What are Doors?

Bulletin board systems can link their users to online games, called "Doors". Most doors are in text, though some feature ANSI graphics and animation, and some even include more elaborate graphics and music. A neat thing about doors is that most of them are multi-player games, where BBS users can compete or cooperate with each other. (This was, of course, VERY exciting back in the 80's when almost nobody had internet access!)

Most doors can handle only one user at a time. Remember that back in BBS days, a server could only accept one caller at a time unless it had multiple modems installed! Some "multi-node" doors can handle multiple players at the same time - chatting, or dueling, or teaming up against the world. Each BBS caller generally had a daily time limit - 30 or 60 minutes, say - in order to let other users log on. The BBS would disconnect them at the end of that time. Most doors limit the amount of stuff a player can do in one day, so that even a large, complex door gets played in 5-to-50-minute chunks.

Most doors were distributed as Shareware. Sysops could download a limited version of the game for free, but would have to pay $10 or $20 or $50 dollars to get the full version. The unregistered version might have an annoying delay at startup, or limit the power-levels that users can reach, or disable all sorts of features.

Some Favorite Doors

Here are some doors that I particularly like:
  • Operation: Overkill - My favorite door of all, an RPG set in a futuristic wasteland. It reminds me a little bit of the Fallout series of games. I love exploring grid-based map, and saving up water crystals to buy a newer, better next weapon.
  • Legend of the Red Dragon (LORD) - This came out after I left the BBS scene, but it's a superb game. Unlike most doors, it's extensible - so instead of just spawning imitators, it gave rise to various add-ons. Maybe I'll write more on this one after I figure out what's going on.
  • Usurper - Another fairly recent door; provides a somewhat Shadowrun-ish blend of trolls and elves and guns and magic and sex and drugs. There are computer NPCs, which is a neat idea (and makes the game feel less empty to the first few players)
  • Trade Wars - A classic, which people still play (a lot). Fly around space, buying and selling goods. After a while, you can construct new planets, fight aliens, and have huge wars with other players. I remember seeing a Trade Wars client, way back when, that would auto-trade between two star systems; clients have come a long way since then. (Creating "bots" to play door games is sometimes as fun as playing the games themselves)
  • Barren Realms Elite - A conquest game, which is now played on inter-bbs leagues(!), making for some very large-scale war indeed. Rather simple, with very short turns.
  • Thieves Guild - More info when (if) find it again

    If you've played BBS doors before, I'm sure you have plenty of favorites. I don't have the space here to talk about all the doors. Maybe I'll put some sort of top-100 list up at some point.

    Breeds of door

    Many doors fall into one of a few categories. That's partly because the really successful doors spawned a host of imitators. There are a lot of Trade Wars clones out there, for instance. Some types of doors you'll see over and over are:
  • Empire building - Games like Global War, Barren Realms Elite. The focus is on expanding and improving your kingdom, and on fighting other players (and forming alliances).
  • Duel games - Direct combat with other players. Typically, one player is logged in, and the opponents read the combat results when they next log on. (Some newer games, like LORD, allow direct PvP combat). Games like Food Fight, Air Combat, and The Pit are focused on duels.
  • RPGs - Role-playing games generally feature exploration, scumming for experience and gold, and stat increases. Games like Operation Overkill and Dungeon Master fit this description. Most RPGs do include duels versus other players, so there's a very fine line between the categories "duelling game" and an "RPG".
  • Trade games - Most of these are based on Trade Wars 2002, one of the best (and most popular) doors ever written.
  • Trivia quiz doors - Easy to program, but hard to make really fun.
  • Text adventures - Some puzzle-driven adventure games ("Interactive Fiction", if you prefer) in the style of classics like Zork. And some menu-driven, "Choose Your Own Adventure" style games.

    There are thousands of doors out there. Most are not especially good. Doors are reasonably easy to program, and many of the doors produced are amateurish, or derivative, or buggy. However, there are some true gems out there. And I think that even lackluster doors are worth preserving for historic interest and for nostalgia value.

    More Door Thoughts

    What makes some doors fun, and others simply dull? Perhaps it's a matter of having just the right amount of interaction between users. Interaction with users is central to why doors are fun, and most full-featured doors do include their own mail and message systems. But you don't want TOO MUCH interaction. Otherwise, the first user to log on has nothing to do, and a newbie has no hope of doing anything but getting pounded by veterans. I think Trade Wars strikes a happy medium - you can always make some money by trading, but (especially in the mid-to-late game) you have to pay close attention to what other players are doing, and be ready to counter their schemes.

    Doors are a lot like MUDs. MUDs grew up around Unix systems on university campuses, and doors grew up on BBSes in people's basements, but many people played both MUDs and doors. Most doors are much simpler than even a simple MUD system like DikuMUD. I think doors would make great mini-games for a modern MUD, since MUDding can get monotonous (though still addictive) after a while. The "chunked" gameplay of most doors (only a certain number of minutes or turns allowed per day) has the great side effect that players can be competitive without spending a lot of time online. Most MUDs are largely a contest of committment - the top players spend hours online every day, and a casual player - even a skilled one - has NO HOPE of topping the player ladders.

    Notes on Inner Workings

    To run a door, the BBS program first writes out a a "drop file" (such as Door.sys, a common format); this file tells the door who is playing. Drop files are a somewhat awkward way for the BBS to communicate with the door, but they do reduce the need for a lot of command-line arguments). There are many, many drop file formats out there. Most BBS systems can write several, and most doors can read several, and if you're unlucky enough not to have a match, there are conversion tools.

    One tricky thing about doors is that the program can access the modem in two ways - it can access the modem's COM port directly, or it can use interrupt 14h (the FOSSIL interface). Older doors written before 1991 tend to access the COM port directly, while later doors generally support FOSSIL. FOSSIL was created, in part, to free door authors from worrying about differences between modems. If you want to run doors on a Windows system, you probably want to use TCP/IP connections instead of a modem. To do this, you need a FOSSIL driver (such as NetFoss), or a COM-port redirector (like NetSerial, depending on how the door works. (A full-featured DOS emulator would probably include such functionality, but I'm not aware of any such things...yet!)
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