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A MUD (pron.: //; originally Multi-User Dungeon, with later variants Multi-User Dimension and Multi-User Domain), is a multiplayer real-time virtual world, usually text-based. MUDs combine elements of role-playing games, hack and slash, player versus player, interactive fiction, and online chat. Players can read or view descriptions of rooms, objects, other players, non-player characters, and actions performed in the virtual world. Players typically interact with each other and the world by typing commands that resemble a natural language.
Traditional MUDs implement a role-playing video game set in a fantasy world populated by fictional races and monsters, with players choosing classes in order to gain specific skills or powers. The objective of this sort of game is to slay monsters, explore a fantasy world, complete quests, go on adventures, create a story by roleplaying, and advance the created character. Many MUDs were fashioned around the dice-rolling rules of the Dungeons & Dragons series of games.
Such fantasy settings for MUDs are common, while many others have science fiction settings or are based on popular books, movies, animations, periods of history, worlds populated by anthropomorphic animals, and so on. Not all MUDs are games; some are designed for educational purposes, while others are purely chat environments, and the flexible nature of many MUD servers leads to their occasional use in areas ranging from computer science research to geoinformatics to medical informatics to analytical chemistry. MUDs have attracted the interest of academic scholars from many fields, including communications, sociology, law, and economics. At one time, there was interest from the United States military in using them for teleconferencing.
Most MUDs are run as hobbies and are free to players; some may accept donations or allow players to purchase virtual items, while others charge a monthly subscription fee. MUDs can be accessed via standard telnet clients, or specialized MUD clients which are designed to improve the user experience. Numerous games are listed at various web portals, such as The Mud Connector.
The history of modern Massively Multiplayer Online Role-Playing Games (MMORPGs) like World of Warcraft, Ultima Online and related virtual world genres such as the social virtual worlds exemplified by Second Life, traces directly back to the MUD genre. Indeed, before the invention of the term MMORPG, games of this style were simply called graphical MUDs. A number of influential MMORPG designers began as MUD developers and/or players (such as Raph Koster, Brad McQuaid, Matt Firor, and Brian Green) or were involved with early MUDs (like Mark Jacobs and J. Todd Coleman).
Colossal Cave Adventure, created in 1975 by Will Crowther on a DEC PDP-10 computer, was the first widely used adventure game. The game was significantly expanded in 1976 by Don Woods. Also called Adventure, it contained many D&D features and references, including a computer controlled dungeon master.
Inspired by Adventure, a group of students at MIT wrote a game called Zork in the summer of 1977 for the PDP-10 minicomputer which became quite popular on the ARPANET. Zork was ported under the filename "DUNGEN", dungeon, to FORTRAN by a programmer working at DEC in 1978.
In 1978 Roy Trubshaw, a student at Essex University in the UK, started working on a multi-user adventure game in the MACRO-10 assembly language for a DEC PDP-10. He named the game MUD (Multi-User Dungeon), in tribute to the Dungeon variant of Zork, which Trubshaw had greatly enjoyed playing. Trubshaw converted MUD to BCPL (the predecessor of C), before handing over development to Richard Bartle, a fellow student at Essex University, in 1980.
MUD, better known as Essex MUD and MUD1 in later years, ran on the Essex University network until late 1987, becoming the first Internet multiplayer online role-playing game in 1980, when Essex University connected its internal network to ARPANet. The game revolved around gaining points till one achieved the wizard rank, giving the player immortality and certain powers over mortals. The game became more widely accessible when a guest account was set up that allowed users on JANET (a British academic X.25 computer network) to connect on weekends and between the hours of 2 AM and 8 AM on weekdays. MUD1 was reportedly closed down when Richard Bartle licensed MUD1 to CompuServe, and was getting pressure from them to close Essex MUD. This left MIST, a derivative of MUD1 with similar gameplay, as the only remaining MUD running on the Essex University network, becoming one of the first of its kind to attain broad popularity. MIST ran until the machine that hosted it, a PDP-10, was superseded in early 1991.
During the Christmas of 1985, Neil Newell, an avid MUD1 player, started programming his own MUD called SHADES because MUD1 was closed down during the holidays. Starting out as a hobby, SHADES became accessible in the UK as a commercial MUD via British Telecom's Prestel and Micronet networks. A scandal on SHADES led to the closure of Micronet, as described in Indra Sinha's net-memoir, The Cybergypsies.
In 1985 CompuNet started a project named Multi-User Galaxy Game as a Science Fiction alternative to MUD1 which ran on their system at the time. When one of the two programmers left CompuNet, the remaining programmer, Alan Lenton, decided to rewrite the game from scratch and named it Federation II (at the time no Federation I existed). The MUD was officially launched in 1989. Federation II was later picked up by AOL, where it became known simply as "Federation: Adult Space Fantasy". Federation later left AOL to run on its own after AOL began offering unlimited service.
In 1978, around the same time Roy Trubshaw wrote MUD, Alan E. Klietz wrote a game called Milieu using Multi-Pascal on a CDC Cyber 6600 series mainframe which was operated by the Minnesota Educational Computing Consortium. Klietz ported Milieu to an IBM XT in 1983, naming the new port Scepter of Goth. Scepter supported 10 to 16 simultaneous users, typically connecting in by modem. It was one of the first commercial MUDs; franchises were sold to a number of locations. Scepter was first owned and run by GamBit (of Minneapolis, Minnesota), founded by Bob Alberti. GamBit's assets were later sold to Interplay Productions. Interplay eventually went bankrupt.
In 1984, Mark Peterson wrote The Realm of Angmar, beginning as a clone of Scepter of Goth. In 1994, Peterson rewrote The Realm of Angmar, adapting it to MS-DOS (the basis for many dial-in BBS systems), and renamed it Swords of Chaos. For a few years this was a very popular form of MUD, hosted on a number of BBS systems, until widespread Internet access eliminated most BBSes.
In 1984, Mark Jacobs created and deployed a commercial gaming site, Gamers World. The site featured two games coded and designed by Jacobs, a MUD called Aradath (which was later renamed, upgraded and ported to GEnie as Dragon's Gate) and a 4X science-fiction game called Galaxy, which was also ported to GEnie. At its peak, the site had about 100 monthly subscribers to both Aradath and Galaxy. GEnie was shut down in the late 1980s, although Dragon's Gate was later brought to America Online before it was finally released on its own. Dragon's Gate was closed on February 10, 2007.
In the summer of 1980 University of Virginia classmates John Taylor and Kelton Flinn wrote Dungeons of Kesmai, a six player game inspired by Dungeons & Dragons which used Roguelike ASCII graphics. They founded the Kesmai company in 1982 and in 1985 an enhanced version of Dungeons of Kesmai, Island of Kesmai, was launched on CompuServe. Later, its 2-D graphical descendant Legends of Kesmai was launched on AOL in 1996. The games were retired commercially in 2000.
The popularity of MUDs of the Essex University tradition escalated in the USA during the late 1980s when affordable personal computers with 300 to 2400 bit/s modems enabled role-players to log into multi-line Bulletin Board Systems and online service providers such as CompuServe. During this time it was sometimes said that MUD stands for "Multi Undergraduate Destroyer" due to their popularity among college students and the amount of time devoted to them.
The first popular MUD codebase was AberMUD, written in 1987 by Alan Cox, named after the University of Wales, Aberystwyth. Alan Cox had played the original University of Essex MUD, and the gameplay was heavily influenced by it. AberMUD was initially written in B for a Honeywell L66 mainframe under GCOS3/TSS. In late 1988 it was ported to C, which enabled it to spread rapidly to many Unix platforms upon its release in 1989. AberMUD's popularity resulted in several inspired works, the most notable of which were TinyMUD, LPMud, and DikuMUD.
Monster was a multi-user adventure game created by Richard Skrenta for the VAX and written in VMS Pascal. It was publicly released in November 1988. Monster was disk-based and modifications to the game were immediate. Monster pioneered the approach of allowing players to build the game world, setting new puzzles or creating dungeons for other players to explore. Monster, which comprised about 60,000 lines of code, had a lot of features which appeared to be designed to allow Colossal Cave Adventure to work in it. Though there never were many network-accessible Monster servers, it inspired James Aspnes to create a stripped down version of Monster which he called TinyMUD.
TinyMUD, written in C and released in late 1989, spawned a number of descendants, including TinyMUCK and TinyMUSH. TinyMUCK version 2 contained a full programming language named MUF (Multi-User Forth), while MUSH greatly expanded the command interface. To distance itself from the combat-oriented traditional MUDs it was said that the "D" in TinyMUD stood for Multi-User "Domain" or "Dimension"; this, along with the eventual popularity of acronyms other than MUD (such as MUCK, MUSH, MUSE, and so on) for this kind of server, led to the eventual adoption of the term MU* to refer to the TinyMUD family. UberMUD, UnterMUD, and MOO were inspired by TinyMUD but are not direct descendants.
In 1989 LPMud was developed by Lars Pensjö (hence the LP in LPMud). Pensjö had been an avid player of TinyMUD and AberMUD and wanted to create a world with the flexibility of TinyMUD and the gameplay of AberMUD. In order to accomplish this he wrote what is nowadays known as a virtual machine, which he called the LPMud driver, that ran the C-like LPC programming language used to create the game world. Pensjö's interest in LPMud eventually waned and development was carried on by others such as Jörn "Amylaar" Rennecke, Felix "Dworkin" Croes, Tim "Beek" Hollebeek and Lars Düning. During the early 1990s, LPMud was one of the most popular MUD codebases. Descendants of the original LPMud include MudOS, DGD, SWLPC, FluffOS, and the Pike programming language, the latter the work of long-time LPMud developer Fredrik "Profezzorn" Hübinette.
In 1990, the release of DikuMUD, which was inspired by AberMUD, led to a virtual explosion of hack and slash MUDs based upon its code. DikuMUD inspired numerous derivative codebases, including CircleMUD, Merc, ROM, SMAUG, and GodWars. The original Diku team comprised Sebastian Hammer, Tom Madsen, Katja Nyboe, Michael Seifert, and Hans Henrik Staerfeldt. DikuMUD had a key influence on the early evolution of the MMORPG genre, with EverQuest (created by avid DikuMUD player Brad McQuaid) displaying such Diku-like gameplay that Verant developers were made to issue a sworn statement that no actual DikuMUD code was incorporated.
In 1987 David Whatley, having previously played Scepter of Goth and Island of Kesmai, founded Simutronics with Tom and Susan Zelinski. In the same year they demonstrated a prototype of GemStone to GEnie. After a short-lived instance of GemStone II, GemStone III was officially launched in February 1990. GemStone III became available on AOL in September 1995, followed by the release of DragonRealms in February 1996. By the end of 1997 GemStone III and DragonRealms had become the first and second most played games on AOL.
The typical MUD will describe to you the room or area you are standing in, listing the objects, players and NPCs in the area, as well as all of the exits. To carry out a task the player would enter a text command such as take apple or attack dragon. Movement around the game environment is generally accomplished by entering the direction (or an abbreviation of it) in which the player wishes to move, for example typing north or just n would cause the player to exit the current area via the path to the north.
MUD clients often contain functions which make certain tasks within a MUD easier to carry out, for example commands buttons which you can click in order to move in a particular direction or to pick up an item. There are also tools available which add hotkey-activated macros to telnet and MUD clients giving the player the ability to move around the MUD using the arrow keys on their keyboard for example.
While there have been many variations in overall focus, gameplay and features in MUDs, some distinct sub-groups have formed that can be used to help categorize different game mechanics, game genres and non-game uses.
Hack and Slash MUDs 
Perhaps the most common approach to game design in MUDs is to loosely emulate the structure of a Dungeons & Dragons campaign focused more on fighting and advancement than role-playing. When these MUDs restrict player-killing in favor of player versus environment conflict and questing, they are labeled Hack and Slash MUDs. This may be considered particularly appropriate since, due to the room-based nature of traditional MUDs, ranged combat is typically difficult to implement, resulting in most MUDs equipping characters mainly with close-combat weapons. This style of game was also historically referred to within the MUD genre as "adventure games", but video gaming as a whole has developed a meaning of "adventure game" that is greatly at odds with this usage.
Player versus player MUDs 
Most MUDs restrict player versus player combat, often abbreviated as PK (Player Killing). This is accomplished through hard coded restrictions and various forms of social intervention. MUDs without these restrictions are commonly known as PK MUDs. Taking this a step further are MUDs devoted solely to this sort of conflict, called pure PK MUDs, the first of which was Genocide in 1992. Genocide's ideas were influential in the evolution of player versus player online gaming.
Roleplaying MUDs 
Roleplaying MUDs, generally abbreviated as RP MUDs, encourage or enforce that players act out the role of their playing characters at all times. Some RP MUDs provide an immersive gaming environment, while others only provide a virtual world with no game elements. MUDs where roleplay is enforced and the game world is heavily computer-modeled are sometimes known as Roleplay Intensive MUDs, or RPIMUDs.
Social MUDs 
Social MUDs de-emphasize game elements in favor of an environment designed primarily for socializing. They are differentiated from talkers by retaining elements beyond online chat, typically online creation as a community activity and some element of role-playing. Often such MUDs have broadly defined contingents of socializers and roleplayers. Server software in the TinyMUD family, or MU*, is traditionally used to implement social MUDs.
A less-known MUD variant is the talker, a variety of online chat environment typically based on server software like ew-too or NUTS. Most of the early Internet talkers were LPMuds with the majority of the complex game machinery stripped away, leaving just the communication commands. The first Internet talker was Cat Chat in 1990. Avid users of talkers are called spods.
Educational MUDs 
Taking advantage of the flexibility of MUD server software, some MUDs are designed for educational purposes rather than gaming or chat. MicroMUSE is considered by some to have been the first educational MUD, but it can be argued that its evolution into this role was not complete until 1994, which would make the first of many educational MOOs, Diversity University in 1993, also the first educational MUD. The MUD medium lends itself naturally to constructionist learning pedagogical approaches. The Mud Institute (TMI) was an LPMud opened in February 1992 as a gathering place for people interested in developing LPMud and teaching LPC after it became clear that Lars Pensjö had lost interest in the project. TMI focussed on both the LPMud driver and library, the driver evolving into MudOS, the TMI Mudlib was never officially released, but was influential in the development of other libraries.
Graphical MUDs 
A graphical MUD is a MUD that uses computer graphics to represent parts of the virtual world and its visitors. A prominent early graphical MUD was Habitat, written by Randy Farmer and Chip Morningstar for Lucasfilm in 1985. Graphical MUDs require players to download a special client and the game's artwork. They range from simply enhancing the user interface to simulating 3D worlds with visual spatial relationships and customized avatar appearances.
Games such as Meridian 59, EverQuest, Ultima Online and Dark Age of Camelot were routinely called graphical MUDs in their earlier years. RuneScape was actually originally intended to be a text-based MUD, but graphics were added very early in development. However, with the increase in computing power and Internet connectivity during the late nineties, and the shift of online gaming to the mass market, the term "graphical MUD" fell out of favor, being replaced by MMORPG, Massively Multiplayer Online Role-Playing Game, a term coined by Richard Garriott in 1997.
Psychology and engagement 
Sherry Turkle developed a theory that the constant use (and in many cases, overuse) of MUDs allows users to develop different personalities in their environments. She uses examples, dating back to the text-based MUDs of the mid-1990s, showing college students who simultaneously live different lives through characters in separate MUDs, up to three at a time, all while doing schoolwork. The students claimed that it was a way to "shut off" their own lives for a while and become part of another reality. Turkle claims that this could present a psychological problem of identity for today's youths.
Observations of MUD-play show styles of play that can be roughly categorized. Achievers focus on concrete measurements of success such as experience points, levels, and wealth; Explorers investigate every nook and cranny of the game, and evaluate different game mechanical options; Socializers devote most of their energy to interacting with other players; and then there are Killers who focus on interacting negatively with other players, if permitted, killing the other characters or otherwise thwarting their play. Few players play only one way, or play one way all the time; most exhibit a diverse style. According to Richard Bartle, "People go there as part of a hero's journey—a means of self-discovery".
Research has suggested that various factors combine in MUDs to provide users with a sense of presence rather than simply communication.
Grammatical usage and derived terms 
As a noun, the word MUD is variously written MUD, Mud, and mud, depending on speaker and context. It is also used as a verb, with to mud meaning to play or interact with a MUD and mudding referring to the act of doing so. A mudder is, naturally, one who MUDs. Compound words and portmanteaux such as mudlist, mudsex, and mudflation are also regularly coined. Puns on the "wet dirt" meaning of "mud" are endemic, as with, for example, the names of the ROM (Rivers of MUD), MUCK, MUSH, and CoffeeMUD codebases and the MUD Muddy Waters.
See also 
- MUD trees
- Chronology of MUDs
- Bartle Test
- MUD client
- Online text-based role-playing game
- Virtual economy
- Digital architecture
- Bartle, Richard (2003). Designing Virtual Worlds. New Riders. pp. 9–10, 741. ISBN 0-13-101816-7. "[pp. 9-10] TinyMUD was deliberately intended to be distanced from the prevailing hack-and-slay AberMUD style, and the "D" in its name was said to stand for "Dimension" (or, occasionally, "Domain") rather than "Dungeon;" this is the ultimate cause of the MUD/MU* distinction that was to arise some years later. [pp. 741] The "D" in MUD stands for "Dungeon" [...] because the version of ZORK Roy played was a Fortran port called DUNGEN."
- Hahn, Harley (1996). The Internet Complete Reference (2nd ed.). Osborne McGraw-Hill. p. 553. ISBN 0-07-882138-X. "[...] muds had evolved to the point where the original name was too confining, and people started to say that "MUD" stood for the more generic "Multi-User Dimension" or "Multi-User Domain"."
- Hansen, Geir Harald (2002-07-31). A Distributed Persistent World Server using Dworkin's Generic Driver (Cand. Scient. thesis). University of Oslo. http://geir-hansen.com/distributedworld.pdf. Retrieved 2010-04-14.
- Boring, Erich (1993-12-03). PangaeaMud: An Online, Object-oriented Multiple User Interactive Geologic Database Tool (Master's thesis). Miami University. http://sc.lib.muohio.edu/bitstream/handle/2374.MIA/248/fulltext.pdf?sequence=1. Retrieved 2010-05-03.
- Cruickshank, Don; De Roure, David (2004). "A Portal for Interacting with Context-aware Ubiquitous Systems". Proceedings of First International Workshop on Advanced Context Modelling, Reasoning and Management: 96–100. Retrieved 2010-10-14.
- Schaefer, Dominik; Mardare, Cezarina; Savan, Alan; Sanchez, Miguel D.; Mei, Bastian; Xia, Wei; Muhler, Martin; Ludwig, Alfred et al. (2011-02-17). "High-Throughput Characterization of Pt Supported on Thin Film Oxide Material Libraries Applied in the Oxygen Reduction Reaction". Analytical Chemistry (American Chemical Society) 83 (6): 1916–1923. doi:10.1021/ac102303u. Retrieved 2011-07-11. "Programs in LPC programming language were developed to perform the following tasks: First, each set of CVs was separated into single CVs, and each of them were plotted. An average CV from all the CVs in one set was calculated and plotted as well. All images belonging to one set of CVs were combined into short animated movies to visualize the changes over time. The graphs of the averaged CVs from all measurement points within a line scan were combined into an animation for demonstrating the systematic changes along each of the Pt stripes. After that, specific parameters were extracted from each CV (see below). These parameters and some derived values were tabulated and plotted versus the x-coordinate of the measurement point. Thus, different graphs for each line scan were created showing the changes in specific properties along the thickness of the Pt stripe. The combined tabulated data for each wafer was then used to plot a 3D image of several parameters vs substrate composition and nominal thickness. The LPC programs were compiled using LDMud (V3.3.719)."
- Turkle, Sherry (1997-09-04). Life on the Screen: Identity in the Age of the Internet (pbk. ed.). Simon & Schuster. ISBN 0-684-83348-4.
- Grimmelmann, James (2004-12-08). "Virtual Worlds as Comparative Law". New York Law School Law Review (New York Law School) (49): 147–184. Retrieved 2010-05-06.
- Castronova, Edward (2006). Synthetic Worlds: The Business and Culture of Online Games. University Of Chicago Press. pp. 10, 291. ISBN 0-226-09627-0. "[pp. 10] The ancestors of MMORPGS were text-based multiuser domains (MUDs) [...] [pp. 291] Indeed, MUDs generate perhaps the one historical connection between game-based VR and the traditional program [...]"
- Shefski, William J. (1995). Interactive Internet: The Insider's Guide to MUDs, MOOs, and IRC. Prima Publishing. p. 41. ISBN 1-55958-748-2.
- Stuart, Keith (2007-07-17). "MUD, PLATO and the dawn of MMORPGs". The Guardian (London). "The thing is, though, that even if the likes of Oubliette did count as a virtual world, they had pretty well zero effect on the development of today's virtual worlds. Follow the audit trail back from World of Warcraft, and you wind up at MUD."
- Taylor, T.L. (2006-02-24). Play Between Worlds: Exploring Online Game Culture. The MIT Press. p. 24. ISBN 0262201631.
- Nelson, Mike (2002-07-02). "Interview: Brad McQuaid". The guru of 3D. Retrieved 2007-03-03.
- Carter, Randolph (2009-04-23). "Psychochild". Grinding to Valhalla. Retrieved 2010-04-19. "The MUDs I played extensively: Genocide (where I first used the name "Psychochild"), Highlands, Farside, Kerovnia, and Astaria."
- Montfort, Nick (2003). Twisty Little Passages: An Approach to Interactive Fiction. MIT Press. ISBN 3-540-63293-X.
- Stewart, William. "Summary MUD History". Living Internet. "Containing many of the features of a D&D game, it added an interesting twist -- the dungeon master, the person who set-up and ran a D&D world, was played by the Adventure computer program itself."
- Anderson, Tim; Galley, Stu. "The History of Zork". "Zork was too much of a nonsense word, not descriptive of the game, etc., etc., etc. Silly as it sounds, we eventually started calling it Dungeon. (Dave admits to suggesting the new name, but that's only a minor sin.) When Bob the lunatic released his FORTRAN version to the DEC users' group, that was the name he used."
- Kelly, Kevin; Rheingold, Howard (1993). "The Dragon Ate My Homework". Wired 1 (3). "In 1980, Roy Traubshaw, a British fan of the fantasy role-playing board game Dungeons and Dragons, wrote an electronic version of that game during his final undergraduate year at Essex College. The following year, his classmate Richard Bartle took over the game, expanding the number of potential players and their options for action. He called the game MUD (for Multi-User Dungeons), and put it onto the Internet."
- Bartle, Richard (1990). "Early MUD History". "The program was also becoming unmanageable, as it was written in assembler. Hence, he rewrote everything in BCPL, starting late 1979 and working up to about Easter 1980. The finished product was the heart of the system which many people came to believe was the "original" MUD. In fact, it was version 3."
- Shah, Rawn; Romine, James (1995). Playing MUDs on the Internet. John Wiley & Sons, Inc. p. 7. ISBN 0-471-11633-5. "The acknowledged original game known as "MUD" was developed in 1978 for the old DEC-10 mainframe system at Essex University by Roy Trubshaw and Richard Bartle."
- Cuciz, D. (2004). "The History of MUDs". GameSpy.com. Archived from the original on 2008-03-24. Retrieved 2009-04-19.
- Bartle, Richard. "Incarnations of MUD". "This is the "classic" MUD, played by many people both internal and external to the University. Although eventually available only during night-time due to the effects of its popularity on the system, its impact on on-line gaming has been immense. I eventually closed it down on 30/9/87 upon leaving Essex University to work for MUSE full time."
- Mulligan, Jessica; Patrovsky, Bridgette (2003). Developing Online Games: An Insider's Guide. New Riders. p. 444. ISBN 1-59273-000-0. "1980 [...] Final version of MUD1 completed by Richard Bartle. Essex goes on the ARPANet, resulting in Internet MUDs!"
- Wisner, Bill (1990-06-29). "A brief history of MUDs". alt.mud. "The point of the game was to gain points until you achieved the rank of wizard, at which point you became immortal and gained certain powers over mortals. Points were scored by killing things or dropping treasure into a swamp. The game gained some popularity in Britain when a guest account was set up that allowed users on JANET (the British academic network) to play during the small hours of the morning each day."
- Lawrie, Michael (2003). "Escape from the Dungeon". "October of 1987 was chaos. The MUD account was deleted, but the guest account on Essex University remained open. I guess it wasn't causing any trouble so they simply left it. ROCK, UNI and MUD all ran from the MUD account so they had gone but... MIST ran from a student account and it was still playable."
- Kate & Frobozz (1986). "Micronet's Multi-user Game". Commodore Computing International. "Written by Neil Newell, originally as a hobby because he enjoyed playing- the original MUD so much on Essex University, SHADES has recently. been launched on Micronet, the computer network, which has a large Commodore user-base."
- Sinha, Indra (1999). The Cybergypsies: a True Tale of Lust, War, and Betrayal on the Electronic Frontier. Viking Press. ISBN 0-670-88630-0.
- Bartle, Richard (1990). "Interactive Multi-User Computer Games". "Pip Cordrey used to run a BBS called 'Labbs', which had a section devoted to MUD1 in its early days. Six people from St. Paul's School worked on that section, and Cordrey organised them into a team to develop a MUA that would run on a home computer. The system was named MirrorWorld because it had rolling resets (as in the film "Westworld"). It went live in 1986."
- Bartle, Richard (1990). "Interactive Multi-User Computer Games". "Although the present system went live in October 1988, Gods began in 1985 as a non-commercial MUA; its author was inspired by MUD1 to write his own game, and was among the first people to do so. Gods was Shades' only rival to be the Prestel Micronet MUA."
- Bartle, Richard (1990). "Interactive Multi-User Computer Games". "The Multi-User Galaxy Game project was begun in 1985 by CompuNet as a SF alternative to MUD1, which then ran on the system. When the other programmer left CompuNet, Lenton rewrote the game from scratch as Federation II. It was officially launched on CompuNet in 1989; reported also to run on MicroLink, and on any other commercial system willing to take it."
- Wisner, Bill (1990-06-29). "A brief (and very incomplete) history of MUDs". alt.mud. "Milieu was originally written for a CDC Cyber owned by the Minnesota Educational Computer Consortium. High school students from around the state were given access to the machine for educational purposes; they often ended up writing chat programs and games instead. I am uncertain of the precise time frame, but I believe Milieu probably predates MUD."
- Klietz, Alan (1992-01-20). "Scepter - the first MUD?". Retrieved 2010-04-26. "As micros became cost effective, the MECC mainframe became obsolete and was shut down in 1983. Scepter then went commercial in a collaboration between several ex-MECC (and by then also post-highschool) game hackers. It was rewritten in C and ran on a PC XT running QNX. It supported 16 dialup users, and dialup installations were set up in 5 states and Canada. This exposed Scepter to a lot of budding MUD developers at a time when the Internet was just getting started." More than one of
- Hyrup, Darrin (2007-02-10). "The Future of Dragon's Gate". Retrieved 2010-04-26. "So after more than 15 years of great memories, with a heavy heart, I am going to officially declare Dragon's Gate closed... at least for now."
- Kennelly, Adrian (2006-09-08). "Massive Multiplayer Online Role-Playing Games". Retrieved 2010-04-26. "The first mainstream product was sold to the public in 1984. The game, Islands of Kesmai, was extremely expensive, and the graphics were anything but impressive."
- Mulligan, Jessica; Patrovsky, Bridgette (2003). Developing Online Games: An Insider's Guide. New Riders. pp. 447, 463. ISBN 1-59273-000-0. "1985 [...] "My memory says that Island of Kesmai went live on CompuServe on December 15, 1985, after a very long internal test. The price was actually $6 an hour for 300 baud, $12 for 1200 baud. Serious players paid the bucks." —Kelton Flinn [...] 2000 [...] In May, Electronics Arts announces the shutdown of most of the Kesmai games, including Legends of Kesmai and Air Warrior Classic."
- Gallear, Mark (1998-09-08). "An Economic History of the Game Industry". Retrieved 2010-04-26. "The company continued to develop massively multiplayer games such as Air Warrior 2 (1997) and Legends of Kesmai (1996), distributing their games through AOL and eventually their own gaming service, GameStorm."
- "A Study of MUDs as a Society". 1998. "Some would insist however that 'MUD' does in fact stand for Multi Undergraduate Destroyer, in recognition of the number of students who may have failed their classes due to too much time spent MUDding!"
- Carroll, Eddy. "5. Reviews -- Rest of the World". "Cox was a player of MUD1 who wrote AberMUD while a student at the University of Wales, Aberystwyth."
- Bartle, Richard (2003). Designing Virtual Worlds. New Riders. p. 741. ISBN 0-13-101816-7. "AberMUD spread across university computer science departments like a virus. Identical copies (or incarnations) appeared on thousands of Unix machines. It went through four versions in rapid succession, spawning several imitators. The three most important of these were TinyMUD, LPMUD, and DikuMUD."
- Skrenta, Richard (1988-11-30). "monster - multiuser adventure game for VMS". comp.sources.games. Retrieved 2010-04-26. "Monster was written in VMS Pascal under VMS 4.6."
- Skrenta, Richard (2002-01-20). "VMS Monster". Skrentablog. Retrieved 2010-11-01.
- Skrenta, Richard (1997-01-13). "An Introduction to Monster". Retrieved 2010-04-26. "Monster allows players to do something that very few, if any, other games allow: the players themselves create the fantasy world as part of the game. Players can create objects, make locations, and set up puzzles for other players to solve."
- Aspnes, James (1990-07-04). "Monster". alt.mud. "TinyMUD 1.0 was initially designed as a portable, stripped-down version of Monster (this was back in the days when TinyMUD was designed to be up and running in a week of coding and last for a month before everybody got bored of it.)"
- Burka, Lauren P. (1995). "The MUDline". Retrieved 2010-04-26. "August 19, 1989. Jim Aspnes announces the availability of TinyMUD to a few friends. Its port, 4201, is Aspnes' office number. TinyMUD is written in C for Unix, and was originally conceived as a front-end for IRC."
- Mulligan, Jessica; Patrovsky, Bridgette (2003). Developing Online Games: An Insider's Guide. New Riders. p. 451. ISBN 1-59273-000-0. "1989 [...] Lars Penjske creates LPMud and opens Genesis. "Having fun playing TinyMUD and AberMUD, Lars Penjske decides to write a server to combine the extensibility of TinyMUD with the adventures of AberMUD. Out of this inspiration, he designed LPC as a special MUD language to make extending the game simple. Lars says, '...I didn't think I would be able to design a good adventure. By allowing wizards coding rights, I thought others could help me with this.' The first running code was developed in a week on Unix System V using IPC, not BSD sockets. Early object-oriented features only existed accidentally by way of the nature of MUDs manipulating objects. As Lars learned C++, he gradually extended those features. The result is that the whole LPMud was developed from a small prototype, gradually extended with features." —George Reese's LPMud Timeline"
- Stewart, William (2002). "MUD History". "The original LPMUD was written by Lars Pensjö and others, and became one of the most popular MUD's by the early 1990s."
- Smedley, John; McQuaid, Brad (2000-03-17). "Sworn Statement". DIKU MUD. Retrieved 2010-04-26.
- McQuaid, Brad; Clover, Steve; Uzun, Roger (2000-03-17). "Sworn Statement". DIKU MUD. Retrieved 2010-04-26.
- Cambron, Melanie (2002). "A chat with Elonka Dunin". Archived from the original on 2007-09-27. "Simutronics was originally the brain-child of David Whatley. As a teenager, he'd been big into the old BBS days and had even written some Fantasy Game BBS software that he sold all over the world, and he did this all from his parents' home. He’d also gotten involved as a player in some of the early multiplayer games that were out there such as Sceptre and Island of Kesmai, and, like many others who play these games, he thought to himself, "I can do this too." So in 1987, at the age of 21, he founded Simutronics Corporation with Tom and Susan Zelinski."
- Dunin, Elonka (2008). "Simutronics Timeline". "December, 1996 - GemStone III and DragonRealms are the top two titles (hours/month) in industry"
- Basic movement commands: The Lands of Evermore Manual
- Tools to simplify the playing of MUD games: WyeSoft MUD Assistant
- Reese, George (1996-03-11). "LPMud Timeline". Retrieved 2010-04-14. "January 1992 ¶ _Genocide_ starts as the first MUD dedicated totally to inter-player conflict, which is a fancy way of saying that its theme is creatively player-killing."
- Shah, Rawn; Romine, James (1995). Playing MUDs on the Internet. John Wiley & Sons, Inc. pp. 98–99. ISBN 0-471-11633-5. "Some Muds are completely dependant on player-killing, and have wars that start every half hour or so. These Muds are becoming more common, basing a lot of their ideas on the extremely popular LPmud known as Genocide."
- Korchmar, Simon (2007). [Countless MUD successors (such as MOO, MUSH, MUCK, etc.) used similar systems and themes from fantasy and science fiction, and increased degrees of role-playing focus up to the so-called "Role Play Intensive MUD (RPIMUD)"]
|chapter=(help). Erlösmodelle in Massively Multiplayer online Games [Revenue Models in Massively Multiplayer online Games] (in German). GRIN Verlag. p. 10. ISBN 978-3-640-22276-6. "Unzählige MUD-Nachfolger (wie etwa MOO, MUSH, MUCK, etc.) verwendeten ähnliche Systeme und Thematiken — v. A. aus Fantasy und Science Fiction — und verstärkten teilweise den Rollenspiel-Charakter bis hin zu den „sogennanten Role Play Intensive MUD (RPIMUD)""
- Burka, Lauren P. (1995). "The MUD Timeline". Retrieved 2010-04-22. "Summer 1991. koosh (Nils McCarty) ports MicroMush to Chezmoto. The name is changed to MicroMuse at the suggestion of Wallace Feurzeig of BBN. MicroMuse evolves into the first educational Mud, with emphasis on K12 outreach."
- "MicroMUSE Charter". MuseNet. 1994. Retrieved 2010-04-22.
- Bartle, Richard (2003). Designing Virtual Worlds. New Riders. p. 3. ISBN 0-13-101816-7. "Confusingly, although the term MUD applies to virtual worlds in general, the term MU* does not—it's used strictly for text-based worlds. The introduction of computer graphics into the mix therefore caused a second spate of naming, in order to make a distinction between graphical MUDs and text MUDs."
- Castronova, Edward (2006). Synthetic Worlds: The Business and Culture of Online Games. University Of Chicago Press. p. 291. ISBN 0-226-09627-0. "[...] established Habitat as a result. This is described as a 2D graphical MUD, and while we now know that Habitat was the first of many massively multiuser graphical chat spaces, we also know that the connection is not direct. [...] Its owners and makers (particularly F. Randy Farmer and Chip Morningstar [...]"
- Damer, Bruce (1998). Avatars!: exploring and building virtual worlds on the Internet. Peachpit Press. pp. 383–384. ISBN 0-201-68840-9. "Some people describe it as a MUD (Multi User Dungeon) with a 3D interface and role playing character."
- Aihoshi, Richard (2000-09-27). "Brad McQuaid Interview". RPG Vault. "Then, in 1996, I was hired by Sony Interactive Studios to create a graphical, commercial MUD. The rest is history."
- Firor, Matt (2003). "Post-Mortem: Mythic's Dark Age of Camelot". In Mulligan, Jessica; Patrovsky, Bridgette. Developing Online Games: An Insider's Guide. New Riders. p. 340. ISBN 1-59273-000-0. "It made perfect sense for us to combine the two technologies and make a graphical MUD."
- King, Brad (2002-07-15). "Games Started Off Without a Bang". Wired News. Retrieved 2010-09-09.
- Dobson, James (2007-05-03). "Q&A: Behind RuneScape's 1 Million Subscriber Success". Gamasutra. Retrieved 2010-04-24. "When I went to university, I discovered text-based MUDs, or multi-user dungeons. I loved the fact that these sorts of games had all these players playing at once - even when you were not playing, the world carried on without you. Because of this, I began creating my own text-based MUD, but I quickly realized that with so many of them out there, there was no way that mine would ever get noticed. So I began to search for a way to make mine stand out, and the obvious way, of course, was to add graphics. With my game, I was trying to emulate text MUDs at the time, purely as a hobby."
- Funk, John (2008-07-23). "WarCry and Jagex Talk RuneScape". WarCry Network. Retrieved 2009-01-06. "Olifiers began with a brief history of Jagex and RuneScape: how Lead Developer Andrew Gower and his brother Paul founded the company in Cambridge in 2001, bringing their love for classic MUDs into the visual realm. The original RuneScape (now referred to as RuneScape Classic) was simply and exactly that: a 2D graphical interface placed on top of a MUD"
- Safko, Ron; Brake, David (2009). The Social Media Bible: Tactics, Tools, and Strategies for Business Success. Wiley. ISBN 0-470-41155-4. "Richard Garriott first coined the term MMORPG in 1997."
- Bartle, Richard (07 1997). "Hearts, Clubs, Diamonds, Spades: Players Who Suit MUDs". In Jacobson, David. Journal of Virtual Environments 1 (1). Archived from the original on 2007-10-29. Retrieved 2010-04-30.
- Stuart, Keith (2007-07-17). "MUD, PLATO and the dawn of MMORPGs". guardian.co.uk (London).
- Towell, John; Towell, Elizabeth. "Presence in Text-Based Networked Virtual Environments or "MUDS"". Presence 6 (5): 590–595.
- Hahn, Harley (1996). The Internet Complete Reference (2nd ed.). p. 553. ISBN 0-07-882138-X. "The word "mud" is also used as a verb. For example, you might hear someone say, "I like to mud more than I like to sleep," or "I am a bit tired, as I was up all night mudding, so maybe you better go to class without me"."
- Ito, Mizuko (1997). "Virtually Embodied: The Reality of Fantasy in a Multi-User Dungeon". In Porter, David. Internet Culture (pbk. ed.). Routledge. p. 93. ISBN 0-415-91684-4. "Often MUD users (or MUDders, as they call themselves) [...]"
Further reading 
- Bartle, Richard (2003). Designing Virtual Worlds. New Riders. ISBN 0-13-101816-7.
- Shah, Rawn; Romine, James (1995). Playing MUDs on the Internet. John Wiley & Sons, Inc. ISBN 0-471-11633-5.
- Busey, Andrew (1995). Secrets of the MUD Wizards. SAMS Publishing. ISBN 0-672-30723-5.
- Carton, Sean (1995). Internet Virtual Worlds Quick Tour. Ventana Press. ISBN 1-56604-222-4.
- Burka, Lauren P. (1995). "The MUDline". The MUDdex.
- Koster, Raph (2002-02-20). "Online World Timeline". Raph Koster's Website.
- Reese, George (1996-03-11). "The LPMud Timeline".
- Mitchell, Don (1995-03-23). "From MUDs To Virtual Worlds". Microsoft Social Computing Group. Archived from the original on 2006-09-26.
Source code repositories 
- Erwin S. Andreasen: Home of the 16k MUD competition, and other resources.
- MudBytes.net: MUD code repository and discussion.
- FTPGame.org: Original archive of dozens of code bases.
- The Mud Connector: Extensive mud portal with hundreds of mud listings
- Top Mud Sites: MUD listings, reviews, discussion forum and rankings by category.
- MUDseek: Google custom search engine indexing MUD and MUD-related web sites.
- MUD Stats: MUD statistics.
- MUDs on Living Internet
- MUDs at the Open Directory Project