Hans Henrik Stærfeldt,
|Initial release||March 1, 1991|
|Stable release||alfa / September 8, 1991|
DikuMUD is a multiplayer text-based role-playing game, which is a type of MUD. It was written in 1990 and 1991 by Sebastian Hammer, Tom Madsen, Katja Nyboe, Michael Seifert, and Hans Henrik Stærfeldt at DIKU (Datalogisk Institut Københavns Universitet)—the department of computer science at the University of Copenhagen in Copenhagen, Denmark.
Commonly referred to as simply "Diku", the game was greatly inspired by AberMUD, though Diku became one of the first multi-user games to become popular as a freely-available program for its gameplay and similarity to Dungeons & Dragons.
Diku's source code was first released in 1990 and became the root of one of the largest trees of derived code from a MUD-like source code package. It has been the basis of a vast number of MUDs, including Avatar, BurningMUD, SlothMUD, TorilMUD, Eris, MUME, Imperial DikuMUD, Northern Crossroads and Arctic MUD, as well as a number of offspring MUD engines such as CircleMUD, Merc, and SMAUG.
Development and history
The making of DikuMUD was first announced on Usenet by Hans Henrik Stærfeldt March 27, 1990. At the time Tom Madsen, Sebastian Hammer, and Stærfeldt were the only developers, joined by Seifert in June 1990. Stærfeldt stated that their intention was to create a MUD that was less messy than AberMUD, less buggy than LPMud, and more like Dungeons & Dragons.
The first DikuMUD was in working development as early as October 1990 and officially opened publicly running at
freja.diku.dk port 4000 on February 3, 1991.
A second DikuMUD appeared in January 1991, running at
hayes.ims.alaska.edu. In March 1991, the first public version of DikuMUD, known as Diku Gamma, became available at
beowulf.acc.stolaf.edu. Afterwards the DikuMUD at
freja.diku.dk was shut down and the game and development moved to
Other Diku Gamma MUDs appeared in March 1991 running at
eris.berkeley.edu, followed by a multiprocessor version running at
sequent.berkeley.edu. By early April 1991, there were DikuMUDs running at
The last official release of DikuMUD was Diku Alfa in July 1991 and the DikuMUD team hereafter continued with the development of DikuII. That version was however never released to the public but continues to run today under the name of Valhalla MUD. 
The DikuMUD license is generous, but does not permit all possible uses. The source code for DikuMUD is publicly available at no charge, anyone can run an unmodified or modified DikuMUD without paying any royalties, and modified derivatives of the DikuMUD code can be publicly distributed. However, the DikuMUD license includes the following requirement: "You may under no circumstances make profit on *ANY* part of DikuMud in any possible way. You may under no circumstances charge money for distributing any part of dikumud—this includes the usual $5 charge for 'sending the disk' or 'just for the disk' etc." Thus, DikuMUD is not open source software as defined by the Open Source Definition (OSD), because the OSD's clause 6 requires "No Discrimination Against Fields of Endeavor", that is, commercial users cannot be excluded. For the same reason, DikuMUD is not Free Software as per the Free Software Definition; it fails to meet the requirement that the program gives "The freedom to run the program for any purpose" (it forbids commercial purposes).[improper synthesis?] However, DikuMUD and its derivatives are developed in the same manner as these similar software production practices.
In his book Designing Virtual Worlds, Richard Bartle (co-creator of the original MUD) cited DikuMUD as one of the five "major codebases used for (textual) virtual worlds". Bartle further described how DikuMUD went in the opposite direction to TinyMUD and LPMud, by providing a very well organised hard-coded game that ran "out of the box".
It has been proposed by Raph Koster (lead designer of Ultima Online and chief creative officer of EverQuest II) that Diku has resulted in the greatest proliferation of gameworlds due to being the easiest to set up and use. He further pointed out that "Diku codebases did eventually popularize many of the major developments in muds", and that the Diku gameplay provided inspiration for numerous MMORPGs, including EverQuest, World of Warcraft and Ultima Online.
There was a minor controversy in late 1999 and early 2000 regarding whether the commercial MMORPG EverQuest, developed by Verant Interactive, had derived its code from DikuMUD. It began at the Re:Game gaming conference in 1999, where the Director of Product Development for EverQuest, Bernard Yee, allegedly stated that EverQuest was "like Diku". He did not specify whether he meant the code itself was derived from DikuMUD, or if it just had a similar feeling. Some attendees had understood it to mean the former and reported to that effect on Usenet. After the Diku group requested clarification, Verant issued a sworn statement on March 17, 2000 that EverQuest was not based on DikuMUD source code, and was built from the ground up. In response, the DikuMUD team publicly stated that they find no reason whatsoever to believe any of the rumors that EverQuest was derived from DikuMUD code.
- Shah, Rawn; Romine, James (1995). Playing MUDs on the Internet. John Wiley & Sons, Inc. p. 22. ISBN 0-471-11633-5. "DikuMud first appeared in mid-March of 1990 when a group of programmers at the Department of Computer Science at the University of Copenhagen, Denmark got together and began work on a multiplayer game that is similar to but improved on AberMuds. These coders were Hans Henrik Stærfeldt, Katja Nyboe, Tom Madsen, Michael Seifert, and Sebastian Hammer."
- Hahn, Harley (1996). The Internet Complete Reference (2nd ed.). Osborne McGraw-Hill. p. 558. ISBN 0-07-882138-X. "DikuMuds are named after the Datalogisk Institut Københavns Universitet (Department of Computer Science, University of Copenhagen), where the original DikuMud was created in 1990 by Katja Nyboe, Tom Madsen, Hans Henrik Stærfeldt, Michael Seifert and Sebastian Hammer."
- Keegan, Martin (2003-02-02). "A Classification of MUDs". Martin Keegan's Home Page. Retrieved 2010-09-20.
- Mulligan, Jessica; Patrovsky, Bridgette (2003). Developing Online Games: An Insider's Guide. New Riders. pp. 452–453. ISBN 1-59273-000-0. "1990 [...] DIKU MUDs are released."
- Staerfeldt, Hans Henrik (1990). "New mud comming up..". alt.mud. "We have started to program a mud, that we hope will be finished some time in the end of the summer. This mud will be better (we hope) than other muds as we have learned from their mistakes."
- Hammer, Sebastian (1991). "New Mud". rec.games.mud. "We consider playing in groups to be one of the more important (entertaining, that is) aspects of mudding, and hence the game includes various features, especially designed to make group-adventuring more fun and rewarding: Four different classes of players, with various abilities; a system which allows members of a group to share the score made at a kill; and lots of other stuff."
- Woodcock, Bruce Sterling (1991). "Mud List: January 31, 1991". rec.games.mud.
- Wisdom, Joseph (1990). "Arki's MUDLIST... promotional posting.". rec.games.mud. "beowulf.acc.stolaf.edu /pub/pub/mud tinymud, tinymuck, login style abermud, lpmud, ubermud, myth, ftp daemon patch for lpmuds, vast array of clients, gb, bt, dikumud."
- Wisdom, Joseph (1991). "MUD List.". rec.games.mud. "dikumud."
- "DikuMUD II running as Valhalla MUD". Retrieved 2013-01-12.
- Shah, Rawn; Romine, James (1995). Playing MUDs on the Internet. John Wiley & Sons, Inc. p. 22. ISBN 0-471-11633-5. "There are Muds for socializing and for being creative, but DikuMuds are for adventure, advancement, and battle."
- "DIKU mud". Virtual Worldlets Network. Retrieved 2010-04-06.
- Bartle, Richard (2003). Designing Virtual Worlds. New Riders. ISBN 0-13-101816-7.
- Koster, Raph (2007-05-29). "MMO long tails". Raph Koster's Website. Retrieved 2010-09-20.
- Koster, Raph. "LP Muds versus Diku-derived muds". Raph Koster's Website. Retrieved 2010-09-20.
- Koster, Raph (2009-01-09). "What is a Diku?". Raph Koster's Website. Retrieved 2010-09-20.
- Koster, Raph (2006-06-16). "From the mailbag: fan mail, UO, ideas". Raph Koster's Website. Retrieved 2010-09-20.
- Bartle, Richard (2003). Designing Virtual Worlds. New Riders. p. 25. ISBN 0-13-101816-7. "If ever there was a case of being in the right place at the right time, EverQuest (EQ) is it. It was basically a DikuMUD with a graphical client bolted on - the similarities are so close that under legal threat its server programmers were forced to sign sworn statements to the effect that they didn't use any actual DikuMUD code in EverQuest."
- "Sony's EverQuest admits to using Diku as a base". rec.games.mud.diku. Retrieved 2007-02-03.
- 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.
- "DikuMUD's statement on Everquest". Retrieved 2007-02-03.
- Romine, James (1995). "Part 1: DikuMUDs". In Shah, Rawn; Romine, James. Playing MUDs on the Internet. John Wiley & Sons, Inc. pp. 19–153. ISBN 0-471-11633-5.
- Busey, Andrew (1995). "9. DikuMUDs". Secrets of the MUD Wizards. SAMS Publishing. pp. 133–177. ISBN 0-672-30723-5.
- Official DikuMud site
- CircleMUD's copy of the DikuMud license
- The MUD Connector: 700+ Dikumud MUD Listings Available
- Mud Magic: 1,200+ Diku Based Code & Snippet Downloads
- MudBytes DikuMUD code and derivative downloads
- rec.games.mud.diku FAQ from 1997
- MUDseek MUD games search engine
- Raph Koster: "What is a Diku?"
- DikuMUDs on the Open Directory Project