====================================================================== @@@@@@@@@@@@ @@@@@@@@@@@@ @@@@@@@@@@@@@@ @@ @@ @@``````````@@ @@``````````@@ @@`````````````` @@@@ @@@@`` @@`` @@`` @@`` @@`` @@`` @@``@@ @@ @@`` @@@@@@@@@@@@ `` @@@@@@@@@@@@ `` @@@@@@@@@@@@ @@`` @@ ``@@`` @@```````````` @@``````````@@ @@```````````` @@`` `` @@`` @@`` @@`` @@`` @@`` @@`` @@`` @@`` @@@@@@@@@@@@ `` @@@@@@@@@@@@@@ @@`` @@`` `` ```````````` `````````````` `` `` ====================================================================== A Fanzine for Free Computer-Moderated Play-By-Electronic-Mail Wargames ====================================================================== volume 94, number 2 may 10, 1994 ====================================================================== Greg Lindahl, Editor gl8f@virginia.edu ====================================================================== World Wide Web: ftp://ftp.erg.sri.com/pub/pbm/pbm.html ====================================================================== Table of Contents: Opening Stuff o The Editor's Corner o Short Summary of Available Games Articles o Modern Core Wars Greg Lindahl Regular Features o Game Descriptions & Information o Archives and subscriptions by email o Hints regarding sending electronic mail to other networks o What's this "ftp" thing anyway? ====================================================================== The Editor's Corner ====================================================================== We have a new publishing philosophy here at PBEM: Deadlines is deadlines. If you want to see articles, you write 'em. The most interesting new development for this month is actually an old development -- while looking around Usenet, I noticed that there is an automated email server for Core Wars, a game of battling computer programs. If you can manage to land in the top 10 of the programs on this server, you can automatically advance to the International Core Wars Tournament. Become famous. Write me an article about it. Arena isn't back up, mainly because Scott is doing his research instead of hacking on Arena. Judgment Day and Celestial Empire are both still looking for moderators. We hope to reorganize the ftp sites real soon now so that everyone mirrors everyone else. More on that when it actually happens. ====================================================================== Short Summary of Available Games (full information down below) ====================================================================== Arena --- fantasy arena combat game. Currently on hold for a few modifications, but it should be back up soon. Celestial Empire --- a more complicated space-opera game. There are 2 games running. New games start occasionally. Dougal Scott is looking for a moderator to take over running these games. Diplomacy --- Play Avalon Hill's Diplomacy boardgame by email. On April 15, there were 1000+ players involved in 297 games, with new games starting frequently on several fully automated email servers. Galactic Conqueror (German language) --- An economic/strategic space-opera game, with fancy interface programs available for PC's and Atari ST's. Galaxy / Galaxy/2 / Galactica / Blind Galaxy --- An economic/strategic space-opera game. There are around 500 players involved in a dozen or so games. New games start occasionally. Republic of Rome --- Play Avalon Hill's Republic of Rome boardgame by email. Star Empires --- A simple strategic/economic space-warfare game. Fly around the galaxy, maim your enemies, capture their planets, and produce more ships to maim the enemy with, etc. Sports Simulations --- a variety of different electronic leagues are available. Each game generally does one or two seasons per year. Decentralized games --- a couple of games are available which are designed for a few players, and the moderation programs are available so you can run your own games. For more information on any of these games, please wade through the "Game Descriptions and Information" section below. It lists ftp sites and the addresses of the moderators. The sports simulations and decentralized games descriptions are located in the "PBM List", which is a separate document available at the FTP sites. ====================================================================== Modern Core Wars Greg Lindahl ====================================================================== Core Wars? Didn't I read about that in Scientific American 10 years ago? Perhaps you remember it, perhaps not. But it's alive and well, and you can play by mail. Core Wars is a game of battling computer programs. Put away your battletech toys; assembly language is now the weapon of choice. Some programming experience is required. Actually, Core Wars is much more like a wargame than you might think. The object of this article is to convince you of this. What sort of assembly language does Core Wars use? It will look somewhat unusual to anyone. There are only 11 different instructions (move, jump, data, conditional jump) and 4 addressing modes. All addresses are relative to the current instruction, and the program memory is of finite size, but wraps around, so that programs can pretend that memory is infinite. The starting location of the enemy program is unknown. The object of the game is to keep your program running while making the enemy program execute an illegal instruction, that is, to kill the enemy program. One of the simplest Core Wars programs is this one, from the original Scientific American article: ; Imp, by A. K. Dewdney imp MOV 0, 1 ; This program copies itself ahead one END ; instruction and moves through memory. This program moves itself forward through memory: the contents of the address 0 is the MOV instruction itself, and it gets written into the next address 1, which, coincidentally, is the instruction which is executed next. As I said earlier, addresses are relative to the current instruction. Imp has a hard time actually killing another program: if it overwrites a location in memory and the enemy program tries to execute that instruction, the enemy will be turned into an Imp. The only way that Imp can score a kill is to overwrite the other program's data or otherwise interfere with it such that the other program self-destructs. A second Core War program from the original article is a "bomber". It tries to kill enemy programs by writing illegal instructions all over memory. If an instruction in the enemy program is overwritten and the enemy attempts to execute it, the enemy dies. Bombers must be careful to not bomb themselves. While the best defense against a bomber is a good offense, there is a good defense against the Imp program, often called an "Imp Stomper". Since Imps can only move forward in memory, a program knows that Imps will always approach from smaller memory addresses. If a program repeatedly bombs some fixed location at a smaller address, it can kill an Imp. Modern Core Wars has a few more instructions than the Core Wars described in the original article. The most important new instruction allows programs to multi-task -- they can create multiple threads of execution. In order to kill an enemy, you must kill all of its threads. I will now explain the 5 major strategies employed by modern Core Warriors. The first is bombing, which I've already described. An efficient bomber must cover a lot of memory quickly, which means that bombers leave gaps between their bombs. The best gap size differs for different enemies, so a bomber designed to fight against many enemies must compromise and depend on luck. The second strategy is scanning. The memory in the Core Wars computer begins initialized to a particular value. A scanner looks around memory for locations whose values have been changed, hopes it just found the enemy program, and then bombs nearby these locations. If a bomber is bombing with the same value that memory is initialized to, then the scanner will ignore the bombs, and only pay attention to the bombing program. Bombing with an illegal instruction different from the initial value is called giving bombs "color", and will make scanners waste time bombing nothing. The third strategy is the Imp-spiral, which is a multi-instruction and multitasking version of our Imp program above. One of the features of the multitasking in Core Wars is that splitting your program into 2 threads means that each thread only executes half as many instructions as a single thread would. This means that an Imp Stomper could be overrun if it is multitasking with anything else. An Imp Spiral consists of multiple cooperating processes which lay down the instructions for each other. An enemy program overrun by an Imp Spiral will be killed unless it happens to have more threads than the spiral. The fourth strategy is the replicator. Replicators are programs which are capable of copying themselves to a new location in memory. They can be thought of as self-moving bombs. The fifth strategy, which I find the most interesting, is the vampire. It is possible to bomb memory with JMP instructions. An enemy program which runs across such an instruction will be "captured", and can be forced to execute useless code. One particularly nasty implementation of a vampire sucks the enemy program into code where it not only splits into many different threads, which slows down all the enemy threads, but also slowly bombs memory in a fashion which will never kill the vampire! Unfortunately, vampires have to leave pointers to their "pits" all over memory, so anti-vampire programs can look for these pointers and bomb the pits or write useful code over them. The most successful modern Core Wars programs are often combinations of two of these five strategies. As you can see, Core Wars programs can be very intricate and interesting. There is an international tournament held every year in addition to the ongoing tournament on the email server. For more information about Core Wars, consult the rec.games.corewar FAQ posting, or ftp to ftp.csua.berkeley.edu:/pub/corewar. Alternately, you can ask the email server for more information, as explained below. ====================================================================== Game Descriptions and Information ====================================================================== Note: This information grows old. If you are looking at this issue from an archive, consult the file "PBM.list.Z" in the ftp archives for more up-to-date information. ====================================================================== FTP Site: ftp.erg.sri.com username: anonymous Directory: pub/pbm Contains back-issues of this magazine, source for Galaxy, and rules for a whole bunch of games. ---------------------------------------------------------------------- FTP Site: ftp.cp.tn.tudelft.nl username: anonymous Gopher Site: gopher.cp.tn.tudelft.nl Directory: pub/pbm The same stuff as sri.com, often a little more up-to-date. European users are encouraged to use this site. ====================================================================== Game: Arena Type: fantasy arena combat Duration: open-ended Turns: run once a day GM: srt@aero.org (Scott Turner) Email server: arena@sun-dimas.aero.org Status: still down Description: Arena burst forth from Scott Turner's fingers after he looked at a Duelmasters' turn. Arena reminds me of the ancient microgame "Melee," designed by Steve Jackson: you begin with a fixed number of points, and spend them to design a gladiator. Unlike Melee, you then send your gladiator off to combat with a set of orders, and the battle is fought without human intervention. Winners grow stronger. The rules are available from the ftp sites. ---------------------------------------------------------------------- Game: Atlantis 2.0 Type: strategic economic/military, fantasy setting Duration: open-ended Turns: one per week GM: rwallace@vax1.tcd.ie (Russell Wallace) Status: on hold pending completion of source... Atlantis 2.0 is the second generation version of Russell Wallace's open-ended fantasy game. It features multiple faction types, a mostly player-run economy, simple economics, and a simple combat system. At least one game of the earlier Atlantis 1.1 system is being run. ---------------------------------------------------------------------- Game: Celestial Empire Type: strategic economic/military space-opera Duration: close-ended, 30+ turns Turns: one per week GM: Dougal.Scott@fcit.monash.edu.au Status: occasionally starting new games Description: Players compete to capture worlds which produce many different types of resources, of which different amounts are needed to manufacture various items. The author, Dougal Scott, is running several games, and he periodically starts new ones. The rules can be ftped from yoyo.cc.monash.edu.au in the directory /pub/celemp. After you have read them, if you still want to join a game, send your name to Dougal at the address above. He is also looking for a new moderator to take over running his games, because he is graduating. ---------------------------------------------------------------------- Game: Diplomacy Type: email version of Avalon Hill's pure strategy game Turns: frequency varies from one per day to one per 2 weeks for different games. Email Server: judge@morrolan.eff.org HELP in body of message; the subject is ignored. Description: The Diplomacy Adjudicator is a fully computer-moderated gamemaster for Avalon Hill's Diplomacy boardgame. To get more information from the moderator, send email with the word "HELP" in the body of the message (the subject is ignored) to judge@morrolan.eff.org. There are also other judges available, but most games are run on the EFF judge. The diplomacy Hall of Fame is available via ftp from ftp.netcom.com, directory /pub/starkey. Diplomacy is probably the biggest PBEM game out there, with 297 games going as of April 15. I'd estimate at least 1,000 players are active in one or more games. ---------------------------------------------------------------------- Game: Galactic Conqueror (German language) Type: strategic, economic/military, space opera setting Duration: typically 25-30 turns Turns: typically 1 per week GM: hz@zardoz.ruhr.de (Harry Zimmermann) Description: Galactic Conqueror is strategic SF-PBeM-Game for up to 50 players. Each player starts the game with a small fleet of starships and is the owner of one of several hundred planets. The winner is determined by an point system which gives points for specific actions each turn. The first player who reaches a pre-set winning score will be the winner of the game. Since there are almost no trade options in the game, player interaction mostly concerns negotiations about borders and coordination of attacks or defense. Players can: o invest in science o build industrial facilities and strongholds on planets o build ships (26 different classes) o attack enemy or neutral planets o engage in espionage or corruption o and much more... At the start of the game, each player can see only 4-10 planets, whose coordinates are given relative to his own starting-planet. Every time a new planet is conquered, all planets up to a given distance from this new one are revealed. The rules and an Atari ST and PC Clone client can be ftped from ftp.cp.tn.tudelft.nl, in the directory /pub/pbm/Galactic_Conqueror. The clients are graphical point-and-click interfaces to the game. You could play without a client, but this is not recommended. An X11 client is in the works, as is an eventual translation of the rules into English. ---------------------------------------------------------------------- Game: Galaxy Type: strategic, economic/military, space opera setting Duration: typically 50-80 turns Turns: typically 1 or 2 per week Email Server: galaxy@acca.nmsu.edu, Subject: HELP GM: bampton@cs.utk.edu (Howard Bampton) GM: rwallace@vax1.tcd.ie (Russell Wallace) Description: The game typically takes place on a 100x100 2D map, with a few hundred planets and 20 to 50 players. Players compete to capture planets, which can be used for economic expansion. You can purchase technology in several different areas, allowing your ships to fight harder and move faster. Galaxy turns range in size from 10kbytes early in the game to 100-200kbytes late in the game. The rules and source code are available for ftp, or via the email server, whose address is galaxy@acca.nmsu.edu. It takes commands in the subject line. Start with "help". There is also (at the moment) a separate mailing-list server at galaxy-request@acca.nmsu.edu, which has mailing lists with game announcements and discussion of code development. There are 21 games running on this server as of March 1, 1994. You can write to humans who run games; they start games occasionally and also have standby positions. They are: bampton@cs.utk.edu rwallace@vax1.tcd.ie Howard Bampton has a variant called "blind" galaxy. You can ftp the source for it from cs.utk.edu:/pub/bampton. It features a wraparound map, a double-blind mail-forwarding system, and you received only limited information about other players other than what you can observe at systems where you have ships. ---------------------------------------------------------------------- Game: Judgment Day Type: strategic economic/military, present day setting Turns: one per week GM: rwallace@vax1.tcd.ie (Russell Wallace) Status: beta-test finished, looking for a moderator Description: Judgment Day is a game for up to 25 players. Each player controls an empire which can build weapons and attack each other. When the nukes start flying, remember to duck and cover. The source code is available at the ftp sites or from Russell. ---------------------------------------------------------------------- Game: Republic of Rome Type: Historical (Roman Empire) Turns: player-paced Email Server: ror@hpeswlw.fc.hp.com HELP in body of message, the subject is ignored Description: RoR is an email adjudicator for Avalon Hill's game Republic of Rome, a cutthroat game of politics set in ancient Rome. All aspects of play are fully automated; there is no human GM. Players control factions of Senators; each turn they must elect officers and vote to raise and deploy forces to fight the many wars that arise; they work to increase the influence and popularity of their own Senators but must also work together to prevent destruction by war or by popular revolt. If Rome falls everyone loses. To get started, buy a copy of the board game, read the rules, then send email to the address above with the word "help" in the body of the message. ---------------------------------------------------------------------- Game: Star Empires Type: strategic empire-building, space setting Turns: one per week, 60+ turns per game GM: rhl@jambo.mitre.org (Roger Lincoln) Status: occasionally starting games; watch rec.games.pbm Description: Star Empires is a very simple game which is very addictive. Players compete to control planets, which produce resources which can be used to build various types of ships. There is generally a large amount of diplomacy, and the GM encourages humorous player press releases. The rules are available for ftp from the Dutch ftp site. ====================================================================== Archives and subscriptions by email ====================================================================== PBEM is archived for ftp at "ftp.erg.sri.com" and "ftp.cp.tn.tudelft.nl", or check archie or use Veronica to look for gopher sites, of which there is at least one, cic.net. I have a mailing list that distributes the magazine, but I prefer that you obtain it via Usenet or CompuServe or other means instead of asking to go on the mailing list. ====================================================================== The remainder of this magazine does not change, and is not of interest to most readers anyway. Skip it. ====================================================================== Hints regarding sending Electronic Mail to other networks ====================================================================== OK, so now you're wondering, "I'm using FidoNet or CompuServe or FoobieBlech and those email addresses he keeps on talking about sure look funny to me!". Welcome to the modern world of networking. See, there's this big amorphous network called the Internet that lots of other networks and services, like FidoNet, CompuServe, DELPHI, America Online, GEnie and Prodigy are hooked up to. And you can send email between all of them, if you know the right incantations. Sometimes size or cost limitations will keep you from being able to play games on another network, but at least you can send me letters to the editor or articles. If your Compuserve ID is [76515,1122] then your canonical Internet address will be "76515.1122@compuserve.com" -- notice that the comma has become a period. To send mail from CompuServe to the Internet, you use this sort of address: >INTERNET:gl8f@virginia.edu Compuserve users have to pay extra for mail to or from the Internet. If you're a flat-fee user, the cost is 5 cents per 2500 characters, minimum 15 cents, but the first $9 per month is free. This can add up to a bit of money if you send frequent messages, or get into a Galaxy end-game where your turns are large. In addition, the maximum size for a given message is 50kbytes, and most Internet games do not split their game turns into pieces if they are too large. Diplomacy and Arena, for example, generally don't have large turns. Diplomacy games with no press don't send that many messages. America Online does not charge any extra fee for Internet email, and has recently removed their limit on message size, so they are perfectly adequate for playing Internet games. Their addresses look like "username@aol.com" Delphi addresses look like "username@delphi.com". Internet access costs $3/month extra, but that gets you access to email, ftp, irc, gopher, etc. at their normal hourly charge. Prodigy has finished their gateway. I don't know how much they charge for sending messages to the Internet. They do have a charge for sending large numbers of messages inside of Prodigy. Their addresses look like "username@prodigy.com" GEnie's addresses look like this: username@genie.geis.com. The maximum incoming message size is 900kbytes, but the biggest outgoing message is 50k or 2500 lines, as limited by the GEnie message editor. These sizes are big enough to play all games. GEnie doesn't charge extra for Internet email. FidoNet addresses, such as "Dale Webber at 1:105/55.0", look like dale.weber@p0.f55.n105.z1.fidonet.org in Internet form. To send email to the Internet from FidoNet, send normal netmail to the user UUCP, and then on the first line of the message, put the line: To: gl8f@virginia.edu Unfortunately, unless your FidoNet BBS is hooked directly to the Internet, they ask that you keep email under 10kbytes and only occasional. Ask your sysop for more information. ====================================================================== What's this "ftp" thing anyway? ====================================================================== ftp is an acronym for "file transfer protocol", and it is only directly available to the privileged few who are directly hooked to the Internet using heavy-duty hardware. There is a way to use ftp via email, and if you can get email to me, I will send you a document explaining how to use it, or send email to ftpmail@decwrl.dec.com, with an empty Subject: line, and the word "help" in the body of the message. The Dutch ftp site, ftp.cp.tn.tudelft.nl, has a way for you to retrieve any of its files via email, either by sending it mail or telneting to it. To get the helpfile either : telnet ftp.cp.tn.tudelft.nl 2001 MAIL HELP (for small help file) or SEND HELP (for big help file) or INDEX (for the index) QUIT or mail to pbm-server@cp.tn.tudelft.nl with the following body : BEGIN HELP or SEND HELP or INDEX END ====================================================================== PBEM is published monthly. Please redistribute it far and wide, but do not modify or delete any articles. Write me if you want to redistribute it in other forms; such permission is easy to obtain. For example, some old articles are being translated into German. PLEASE CONTRIBUTE! Our focus is primarily on free wargames, but we're interested in articles about anything relevant.