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.