Yes, you need to understand all the other processes, but in most cases, there are no other processes. You are writing everything the system is doing. It's up to

Yes, you need to understand all the other processes, but in most cases, there are no other processes. You are writing everything the system is doing. It's up to you to determine what is running in each thread and set it's priority appropriately so that each thread has enough time to run. Real time OSes give you complete control. What you do with that control is up to you based on your needs.