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[Last revised: Thu Jul 29 12:16:13 EDT 1999 ]

DOoM Frequently Asked Questions

This file is available in HTML form at: http://www.poslarchive.com/math/doom/faq.html. A Japanese HTML version is also available. Please send comments, corrections and additions to John J. Chew, III.


1. What is DOoM?

DOoM stands for Distributed Object-oriented Mud, and was first written by John Chew in late 1993, to replace the then recently demised ScrabbleMOO. It's written entirely in Perl, and has been tested so far on a variety of Unix systems.

2. Getting access to a DOoM

2.1. Where can I find a DOoM?

You can find DOoMs at:

If you're looking at the HTML version of this document, you can also browse the servers directly on the web here: MarlDOoM, WisDOoM (defunct), PoslDOoM.

2.2. How do I connect to DOoMs?

You're probably already a subscriber to an Internet Service Provider - if you aren't, then phone one up and ask how to get connected to the net. Tell the ISP that you need 'Telnet' access, though very few ISPs offer Internet access without it. I'm told that as of version 3.0, AOL works as an ISP.

Once you've got your Internet connection, follow the instructions below for your type of computer:


I strongly recommend TinyFugue. Even if you don't have a Unix system at home, odds are your service provider will give you Unix access, and may even have tf installed for your use. If they don't, ask them to. When you've installed it, fetch a copy of the sample tfrc initialisation file.


You can use NCSA Telnet (which is probably installed with the rest of your Internet software), but you'll find it confusing that people keep overwriting what you're trying to type. It's easier to use a MUD-specific client such as MUDDweller, or telnet to your service provider's Unix service and use TinyFugue.


There's an old version of TinyFugue that's been ported to VMS, but I don't know much about it. I suspect it's better than using straight telnet.


TinyFugue (see under Unix above) is also available for OS/2. I haven't tried it with OS/2 though.


(sigh...) In order to connect to a MUD-like server, of which PoslDOoM and MarlDOoM are examples, you need a 'Telnet client'. A 'Telnet client' is a program that runs on your Windows machine and connects you to machines elsewhere that are running 'Telnet servers'. ('Telnet' is just the name of a communications protocol.) When you type into the window of your Telnet client, what you type gets sent off to the server, and whatever the server sends back will appear in the window. It's like having a window open to another PC's DOS prompt, if that helps any.

It should not surprise you to learn that while Windows comes with a Telnet client (called 'TELNET'), it doesn't work. There are however plenty of Telnet clients that do work, that you can download from the usual places on the web.

Several players have strongly recommended Mark Watkins' BobGrid, a Java-based front-end for DOoMs that goes far beyond any Telnet client. I can't personally recommend it, as depending on your board configuration, you might be fooled into thinking that you were playing a copyrighted and trademarked crossword game, instead of a completely generic crossword game.

Bob Felt enthusiastically recommends Pueblo. I've looked at MUTT Lite and it seems useable. (Use the TINY.MUT connection script.) Some people have recommended AVPlay and zMud instead. Carl Barish has reviewed several Windows clients and their usefulness for connecting to DOoM servers on his home page. Yaegar's MUD Client Page lists several Windows clients. There are also client reviews in the Crossword Games Pro mailing list archive. Pick whichever one you like, and follow the instructions that come with it.

Whichever one you pick, there's a good chance you'll need a utility called WinZip to unpackage what you download. Click on the word WinZip in the previous sentence to download a copy of WinZip.

2.3. What do I type at the login: prompt?

You shouldn't get a login: prompt. If you do, it's because you didn't specify the port number when you telnetted, and have been connected to the default login port instead of the DOoM. On a Unix system, you can just type the port number after the address, separated by a space. If you have a web browser, try pointing it at the URLs shown above.

2.4. What do I do once I find it?

When you connect to it, you'll appear in the who list as a numbered connector. If you have a password, you can use the connect command to log on at this point. If you don't, you can still browse the online help files (type: help intro), look at games in progress (type: look bd_poslfit), talk with people, and do just about anything except move out of the login area or play a game.

To request a password, you need to use the request command. For example, I would type:

request poslfit poslfit@gmail.com John J. Chew, III

to request a password for myself (John J. Chew, III) if I wanted to be known online as poslfit. If my request were approved, my password would be e-mailed to the address I gave, poslfit@gmail.com in a day or two.

Do not type poslfit@gmail.com when you type the request command yourself. If you don't type your own address, I won't be able to send you your password, nor will I be able to send you a note asking for a correction, because I won't have your address. This may seem obvious to 95% of you, but sadly enough, 5% of requests do in fact make this mistake, and another 5% make some other sort of error in the e-mail address they provide.

If you are an expert player, request your password on MarlDOoM first, then e-mail me to have your password activated on PoslDOoM too.

2.4.1. What about my partner/sibling/parent...?

Each player should request their own account, even if they share a computer or an e-mail address. Two people playing under the same identity cause problems for the rating system, as does one person playing under two identities.

2.5. How do I set up MUDDweller?

If you're not using a Mac running MUDDweller, why are you reading this answer? If you are, and you've downloaded a copy of MUDDweller and are wondering what to do next:
  1. Run MUDDweller
  2. Select TCP/IP Address... from the Configure menu
  3. Enter www.math.utoronto.ca as your Host.
  4. Enter 7776 as your Port.
  5. Click OK.
  6. Select Communication... from the Configure menu
  7. Deselect Local echo.
  8. Click OK.
  9. Select Save from the File menu and save your settings. From now on, open that document to connect to MarlDOoM.
Once you get your password, you can use MUDDweller macros to avoid having to enter it each time you connect. Set your Login macro to send co $p $n\n, enter your name and password under Preferences... and don't forget to resave the settings.

3. Crossword games on DOoMs

3.1. Crossword game? Huh? Where can I play Scrabble®?

Scrabble® is a registered trademark owned by Hasbro, Inc. in the United States. It would be a violation of Hasbro's rights for anyone to use their trademark in an unauthorised fashion. Hasbro has also copyrighted the design of a standard board, so it would be illegal for an unauthorised server to offer Scrabble® boards.

However, for some time now, Hasbro has apparently tolerated the existence of generic crossword game software, that is, software that allows the user to play any of a variety of crossword games (including Scrabble®) depending on how the user chooses to configure such things as tile distribution, tile values and board layout. For this reason, DOoM servers are properly referred to as crossword game servers, and it is up to each individual user to decide whether or not to violate Hasbro's rights.

For more information about Scrabble®, see the FAQ.

3.2. What's an easy way to configure my board?

There isn't one, and if there were one, I couldn't write about it for legal reasons. See the previous question.

3.3. Why doesn't my board certify?

To ensure that there is some standardisation of board design, players are allowed to try to `certify' their boards. Some configurations are certifiable and others are not. Rated games may only be played on certified boards. If you try to certify a board and are told that the board is not certifiable, then one of the following must not match the acceptable certifiable configurations: the tile distribution, the tile values, or the board layout. It's up to you to try changing one or more of these to find a certifiable configuration.

3.4. Where did my board go?

If you can't remember where your board is, type join bd_yourname to go to where it is. For example, if your name is poslfit, you should type join bd_poslfit.

3.5. Why can't I go to my board?

Boards have to be placed in ordinary rooms before you can enter them. They didn't used to have this restriction, but then someone entered a board that he was carrying and then dropped it.

If you're not already carrying your board (type look me), go to where it is as described in the previous section, take it, go to a room and drop it.

4. Help on DOoM

4.1. Where can I get a complete set of help files for DOoM?

The current help files for DOoM are available on the web at http://www.poslarchive.com/math/doom/help.

5. The ratings system

5.1. How do I get a rating?

You will be awarded your initial rating after you have played five games against rated players. This initial rating will be equal to the rating that you would have had to have had before those five games, in order for those five games not to have changed your rating. The players you play for those initial five games will not gain or lose any ratings points by playing you. If you can't find a human player willing to play one of those five games with you, try playing ACBot, the robot.

5.2. How does the ratings system work?

When you play a rated game against someone, the system calculates what the chances of your winning are, based on the difference between your ratings. (If you are rated 72 points higher, it's 60%; 148 points means 70%; 239 points means 80%; and 362 points means 90%. For the numerate, every 400/sqrt(2) points corresponds to one standard deviation of a normal distribution.) It expresses these chances as the fraction of the game that it expects you to win (e.g. 0.6 for a 72 point difference) and then adjusts your rating at the end of the game by the difference between these expected fractional wins and the actual result of the game, multiplied by a constant called the ratings multiplier.

For example, if your ratings multiplier is 20 and you beat someone rated 148 points below you, you gain 20 * ( 1 - 0.7 ) = 6 ratings points.

Your ratings multiplier depends on the number of games that you have played and on your rating, as follows:

                           games played
1-5 6-10 11-25 26-49 50+
1-1799 n/a 100 50 30 20
player 1800-1999 n/a 100 50 24 16
rating 2000+ n/a 100 50 15 10

5.2.1. Is that exactly how the NSA system works?

The NSA system differs from the system we use online in some minor details.

Because a long interval sometimes elapses between an individual player's rated games and a player's strength can improve substantially in the interim, the NSA uses what are known as `acceleration points'. If over the course of a tournament a player earns more than five points per game played, the player earns a bonus amounting to the excess points. For example, if the system would otherwise award you seventy points for your performance in a six game tournament, you get 70 - 6 * 5 = 40 acceleration points for a total of 110 points. Furthermore, everyone who has the misfortune to play you gets so-called `feedback points' as compensation, amounting to one twentieth of your acceleration points for each game that they played with you. In the preceding example, an opponent that played you three times in the tournament would receive 3 * (40 / 20) = 6 feedback points. Note that you do not lose acceleration points when you lose a lot of ratings points in a tournament.

The NSA also updates ratings after each tournament (or occasionally midway through a huge tournament) rather than after each game. This probably results in more abrupt changes in individual ratings.

I have a spreadsheet that calculates ratings which has been able to reproduce NSA results about half the time, and is accurate to within a point or two the rest of the time. I would be interested to hear if anyone can account for the remaining discrepancies.

5.3. How do I get my NSA rating to appear online?

E-mail your current NSA rating to poslfit@gmail.com when you first receive your DOoM password, and e-mail again whenever it changes changes. In each message, please include your name online, your name as it appears in the NSA member list, your new rating, and the date of the tournament in which you earned it. I also appreciate it greatly when at least one online player attending each tournament sends a list of the new ratings for all the online players that attended that tournament, as it saves me time and effort.

If your NSA rating is at least 1600, you are eligible to play on PoslDOoM. If you qualify but don't yet have a password, please e-mail me a note, again at poslfit@gmail.com.

5.4. How do I get a game rated manually?

Once in a while, the ratings system doesn't work because circumstances have arisen that I haven't anticipated. More frequently, a game won't get rated because someone forgets to type 'endgame' or both players forget to make sure the game is a rated one before they play. In either case, this is what you need to do.

Have the losing player (or the higher-rated player, if a tie) e-mail me at poslfit@gmail.com with the following information:

  1. the date on which the game was finished
  2. the online name of the player who played first
  3. the online name of the player who played second
  4. player one's score
  5. player two's score
If the right person doesn't send me all of the above information, you'll get a polite (if canned) note referring you to this FAQ.

6. Contacting other players

6.1. How do I leave a message for a player?

Look at the player (type e.g. look poslfit) to see their e-mail address. There may not be one, if they don't want you to know. Then send them e-mail.

6.2. Why isn't there a message system on the server?

No one has ever persuaded me that it's worth the programming effort to duplicate the existing Internet e-mail system. That is, I'd be happy if someone wrote one for me, or I'd write one myself if I were persuaded that it was a sufficiently Good Thing.

6.3. How do I change my e-mail address?

Send e-mail to poslfit.

7. Setting up a server

7.1. What happened to WisDOoM?

Chad Wilson, who provided a machine for WisDOoM to run on in 1994 and 1995, is no longer available to do so. It should also be noted that he was responsible for setting up and running ScrabbleMOO in 1993, which server's eventual termination was the impetus for the creation of the DOoMs.

7.2. Can I set up my own server?

Sure. I'd love to have more than one public server on the net, both to spread the load a bit and in case one of them becomes temporarily unavailable. You need a Unix machine with a copy of Perl 5 and at least 10 Mb of disk space and 4 Mb of memory available for the server process, and I'll need to be able to rlogin to that machine. It's work for me to set up and maintain a server though, so don't ask unless you think you can keep the server for at least a year. If you do, e-mail me without delay!