Is there a scheme for servicing disk requests that we would be even less inclined to call disk scheduling than FCFS?

What will be an ideal response?

We could certainly choose the requests at random. Some people would argue that this
would deliver even worse performance than FCFS, but on reflection one realizes that random
and FCFS should perform identically, since we are assuming random arrivals of disk requests
to begin with. In the text we pointed out several examples, however, where disk requests do not arrive randomly, so in fact FCFS probably would tend to be at least a bit better than random.
In addition, a purely random scheduling algorithm allows for indefinite postponement
because an unlucky request might never be chosen.