Appendix A
An Introduction to Multi-User Dungeons

Much of this document makes two assumptions about the reader: a knowledge
of the C or C++ programming languages, and a familiarity with Multi-User
Dungeons (MUDs), or their relatives, or at the very least with some kind
of role- playing adventure games, preferably in the fantasy genre.  While
knowledge of C cannot be acquired by reading a few short pages, I can
provide a cursory understanding of MUDs and adventure games for those who
may be reading this for purely academic purposes. 

All adventure games present the player or players with a world to explore
and hordes of enemies to fight.  Most include some kind of plot line, with
some big, bad demon at the end to destroy, and many offer a choice of
character parameters.  Some, such as Daggerfall, the "Zork" series, and
Tomb Raider, are for a single player, playing a single character.  Others,
like the "Wizardry" series, Bard's Tale, and many Dungeons and Dragons
games, are for a single player controlling a team of characters.  Still
others, such as Diablo, Hexen, MUDs and other MUD relatives, give each
player a single character, but allow multiple players to explore the world
simultaneously.  Many require players to make certain decisions which
affect the performance of your character.  Some require these decisions to
be made up-front, while others allow decisions to be made or changed later
on.  Almost all have an "experience" system, through which a character
improves over time, gaining greater power and more abilities with each new
"level" attained. 

MUDs specifically are Internet-based multiplayer text adventure games, in
which several players connect simultaneously and interact with each other
and with automated characters in some kind of text-rendered world.  What
sets them apart from most of the other multiplayer games, especially
PC-based games, is that the game itself only runs on one machine, a MUD
"Server", and the players connect using a simple terminal program.  Other
multiplayer games, such as Diablo, Hexen, Doom, Command & Conquer, and
X-Wing vs. TIE Fighter, require that the full game, or a very large part
of it, be running on every machine, with one of these machines acting as a
"host" to coordinate the others. 

The majority of MUDs are fantasy adventures, in which player characters
explore the wilds of the unknown, fighting computer-controlled characters
called "mobiles", or "mobs" for short, picking up money and items, and
buying, selling and trading with stores and other characters.  Different
MUDs have different command sets, but most are based on the command set
used in Zork, a 1970's era text adventure game which was written at MIT,
and later published for personal computers by Infocom, a company founded
by the game's original authors, as that company's first offering in a long
string of text-based adventure and mystery games.  Players issue their
characters instructions using either direction names or English commands,
for example: "north", "take painting", "drop egg", "turn on lamp", and
everybody's favorite, "kill troll with sword". 

Many MUDs also define different character classes, with the core classes
being Warrior, Cleric/Healer, Thief/Rogue, and Magic-User.  Other frequent
additions include such things as Ranger, Paladin, Ninja and Jedi. 
Different classes have different basic requirements and specifications,
different sets of acquirable abilities, and the ability to use different
equipment.  For example, a Warrior cannot use a Magic Scepter, while the
Magic-User cannot wear heavy armor, and the Cleric cannot wield any weapon
with a blade.  Some MUDs require the player to define a character's class
at the beginning, while others create a generic character which can join a
"Guild" to become a member of one class or another, and may be able to
switch classes during the course of play. 

Players have the ability to save and restore their characters' statistical
information and physical status from session to session.  Whether and how
they can save their characters' possessions varies from one MUD to the
next.  Money is almost always saved with the character's physical status,
and most methods of storing equipment require the player's character to
pay a fee or "rent" for the storage. 

Most mobs have the ability to move around, and many do within a set region
specific to that type of mob.  Almost all mobs in combat-enabled MUDs can
be engaged in fights, and all slain mobs will "respawn", or be
reinitialized or reloaded back to life, after a set time delay. 

Player characters can improve their attributes over the course of the
game.  Most games have an "experience" and "levels" system, giving
characters "levels" which increment with experience.  Reaching a new level
improves some of the player's physical attribute values and allows players
to learn new abilities and/or improve existing abilities.  This makes the
player a more lethal fighter, and in some MUDs also a handier companion. 
In many MUDs, players can even achieve low-level "God" or "Wizard" status
simply by playing the game and reaching a certain level. 

The terms "God" and "Wizard" refer to the characters who have the rights
and powers to actively administer the game.  They settle disputes between
players, set policies of what is and isn't acceptable behavior, and
enforce the rules which aren't enforced by the game engine itself.  Many
of these are also responsible for the maintenance of the world and the
periodic manipulations of the game source code itself, and have the right
to take the game off-line for maintenance or in order to reboot it in an
updated form. 

Many MUDs have "missions" or "quests," which are segments of the game
which involve a particular set of tasks that must be accomplished toward a
single final goal.  While many of these quests can be on the short side,
and can be accomplished in only a few minutes, many are lengthy adventures
in and of themselves, and can take players hours or even days to complete. 
Some MUDs even require that a character complete certain quests or a
certain number of quests before advancing to the next level, in addition
to having enough experience points. 

Playing a MUD requires a program called a "Telnet" client.  Any decent
version of Unix includes a telnet client which works very nicely with
MUDs.  Windows 95 and NT also include one, but it is one which does not
handle MUDs very will.  For these platforms and for Windows 3.1, the best
telnet client I have encountered for MUDding is "EWAN", by Peter Zander. 
The newest version can be found through c|net's Shareware.com search
engine, located at http://www.shareware.com, or from the EWAN home page at
http://www.lysator.liu.se/~zander/ewan.html.  As of this writing, the
current version is 1.052, dated January of 1995.  For Macintosh users, the
last version of NCSA Telnet will do nicely.  This can also be found
through Shareware.com.  Users of other platforms should consult your
Internet Service Provider, your friendly neighborhood computer hobbyist or
a specialist on your operating system for the availability of a telnet
client.  There are also special MUD clients available for several
platforms.  For a recommendation of which ones to try, contact a serious
MUD aficionado, or the administration of one of the larger MUDs. 

There are a number of MUDs available for play on the Internet.  To find
them, point your World Wide Web browser to your favorite search engine,
and enter the words "mud list" as the search criteria.  Select a
promising-looking MUD from one of these lists.  While I cannot direct you
to my own MUD, as I do not have one which I actively run, I can recommend
an excellent Diku-class MUD which has a large world and a large player
base, and which, while not a member of the Circle class which this
document works with, employs many of the features and enhancements to the
Diku class which are part of the CircleMUD public source code base, and
contains good examples of the kinds of additions and enhancements that can
be made to a MUD.  I play this MUD myself, from time to time. 

Appendix A	An Introduction to Multi-User Dungeons
	Page A-2
