I'm new to multiplayer programming, and I'm planning to build a 2D multiplayer action game (with entities and projectiles) as a start. I got critical questions in mind that I can't yet solve: 1a. What logic do multiplayer action games such as CS, Doom, Quake commonly use? -b. What's their pseudo-code / logic? -c. What should be sent to the server? -d. What should the client receive? -e. How is entity update being done? -f. How do you update the state of the projectiles (rockets / missiles)? -g. Where can I find a document that describes such multiplayer system? I think I found one on the internet a long time ago, but I have forgotten the link to that document. 2. Where do I find a tutorial for newbies on designing such multiplayer systems? 3. In most cases, it seems favorable for me to have multiple threads access a single FIFO data structure in order to allow for asynchronous events to happen independent of each other. Often times, I always have the fear that my program would break if 2 or more threads try to read/write to this FIFO data structure at the same time. Is this the case? If it is, what steps should I take to prevent it from happening?