Section 4: 12 Points In the lecture, we have discussed the D…

Section 4: 12 Points In the lecture, we have discussed the Dining Philosophers problem: N philosophers sit around a table, with a fork between each pair of philosophers and a bowl of spaghetti in the middle. When a philosopher gets hungry, she picks up her left fork, then her right fork, then eats some spaghetti, and then puts down the fork, thinks some deep thoughts, and repeats. This famously can lead to a deadlock.

Suppose the water dispenser has a built-in scale that the se…

Suppose the water dispenser has a built-in scale that the server can read to see how much water is left in the dispenser. Can Alice use this feature to dispense water exactly once, even if the server does crash? If so, what changes are necessary? If not, why not? 

Bob later discovers that the customer’s machine room has fau…

Bob later discovers that the customer’s machine room has faulty electrical wires; the power goes out about once per week and comes back only after an hour. Explain why, if all the servers will be in this room, the customer cannot achieve six-nines availability.