By marking PTE’s invalid, no physical page needs to be allocated for that entry.

hex offset   0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1fdec offset   0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 310×44 ( 68): 06 09 18 1a 05 01 14 19 1d 0f 0f 17 03 04 14 13 08 03 0d 0e 06 1c 0d 01 14 1a 03 0a 11 0f 1e 020×45 ( 69): 01 00 14 18 12 17 10 12 19 01 12 19 11 02 0e 1e 1d 0a 0d 19 18 05 0b 14 0e 13 14 1b 10 19 15 1e0x46 ( 70): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×47 ( 71): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×48 ( 72): 02 1b 0a 09 14 17 1a 15 10 18 15 17 11 19 08 0d 04 19 1a 1e 19 15 02 07 1a 11 1c 11 14 14 03 0d0x49 ( 73): 10 06 0b 1d 18 07 1c 03 03 17 15 02 12 19 00 04 04 0c 0a 18 1b 18 11 09 11 1b 19 14 05 12 0b 0d0x4a ( 74): 7f 7f 7f fc 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 84 7f 7f 7f 7f f8 7f 7f0x4b ( 75): 10 07 1c 0e 17 19 15 09 17 1d 0f 00 1b 0d 11 11 0e 00 18 01 11 06 17 02 04 1a 11 16 18 19 1e 170x4c ( 76): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000x4d ( 77): 11 00 01 14 13 0d 1b 17 1b 1c 0c 00 1d 1c 15 10 01 0b 17 14 0b 0c 13 16 11 09 1e 17 05 17 1a 130x4e ( 78): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000x4f ( 79): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×50 ( 80): 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f e6 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f0x51 ( 81): 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f d3 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f df a2 ac 7f 7f 7f 7f 7f0x52 ( 82): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×53 ( 83): 07 1c 02 0c 17 18 02 14 14 05 0d 00 1d 00 15 19 19 0b 09 0c 0e 13 15 0e 1b 0e 0c 0d 08 0e 02 170×54 ( 84): be a7 e4 9d 7f 7f 92 7f d7 99 a0 e5 a9 9c a1 82 ca ba f2 7f b8 97 bd c1 e8 e2 d0 d1 ab d9 c3 8b0x55 ( 85): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×56 ( 86): 05 08 08 1a 00 10 03 03 08 19 0e 11 10 13 00 15 0b 10 0d 0f 01 11 07 17 1b 00 08 1b 0a 0b 18 100×57 ( 87): 7f 86 7f 87 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f ed 7f 7f 7f 7f 7f 7f 7f 7f d6 7f 7f 7f 7f 89 7f0x58 ( 88): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×59 ( 89): 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f e1 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f cb 7f 7f 7f 7f0x5a ( 90): 08 0e 03 07 02 08 0f 10 07 1c 01 0a 0e 15 15 0e 15 02 16 1b 1e 10 11 16 16 1a 06 05 1e 18 1c 010x5b ( 91): 05 05 16 15 12 10 13 17 14 04 07 1a 0b 14 16 07 0c 0c 0c 07 0d 0f 1c 19 1c 12 18 09 07 1d 1b 190x5c ( 92): 1b 1b 1d 04 0b 0b 03 06 08 0e 16 1a 1a 0c 0a 0f 1a 06 13 0d 03 09 0e 0a 19 15 1b 02 19 18 04 1e0x5d ( 93): 13 00 09 12 0e 06 05 1b 05 18 1a 00 16 11 11 13 14 12 1e 0f 1e 0a 0c 01 14 1e 09 16 17 01 00 1b0x5e ( 94): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000x5f ( 95): 0c 11 0a 09 07 1b 1c 02 07 10 12 02 09 1a 13 02 15 04 19 08 18 17 06 19 10 13 09 1c 0f 1d 02 0d0x60 ( 96): 0a 16 05 12 1d 1d 04 05 04 0d 0a 05 0c 11 18 06 10 07 10 0b 15 03 14 08 18 04 02 08 0c 16 12 0d0x61 ( 97): 13 01 01 16 11 0c 0e 10 02 0f 00 06 10 19 0a 0d 0f 17 14 14 04 1c 15 19 15 07 03 10 1b 0d 1b 1d0x62 ( 98): 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f bf 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f0x63 ( 99): 16 00 16 0d 05 0f 0c 10 0c 15 03 06 01 1e 17 0b 08 1e 09 0d 18 1b 12 19 05 00 03 0b 06 0d 0e 1a0x64 (100): 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f fa 7f 7f 7f 7f 7f 7f0x65 (101): 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 8c 7f 7f ef 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f0x66 (102): 02 05 07 19 06 1a 16 0e 16 01 1e 14 17 05 11 0d 04 1c 10 12 19 07 04 17 15 12 18 08 1e 05 17 170×67 (103): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×68 (104): 7f 7f 7f 7f 7f 7f 7f 7f da 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f ee 7f 7f 7f 7f0x69 (105): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000x6a (106): 14 13 0e 17 0c 02 04 18 0e 14 01 18 12 17 1a 14 0d 14 16 0c 03 12 1d 07 08 16 06 02 0b 0d 1a 040x6b (107): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000x6c (108): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000x6d (109): 07 14 05 11 0a 07 0a 0f 08 0b 0d 0a 19 08 0d 0d 01 18 04 13 1b 01 09 0e 0e 1e 1a 03 0f 0a 01 1d0x6e (110): 12 02 19 1d 0f 1c 0e 1b 02 16 01 01 1d 02 0a 1d 05 08 01 1e 00 1d 16 0a 1b 19 1a 1a 1c 06 13 0e0x6f (111): 19 0a 00 02 0a 08 08 0d 07 01 14 18 04 02 16 0c 0b 1c 1b 04 05 0d 11 04 00 02 09 1b 01 15 04 0d0x70 (112): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×71 (113): 14 17 05 08 14 18 0c 14 1b 0b 18 13 0c 13 06 1e 10 12 0c 04 1c 05 11 1d 05 10 05 1a 15 14 13 030×72 (114): 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 93 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f 7f0x73 (115): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×74 (116): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×75 (117): 1c 0d 19 0e 03 1c 1d 18 0c 10 18 1a 1a 08 0b 08 15 04 06 1a 1d 14 0b 17 00 1b 1b 1e 09 17 10 060×76 (118): 18 06 19 09 01 11 11 1d 08 0f 10 1c 10 1e 0f 05 0e 0e 04 13 0a 11 1c 11 0f 0e 06 17 12 02 06 0c0x77 (119): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000×78 (120): 1c 15 15 1c 11 06 18 09 07 00 17 0b 05 18 17 08 01 01 02 14 00 13 10 19 05 11 01 13 05 06 1e 190×79 (121): 19 07 04 19 07 14 14 06 01 14 19 02 15 0d 14 0f 14 01 06 04 13 0c 0a 15 13 03 12 1e 07 13 11 020x7a (122): 04 00 06 01 1a 13 03 1d 00 03 02 0d 1a 11 0f 14 0c 16 04 18 05 0b 03 17 1a 09 10 17 13 14 00 1c0x7b (123): 12 17 1e 06 1c 1d 02 0a 1a 1c 02 02 11 06 07 1a 0d 1c 1a 1a 09 12 0b 02 16 09 16 08 03 1a 1b 170x7c (124): 13 1a 09 1d 1a 17 10 08 0c 0a 04 0f 13 13 04 04 00 14 15 1b 10 14 05 11 03 1a 05 18 14 04 1e 0b0x7d (125): 12 1c 06 0e 0b 12 0d 0f 04 19 17 07 09 1c 07 10 04 10 07 0b 0b 1a 09 04 09 1e 1e 06 05 1d 05 010x7e (126): 16 0a 03 1a 1d 06 0f 0c 16 0f 0a 19 07 04 00 02 0c 1d 0c 1e 1c 19 1d 15 0c 0b 18 03 17 0f 15 1c0x7f (127): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

The segment table for a process running in this system is shown below:

A page table entry holds the virtual page number for a given physical page.

When prog is executed how many times will the number 3 be printed?

Sparsely used address spaces are poor candidates for multi-level page tables.

Virtual Addressing using Segmentation

When a user program attempts to access virtual address 0x6da9, what will be the first page accessed (decimal)?

For the same address space size, having smaller pages means you will have smaller page tables.

What is the size of a virtual address?