View source for Persistent world

{{Refimprove|date=June 2023}}
{{Short description|Virtual world which continues to exist even when there are no people interacting with it}}
{{Use dmy dates|date=December 2020}}
A '''persistent world''' or '''persistent state world''' ('''PSW''') is a [[virtual world]] which, by the definition given by [[Richard Bartle]], "continues to exist and develop internally even when there are no people interacting with it".<ref name="Bartle2003-Designing" /> The first virtual worlds were text-based and often called [[Multi-user dungeon|MUD]]s, but the term is frequently used in relation to [[massively multiplayer online role-playing game]]s (MMORPGs)<ref name="Bartle2003-Designing"/> and [[pervasive game]]s.<ref name="deSouzaeSilva2009-Cityscapes" /> Examples of persistent worlds that exist in video games include ''Battle Dawn'', ''[[EVE Online]]'', and ''Realms of Trinity''.{{fact|date=June 2023}}

A persistent world can be achieved by developing and maintaining a single or dynamic instance state of the game world that is shared and viewed by all players around the clock.{{Citation needed|date=June 2015}} The persistence of a world can be subdivided into "game persistence", "world persistence" and "data persistence". [[Persistence (computer science)|Data persistence]] ensures that any world data is not lost in the event of computer system failure. World persistence means the world continues to exist and is available to players when they want to access it. Game persistence refers to the persistence of game events within the world (a ''[[Groundhog Day (film)|Groundhog Day]]'' [[Multi-user dungeon|MUD]] is a virtual world where the entire (game) world is reset periodically).<ref name="nevelsteen2016-persistence" /> When referring to a "persistent world", world and game persistence are sometimes used interchangeably. The persistence criterion is the trait that separates virtual worlds from other types of video games.<ref name="bell2008-virtualworld"/>

== Pervasive games ==
The [[Reality|real world]] is persistent. The game world of a [[pervasive game]] takes place in the real world and so pervasive games are also persistent.<ref name="deSouzaeSilva2009-Cityscapes"/><ref name="Nieuwdorp2007-Discourse"/> In other words, pervasive games share the persistence trait with virtual worlds.<ref name="nevelsteen2016-persistence"/><ref name="Montola2009-PG"/> An example of a pervasive game that makes heavy use of a virtual world is ''[[Can You See Me Now?]]'', where street runners exist in a virtual world while simultaneously running around the real physical world; the game was persistent during play, as well as the virtual world.{{fact|date=June 2023}}

== Simulated persistence ==
To give the illusion that the game world is always available, persistence can be simulated. This can be achieved by scheduling when players are allowed to play, around times when the world is offline, or as in the ''[[Animal Crossing (series)|Animal Crossing]]'' series, having the game generate events that could have happened during the period of inactivity. Aside from virtual worlds, the simulation of a persistent world is also possible in single player games. In ''[[Noctis (video game)|Noctis]]'', players are advised to turn off the game while refueling because it takes so long. In addition, if a player who has landed on a planet stops playing and then after a while resumes, he or she can see visible changes in the sea level or the daytime/nighttime cycle.{{Citation needed|date=November 2013}} 

A form of simulated persistence referred to as "pseudo-persistence" has been used in both video games and pervasive games. Pseudo-persistence means making relevant world data available when the relevant players reconnect to the world instance. In a [[mobile game]], a virtual world might exist on a [[Distributed computing|distributed]] collection of mobile devices. If a player reconnects to a device they previously connected to, they find that their relevant world data is still present.<ref name="deSouzaeSilva2009-Cityscapes" /> In the video game ''[[Destiny (video game)|Destiny]]'', a World Server provides the persistent world data for the game instances (called "bubbles"), which are created on demand as a number of players are matched to play the game together.{{Citation needed|date=June 2015}}. The term 'persistent world' is frequently used by players of ''[[Neverwinter Nights (2002 video game)|Neverwinter Nights]]'' (2002) and ''[[Neverwinter Nights 2]]'' (2006) to refer to MMORPG-like online environments created using the toolkit.<ref>{{cite web|url=https://www.engadget.com/2014-05-24-the-game-archaeologist-the-persistent-worlds-of-neverwinter-nig.html|title=The Game Archaeologist: The persistent worlds of Neverwinter Nights 1 & 2|last=Olivetti|first=J.|work=[[Engadget]]|date=2014-05-24|accessdate=2022-04-05}}</ref>

== First virtual worlds ==
The first multi-player game to demonstrate on-line persistence was the text-based [[MUD1]] written in 1978 by Rob Trubshaw and [[Richard Bartle]]. Initially only available for a few hours in off-peak time at Essex University, UK,{{R|Bartle2003-Designing1}} it featured a world reset every 105 minutes. Nevertheless, it persisted independent of players logging in for the time it was running. The subsequent decade saw many [[Virtual world|on-line worlds]] clone this template, but all featured variations on timed resets and reboots or did not allow players to retain objects within the game other than running point totals such as treasure or experience points as a marker of progress.{{fact|date=June 2023}}

''[[Avalon: The Legend Lives]]'' can be considered the first game to introduce a '''true persistent state''' world in 1989.{{R|BartleMud}} Avalon pioneered the ability for items to be retained by the player whilst offline while the Avalon realm at large continued 24/7 with only a morning backup to mark the world pausing briefly. It is currently the longest running online virtual world.{{fact|date=June 2023}}

== See also ==
* [[Multi-user dungeon|MUD]]
* [[Instance dungeon]]

== References ==
{{Reflist|2|refs=
<ref name="Montola2009-PG">{{cite book
 | title = Pervasive Games. Theory and Design. Experiences on the Boundary Between Life and Play.
 | first1= Markus | last1 = Montola
 | first2= Jaakko | last2= Stenros
 | first3 = Annika | last3= Waern
 | year= 2009
 | publisher = Morgan Kaufmann Publishers | isbn=978-0-12-374853-9}}</ref>
<ref name="deSouzaeSilva2009-Cityscapes">{{cite book | title = Digital Cityscapes: merging digital and urban playspaces | first1 = Adriana | last1 = de Souza e Silva | first2 = Daniel M. | last2 = Sutko | year = 2009 | publisher = Peter Lang Publishing, Inc | location = New York}}</ref>
<ref name="Nieuwdorp2007-Discourse">{{cite journal | last1 = Nieuwdorp | first1 = E. | title = The pervasive discourse | doi = 10.1145/1279540.1279553 | journal = Computers in Entertainment | volume = 5 | issue = 2 | pages = 13 | year = 2007 | s2cid = 17759896}}</ref>
<ref name="nevelsteen2016-persistence">{{Citation
 | last = Nevelsteen
 | first = Kim JL
 | title = Encyclopedia of Computer Graphics and Games
 | publisher = Springer International Publishing
 | chapter = Physical, Virtual, and Game World Persistence
 | date = 2016
 | pages = 1–5
 | doi = 10.1007/978-3-319-08234-9_72-2 | isbn = 978-3-319-08234-9| doi-access = free
 }}</ref>

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 | title = <nowiki>Metal Gear Solid 3 HD | The End Dies Of Old Age (Hidden Cutscenes) HD</nowiki>
 | medium = YouTube
 | publisher = Edsta713TX
 | date = 14 January 2012
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<ref name="Bartle2003-Designing">{{cite book
 | isbn         = 0-13-101816-7
 | title        = Designing Virtual Worlds
 | last1 = Bartle | first1 = Richard
 | title-link = Designing Virtual Worlds
 | author-link1  = Richard Bartle
 | year         = 2003
 | publisher    = New Riders}}</ref>
<ref name="bell2008-virtualworld">{{cite journal
 | last = Bell
 | first = Mark W.
 | title = Toward a Definition of "Virtual Worlds"
 | journal = Journal of Virtual Worlds Research
 | volume = 1
 | issue = 1
 | date = 2008
 | url = https://journals.tdl.org/jvwr/article/view/283
 | access-date = 2012-07-29
|doi=10.4101/jvwr.v1i1.283	
| doi-broken-date = 12 July 2025
 | doi-access = free| url-access = subscription
 }}</ref>
<ref name="Bartle2003-Designing1">{{cite book
 | isbn         = 0-13-101816-7
 | title        = Designing Virtual Worlds
 | last1 = Bartle | first1 = Richard
 | title-link = Designing Virtual Worlds
 | author-link1  = Richard Bartle
 | year         = 2003
 | publisher    = New Riders
 | quote = p. 23 In the teeth of complaints about wasted resources, members of the university's Computer Society were allowed to spend off-peak time doing anything non-academic they liked. Many of them chose to play MUD.}}</ref>
<ref name="BartleMud">{{cite web
 | last = Bartle | first = Richard
 | title = Legacy Reviews of MUA and MUDS
 | date = 2015-12-15
 | url = http://mud.co.uk/richard/imucg4.htm
 | access-date = 2015-12-14}}</ref>
}}

{{Multiplayer online games}}
{{Pervasive games}}
{{Mixed reality}}
{{MUDs}}
{{Authority control}}

[[Category:Virtual reality]]
[[Category:Video game terminology]]
[[Category:Open-world video games]]