Releasing Linux versions has always been a matter of higher code quality, good software architecture, and technical interest for the platform. - Timothee Besset

I'll be damned if we don't find the time to get Linux builds done.

id is both a technology and an art company, so we try to push the art and the technology to its edge on each game, and when you're into high-tech you want to make sure your game can run on several platforms, and you have some room to experiment with several architectures. We don't want to have a basic product, get it out the door, sell as many copies as we can, and then just do the next one. Everyone's putting a lot of soul into the games, and id has got enough money overhead to decide that they can afford to have game ports to show that technology is good on Linux and on Apple hardware.

Most of the network related programming in games has to do with providing a good interactive experience when playing over the internet. This matter is very different from serving web pages. The primary concern there is to handle connection latency, latency fluctuations, packet loss and bandwidth limitations, and pretty much hide all of that from the player's experience.