A mudlib, short for mud library, is a library of code forming part of the technical infrastructure of a MUD

MUD

A MUD , pronounced , is a multiplayer real-time virtual world, with the term usually referring to text-based instances of these. MUDs combine elements of role-playing games, hack and slash, player versus player, interactive fiction, and online chat...

. Though different varieties of MUD may be considered to have mudlibs, the term is most often used with LPMud

LPMud

LPMud, abbreviated LP, is a family of MUD server software. Its first instance, the original LPMud game driver, was developed in 1989 by Lars Pensjö...

s. In an LPMud, the mudlib consists of interpreted code written in the LPC language, which is interpreted on the fly by a driver. The driver acts as a virtual machine

Virtual machine

A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...

 while the mudlib acts as an operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 by defining how the world acts and controlling its processes.

Publicly available LPC mudlibs include:

• CDlib
  CD gamedriver and mudlib
  CD gamedriver and CD mudlib are popular LPMud gamedriver and mudlib. The name CD comes from Chalmers Datorförening , which most of the developers were members of.- History :...
  
  
• Dead Souls
  Dead Souls MUDlib
  Dead Souls is a MUD library , a software infrastructure for creating a text-based virtual world. It is classed in the following versions:* Dead Souls 1.1 was the final release by its original head developer, George Reese...
  
  
• Lima
  Lima Mudlib
  The Lima Mudlib is an LPC framework for building multi-user role playing games. It was originally written for the MudOS game driver by Zachary "Zakk" Girouard, Tim "Beek" Hollebeek, Greg "Deathblade" Stein, and John "Rust" Viega...
  
  
• Sapidlib, also known at one time as the LPUniversity Mudlib
  LPUniversity Foundation
  The LPUniversity Foundation was an umbrella community project founded on April 2, 2005 by C.A. Wayne "Tacitus" Somerville that aspired to revive the LPC community through offering community driven services, offering mutual location for education, research, development, discussion and certification,...
  
  
• Nightmare
  Nightmare Mudlib
  The Nightmare Mudlib is a set of LPC programming language frameworks created by George Reese for building multi-user role playing games using the MudOS LPMud driver...
  
  
• TMI
  TMI Mudlib
  The TMI Mudlib from The Mud Institute was an attempt to create a framework driven mudlib for the MudOS LPMud driver. It consisted of many contributors to MudOS as well as people who became influential in the LPMud community. When TMI began work in 1992, a mudlib was generally packaged with both an...
  
  

An example of a non-LPC MUD with a clearly identifiable mudlib is MUME

MUME

MUME, Multi-Users in Middle-Earth, is a MUD, one of the early offspring of DikuMUD, founded in 1992. MUME enjoys a measure of popularity in the MUD world...

, a DikuMUD

DikuMUD

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 Staerfeldt at DIKU —the department of computer science at the University of Copenhagen in Copenhagen,...

 that implements global support code in its language Mudlle

Mudlle

-External links:*...

.