os82 - b) 110 c) 2500 d) 3400 e) 4112 Answer 8.23 Logical...

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s Question 8.17 Assuming a 1KB page size , what are the page numbers and offsets for the following address references (provided as decimal number) a) 2375 b) 19366 c) 30000 d) 256 e) 16385 Answer 8.17 If size logical address space is 2 m and a page size is 2 n addressing units(bytes or word) , then the high order m – n represent Page number , and the low n order bits designate offset . Page Number Page offset p d m—n n As 1 kb = 1024 .so n = 1024 a) 2375 = 2375 % 1024 = 1 and rem = 1351 So Page Number = 1 Page offset = 1351 1 1351
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b) 19366 = 19366 % 1024 = 4 and rem = 2982 So Page Number = 4 Page offset = 2982 4 2982 c) 30000 = 30000 % 1024 = 4 and rem = 13616 So Page Number = 4 Page offset = 13616 4 13616 d) 256 = not possible as m < n I .e m-n < 0 e) 16385 = 16385 % 1024 = 4 and rem = 1 So Page Number = 4 Page offset = 13616 4 1 Question 8.23 Consider the following segment table :- Segment Base Length 0 219 600 1 2300 14 2 90 100 3 1327 580
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4 1952 96 What are the physical addresses for the following logical addresses ? a) 0,430
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Unformatted text preview: b) 110 c) 2500 d) 3400 e) 4112 Answer 8.23 Logical Address consists of two parts ; a segment number , s , and offset into that segment d. Logical address Segment Offset So to calculate the physical address =&gt; If the offset d of the logical address lies between 0 and the segment limit, then Physical address = &gt; Offset + Base , else it will trap the operating system displaying illegal offset. a) So for 0 , 4 30 logical address , 0&lt;430&lt;600 true 0 , 4 30 430 Physical address = 430 + 219 = 649 b) So for 110 logical address 0&lt;10&lt;14 true 110 1 10 Physical address = 10 + 2300 = 2310 c) So for 2500 logical address there is no length so we cant determine physical address d) ) So for 3,400 logical address 0&lt;400&lt;580 true 3400 3 400 Physical address = 400 + 1327 = 1727 f) So for 4,112 logical address there is offset is 112 &gt; 96 (maximum length ) so it will trap and display and error length ,so we cant determine physical address...
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os82 - b) 110 c) 2500 d) 3400 e) 4112 Answer 8.23 Logical...

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