Elk Cloner was the first computer virus known to have spread in the wild. In 1982, Richard Skrenta, then fifteen years old, wrote the virus for the Apple II operating system, which was stored on floppy diskettes. When a computer booted from a floppy disk infected with Elk Cloner, the virus would start, and would subsequently copy itself to any uninfected floppy disk that was accessed. Because computers of that time had dual floppy disk drives, and because diskettes were often passed around among friends, the virus was frequently copied. After contagion, every 50th time that a computer booted up, it would display the following text:

Elk Cloner: The program with a personality It will get on all your disks It will infiltrate your chips Yes it's Cloner! It will stick to you like glue It will modify ram too Send in the Cloner!

Elk Cloner was not intended to cause damage, but was created as a practical joke. According to WorldHistory.com, the adolescent Skrenta had a penchant for modifying programs so that they stopped working after some code-specified time period had elapsed, at that point displaying some joke text that Skrenta had written. Not surprisingly, the young programmer's friends grew leery of allowing him access to their diskettes. Elk Cloner's capacity to copy itself (the major criterion of a virus) made it possible for Skrenta to continue to annoy his friends without requiring physical access. The virus is reported to have spread widely among his fellow students (and also to his math teacher), thus ensuring Elk Cloner's place in history.

Content Continues Below