Answer: Boot Viruses

One of the earliest and most prevalent forms of computer viruses was known as a “boot virus”. Long before the age of widespread Internet access where network-aware viruses could tear around the globe in a matter of days, viruses took months (and sometimes years) to slowly propagate computer-by-computer hitching a ride on the floppy disks used in the machines.

These viruses were hidden in the boot sector of the floppy disk, and when an unsuspecting user booted the machine with the disk in (or rebooted after forgetting to remove the disk) the virus would activate, install itself on the computer, and begin infecting other floppies used on the machine. One of the most famous of the boot sector viruses was the Michelangelo Virus.

While viruses can still hitch a ride on removable media, the decrease in removable media usage coupled with an increase in quality anti-virus software and better OS-native security procedures has rendered removable media viruses a very minor part of the computer virus ecosystem.