Using the above example, a file is created on an infected microcomputer and the file is saved on a floppy disk. The disk is then taken to an uninfected microcomputer. The uninfected microcomputer retrieves the data file and by so doing is itself infected with the virus. These pranks can cause annoyance and loss of efficiency. Harmful and destructive viruses are rarer but have received more attention in the press.
Viruses can be acts of sabotage or simple vandalism.
Most viruses encountered in microcomputers are acts of vandalism. Usually, a virus begins as a practical joke or an experiment. Bootstrap virus codes replace the bootstrap code in memory. COM file in DOS-based computers. Joiner viruses act by joining with the system files necessary for the operation of the computer.