Computer Viruses Virus is the generic term that people are now using these days to describe a group of
willfully destructive computer
programs. The three most common types of destructive computer programs are the Trojan horse, the Logic Bombs and the worm. A virus is just a worm with a Logic Bomb or Trojan horse component. A worm is a program that replicates itself. It creates an image of itself either in a whole or at a particular location on a disk. A Trojan horse program acts like the Trojan horse of Greek mythology. A malevolent program is hidden inside another, apparently useful program. A bomb is a piece of code embedded in a program or the operating system itself that waits for particular event to occur. You can also classify viruses by their preferred habitat. Some viruses
attached themselves to other programs; these are known as parasitic viruses. Other, which prefers lodging in the boot sector of your floppy or hard disk, is known as Boot Sector Viruses. Parasitic viruses start when the executable file to which they are attached is ruined. Some viruses have multi parts to them. The first part hides the virus and another part that would change the first par. Sort of sneaking by any virus checker. Computer viruses are a specific type of program written deliberately to cause harm to someone’s computer or to use that computer in an unauthorized way.