Cyber Crime

The person who wants or invade or harm a computer system by making use of variety of tools and tricks are cyber criminals .
These tricks are related to unauthorized access.The types of activities that a criminal do with the help of computer and internet are as follows:

1) Password Guessing :The computer usually use some type of authentication technique by the use of plain text passwords to protect the
computer from the uninvited guests .But some poeple hackers break the authentication code and access the computer resources.This activity
can be carried out by the following method.

a)Password Guessing
b)Shoulder Surfing(look from shoulder for someone using password)
c)Packet Sniffers (A program that checks all the traffic on a section of a network)
d)Dumpster Diving (look in dumped documents for password)
e)Social Enginnering(false call for a password as if you are the user)
f)Superuser status(provide facility to access all the files and documents protected like in UNIX or Windows NT )

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.