Playing with MUD helps ai research

The artificial intelligence (ai) department at one of the UK's leading technological universities is the last place you might expect to find people playing 'Dungeons and Dragons'. But wander along to Essex University in the evening and you could well find a row of people hunched over terminals, oblivious to what is going on around them.

At the same time, a number of people around the country with access to the British Telecom packet switching service (PSS) may well be similarly hunched and similarly oblivious to their surroundings.

The odds are that they will be engrossed in a game of what has come to be known as 'MUD'. The initials stand for Multi-User Dungeon and despite its outward appearance as just another computerised fantasy, MUD is a great deal more than that, and what it promises is even more intriguing.

MUD was written by Roy Trubshaw and Richard Bartle. Trubshaw has since left Essex to work as a contract programmer in the US but Bartle remains as a lecturer in the university's department of computer science and cognitive studies.

'I am most interested in the ai side of MUD,' says Bartle. 'In fact the system has a number of interesting features in this area including a natural language parser.'

As computer 'games' go (some would argue that MUD is not a game in the accepted sense), it is remarkably sophisticated. The version currently working on the university's Digital Equipment (DEC) System 10 is set up to look like a Dungeons and Dragons game but the 'scenario' is quite flexible and can be changed for other purposes.

A user conference, for example, could just as easily be set up, since the main feature of the system is its networking features. Communication with other players in the game is not only possible, it is the exciting thing about MUD.

Although in the context of a Dungeons and Dragons game, players take on roles as they would in an ordinary game without a computer as the medium, people's real personality tends to shine through.

'When you actually meet the other players,' noted Bartle, 'they are much the same in real life as they are in the game.'

At the front end of MUD, there is a parser to interpret the natural language commands used to move through the system. This will allow many different variations on the vocabulary, thus making the game extremely accomodating.

The serious side of MUD has to do with various ai projects under way at the university - some under the auspices of Alvey grants. Bartle is involved the study of planning methods as applied to a variety of problem solving situations.

'We were working in these areas long before Alvey came along,' said John Oliver, the head of the computer science department. 'Although the Alvey interest has given a boost to the whole area.'

Essex's involvement goes back to the beginning of the 1970s - not long after the university opened in 1967. As well as an Alvey-funded project looking at formal methods in specifying programs in a development environment, the department also has a joint project going with Essex County Council under the Esprit scheme set up by the European Economic Commission. So far these projects have not attracted quite the same interest that Bartle and Trubshaw's MUD program has.

Bartle has reached agreement with Century Publishing, the computer book publisher, to market the game to a wider audience. At the moment MUD playing is restricted to those with access to a terminal at the university or those with PSS accounts.

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Richard Bartle of Essex University (above right) claims that MUD is two years head of any other computer game in the world

But Bartle and Century have recently made a version of MUD available to run on the Compunet service set up for Commodore 64 users. The Compunet version of the system runs on another DEC System io which is part of the ADP Network Services used to carry Compunet.

The system was due to be up at the time of writing and, according to Nick Green of Compunet, will be much more accessible. It is also likely to be a bit cheaper than the Essex version. A PSS account costs about £50 to start and then charges are made according to how many packets are sent. The Compunet version costs £5 a month plus a standing charge of ١ an hour. With telephone charges on top of this, the cost of playing MUD is likely to be prohibitive to all but the most addicted for some time to come.

'The telephone and PSS charges are the biggest obstacle to making MUD more widely available,' said Bartle. This did not stop one MUD devotee from running up a £3,000 'phone bill in eight months, however. 'It was someone known as Sue the Witch and she used to play between midnight and dawn every night,' Bartle said. 'She had to stop when the 'phone bill came in,' he added.

Another restriction at present is the machine used to run MUD. It has to be a DEC System 10 because the system is not portable. 'It is written mostly in BCPL but has several machine specific routines that would be difficult to move to another machine,' explained Bartle.

He and Trubshaw intend to begin rewriting MUD in 'C' next year so that it can be taken to many more machines.

What makes the game so exciting is its ability to combine the interest of an adventure game like 'The Hobbit' - a particularly successful home computer game - with the unpredictability of human involvement. At a time when the microcomputer software industry is entering a period of crisis - the number of new ideas for computer games is painfully small - the idea of multi-user games has been put forward as the next big area for development.

If this is combined with networking, as it is in MUD, there would seem to be the potential for a hit - even on a worldwide scale.

Bartle claims that MUD is two years ahead of anything else in the world, including the US where the Dungeons and Dragons craze has been far more popular than in the UK for some years now.

'There are one or two networked adventure games about in the US. There is one called Smaug which I think has just got off the ground. And there is, I believe, one in Australia too. But they are not nearly so sophisticated as MUD,' Bartle said.

This year has seen home networking begin to take off with some 10,000 subscribers to the viewdata-based Micronet service on Prestel paying out between £50 and £100 for a modem and a subscription to the Prestel Microcomputing Service.

Green at Compunet is hoping for some 2,000 users very quickly on Compunet (again about £100 for the modem and a year's subscription). It could mean that there is a substantial market there already. The main objection many of these subscribers have (judging by the networked correspondence on the so-called bulletin boards) is the lack of user-to-user communication on these systems.

Micronet runs a service called Chatline during the evenings, allowing users to send messages to each other over the network. The limitations of the Prestel technology, however, make this an unwieldy process. Each message sent in has to be re-entered by Micronet staff meaning there can be a delay of between two and 10 minutes before your message reaches the queue. MUD gets around this by passing messages straight through the system, so online 'chatting' is easily achieved.

It is easy to see such a service attracting even more people to home networking as it's widely available and perhaps most important of all, cheap. Until then MUD will be the game for the rich or resourceful home computer owner.

Phil Manchester is a freelance journalist.