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PROFESSOR: So case A-- weak Zeeman effect. So what are our states here? We discovered that and we know those are the coupled basis states. And the states of H0 tilde eigenstates-- they are approximate eigenstates-- are the states n, l, j, mj. And the energies were energies dependent on n and j. So the 1S 1/2, 2S 1/2, 2P 1/2, and 2P 3/2. Roughly, to remind you of what happened, the original states were shifted, and we used the j quantum number in here. And those are our multiplets. Those are our multiplets. And we have a lot of degeneracy as usual. So this is degeneracy here and degeneracy here because a multiplet P 3/2 is j equal 3/2. And that's four states. Here you have two states, and here you have two states as well. So quite a bit of states that are degenerate. So in principle, when we do the Zeeman splitting, we may have to consider the full matrix n, l, j, mj, delta H Zeeman, nl prime j m prime j. So what are our degeneracies? Our degeneracies are when you have...

In a weak priority system the currently-running task will always run to completion before considering what to run next. This means the worst-case latency for a device always includes the worst-case service time across all the other devices, i.e., the maximum time we have to wait for the currently-running task to complete. If there's a long-running task that usually means it will be impossible to meet tight deadlines for other tasks. For example, suppose disk requests have a 800 us deadline in order to guarantee the best throughput from the disk subsystem. Since the disk handler service time is 500 us, the maximum allowable latency between a disk request and starting to execute the disk service routine is 300 us. Oops! The weak priority scheme can only guarantee a maximum latency of 800 us, not nearly fast enough to meet the disk deadline. We can't meet the disk deadline using weak priorities. We need to introduce a preemptive priority system that allows lower-prio...