During the mainframe era, the antivirus never existed. At the very least, users were not involved in cleaning their terminals. e Central Data Processing Department had to take the system down and do the cleaning. Terms like corrupt files, tracking cookies, worms, and Trojans never existed. In fact the term virus was not born yet until the days of the rst PCs in 1982. On MS-DOS, contamination took place through oppy disks only.