"Elk Cloner" - One of the first computer viruses

"Elk Cloner" - One of the first computer viruses

It was written in 1981 by 15-year-old schoolboy Richard Skrenta for Apple II computers. It spread by infecting the DOS operating system for the Apple II, recorded on floppy disks.

After the computer booted from the infected floppy disk, a copy of the virus was automatically launched. The virus did not affect the operation of the computer, except for monitoring access to disks. When an uninfected floppy disk was accessed, the virus copied itself there, infecting it, slowly spreading from disk to disk.

The virus did not intentionally cause harm, although it could damage disks containing a non-standard DOS image, erasing the disk's backup tracks regardless of their contents.