I get what you are saying but does every operating system have the goal of allowing unpredictable multiple user applications running? A cooperative system can easily be correct for something well managed like an IOT device with only certain tasks or something somewhat general purpose but still more restricted like a video game console.
> I get what you are saying but does every operating system have the goal of allowing unpredictable multiple user applications running?
Certainly not, cooperative multitasking is used all the time in userspace programs to great effect, and OSs can do the same thing if the limitations are understood.
For the OS that's the focus of this post though, I think it does have the aim of being general purpose and running whatever you want on it. At that point the limitations aren't really acceptable (which the author acknowledges), and that's why the whole question of "what happens when a program misbehaves?" has come up. If the answer is "preempt the process to run it later" then it's not actually a cooperative system and application developers need to keep that in mind.
