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NVEs and MUDs

This is not a full set of notes: it is an outline of what will be/was discussed in the lectures. The topics here are not covered in the unit textbook or indeed any one book.


These two lectures take a high level look at Internetworked Virtual Reality: where it comes from, what people do with the system, and how they behave to each other.

The textbook, and most of the lecture content and unit assessment, is concerned with how Internetworked Virtual Reality systems are implemented. This is a fascinating topic. But it is important to think about why anyone would want one in the first place. And since you can't have an internetworked VR without at least one other person involved, it is also important to consider what they will do with it.

What is an NVE?

A Networked Virtual Environment, or NVE, is what we build with Internetworked Virtual Reality technology.

NVEs are themselves a subset of what is called groupware or CSCW (Computer Supported Collaborative Work) software.

NVE examples


MUDs and MOOs



Text as medium



Implementing a MUD/MOO

A MUD or MOO has two components: the server and the database.

The server does low level network and file I/O, but is primarily the interpreter for the higher level MOOcode or MUDcode programming language.

The database is not a traditional row/column SQL type database, but more a persistent object store. Every object in the MUD/MOO has a single unique magic number identifier, which is never re-used. Every object also has a number of properties: name, description, interaction code, etc. Everything, including the online personas themselves, is described by an object and code.

The MUD or MOO is divided into rooms, objects which may contain other objects and participants. A park, spaceship, or town square is still a room. Every participant or object is always "in" some room, and navigation in a MUD/MOO is from room to room without your location being tracked to any finer level. Everybody in a room can see and hear each other.

The LambdaMOO server can be downloaded from SourceForge. It is 355K, about 37,700 lines, of C code. The LambdaMOO database, which is really what makes LambdaMOO a distinct place, is about 900,000 lines of MOOcode.

In 1999 LambdaMOO had a population of around 10,000 people, and was running on a host computer with 256M of real RAM and using around 360M of virtual memory. MOOs with a population less than 50 can be run on a Pentium/75 PC.

Written by Hugh Fisher

< Internetworked VR : Hugh Fisher's presentations >
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See the "Links" link above to find out the sources of the proposed informations
Pascal Vuylsteker / eScience / Computer Science / ANU
Last modified: 27/7/2003
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