Rumor has it that many MMORPGs (Massively Multiplayer Online Role-Playing Games) are using Linux on the back end to run their worlds, so your humble Gaming Industry editor decided to start knocking on some doors. The first kind folks to answer were those at Mythic Entertainment (www.mythicentertainment.com), who are the creators of the popular Dark Age of Camelot (DAOC, www.darkageofcamelot.com) game. Rob Denton, chief technology officer of Mythic Entertainment, took a few moments to answer some questions.

LWM: Please tell us briefly about Dark Age of Camelot. It's an MMORPG, correct?
Rob Denton: Yes, Dark Age of Camelot is a massively multiplayer online role-playing game, where people can create characters in a fantasy world based on Arthurian myths and legends (as well as Viking and Celtic lore). They can adventure with friends, make enemies, fight one another, and basically grow their characters in this online world.

LWM: Where is Linux involved in DAOC's back end?
Denton: Our game and Web servers are all running Red Hat Linux. Because we are an online game, we rely extensively on our server technology for game rules, logging, and billing. All of this is done on Linux servers.

LWM: Why was Linux selected to handle the back-end tasks that it handles?
Denton: Well, first and foremost because it is free - that and because we had been using Linux for a few years as back-end server technology for other smaller titles we published. We were very comfortable with developing on that platform and rely on its stability.

LWM: What other titles had you used Linux with?
Denton: We used Linux for back-end game servers on many titles between 1996 and 2001, when Camelot launched. They are: Darkness Falls; Darkness Falls: the Crusade; Magestorm Millenium; Splatterball Plus; and Spellbinder: the Nexus Conflict. DF and DFC were text-based online role-playing games; Magestorm, Splatterball, and Spellbinder are first-person shooters.

LWM: Why were the other back-end platforms selected to handle what they handle?
Denton: We don't have any other back-end server technology at all in Dark Age of Camelot - it's all Linux based.

LWM: What were some of the challenges involved in building your MMORPG? Were any of them Linux-specific?
Denton: The challenge in building a game of this type is the game design. Technology is very important - the game must be stable - but making the game fun is the game developer's greatest challenge.

LWM: What technical lessons have you learned along the way?
Denton: We're constantly learning lessons not only about game design, but also about the technology that our game uses.

LWM: Could you share a couple of examples with us, in both the game design and the technology?
Denton: The best example of this is when we found that we can support many more players on a server than we allow. So, we made a game decision to limit the amount of players simultaneously connected to one of our "shards" to 3,500. There's no strict technical reason for this; it's just that when more players than that connect, the world starts to feel crowded and it is harder to find places to go that aren't overrun with other players. Simply, it's not fun to play an online game when it is overcrowded.

LWM: What business lessons have you learned along the way?
Denton: Keeping your customers happy is, in our experience, the number-one challenge. Camelot is a subscription-based service, and we know that without our subscription-paying community, the game would quickly become unprofitable. So we spend lots of resources on updating the game, fixing bugs, and ensuring that our server code is stable and reliable.

LWM: Is there a Linux client?
Denton: No, currently we run only on MS Windows, since we utilize DirectX.

LWM: Do you plan to provide a Linux client?
Denton: When there is sufficient demand for one. This is a risky thing for us - it would take a lot of work to develop a new client, and of course support it over the years that Camelot will continue to be played. Camelot was written using a commercial graphics engine API called NetImmerse that "sits" on top of DirectX. When we start thinking about porting the client to another OS, we'll have to come up with another graphics engine solution, and that will be time consuming.

LWM: If you don't plan to provide a Linux client at the moment, what would have to change in order for you to consider such a move?
Denton: Having a huge upswing in the amount of Linux desktop machines, plus a commercially accepted 3D graphics standard that we could port to. We are very happy with Linux as a back-end server technology - our entire business is based on it - but we feel that Linux client technology is lagging a bit behind. It'll catch up soon enough, and when it does, we'll think about porting.

LWM: OpenGL is the standard used for both OS X and Linux games, and is heavily backed by game companies like id Software. id doesn't use DirectX at all to my understanding, they use entirely OpenGL, even for Windows.
Denton: That's true, but id is in the business of making graphics engines that they license to other companies (as well as developing games, of course). Mythic is not in that business; we licensed an engine technology to develop Spellbinder and Camelot with, and that happens to be based on DirectX on the Windows platform. Of course it's possible for us to license another technology that is more portability friendly, but we need to have a compelling business reason to do so.

LWM: Have the changes in Red Hat (the split between its community Fedora Project and its non-free RHEL) caused you any concern over which Linux platform you will use for your next offering, or for your current platform?
Denton: Yes, we're very concerned over the RHL/RHEL/Fedora split. It has caused us to closely re-examine our choice in both Linux distribution and server hardware vendor (due to support issues with alternate Linux distributions as we move forward). As of now we still haven't made a decision as to what we're doing, but we're leaning toward creating and supporting our own internal Linux distribution rather than moving forward with RHEL or Fedora.