About Computer

The word computer refers to calculate something.To calculate is to do some mathematical operation About 30-40 years ago computer was introduced as a calculating device .Computer was first developen in 1940's AD.It is a digital electronic device .Before it tooks lot of time and was dificult to store a data .To reduce the inconvienet of calculator computer was introduced in the market .In the beggining the computers were huge size and accumulate the large space . Later on its size reduces whereas the processing capabilties and speed increased tremenduously. Hence in short computer is an operating device .It is very powerful device to aid the device in the field of data processing and research. Computer is a programmable device .It is aset of a well defined instruction and it operates with the machinary language.It is easy to operate because it use high level language.Now the computer that we are using are electrical and digital and it consists of two parts hardware and software.Without its components computer cannot function properly.It help us to do work easily and faster.

Computer History

The development of the computer had begun with the development of the world. In the ancient time people used to counting the stones.Then the first counting device Abacus was found.Then the decelopment of computer flourised.In the earlier time the computer were very huge and expensive.It occupied a whole room and were very bulky.But with the rise of different scientist and mathematician sklowly the computers became advanced .Now the computers are more advanced and fast too.And the results are in front of us.Now the world is advanced in technology and the world is incomplete without computer. Around fifth century one of the hindu philosopher developed a method of counting 0 to 9 which is called decimal method of counting.In mid 1940's the first electronic digital computers were manufactired.

1)Abacus : History of the computer began the development of abacus.It was the first countig machine.In the earlier time people used it for countig purposes only. Abacus came into exsitence betwen 2000 to 5000 years ago and it had its origin in ancient China,Egypt and Greece .This machine was divided in two parts.The first part is heaven and the another is earth.Abacus could add ,multiply and subtract.
2) Napier's Bone:Napier's Bone was invented by John Napier in 1614 AD.Nappiers was a scottish mathematician .Napiers Bone can perform multiplication ,division and addition.

3)Slide Rule: In 1620 ,William Outgred invented the slide rule .Slide Rule is a calculating device that uses the principles of logarithm .

4)Pascaline:In 1642 ,Blaise Pascal a french mathematician devised the first true calculating machine .He invented Pascaline to help his father who was a tax controller.Rascaline could add and subtract easily by movement of wheels.In late 1960s' professor Nikalus Writh developed a new computer programming language and was named as Pascaline.

5)Leibniz Stepped Recknor:A German mathematician Gottfried Von Leibniz invented a calculting machine which could perform multiplication and division .Leibniz machine could multiply ,divide and find square roots.

6)Analytical Engine;Charles Babbage ,the father of computer science invented Analytical Engine.Babbage had a concept of using biniary digits (Bits)in this machine.Analytical Engine is a general purpose automatic calculator.But Charles Babbage couldnot get sucess in his Analytical Engine due to his economic condition and mechanical difficulties.However the engine couldnot get succeded but the concept used in this engine was still in the modern computer.His concept is still in used due to this he is known as the father of computer science.This engine could operate 50 decimal number and have high storage capacity.

7)Holleirth's Tabulating Machine: Dr. Herman Hollerith was a census statician at the US in 1880 in census bureau.Hollerith proposed a mechanised solution to the problem which was based on punched card .Tabulating machine is also called as Electromechanical Punced card .He invented Tabulating Machine for the census data calculation in 1890s.

8)Electromechanical Computer:In 1937 AD.Professor Howard Aiken invented an automatic calculating machine with the punched card technique. The first electrical binary programmable Computer is Z1 which was inveted Konard Zuse in 1938 AD.Konard Zuse was a German Enginner and later on he invented Z2,Z3,Z4 an d so on with the latest technology. The first electronic computer came into the existence is ENIAC which was invented by J.P.Ekret and John Mauchly.This computer was very hugeand occupied 18000 sq. feet .This computer used nearly 18000 vaccum tubes.It was the first digital computer. EDSAC was the first electrical stored program computer which was invented in 1949 and this computer could ran the grphical computer game also. Mark I was invented by Havard Professor Howard Aiken .The Mark I was huge and take large time for data processing .Mark I helped for the US force in the war.This computer help to store data and find information of the enemy in the war.Similarly Professor Howard Aiken invented MarkII and many other electrical Digital Computer.

Types of computer

The major classification of computer are

1. On the basis of work
2. On the basis of size
3. On the basis of brand
4. On the basis of model

1. On the basis of work

• Analog Computer:An analog computer measures the physical values such as temperature or pressure.Analog computers are faster than digital.Speedometer and seisomography are also an analog computer.It is useful in kidney and mental diseases.PLESLY is an analog computer used in International Telecommunication System.Analog computers are used in thefield of science,technology,school,college,business etc.
  

• Digital Computer:It directly counts number or digits represents numbers ,letters or other special symbols.It doesnot measures the distance or liters of petrol etc.Digital computer doesnot work countinuously.Digital computers are used in the preparation of reports,result tabulating and graphic representation . Digital computers helps in mahtematical engineering,counting,statstics...etc.

• Hybrid Computers:Hybrid means the combination of work.The combination of the analog and digital computers is called Hybrid computers.It can transfer data from analog to digital and vice versa.Hybrid computers are used in big industries ,scientific research center,institution, airplanes, etc.In an intensive care unit of hospital ,for experiment analog device measures patient's heart function ,temperature or other vital sign.

2.On the basis of size:

• Mainframe Computer:Mainframe means a big computer which process at a high speed and occupies a big space.These computer have faster processing speed and greater storage capacity.These computer need 100 sq ft.space.This amchine have big capacity of processing task.About 100 people can work in this computer at a time.This computer can communicate with a country at a distance vis satellite and transfer data can take place.
• Mini Computer:Medim in size but smaller than mainframe and bigger than micro computer. This required small space than mainframe .It can communicate with 50 terminal.It can be used in Local Area Network and are less expensive.This computer is faster than micros.The series of mini computers are PDp1, The Prime series ,Ap3 , As-400 etc.
• Micro Computer: Micro Computer are based on microchips . It is also called Home computer or Personal Computer.Micro Computer are extensively used at home and offfice.Its capabilities and speed have increased .It is available at many brands, model and sizes.They are Laptop,Pocket,Pocket computer and notebook. They can communicate with LAN or MAN with the help of MODEM.

3.On the basis of brand:

• IBM PC:International Business Machine Corporation was establised in 1942 inUSA . The computer manufactured by this company are called IBM computer.IBM computers are reliable,strong and they posses high speed processing.
• IBM Compatible:Compatible means principles or ideas that can exist together.HTese computer can perform all the tasks that an IBM computer does. The Architectural design of these computer are similar to that of IBM computers.
• Apple Macintosh computer:Apple computer was establised in USA ,in late 1970s.It develop diferent type of Computers ,more than that of IBM in architectural and ystem configuration as well.The software used in this are much better because they are friendly and easy to handle.Macintosh is a new brand of Apple Computer.

4.On the basis of Model:

• Xt Computer:Xt computer were based with the processor named 8086.Later some changes were made in the main processor of the computer.
• AT Computer:Advanced technology computer are are faster than Xt computer.In these computer math co-processor are used to suppliment the airthmetic section of the main processor which enable us to process complex mathematical problem.
• PS\2:This computer is more faster than IBM and IBM Cpompatible.Its architectural design is advanced than other.
  

Computer Architectural

Computer is a group of parts that are grouped for the purpose of acheiving an objective ,called programs ,which are being executed qualifies itself is called computer system.
Computer System is a made of

• Input unit
• Output unit
• Central Processing Unit(CPU)

1. Input Unit:Input are the accumulation of the raw facts and instruction which are given to the Computers.Input devices are used to enter data and instruction into the computer .Some of the input devices are Keyboard,Mouse,Scanner,Touch Pad, Touch Screen,Joystick.Light Pen and so on.
2. Output Unit :Output are the information which are given by the computer after processing the raw facts and data.Output devices are used to show the information or to display output .Some of the output devices are monitor,printer ,speakerand so on.
   
3. CPU:Central Processing unit is the brain of the ocmputer. The CPU is the part of a system which contains circuitory to control the interpretation and execution of the instruction. All the work of processing,calculating and works is done in this unit. It controls ,monitors,manage and coordinates the activities of all the units computer by issuing proper components.This unit consist of three parts.They are

a. Memory Unit
b.Airthmetic and Logic Unit
c. Control Unit

Computer Hardware

The physical of the computer which can be touch or felt is called computer hardware.A person who is involved in the assembling the maintenance and repair of these compinent is called hardware engineer.Hardware gives the complete setup of computer system.Hardware includes both external ,internal and built in components which are simultaneously associated for running of system .eg Keyboard,mouse ,slots,RAM,ROM,capacitors and so on.

Types of hardware

• Peripheral Device
• Processing Device
• Storage Device
• Peripheral Device:Computer Peripheral are the device which are associate or connected with the main device of computer .They can be input or output device as per the required of the user.eg. mouse,keyboard,printer,sound card,modem,scanner etc.
• Processing Device:Processing device are used to process data.eg. CPU
• Storage Device:Storage device are used to store data or information.eg.CD-ROM ,Harddisk,Floppy disk and so on.

Some of the computer hardware are:

• Computer Device
• Computer Media:eg.Secondary Storage unit such as floppy disk ,hard disk ,magnetic tape etc.
• Motherboard:Some of its components are
• Buses
• System Clock
• Microprocessor
• ROM Chips
• Socket For RAM
  
• Expansion Slots

Parts of the Mother board are:

• Power Supply
• Cooling Fan
• Speaker
• Driver Bays

5.Microprocessor
6.Ports:

• Serial Ports
• Parallel Ports
• SCSI ports
  

7.Memory of the computer

• RAM
• ROM
• Cache Memory
• Virtual Memory
  

8.Input Device

• Keyboard
• Mouse
• Scanner
• Light Pen
• Joystick
• Trackball
  

9.Power supply Device

• Voltguard
• Voltage
• UPS
  

10.Output Device

• Monitor
• Printer
• Speaker
• Graphploter
  

11.Storage Device

• Magnetic tape
• Floppy Disk
• Hard disk
• Micro flim
• CD Rom
• Optical Storage Device
  

12.Communication Device

• MODEM
  

13.Connectivity Device

• Ports
  
• Expansion Slots
  

Computer Software

Software is the collection of computer programs and instruction that gives life to the computer or makes the system to work accurately and perfectly.

Types of Software

1.Aplication Software:
They are design for specific purpose.It is written or developed as per the requirement of the user or institution .It works as online biling ,Bill Formatting ,SLC result Processing and so on.
Types of Application Software

• Package Software
• Custamized or Tailored Software

2.Utility Software
This software keeps the desk management claen and smooth.This software are also called Service programs.They provide a useful service to the user by providing facilities for performing tasks.

3. System Software
This software controls over all operation of the computer system.It consists variety of programs that supports the operation of computer.

Types of System software

• Operating System
• Translating Software
  

Processing Capabilities

Computer manipulates the symbols that are used to reprsent thing and can process one step at a time in fraction of second .It process the data or facts and gives the desired results which is called information.The operation that take place during data processing are:

1. Input/Output Operation:a computer can accept raw facts are called input from suitable devicegiven by user and process it and supply it to the user called output.
2. Text Manipulation and Calculation:Computer manipulates the non numeeric letters and other symbols used in words and sentences.They also can calculate on numbers.
3. Logic /Comparis Operation:With the help of CPU computer had the ability to perform logic operation .It compares two data or items and gives the output.
   

Storage

Computer can store large volume of data.The Storage capacity of the computer is measured in Kilobytes.Storage capacity helps in analysing data and take quick decision.Data Store in computer can can be retrieve ,delete and updated.

1. Temporary Memory

It is a Volatile memory .In this memory the data are erased when the power of the computer is off or when the computer is shut down.In this memory we can both read and write and can modify .In this data are not store for long time.RAM is the example of Temporary memory.

2.Permanent Memory

It is a non volatile memory.Once the data is stored in it ,it cant be erased nor modified.It saves the data although the computer is shut down or the power is off.The data and the program in the ROM is uinalterned.ROM is the example pf permanent memory.It is only Read Only Memory.

Storage
4 Bits-1 Nibble

8 bits-1 Byte
1024 byte-1 KB
1024 KB-1 MB
1024 MB -1 GB
1024 GB-TB

Capabilities of Computer

The capabilities of the computer are as follows:

• Computer provide us the information that we can usse in the decision making .
• Computer provide us the faster and cheaper communication with the help of the internet.
• Computer can also do the task that are critical or dangerous to human beings.
• Computer can perform almost all the work when user provide appropriate software and hardware componets.
• Computer process the data in the very fast speed and steady.
• Computer can store large volume of data
  
• Computer can perform repeated task with the same speed and accuracy.
• Computer helps to ssearch the information with the help of different search engine.
  

Programming Language

The language which are used to write program or software is called programming language.It is a language with its own grammar and syntax and that can communicate with computer . It is a set of a codes that are writen by programmer to instruct or to guide the computer hardware to perform the specific task.
Programming Language are clasified as:

1. Machine Level Language:Its a machine oriented language that a computer can understand.Its made up a series of 0 or 1 and a sequence of bits.It is very tedious , time consuming and troublesome to write program in this language.Program,codes or statement can be loaded directly into the computer memory.
2. Asembly Language:Its a low level language which was introduced to overcome the some of the difficulties of the machine level language.It permits the use of mnemonics (alpha numeric codes).Computer doesnot understand mnemonics language,program written on assembly language are translated into machine level language before execution.This translation is done by assembler.The program written on assembly language is called source case.Program after translating into machine code is called object code.
3. High Level Language:It is a language in which instruction are closer to the english language and mathematical notation .This language is very easy to modify and maintain.Program written on this language are also classified according to whether they solve the general problem or specific problem.

Types of High Level Language are

• Procedual Oriented Language
• Program Oriented Language
• Natural Oriented Language

Scopes of Computer

1. Communicatiion: Development of computer had developed the easy means for communication .Computer helps to communicate from one part of the world to another through voice mail,chat,Email,Net phone ,video confercing and so on.
2. Banking system and Ticket reserving:In tthe recent years the computers are more advanced.It helps in banking system,airplane ticket reserving ,account transfer and much more facilities.
3. Business: Industrial business ,agricultural ,business,commerce,medicine,tourism and banking.are some area where computers capabilities are utilized.It helps to keep data of daily transcation and also help in reseach.
4. Studies: Computers are used as aids in the study and analysis of many vast subjects.It assist student in learning and understanding the subjects matter easily .It helps in the research of mines, golds, minerals ,distance education,It education and also can study features of computer.It helps students for doing different works nd increase their creativity.
5. Search Engine:Computer helps to search different information with the help of different search engine like yahoo,goggle,hotmail and so on .With the help of these search engine people can many information related with different topics.
   

Limitation Of Computer

Computer is very useful machine in our daily life.It helps to do our work faster and makes it easier.But it have certain limitation .They are:

• Computer can't do anything unless it is programmed for that work with specific instruction.
• If there any error in the syntax or information given by the programmer or designer then the output given by the computer is also incorrect which is always difficult to correct.
• Computer doesnot have its own intelligence.It has got Artificial intellience or it is only function by the guide of the user or programmer.
• Computer doesnot work untill the prsence of the electricity, sine it is an electrical device.
• Computer cannot care itself nor thinking itself.Though in programmed work done by computer is perfect and faster then a human can do .
• Computercannot take a quick decision itself because it doesnot have brain to think.
  

Diagnostic Software

Diagonistic software helps in the easy use of the computer software and saves the time . Diagonistic Software donot detect the problem in the software but gives the hints and valuable information about the computer system and its working.The Diagonistic also provide the basic information of the system.delete unnecessary files ,improve the computer's performance and repair window resistration.The main purpose of the diagonistic software is to diagonise the potential problem and to test drive.This software can be download from manufacture's website with no cost.Diagonistic software helpshould always be run when there is problem in the harddisk to check the status of the drive.

Computer Security

The computer is delicate electronic equipment. Computer should not be kept in a crowded place, smoky and dusty place. Computer is very sensitive to heat ,light, smoke , dust, fire because these components damage the its accessories. For the proper management of the computer the security is classified as follows: 1. Hardware Security 2. Software Security

1. Hardware Security: Protecting computer from physical damage, theft, etc fall in this category .For the proper management of the physical security of the computer system, we have to maintain following components: · Regular Maintenance · Insurance · Free Of Dust · Protection From Theft · Size of room · Ventilation and Light · Power Supply · Furniture · Computer

2. Software Security: Software security is the one of the important security measures. The program, software and data security s another important part before installing the computer. Software security requires : · Prevention of loss off data · Prevention of data and software program piracy · Prevention of corruption of data · Prevention from error reading of data
The measures of software security are: · Password Protection Prevents unauthorized access. · Virus free helps to keep the computer from virus infection. · Regular backup the data helps to restore the lost data. · Maintenance of hard disk using defragmentation of the files. This helps to manage and to store fragmented files. · Scanning the files using scandisk finds the files corrupted and repair them. · Using Firewall to prevent from virus infection.

Computer Virus

A virus is a small malicious computer program which has the ability to clone or replicate itself onto other computers and transfer quickly causing the predictable impedient in the normal functioning of the computer.The fulll form of the virus is Vital Information resources under seize.A virus is a destructive intellectual creation of highly talented computer criminals for the destructive of other computers.First the virus was created by John Von Neuman .HE gave the idea of replicating programs from media to media whereas Fred Cohan gave the name computer virus for the self replicating computer programs.First the virus was created by Alvi Brothes of Pakistan name C Brain.

The two important features of virus are:

• The feature of replication immediately onto the other computer.
• Transmission to the other computer without hte knowledge of user.
  

Types of computer virus on the basis of area they infected:

• Message Carrying Virus:Message carrying virus donot infect the computer rather displays the intresting message ,pictures ,to entertain you and to transfer your attention towards it.They are Mr Joshi virus.
  
• System Infectors:These virus destroys or corrupts the essential system fileshaving sys. or com. extension which helps in the operation of the computer.When one of these files run then these virus activate and create the damages in the program.Due to it the computer fails to perform normally and doesnot boot too .They are Aircop,Badhead virus etc.
  
• Start up infector:This virus damages the boot sector and information store in the IO sys. and MS-DOS .sys files.Due to htem data and aplicaton software would be altered cannot function normally.This virus affect the boot sector of the floppy and hard disk.Some of this virus are CBrain,Stone,8290 virus ,Marijuiana and so on.
  
• Application Infectors:These virus infect and damage the application software like Word Processing ,Spreadsheet Package ,data base PAckage atc and also destroys the program you created .The eg of these virus are Darkavenger ,The vienna virus and so on.