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CircleMUD is a MUD codebase written by Jeremy Elson and first released on July 16, 1993. It is a derivative of DikuMUD that was written in 1990 by Katja Nyboe, Tom Madsen, Hans Henrik Staerfeldt, Michael Seifert and Sebastian Hammer.[1]


CircleMUD is designed as a small and efficient MUD engine with a minimal set of gameplay features. The project's goal is to provide a stable and bug free codebase that developers can use as a blank slate for incorporating their own ideas.[2]

CircleMUD is freely available, with restrictions provided by the CircleMUD license[3] and the DikuMUD license.[4]

Technical information[]

The last version of CircleMUD released by Jeremy Elson was 3.1. It was released on November 18, 2002.[5]

CircleMUD is written completely in the C programming language. CircleMUD 3.1 has 40,538 lines, including comments and blank lines.[6]

It lacks world building facilities or a scripting language for game events. These features are provided by third party patches.

CircleMUD 2.0 has a memory footprint of about 2MB.[2]


The original CircleMUD began as a modified DikuMUD running on a DECstation at Johns Hopkins University in 1991. Its name was inspired by the hostname of the server which was Initially CircleMUD was run covertly without the knowledge of the local system administrator. By 1992 the number of online users had risen to between 9 and 12. At this point Jeremy Elson decided to request formal permission to run CircleMUD. His request was granted with one requirement: the disk space usage must be kept below 2.5M.[7]

CircleMUD continued to grow by word of mouth until it had an average of 30 to 40 players online at any one time. Several times the MUD hit its maximum player limit of 58. However, due to a result of conflict that surfaced among the MUD's administrators, Elson permanently closed down CircleMUD on August 26, 1992. Several months later, in May 1993, Elson decided that the CircleMUD codebase could be used to fill a niche in the MUD community. He felt that there were many problems with the existing public MUD codebases such as portability and stability. He also felt that most developers wanted to start with a clean slate and did not want a codebase filled with fancy features.[7]

Elson set out to achieve this goal in the summer of 1993. He began modifying the original CircleMUD codebase, and the first public release of CircleMUD arrived on July 16, 1993.[7]

Since then CircleMUD has undergone many revisions. The last release by Jeremy Elson was 3.1.,[5] released on November 18, 2002.

In 2006, a number of discussions[8] between Mark Garringer, Thomas Arp, Nathan Winters, and Jeremy Elson resulted in the release of CircleMUD 3.5[9] on December 11, 2006. Following this final release of CircleMUD, the name was changed to tbaMUD with the release of version 3.51, and this has now become the continuation of the CircleMUD line.[10]

There have been a number of tbaMUD releases, with the latest being tbaMUD 3.63.[10]

Third party patches[]

There are several public patches for the CircleMUD codebase to add additional features.

  • DG scripts adds a scripting language for game events.
  • Oasis OLC adds a building interface so that zones can be built within the MUD environment.
  • CircleMUD with Goodies Project (CWG)[11] is a compilation of patches that provides DG Scripts, Oasis OLC, Mud Client Compression Protocol, bug fixes, and more.


  1. Bartle, Richard (2003). Designing Virtual Worlds. New Riders. pp. 10. ISBN 0-13-101816-7. "...several major codebases (standalone MUD program suites) were created from the basic DikuMUD original, the main ones being Circle, Silly, and Merc." 
  2. 2.0 2.1 General information about CircleMUD Accessed December 14, 2007
  3. CircleMUD license Accessed December 14, 2007
  4. DikuMUD license Accessed December 14, 2007
  5. 5.0 5.1 CircleMUD 3.x changelog Accessed December 14, 2007
  6. CircleMUD source code Accessed December 14, 2007
  7. 7.0 7.1 7.2 The History of CircleMUD Accessed December 14, 2007
  8. CWG Forum Jeremy Elson conversation Accessed December 14, 2007
  9. CircleMUD 3.5 download page Accessed December 14, 2007
  10. 10.0 10.1 tbaMUD Homepage Accessed December 14, 2007
  11. CWG Project Homepage Accessed December 14, 2007

External links[]

This page uses content from Wikipedia. The original article was at CircleMUD.
The list of authors can be seen in the page history. As with MUD Wiki, the text of Wikipedia is available under the Creative Commons Attribution-Share Alike License 3.0 (Unported) (CC-BY-SA).