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Online Creation (OLC) is a type of software add-on for Merc/Diku MUDs that allows users to edit world data while simultaneously playing the game. Referred to by the acronym "OLC" or "OC", this was a significant improvement for Dikumud variants, because they typically require a restart to implement any changes to game data. (this was a "new" feature only for Merc variants, other online multiplayer text games like TinyMUSH have had extensive in game world edit capabilities long before)

OLC was initiated as a periodically updated software package under the names NiMUD or "The Isles MUD" by authors Herb "Locke" Gilliland and Christopher "Surreal" Woodward, and was officially released on July 29th, 1994, though versions were released as early as October 1993 by request on Usenet, and by Locke uploading early copies of The Isles (TheIsles15 and TheIsles16) to hosted by Derek Snider.

Changes to license[]

OLC was originally shipped with a relatively restrictive license compared to other editors and DikuMUD itself, because one needs to not only contact and inform the author before doing so, but also get authorization to distribute derivatives. Locke spoke of the original release requirements as a way to drum up support for his game and encourage other programmers to collaborate. Shortly after the release, however, Locke moved ISPs and could no longer be reached at his Telerama email address ( and Surreality died and thus could not be contacted.

Since the original release, the surviving author has made attempts to change the license to require the users of the software to credit the authors of The Isles OLC with the tagline Based on NiMUD by Locke and Surreal on the MUD title pages, similar to the credit required by the DikuMUD License, instead of contacting the author.

Relationship to the Hotboot Snippet[]

After Richard Bartle referred to the add-on's perpensity to cause instability, the feature was later improved with Copyover Recover (or the synonymous Hotboot feature), which stabilized MUDs using OLC by providing persistent connectivity for users while the MUD recovers from a crash or scheduled reboot.

Feature History[]

Monster is credited with being the first MUD to contain editing features for live content manipulation. It has object, location and puzzle creation and editing features, the same functionality which was later implemented for Merc/Diku as Online Creation. Online editing became the final accepted feature of Diku-derived MUDs, and was implemented in most MUDs after Monster, such as seen in MUSH, MUCK, MOO and LPMud prior to the release of DikuMUD. To be clear, the software package OLC is not directly influenced by Monster, and is similar only in that its editing features are accessed from within the game. Indirectly, Monster influenced OLC via MUSHes, but no source code was ever borrowed from any of the other softwares to create OLC.

VMS Monster, TinyMUD, LPMUD and MUSH, MUCK and MUX software are all similar in that they provide extensibility and customization live without rebooting the game server, but typically use other words to refer to their editors. Many refer to the power to create online as "wizard", "builder" and "immortal" features, or "online building". This article deals primarily with OLC, and software expansion packages (add-ons) called Online Creation.

Hidden Worlds online building system was written for Merc 1.0 by Kalgen of Zebesta. It was used as inspiration for NiMUD's OLC system, which became the most popular OLC for Merc/Diku, the most popular MUD software with the highest number of derivatives.

Reason for Development[]

At the time, no publicly distributed Diku or Merc MUDs were capable of permitting immortals to build new rooms, objects and NPCs in a single "plug-in" package, nor in a native Diku or Merc codebase. (The feature was available in MUSHes, but not in the popular Aber/Diku family in the MUD tree.) A room creation snippet was distributed on Usenet, and there was a way to customize copies of objects, but no way to build entirely new zones (also called areas, the maps in the game that consist of rooms, objects and creatures).

AI was hard-coded as spec_funs and world files were edited using a series of offline area editors which provided functionality to edit the world prior to OLC. It is still sometimes the preferred way of editing the MUD, and continues to develop parallel to OLC. OLC is often added as an extension to MUDs that come without it. MUDs created after 1993 in the Merc/Diku family tend to have OLC or equivalent features packaged with them out-of-the-box.

After their first mud, CthulhuMUD, was hacked and vandalized only a few short days after the project was initiated, in the following weeks the duo produced a project called NiMUD, which contained the first publicly available OLC for Merc/Diku MUDs, and pre-dates CircleMUD's OLC. News of the release was spread on Locke and Surreal's favorite muds and Usenet, distributed via which offered places to host mud software, and on ISCABBS, where Locke had first started mudding in 1992. Even before they had been hacked, NiMUD was to be an open source project under the name TheIsles, where the code was given away because Locke had decided that security was an illusion and he wanted to combat negative energy by avoiding revenge on the hacker and instead produce quality open source software.

The Isles NiMUD's OLC system was inspired by the online building system of Hidden Worlds, which Locke was a player on. The system used by Hidden Worlds was not publicly available open source, and thus its usage was limited to that single MUD. He invited his friend, Chris Woodward, who named himself Surreality, though on The Isles he was known only as Surreal. On Hidden Worlds, Locke never reached the level of immortality required to build, though Surreal did. Surreal built a few rooms and objects using the Hidden Worlds online building system.

The Isles OLC[]

Locke and Surreal decided to write an online creation system, and start a MUD derived from Merc, which itself was derived from Diku. Though the project had started around the time of CthulhuMUD in May of 1993 using Merc 2.1, they adapted it to Merc 2.2 after its release on October 13, 1993 [2]. It was publicly released in various stages of development from 1993 to 2009, by its surviving author.

Quotes from The Isles original web documentation [3]: "The virtual locations, objects, players and creatures that you see are all contained in a set of seperate [sic] but inter-referencing databases that build the "rules" of the world beyond the game mechanics. Due to the complexity of this system, a set of universal terms has been developed over time to describe various values and references within the database and how they are used within the world. . . . It is important that you familiarize yourself with the terms defined below, they will be used throughout the remainder of the Guide and are frequently used when discussing projects with other builders . . . the most fundamental of these terms, the virtual number or
vnum. A vnum refers to the index in the hash table that holds a single database entry. In other words, the vnum is a unique number that references a specific entry in the database. In each of the three seperate [sic] database that make up the majority of the virtual objects, vnums are unique and do not repeat. A vnum in one database might match the value of a vnum in another database, but within a single database a vnum is never repeated and references only one entry."

Ported to other Merc MUDs[]

The Isles OLC became the source work for derivatives such as ROMolc, Ivan's OLC (dubious, please discuss, Ivan's OLC code looks like clean room implementation) and ILAB/OLC. It was influential in the design of some other online building systems for Diku-derived muds and multiplayer games. It was the first complete package for Diku, and did not expand upon "modification" commands found in Merc at the time. The version ROMolc had the widest distribution due to the popularity of the ROM codebase.

Breakdown of Ports and Derivatives[]

ILAB/OLC for Merc/Envy[]

Jason Dinkel was given permission by both Herb Gilliland and Chris Woodward to port The Isles NiMUD's OLC to Merc/Diku-derived software as the "ILAB/OLC" package. Minimal changes were needed to develop the port, but the port's success came from its easy installation into Merc/Diku variant MUD software. The software's popularity continues to grow, and it has been ported to a variety of MUD softwares and is currently included in at least 35 derived works, many of which were released to public consumption without permission, in ways similar to the way Dikumud was originally 'leaked'.

Oasis OLC[]

"Your Job as a Tinyworld Architect: Wow, you finally got your mud up and running, and now you want to create a world to fit all of those stories you have running around your head. As a Tinyworld Architect or builder, your job is to create areas for players to roam around in, solve puzzles, and gain experience. There is a world included with the CircleMUD distribution which is intended to serve as a stepping stone and a basic guide on what can be done with a world for your mud.
Muds may have many different ways of coding things, but in general, most people tend to judge them on the number and quality of areas that they possess. The areas are what tend to make a mud original. For example, one mud could be based upon a magic-rich world and the code and areas would reflect this, while another could revolve around cities and thieves. Each of these muds would have its areas designed in such a way to flesh out this theme. In essence, building an area is like writing a book. It needs to have a plot, needs to be descriptive, and needs to be populated with memorable people and places." (quote from the CircleMUD 3.0 Builder's Guide)

Mozart OLC[]

"Mozart is one of the oldest, most developed muds on the net. The world has over 28,000 rooms in 200 zones among three major areas. The Surface is the largest and most newbie-friendly. Beneath, the svirfneblin city Galtherdelve and the drow city of Aluhryn in the Underdark are more dangerous, and player-killing is legal. All the major features of mud clients, including aliases, speed-walking, and command history, are provided by the game itself, so all our players - even those on telnet - are on an equal footing. Immortals have access to full OLC including every feature we can think of, all the way up to LP-mud style scripting. If you have a new idea, we'll work to make it possible." (quote from Mozart MUD)

Samedi's OLC for SillyMUD[]

A version of OLC written for SillyMUD which is a rewriting of the basic features of OLC for a different derivation, without the modal editor functionality, but with the same command names.

Other Methods of Live Content Creation for MUDs[]

Diku and Merc MUDs did not originally support online creation's capabilities — DikuMUD was specifically designed to be a better AberMUD, which was notorious for having a hard-coded world.[1] A number of different packages were created to add online content editing capabilities, the first of these was Armageddon for DikuMUD by Dan Brumleve, Nasri Hajj, and Santiago Zorzopulos, which allowed builders to create rooms (the snippet was released in 1993), and later zones, exits, objects, and mobiles interactively through a VT100 menu, or MUD command driven interface.[2] Their online creation system was added to the DikuMUD derived SillyMUD codebase, released after 1993.[3] The Merc derived codebase The Isles (details above) also featured online creation which was written by Christopher Woodward, and dubbed OLC by co-developer Herb Gilliland. The Isles was released at the end of 1993.[4] SMAUG, a descendant of the Diku and Merc branches, included a feature called Online Building.[5]

Other MUD-like systems that allow live creation of game content have been written after Monster, and some were already available before Online Creation was available. They are:

  • Gods, a game first written in 1985 which had the sole focus of the player being a creative "god" that could create objects, locations, rooms and the like within the plot of the game
  • Monster heavily influenced the design of TinyMUD.[6] TinyMUD was an attempt to create a "stripped-down" version of Monster with just object creation and locking. [7] As time went on some of the functionality that was deliberately left out was reinvented. [8] TinyMUD itself inspired an entire family of MUDs based entirely on the premise of allowing users to build online. Among those subsequent MUDs are TinyMUCK and TinyMUSH.
  • TinyMUCK[9] added the following features to the "online building" interface: the ability to write and modify multi-user Forth programs online, the ability to attach these programs to things — such as objects, rooms and players — and the ability to delete objects online. TinyMUSH's online creation language is more Lisp-like in nature.
  • LPMud tries to avoid the stability risks by abstracting the system into a virtual machine which is protected from mistakes made in objects written in the game's LPC programming language. Other MUDs that shipped with live content creation features include LambdaMOO, and CoolMUD.


Chris Woodward left the project shortly thereafter and went to Penn State University, where he was subsequently diagnosed with a benign brain tumor and died from complications of surgery the following year. The surviving author, Herb Gilliland, dedicated OLC to his memory.

External links[]


  • Locke's September 1st, 1993 usenet posting CthulhuMUD Announcement
  • More discussion of what "OLC" had meant to mudding, announcement of Merc 2.1 [project start] August 30, 1993 [4]
  • Locke posting under friend Don's account [5]
  • Locke's original attempts at supporting OLC posted May 8, 1993 [6]
  • Locke's original posts to Usenet once he got access to Usenet from his site in the UK, on which NiMUD was first developed May 1, 1993 [7]

Additional References

  1. Richard Bartle (2003). Link. New Riders. pp. 741. ISBN 0131018167. "DikuMUD ... was designed purely as a better AberMUD, and made no reference to either TinyMUD or LPMUD. Whereas these other two games had moved toward allowing on-the-fly changes to be made to the virtual world, DikuMUD's designers went in the opposite direction and hard-coded everything they could." 
  2. Santiago Zorzopulos. "Armageddon". "Yeh, that's right.... You can do zone files on-line.... Just load all your mobiles, give them equipment, "zsave," and POOF! Instant zone file."
  3. J. Brothers, J. Sievert, K. McClelland, S. Gardner, R. Forsman, P. Martin (1993) SillyMUD
  4. Herb Gilliland, Christopher Woodward (1993) The Isles 1.1
  5. Derek Snider (1996) SMAUG
  6. Martin Keegan, "A Classification of MUDs", [1] last accessed 2 October 2006
  8. MUD history
  9. Stephen White, TinyMUCK, 1990