Editing Clone (computing)

{{for|copying an object in computer science|Cloning (programming)}}
{{distinguish|fork (software development)|remaster}}
{{More citations needed|date=August 2014}}
In [[computing]], a '''clone''' is [[computer hardware|hardware]] or [[software]] that is designed to function in exactly the same way as another system.<ref>[http://www.outpost9.com/reference/jargon/jargon_18.html#SEC25 clone /n./ ] ''"An exact duplicate: "Our product is a clone of their product." Implies a legal reimplementation from documentation or by reverse-engineering"'' from the [[Jargon File]]</ref> A specific subset of clones are '''remakes''' (or '''remades'''), which are revivals of old, obsolete, or discontinued products.

== Motivation ==
Clones and remakes are created for reasons including competition, [[standardization]], availability across platforms, and as [[Homage (arts)|homage]]. [[computer compatibility|Compatibility]] with the original system is usually the explicit purpose of cloning hardware or low-level software such as [[operating system]]s (e.g. [[AROS Research Operating System|AROS]] and [[MorphOS]] are intended to be compatible with [[AmigaOS]]). Application software is cloned by providing the same functionality.

Commercially-motivated clones are made often during a competitor product's initial successful commercial run, intentionally competing with the original and trying to participate in their success.

==Hardware==
[[File:FC-Twin-Console-Set-H.jpg|thumbnail|The FC Twin famiclone designed to look like an [[SNS-101]]. This unit plays both NES and SNES cartridges.]]

===Hardware clones===
When [[IBM]] announced the [[IBM PC]] in 1981, other companies such as [[Compaq]] decided to offer clones of the PC as a legal reimplementation from the PC's documentation or [[reverse engineering]]. Because most of the components, except the PC's [[BIOS]], were publicly available, all Compaq had to do was reverse-engineer the BIOS. The result was a machine with similar performance and lower price than the machines cloned. The use of the term "PC clone" to describe [[IBM PC compatible]] computers fell out of use in the 1990s; the class of machines it now describes are simply called PCs, but the early use of the term "clone" usually implied a higher level of compatibility with the original IBM PC than "PC-Compatible", with (often Taiwanese) clones of the original circuit (and possibly ROMs) the most compatible (in terms of software they would run and hardware tests they would pass), while "legitimate" new designs such as the [[Sanyo]] [[MBC-550]] and [[Data General/One]], while not infringing on copyrights and adding innovations, tended to fail some compatibility tests strongly dependent upon detailed hardware compatibility (such as ability to run ''[[Microsoft Flight Simulator]]'', or any software that bypassed the standard [[Ralf Brown's Interrupt List|software interrupts]] and directly accessed hardware at the expected pre-defined locations, or—in the case of the MBC-550 for example—wrote [[diskettes]] which could not be directly interchanged with standard IBM PCs).

While the term has mostly fallen into commercial disuse, the term ''clone'' for PCs still applies to a PC made to entry-level or above standard (at the time it was made) which bears no commercial branding (e.g., [[Acer Inc.|Acer]], [[Dell]], [[Hewlett-Packard|HP]], IBM). This includes, but is not limited to, PCs assembled by home users or corporate IT departments. (See also [[White box (computer hardware)]].)

There were many [[Nintendo Entertainment System hardware clone]]s due to the popularity and longevity of the [[Nintendo Entertainment System]].

===Hardware remakes===
Examples for hardware remakes include recent home computer remakes.

A special kind of hardware remakes are [[emulator]]s which implement the hardware functionality completely in software. For instance, the [[WinUAE]] emulator software tries to behave exactly like a physical [[Amiga]].

==Software==
Software can be cloned by [[reverse engineering]] or legal reimplementation from documentation or other sources, or by observing a program's appearance and behavior. The reasons for software cloning may include circumventing undesirable licensing fees, acquiring knowledge about the features of the system or creating an [[Interoperability|interoperable]] alternative for an unsupported [[Computing platform|platform]]. [[GNU]], a clone of [[UNIX]], was motivated by a need of the [[free software movement]] for an operating system composed of entirely [[free software]].

In the United States, the case of ''[[Lotus v. Borland]]'' allows the functionality of a program to be cloned so long as [[copyright]] in the code and interface is not infringed.

Yet, the public interface may also be subject to copyright to the extent that it contains expression (such as the appearance of an icon). For example, in August 2012, [[Electronic Arts]], via its [[Maxis]] division, put forth a lawsuit against [[Zynga]], claiming that its [[Facebook game]], ''[[The Ville (video game)|The Ville]]'', was a direct clone of EA's own Facebook game, ''[[The Sims Social]]''. The lawsuit challenges that ''The Ville'' not only copies the gameplay mechanics of ''The Sims Social'', but also uses art and visual interface aspects that appear to be inspired by ''The Sims Social''.<ref>{{cite web | url = https://www.forbes.com/sites/danielnyegriffiths/2012/08/06/ea-sues-zynga-but-deeper-social-issues-threaten/ | title = EA Sues Zynga, But Deeper Social Issues Threaten | first = Daniel Nye | last = Griffen | date = 2012-08-06 | access-date = 2012-08-07 | work = [[Forbes]] }}</ref><ref name="zynga clone">{{cite web |last=Brown |first=Nathan |date=2012-01-25 |title=How Zynga cloned its way to success |url=http://www.edge-online.com/features/how-zynga-cloned-its-way-success |archive-url=https://web.archive.org/web/20120709080034/http://www.edge-online.com/features/how-zynga-cloned-its-way-success |archive-date=Jul 9, 2012 |access-date=2012-08-07 |work=[[Edge (magazine)|Edge]]}}</ref><ref>{{cite web |last=Jamison |first=Peter |date=2010-09-08 |title=FarmVillains |url=http://www.sfweekly.com/2010-09-08/news/farmvillains/ |archive-url=https://web.archive.org/web/20120802144310/http://www.sfweekly.com/2010-09-08/news/farmvillains/ |archive-date=Aug 2, 2012 |access-date=2012-08-07 |work=[[SF Weekly]]}}</ref> The two companies settled out of court on undisclosed terms in February 2013.<ref>{{cite web |last=Cifaldi |first=Frank |date=2013-02-15 |title=EA and Zynga settle ''The Ville'' copycat case out of court |url=http://www.gamasutra.com/view/news/186789/EA_and_Zynga_settle_The_Ville_copycat_case_out_of_court.php |archive-url=https://web.archive.org/web/20130217145844/http://www.gamasutra.com/view/news/186789/EA_and_Zynga_settle_The_Ville_copycat_case_out_of_court.php |url-status=dead |archive-date=February 17, 2013 |access-date=2013-02-15 |publisher=[[Gamasutra]]}}</ref>

Examples of software cloning include the [[ReactOS]] project which tries to clone [[Microsoft Windows]], and [[GNU Octave]], which treats incompatibility with [[MathWorks]] [[MATLAB]] as a bug.<ref>[http://www.manpagez.com/info/Octave-FAQ/Octave-FAQ-3.2.3/Octave-FAQ_39.php 11. Porting programs from MATLAB to Octave] "There are still a number of differences between Octave and MATLAB, however in general differences between the two are considered as bugs."</ref>

===Video games ===

{{main|Video game clone}}
Since the start of the [[video game]] industry, clones of successful concepts and games have been common. The first influential [[first-person shooter]], ''[[Doom (1993 video game)|Doom]]'', led in the 1990s to the creation of a new genre dubbed as [[Doom (1993 video game)#Clones|''Doom'' clones]]. In the 2000s, the [[open world]] [[action game|action-adventure]] ''[[Grand Theft Auto]]'' inspired the creation of many [[Grand Theft Auto clone|''Grand Theft Auto'' clone]]s.

===Software remakes===
{{main|Video game remake}}
Remakes of software are revivals of old, obsolete, or discontinued software.

A good share of software remakes are [[fangame]]s of [[computer games]] and [[game engine recreation]] made by the [[fan community]] as part of [[retrogaming]], to address e.g. [[Forward compatibility|compatibility]] issues or non-availability of the original, e.g. a shutdown server gets substituted with a [[server emulator]].

Since the 2000s there has been an increasing number of commercial remakes of classical games by the original developer or publisher for current platforms as the [[digital distribution]] lowers the investment risk for niche releases.<ref name=newell2007>{{cite web|publisher=[[Rock, Paper, Shotgun]] |url=http://www.rockpapershotgun.com/2007/11/21/rps-exclusive-gabe-newell-interview/|title=RPS Exclusive: Gabe Newell Interview |date=2007-11-22 |access-date=2013-06-28 |first=John |last=Walker |quote=''The worst days [for game development] were the cartridge days for the NES. It was a huge risk – you had all this money tied up in silicon in a warehouse somewhere, and so you’d be conservative in the decisions you felt you could make, very conservative in the IPs you signed, your art direction would not change, and so on. Now it’s the opposite extreme: we can put something up on Steam, deliver it to people all around the world, make changes. We can take more interesting risks.[...] Retail doesn’t know how to deal with those games. On Steam [a digital distributor] there’s no shelf-space restriction. It’s great because they’re a bunch of old, orphaned games.''}}</ref> When enhanced in some way (audio, graphics, etc.) new releases might be called "high definition" release or "special edition"; an example is ''[[The Secret of Monkey Island: Special Edition]]''.<ref name="monkeyislandrerelease">{{cite web |url=http://www.gamespot.com/iphone/adventure/thesecretofmonkeyislandspecialedition/tech_info.html |title=The Secret of Monkey Island: Special Edition Tech Info |publisher=[[GameSpot]] |access-date=November 15, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20100402125042/http://www.gamespot.com/iphone/adventure/thesecretofmonkeyislandspecialedition/tech_info.html |archive-date=April 2, 2010 }}</ref><ref>{{cite web|url=http://www.ign.com/articles/2009/06/03/e3-2009-the-secret-of-monkey-island-special-edition-preview|title=E3 2009: The Secret of Monkey Island: Special Edition Preview |date=June 2, 2009 |first=Charles |last=Onyett |publisher=IGN |access-date=November 15, 2011}}</ref>

== Other uses of the term==
{{Unreferenced section|date=October 2014}}

===Databases===
A [[database]] clone is a complete and separate copy of a database system that includes the business data, the [[database management system]] software and any other application tiers that make up the environment. Cloning is a different kind of operation to [[Data replication|replicate]] and [[backup]], in that the cloned environment is both fully functional and separate in its own right. Additionally, the cloned environment may be modified at its inception due to configuration changes or data subsetting.

===Desktop===
{{see also|Remote desktop|Desktop virtualization}}
Since 2010, clone computing, in the sense of replicating a session on a host computer in a virtual instance in the [[Cloud (computing)|cloud]], has been introduced.  This allows the user to have access to a copy of their PC's desktop on any other computing device such as a [[tablet computer]], a personal computer running any operating system, WebOS, [[smartphone]]s, etc.

The clone computer replicates, runs, and is always available through a series of cloud servers.  Unlike remote management software, clone computing has no dependency on the host computer.

===Disk cloning software===
{{main|Disk cloning}}
Disk cloning is the process of copying the contents of one computer hard drive to another disk or to an "image" file. Typically, the contents of the first disk are written to an image file as an intermediate step, and the second disk is loaded with the contents of the image. A cloned drive can replace the original, rather than simply containing backup copies of files.

Cloning software replicates the operating system, drives, software and patches of one computer for a variety of purposes, including setting up multiple computers, hard drive upgrades, and system recovery in the event of disk failure or corruption.<ref>{{Cite web |title=Definition of cloning software |url=https://www.pcmag.com/encyclopedia/term/cloning-software |access-date=2023-08-29 |website=PCMAG |language=en}}</ref>

===Programming===
{{main|Cloning (programming)}}
In [[computer programming]], particularly [[object-oriented programming]], ''cloning'' refers to [[object copying]] by a method or [[copy factory]] function, often called <code>clone</code> or <code>copy</code>, as opposed to by a [[copy constructor]]. Cloning is [[Polymorphism (computer science)|polymorphic]], in that the type of the object being cloned need not be specified, in contrast to using a copy constructor, which requires specifying the type (in the constructor call).

== See also ==
* [[Clean room design]]
* [[Game engine recreation]]
* [[Plug compatible]]
* [[Video game clone]]
* [[Video game remake]]
* [[:Category:Computer hardware clones]]
* [[:Category:Video game console remakes]]

==References==
<references/>

[[Category:Computing terminology]]