Sarah owns a book store. she is planning to stock some books by a famous author. but she has a tight budget, and she is not sure whether to stock all the previous books by the author or only the latest ones. what is the scarce resource in this scenario?
books

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4,999. the drive is currently serving a request at cylinder 2,150, and the previous request was at cylinder 1,805. the queue of pending requests, in fifo order, is: 2069, 1212, 2296, 2800, 544, 1618, 356, 1523, 4965, 3681