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.

TYPES OF COMPUTER

Computer is an electronic device which accepts the input and processes them to give desired output. There are various types of computers available onthe market.Computer are classified on the basis of work, on the basis of size, on the basis of model and on the basis of brand. It is also divided into general purpose and special purpose. General purpose computers are the digital computer and special purpose computer are mostly analog and hybrid computer. This classification is according to the working principle or function of the computers.
On The Basis Of Work
1. Analog Computer
An analog computer is one that measures physical values such as temperature or pressure that fall along a continuous scale in temperature or pressure. For example, a service station gasoline pump contains an analog processor and analog device that converts fuel measurements into quantity and price values. The term amalog computer is derived from a Greek word Analog.
2.Digital Computer
A digital computer is one that directly counts numbers or digits that present numbers, letters or other special symbol. Digital computer does not measure the distance or does not measure how many liters of petrol are taken or what is the pressure of compressions etc.Digital computer are the most used computer for report, documentations, billing and other graphical work.
3.Hybrid Computer
These are the computers, which work in digital as well as analog computer type. The good qualities of analog and digital computer are combined on these computers made the hybrid computer. These are used on Intensive care unit of hospital, jet planes and others data analysis terminals.Hybrid computer transfer the data from analog to digital to analog and vice versa.
On The Basis Of Size
1.Super Computer
Mullti-user, multiprocessor large computer of very high efficiency and storing capacity is called super computer able to solve a difficult problem within a nana seconds. A number or RISC(Reduce Instruction Set Computer)processors are used. Its word length is 64 bits. For eg: CRAY,XMP/14, CDC-205 etc.
2.Mainframe Computer
It is also very powerful multi-user computer used in large business organizations, industries and defense to process data of complex nature. It can response several CPU for data processing.More than 100 user can use at a same time because it work on time sharing mode.For examples: IBM4300 Series, ICL39 Series & IBM1401 etc.
3.Mini Computer
Mini computer is general purpose computer which is smaller than mainframe and super computer. Mini computer has limited data channel capacity and limited software is available.Example- AS/400, AP-3,PRIME Series etc. They cam be maintained and operated easily.
4.Micro computer
They are the smallest general purpose computers. They are easy to handle and are used in difersnt application areas like business, engineering, schools etc. Micro computer are general purpose computer which can do a variety of jobs.Micro computer are also called personal computer.Example:IBM PCs, Apple Mac, IBM PS/2 etc.
On The Basis Of Model
1.XT: Xt is acronym for Extra Technology and had a processing speed 4077MHz. XT computer has 8086 or 8088 microprocessor. It was released in 1983.
2.AT: AT is acronym for Advance Technology and is faster than XT.AT computer have higher capacity of RAM and are expensive. The microprocessors used in AT are 80286 SX,80286 DX,80386 SX,80386 SX
3.PS/2: These computer were released in 1990. The processing of this computer is higher than AT computer.Most of Laptop computer manufactured by IBM are based on PS/2.
On The Basis Of Brand
1.IBM PC: IBM PC is acronym for international Business Machine Personal Computer. These are micro computer made by IBM company. These computer are more reliable, durable and have better quality.
2.Apple'Macintosh: Apple company of USA developed Apple 'Macintosh computer .The Apple computer have their own hardware and software.

APPLICATION OF COMPUTER

Computer is used in large areas such as bankig,office,railway,libary education,hospital,industries,reasearch,data processing, science and engineering,advertisement,communication etc.
1.Banking:-
Computer are used in bank and financial company for electronic money transfer, statistical report, voucher,ledger, balance sheet ect.There are different system used in financial company such an ATM(Automatic Telling Machine),DFTS(Electronic Fund Transfer System) etc,are computer based system for customer services provided

2.Education:-
Computer can be used as teaching learning tool, result processing, student data processing, question preparation, handouts and note preparation etc.It is very effective tools for on line education.The learning materials are packed in CD-ROMwith interactive multiledia.The CAL(Somputer Aided Learning), CAT(Computer Aided Indtruction) are done through computer.

3.Industries:-
Industrial research, budgeting, process control all are computer based.The robotics is also a branch of computer science.Now a day , robot are used in complicated industrial process ehich is dangerous for human.CAD(Computer Aided Design) is used in manufacture sector to design model of electrical, electronics, mechanical models of machine and it is more popular among architect engineers also.CAM(Computer Aided Manufacture).

4.Research:-
Computer are used in different types of reasearch field such as account, database, graphics, mathematisc etc. New theory is formulated by research in computer. The collected data for the research is given to the program of computer then final result is return back.

5.Hospital
Computer are used for the research in health.It is applied in medicine, surgery, and research. The expert system for doctors are also available in market. The multimedia kits for surgeon are also available to learn surgery on virtual patients.The concept of expert system is also introduced in computer science. An expert system is a computer program designed to operate at the level of an expert in particular field. It shows performance at export level. MYCIN is a name of export system designed at stanford university for diagnosis of blood and meningitis infection. The other expert system is a CADULEUS or INTERNIST 2 designed by computer engineer Harry Poplet and master of medicine, Dr.Jack Meyer at University of Pittsburgh to diagnose more than 500 diseases at expert level.

INTRODUCTION
Let us begin with word 'compute'. It means 'to calculate'. We are familar with calculations in our day-to-day life. We apply mathematical operations like addition, subtraction, multiplication,etc. and much other formula for calculations.Silpler claculations take less time. But complex calculations take much longer time. Another factor is accuracy in calculations.So man explored with the idea to develop a machine, which can perform this type of arthmetic calculation faster, and with full accuracy. This gave birth to a device or machine called 'computer'.
Computer is a fast and accurate electronic device that accepts data through input device then store and process them, and resulted data are displayed from output device.The computer we see today is quite different from the one made in the beginning.As mentioned in the introduction it can do arthmetic calculations faster.The number of applications of a computer has increased, the speed and accuracy of calculation has increased.For a common man computer is simply a calculator, which works automatic and quite fast.For a person who knows much about it, computer is a machine capable of solving problems and manipulating data.Therefore, we may define computer as a decive that transforms data.Data can be anything like marks obtained by you in various subjects.It can be also be name, age, sex, weight, height,etc.Human beings do calculations on their own.But computer is a dumb machine and it has to be given proper instructions to carry out its calculation. This is why we should know how computer works.

Application of computer

APPLICATION OF COMPUTER
Computer is used in large areas such as bankig, office, railway, libary education, hospital, industries, reasearch, data processing, science and engineering, advertisement, communication etc.Some are:-
1.Banking:-
Computer are used in bank and financial company for electronic money transfer, statistical report, voucher,ledger, balance sheet ect.There are different system used in financial company such an ATM(Automatic Telling Machine),DFTS(Electronic Fund Transfer System) etc,are computer based system for customer services provided

2.Education:-
Computer can be used as teaching learning tool, result processing, student data processing, question preparation, handouts and note preparation etc.It is very effective tools for on line education.The learning materials are packed in CD-ROMwith interactive multiledia.The CAL(Somputer Aided Learning), CAT(Computer Aided Indtruction) are done through computer.

3.Industries:-
Industrial research, budgeting, process control all are computer based.The robotics is also a branch of computer science.Now a day , robot are used in complicated industrial process ehich is dangerous for human.CAD(Computer Aided Design) is used in manufacture sector to design model of electrical, electronics, mechanical models of machine and it is more popular among architect engineers also.CAM(Computer Aided Manufacture).

4.Research:-
Computer are used in different types of reasearch field such as account, database, graphics, mathematisc etc. New theory is formulated by research in computer. The collected data for the research is given to the program of computer then final result is return back.