(b) Explain what the page table (PT) and the translation lookaside buffer (TLB) are and how they are used in a paging system to compute physical addresses. (6 marks) (c) Assume that accessing and searching the TLB takes 5 ns, transferring the data from the TLB into a register takes 10 ns, updating a record in the TLB takes 15 ns, accessing and searching the PT takes 50 ns, transferring the data from the PT into a register takes 70 ns, the TLB hit ratio is 0.6. How many nanoseconds are needed on average to perform all the TLB and PT operations needed to compute the physical address for a given virtual address (assuming that all referenced pages are in main memory) 8 marks)