7. [12 points] Page swapping writes memory pages to the disk to free up physical memory space. When page faults occur, the swapping mechanism will reload the pages back into the memory. Page swapping involves significant disk V O. Assume we use traditional magnetic disk for swapping, which performs quite well for sequential access but poorly for random access. Discuss whether the following practices would improve the performance of page swapping (remember to provide your reasons). (a) When swapping out pages to the disk, try to write the pages as a series of contiguous blocks on the disk (b) When the system is not busy, swap some rarely used pages to the disk even though the system may not be short of physical memory space at that moment (c) Form a RAID-5 disk array for handling the page swapping