The role of the operating system
The operating system (OS) stands in the center of everything we do as programmers (well, unless you’re writing an operating system or working in the embedded realm), so there is no way for us to discuss any kind of fundamentals in programming without talking about operating systems in a bit of detail.
Concurrency from the operating system’s perspective
This ties into what I talked about earlier when I said that concurrency needs to be talked about within a reference frame, and I explained that the OS might stop and start your process at any time.
What we call synchronous code is, in most cases, code that appears synchronous to us as programmers. Neither the OS nor the CPU lives in a fully synchronous world.
Operating systems use preemptive multitasking and as long as the operating system you’re running is preemptively scheduling processes, you won’t have a guarantee that your code runs instruction by instruction...
