First post here, glad I found this exchange. I am in my Operating Systems course at university learning process scheduling. In my homework assignment we have to fill out a simulated scheduling chart along with the corresponding Gant chart. The arrival time of the first process is at time 0, and it's service time is 5 seconds. The second process doesn't arrive until time 7. The time quantum is 6. How do I fill out the gant chart if nothing is in the queue?
All operating systems have some sort of idle loop, twiddling it's thumbs if there is nothing else to do. If there are no ready tasks (no user tasks, and no kernel-internal tasks either), just waste time (today perhaps even power down the processor and schedule to wake up in a short while if nothing else happens).