首页 > 试题广场 >

Consider a simple paging syste

[问答题]

 Consider a simple paging system with the following parameters: 2 32 bytes of physical memory; page size of 2 10 bytes; 2 16 pages of logical address space. 10 pts

1 How many bits are in a logical address? 2 pts

2 How many bytes in a frame? 2 pts


3 How many bits in the physical address specify the frame? 2 pts

4 How many entries in the page table? 2 pts

5 How many bits in each page table entry? Assume each page table entry contains a valid/invalid bit. 2 pts

四、 Answer 10 pts

1 The number of bytes in the logical address space is (2 16 pages)*(2 10 bytes/page) = 2 26 bytes. Therefore, 26 bits are required for the logical address.

2 A frame is the same size as a page, 2 10 bytes.

3 The number of frames in main memory is (2 32 bytes of main memory)/(2 10 bytes/frame) = 2 22 frames. So 22 bits is needed to specify the frame.

4 There is one entry for each page in the logical address space. Therefore there are 2 16

entries.

5 In addition to the valid/invalid bit, 22 bits are needed to specify the frame location in main memory, for a total of 23 bits.

发表于 2017-05-16 21:26:23 回复(0)