Question: Understanding how OS works in depth

[ajaykmr2292]

I hope you have extensive experience in OS. I am pretty familiar with OS concepts but I am confused in understanding how these independent components cooperate and run on a single piece of hardware: the processor. How can I understand these things?
Example: I know that there are long-term, short-term schedulers in a OS. Short-term scheduler is going to be triggered on time-slice interrupts and its going to context-switches processes (in multitasking system). When does long-term scheduler run on the processor then?