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:

1. 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.
2. 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.
3. 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.
4. 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.
   

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

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

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.
   

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.