“Elk Cloner,” largely believed to be the first computer virus released outside a lab environment, turned 30 this year and tech news website The Register took the opportunity to interview its author Rich Skrenta, who was just 15 at the time of its release in February, 1982.

The boot sector virus was written for Apple II systems, the dominant home computers of the time, and infected floppy discs. If an Apple II booted from an infected floppy disk, Elk Cloner became resident in the computer’s memory. Uninfected discs inserted into the same computer were given a dose of the malware just as soon as a user keyed in the command CATALOG for a list of files. Infected computers would display a short poem, also written by Skrenta, on every fiftieth boot from an infected disk:

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!

According to Skrenta, who wrote the program as a prank, “Elk Cloner created a rattling noise when the program started. If a disc was infected you could hear it. If you inserted an infected disc in an Apple II you can hear the head swoosh sound, an audible signature. It would infect a new disc if machine wasn’t rebooted. If an Apple II was rebooted every time, Elk Cloner wouldn’t have spread. But, given people computer habits, it spread like crazy.”

Wikipedia has a brief description of the virus here, and Skrenta maintains a page of information about Elk Cloner, including historical articles, an alt.hackers Usenet post from 1990, and source code for the program.

Mike is the editor-in-chief of A2Central, as well as a blogger and rescuer of classic manuals and books.