(1) What is the primary problem in FIFO page replacement algorithm? (2) Although paging eliminates external memory fragmentation, it causes another problem. What is it? (3) What is the primary (most essential) advantage in "virtual memory"? 4) Although the contiguous space allocation scheme has a couple of major problems, i is still popularly used in many operating systems today. Mention two (essentially different) examples for the use of contiguous allocation. (5) Between any two processes, if a shared memory, accessible by a pointer, is the only shared resource, deadlock will not happen (i.e., accessing a shared memory by pointers usually does not cause a deadlock). This means that at least one (but potentially some, all) of the four necessary conditions of deadlock never happens. Which of the following condition(s) does (do) not happen? Select all that apply. (a) Mutual exclusion (b) No preemption (c) Hold and wait (d) Circular wait (f) None of the above