But this digital computer was supposed to act as a flight simulator, a machine for which there was never any “answer,” just a constantly changing sequence of pilot actions and simulated aircraft responses. So Forrester and his team would have to create not a calculator but a computer that could monitor its inputs constantly, staying ready for whatever might come along; that could respond to events as fast as they occurred, without ever falling behind when things got hectic; and that could keep going until the simulation was over, however long that took. In short, they would have to create the world’s first real-time computer.
M. Mitchell Waldrop in The Dream Machine.
This is happening between 1945-1947.
Real-time computing is computer games’ heart and soul. It is the most complex type of programs and software, for it has to be solid in real time.
Today a modern computer game monitors in real-time inputs from 40 folks while simulating a 2-mile wide 3D world with real-time physics from lighting to sound to gravity (yeah we still cheat on all that, using pre-baked stuff as much as we can) simultaneously rendering all of this on 40 folks’ monitors at the rate of 60 frames per second, each frame being a grid of 2560 x 1440 pixels or more. Without crashing even if things become hectic. For as long as people play.
The complexity of something like Fortnite is beyond your comprehension (and mine).