# 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>`