Consider a pure paging system that uses two levels of page tables and 32- bit ad
ID: 3741750 • Letter: C
Question
Consider a pure paging system that uses two levels of page tables and 32- bit addresses. Each virtual address is the ordered set v=(p, t, d), where the ordered pair (p, t) is the page number and d is the displacement into the page. Each page table entry is 32 bits (4 bytes). The number of bits that store p is np, the number of bits that store t is nt
1. Assume np = nt = 12.
a. How large (in bytes) is the table at each level of the multilevel page table? Hint: we have two levels, so we have two page tables (see slide 39 “Multilevel Page Tables”). How many entries each table has? Each entry has 4 bytes.
b. What is the page size, in bytes? Hint: how many bits are used to specify d?
2. Assume np = nt = 9.
a. How large is the table at each level of the multilevel page table?
b. What is the page size, in bytes?
3. Based on the above two settings, discuss the trade-offs of large and small table sizes.
Explanation / Answer
1.a) there are
32 bits in each page level entry so we use two able so 25= 5 pages in each table so that for two tables =2*5=10
b)210=1K=1024 bytes
a)25=32
b) The page size is= 24=16