Brain the world‘s first virus which runs on MS DOS was in fact actually written for protecting a medical software from piracy, Basit and Amjad Farooq Alvi were two brothers who wrote the code that tracked illegal distribution of the heart monitoring software program .The virus affects the IBM PC computer by replacing the boot sector of a floppy disk with a copy of the virus. The virus came complete with the brothers’ address and three phone numbers, and a message that told the user that their machine was infected and for inoculation the user should call them:
