The Apple Worm is a
computer program
A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components.
A computer program ...
written by
Apple Computer
Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company b ...
, and especially for the
6502 microprocessor
The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small te ...
, which performs
dynamic self-relocation
In computer programming, a self-relocating program is a program that relocates its own address-dependent instructions and data when run, and is therefore capable of being loaded into memory at any address. In many cases, self-relocating code is a ...
. The
source code
In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...
of the Apple Worm is the first program printed in its entirety in
Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...
.
The Apple Worm was designed and developed by James R. Hauser and William R. Buckley. Other example Apple Worm programs are described in the cover story of the November 1986 issue of Call_A.P.P.L.E. Magazine.
Because the Apple Worm performs dynamic self-relocation within the one
main memory
Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers.
The central processing unit (CPU) of a computer ...
of one computer, it does not constitute a
computer virus
A computer virus is a type of computer program that, when executed, replicates itself by modifying other computer programs and inserting its own code. If this replication succeeds, the affected areas are then said to be "infected" with a compu ...
, an apt if somewhat inaccurate description. Although the analogous behavior of copying code between memories is exactly the act performed by a computer virus, the virus has other characters not present in the worm. Such programs do not necessarily cause collateral damage to the computing systems upon which their instructions execute; there is no reliance upon a vector to ensure subsequent execution. This extends to the computer virus; it need not be destructive in order to effect its communication between computational environments.
Programs
A typical computer program manipulates data which is external to the corporeal representation of the computer program. In programmer-ese, this means the code and data spaces are kept separate. Programs which manipulate data which is internal to its corporeal representation, such as that held in the code space, are self-relational; in part at least, its function is to maintain its function. In this sense, a dynamic self-relocator is a self-referential system, as defined by
Douglas R. Hofstadter
Douglas may refer to:
People
* Douglas (given name)
* Douglas (surname)
Animals
*Douglas (parrot), macaw that starred as the parrot ''Rosalinda'' in Pippi Longstocking
*Douglas the camel, a camel in the Confederate Army in the American Civil ...
.
Other examples
The instruction set of the
PDP-11
The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, ...
computer includes an instruction for moving data, which when constructed in a particular form causes itself to be moved from higher addresses to lower addresses; the form includes an automatic decrement of the instruction pointer register. Hence, when this instruction includes autodecrement of the instruction pointer, it behaves as a dynamic self-relocator.
A more current example of a self-relocating program is an adaptation of the Apple Worm for the
Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
80x86
x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was introd ...
microprocessor and its derivatives, such as the
Pentium
Pentium is a brand used for a series of x86 architecture-compatible microprocessors produced by Intel. The original Pentium processor from which the brand took its name was first released on March 22, 1993. After that, the Pentium II and Pe ...
, and corresponding
AMD
Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...
microprocessors.
See also
*
Worm memory test
References
External links
The Apple Worm source codeVideo of executing Apple Worm program
Worm
Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always).
Worms vary in size from microscopic to over in length for marine polychaete wor ...
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