1 Explain the difference between internal and external fragmentation. 2 Given memory partitions of 100K, 500K, 200K, 300K, and 600K (in order), how would each of the First-fit, Best-fit, and Worst-fit algorithms place processes of 212, 417K, 112K, and 426K (in order)? Which algorithm makes the most efficient use of memory? 3 Consider a paging system with the page table stored in memory a. If a memory reference takes 200 nanoseconds, how long does a paged memory reference take? b. If we add a TLB, and 75 percent of all page-table references are found in the TLB, what is the effective memory reference time? (Assume that finding a page-table entry in the associative registers takes 10 ns, regardless a TLB hit or miss) 4 Consider the following page reference string: 1, 2, 3, 4, 2, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6. How many page faults would occur for the following replacement algorithms, assuming one, two, three, four, five, six, or seven frames? Remember all frames are initially empty, so your first unique pages will all cost one fault each. . LRU replacement . FIFO replacement Optimal replacement 5 A system has a 32-bit architecture so each process has 32-bit virtual address space. Each page is 4KB. If a program's total data/code can be fit into two pages, then what are the minimal/maximum page table overhead (in terms of the number of page table entries) for (a) a one-level page table; and (b) a two-level page table, assuming level-1 and level-2 tables are of the same size