.
7.It is accurate machine.

Impact of computer on society

Computer plays an important role in man's life. People are becoming more dependent on computer. Many products used in everyday life now incorporate computer system. Programmable microwave, ovens in kitchen, programmable thermostats to control heating and coolong system- the list seems endless. This section will give brief ides of impact of computer usage on various sectors of our society.
a.Education:

Computer have become increasingly important in education not only as a field of study but also as reference and teaching aids. Teachers are using computer to organize and prepare course material; children are being taught to use computer at early age.
b.Police:

The record keeping task of police work was long handled by using a diversity of manual system. Quidk nationwide or international utilization of records and files was impossible.Advance in computer networking pemit the linking of many police and investigate database and make possible development of national criminal investigation system
c.Science and Technology:

Computer are now increasingly employed to improve scientific and technological advancements. They are used in design and operation of manmade satellite, space exploration vehicles.
d.Hospital:

It is used in hospital in keeping records of patient's case histories, symptoms of rare and common disease and their corresponding medication, monitoring heart-beat pulse, blood-pressure and other such a vital human features through computerizes sevice such as ECG monitors & computer Axial Tomography(CAT) scanner.