A processor system has 16 pages of virtual address space but only four page 1 Initially, the memory is empty. A program references the virtual pages in the order frames. 7, 5, 2, 5, 5, 7, 9, 3, 0, 9 a. Which references cause a page fault with LRU? b. Which references cause a page fault with FIFO?

Suppose a computer system uses 16-bit addresses for both its virtual and physical addresses. In addition, assume each page (and frame) has size 256 bytes. How many bits are used for the page number? How many bits are used for the offset? 8 bits each. With this system, what’s the maximum number of pages that a process can have? 256 Suppose that each entry in the page table comprises 4 bytes (including the frame number, the valid bit, and miscellaneous “bookkeeping bits”). An OS uses an array to store the page table. What is the size of the page table? 1024 Bytes Furthermore, suppose the first 6 pages of a process map to frames 222 to 227 (as decimal numbers), and the last 5 pages of the process map to frames 1 to 5 (also decimal numbers). All other pages are invalid. Draw the page table, including the valid bit and the frame number. DONE Translate the following virtual addresses to physical addresses, and show how you obtain the answers. (Hint: You do not need to convert…

Exercise: A computer has 4 frames. Page size is 2KB (2048). The loaded time, the R and M bits for each page are shown below Page Frame Loaded time M R 11 1 15 3 13 4 5 5 7 6. 3 3 Question: compute the physical address of the following virtual address a) 1000 using FIFO b) 3100 using NRU c) 3100 using LRU d) 6200 using Second chance Note: consider each case separately

8.9. The IBM System/370 architecture uses a two-level memory structure and refers to the two levels as segments and pages, although the segmentation approach lacks many of the features described earlier in this chapter. For the basic 370 architecture, the page size may be either 2 Kbytes or 4 Kbytes, and the segment size is fixed at either 64 Kbytes or 1 Mbyte. For the 370/XA and 370/ESA architectures, the page size is 4 Kbytes and the segment size is 1 Mbyte. Which advantages of segmentation does this scheme lack? What is the benefit of segmentation for the 370?