# 2018q3 第 15 週測驗題 ### 測驗 1 Virtual memory can be thought of as a mechanism that caches virtual pages in the physical memory. A virtual page can be stored at any physical page frame. Which of the following statement is true? ==作答區== * (a) virtual memory is fully associative * (b) virtual memory is set associative * (c) virtual memory is direct mapped ### 測驗 2 If we need 32 bits to represent a virtual address and our page size is 4KB, how many page table entries (PTE) do we need? ==作答區== * (a) 2^22^ * (b) 2^20^ * (c) 2^12^ * (d) 2^10^ ### 測驗 3 A page table is a map of <vpn, ppn>, where vpn is a virtual page number and ppn is a physical page number. The process of generating the appropriate ppn for a vpn is referred to as: ==作答區== * (a) address counting * (b) address swapping * (c) address translation * (d) address protection ### 測驗 4 A single-level page table has only one table, where a multi-level page table has multiple tables organized in a hierarchical manner. Which of the following statements are true? ==作答區== * (a) If your program uses 100% of the virtual address space (even the parts normally not used), having a multi-level page table requires less space than a single-level page table * (b) For a multi-level page table, the amount of space it requires varies based on how many pages are in use * (c) For a single-level page table, the amount of space it requires varies based on how many pages are in use ### 測驗 5 A page table is a map of <vpn, ppn>, where vpn is a virtual page number and ppn is a physical page number. The virtual address can be split as <vpn, po>, where po is the page offset. Given this information, how would you form the physical address? ==作答區== * (a) <ppn> * (b) <ppn, vpn> * (c) <ppn, po> * (d) <vpn, po>