Editing Wikipedia (section)

=== Software operations and support ===
{{see also|MediaWiki}}
The operation of Wikipedia depends on [[MediaWiki]], a custom-made, [[free software|free]] and [[open-source software|open source]] [[wiki software]] platform written in [[PHP]] and built upon the [[MySQL]] database system.<ref name="nedworks database system">{{cite web |url=https://www.nedworks.org/~mark/presentations/san/Wikimedia%20architecture.pdf |title = Wikimedia Architecture |first = Mark |last = Bergsma |publisher = Wikimedia Foundation |access-date = June 27, 2008 |archive-url=https://web.archive.org/web/20090303204708/https://www.nedworks.org/~mark/presentations/san/Wikimedia%20architecture.pdf |archive-date = March 3, 2009}}</ref> The software incorporates programming features such as a [[macro (computer science)|macro language]], [[variable (programming)|variable]]s, a [[transclusion]] system for [[web template system|template]]s, and [[URL redirection]]. MediaWiki is licensed under the [[GNU General Public License]] (GPL) and it is used by all Wikimedia projects, as well as many other wiki projects. Originally, Wikipedia ran on [[UseModWiki]] written in [[Perl]] by Clifford Adams (Phase I), which initially required [[CamelCase]] for article hyperlinks; the present double bracket style was incorporated later. Starting in January 2002 (Phase II), Wikipedia began running on a [[PhpWiki|PHP wiki]] engine with a MySQL database; this software was custom-made for Wikipedia by [[Magnus Manske]]. The Phase II software was repeatedly modified to accommodate the [[exponential growth|exponentially increasing]] demand. In July 2002 (Phase III), Wikipedia shifted to the third-generation software, MediaWiki, originally written by [[Lee Daniel Crocker]].

Several MediaWiki extensions are installed<ref name="WP extensions installed">{{cite web |url=https://en.wikipedia.org/wiki/Special:Version |title = Version: Installed extensions |date = September 28, 2018 |access-date=August 18, 2014}}</ref> to extend the functionality of the MediaWiki software.

In April 2005, a [[Lucene]] extension<ref>{{cite web |url=https://en.wikipedia.org/wiki/Wikipedia:Wikipedia_Signpost/2005-04-18/Lucene_search |title = Lucene search: Internal search function returns to service |publisher = Wikimedia Foundation |first = Michael |last = Snow |access-date = February 26, 2009 |date = December 29, 2016}}</ref><ref>{{cite web |url=https://lists.wikimedia.org/pipermail/wikitech-l/2005-April/016297.html |title = [Wikitech-l&#93; Lucene search |first = Brion |last = Vibber |access-date = February 26, 2009}}</ref> was added to MediaWiki's built-in search and Wikipedia switched from [[MySQL]] to Lucene for searching. Lucene was later replaced by CirrusSearch which is based on [[Elasticsearch]].<ref>{{Cite web|title=Extension:CirrusSearch – MediaWiki|url=https://www.mediawiki.org/wiki/Extension:CirrusSearch|access-date=2021-04-10|website=MediaWiki.org|language=en}}</ref>

In July 2013, after extensive beta testing, a WYSIWYG (What You See Is What You Get) extension, [[VisualEditor]], was opened to public use.<ref name="thenextwebve">{{cite news |newspaper = TNW &#124; Insider |url=https://thenextweb.com/insider/2013/07/02/wikimedia-rolls-out-its-wysiwyg-visual-editor-for-logged-in-users-accessing-wikipedia-articles-in-english/ |title = Wikimedia rolls out WYSIWYG visual editor for logged-in users accessing Wikipedia articles in English |first = Emil |last = Protalinski |date = July 2, 2013 |access-date = July 6, 2013}}</ref><ref>{{cite news |url=https://www.telegraph.co.uk/technology/wikipedia/10196578/Wikipedia-introduces-new-features-to-entice-editors.html |archive-url=https://ghostarchive.org/archive/20220110/https://www.telegraph.co.uk/technology/wikipedia/10196578/Wikipedia-introduces-new-features-to-entice-editors.html |archive-date=2022-01-10 |url-access=subscription |url-status=live |newspaper = The Daily Telegraph |title = Wikipedia introduces new features to entice editors |author = Curtis, Sophie |date = July 23, 2013 |access-date = August 18, 2013}}{{cbignore}}</ref><ref name="TheEconomistVE">{{cite news |newspaper = [[The Economist]] |url=https://www.economist.com/blogs/babbage/2011/12/changes-wikipedia |title = Changes at Wikipedia: Seeing things |author = L. M. |date = December 13, 2011 |access-date = July 28, 2013}}</ref><ref name="softpedia-best">{{cite web |website = [[Softpedia]] |url=https://news.softpedia.com/news/Wikipedia-s-New-VisualEditor-Is-the-Best-Update-in-Years-and-You-Can-Make-It-Better-365072.shtml |title = Wikipedia's New VisualEditor Is the Best Update in Years and You Can Make It Better |first = Lucian |last = Parfeni |date = July 2, 2013 |access-date = July 30, 2013}}</ref> It was met with much rejection and criticism, and was described as "slow and buggy".<ref name="Orlowski, Andrew">{{cite web |url=https://www.theregister.co.uk/2013/08/01/wikipedians_reject_wysiwyg_editor/ |title = Wikipedians say no to Jimmy's 'buggy' WYSIWYG editor |author = Orlowski, Andrew |date = August 1, 2013 |website = The Register |access-date = August 18, 2013}}</ref> The feature was changed from opt-out to opt-in afterward.