Elk Cloner
Encyclopedia
Elk Cloner is one of the first known microcomputer viruses
that spread "in the wild," i.e., outside the computer system or lab in which it was written. It was written around 1982 by a 15-year-old high school student named Rich Skrenta
for Apple II
systems.
operating system
using a technique now known as a "boot sector
" virus. If a computer boot
ed from an infected floppy disk
, a copy of the virus was placed in the computer's memory
. When an uninfected disk was inserted into the computer, Elk Cloner would be copied to the disk, allowing it to spread from disk to disk.
An infected computer would display a short poem
on every 50th boot:
Computer virus
A computer virus is a computer program that can replicate itself and spread from one computer to another. The term "virus" is also commonly but erroneously used to refer to other types of malware, including but not limited to adware and spyware programs that do not have the reproductive ability...
that spread "in the wild," i.e., outside the computer system or lab in which it was written. It was written around 1982 by a 15-year-old high school student named Rich Skrenta
Rich Skrenta
Richard "Rich" Skrenta is a computer programmer and Silicon Valley entrepreneur who created the search engine blekko....
for Apple II
Apple II
The Apple II is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977...
systems.
Infection and symptoms
Elk Cloner spread by infecting the Apple IIApple II series
The Apple II series is a set of 8-bit home computers, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977 with the original Apple II...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
using a technique now known as a "boot sector
Boot sector
A boot sector or boot block is a region of a hard disk, floppy disk, optical disc, or other data storage device that contains machine code to be loaded into random-access memory by a computer system's built-in firmware...
" virus. If a computer boot
Booting
In computing, booting is a process that begins when a user turns on a computer system and prepares the computer to perform its normal operations. On modern computers, this typically involves loading and starting an operating system. The boot sequence is the initial set of operations that the...
ed from an infected floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
, a copy of the virus was placed in the computer's memory
Ram
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...
. When an uninfected disk was inserted into the computer, Elk Cloner would be copied to the disk, allowing it to spread from disk to disk.
An infected computer would display a short poem
Poetry
Poetry is a form of literary art in which language is used for its aesthetic and evocative qualities in addition to, or in lieu of, its apparent meaning...
on every 50th boot:
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 did not cause deliberate harm, but Apple DOS
Apple DOS
Apple DOS refers to operating systems for the Apple II series of microcomputers from late 1978 through early 1983. Apple DOS had three major releases: DOS 3.1, DOS 3.2, and DOS 3.3; each one of these three releases was followed by a second, minor "bug-fix" release, but only in the case of Apple DOS...
disks without a standard image had their reserved tracks overwritten.
Development
Elk Cloner was created in 1981 by Rich SkrentaRich Skrenta
Richard "Rich" Skrenta is a computer programmer and Silicon Valley entrepreneur who created the search engine blekko....
, a 15-year-old high school student. Skrenta was already distrusted by his friends because, in sharing computer games and software, he would often alter the floppy disks to shut down or display taunting on-screen messages. Because his friends no longer trusted his disks, Skrenta thought of methods to alter floppy disks without physically touching them. During a winter break from the Mt. Lebanon High School in Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, Skrenta discovered how to launch the messages automatically on his Apple II
Apple II
The Apple II is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977...
computer. He developed what is now known as a boot sector
Boot sector
A boot sector or boot block is a region of a hard disk, floppy disk, optical disc, or other data storage device that contains machine code to be loaded into random-access memory by a computer system's built-in firmware...
virus, and began circulating it in early 1982 among high school friends and a local computer club. 25 years later in 2007, Skrenta called it "some dumb little practical joke."