Question Paper

Start: 15:47 Paused: 16:40 Resume: 17:40

1. c
2. c
3. d
4. a
5. b
6. c
7. c
8. a (disagreement)
9. b
10. d
11. a
12. c
13. d (incorrect?)
14. c
15. d
16. a
17. b
18. b
19. d
20. a
21. b
22. a (verify)
23. b
24. d
25. a
26. c
27. b
28. d
29. a
30. b
31. b
32. a
33. c
34. c
35. b (off by 10
36. a (wrong)
37. b
38. a
39. b
40. c
41. b
42. d
43. a
44. fuck this question

fuck this q. p2

Cache access time = 20ns Memory access time = 500ns HDD access time = 0.01ms

; pseudocode function fetch(address) { data = fetchFromCache(address); if data { return data; }

return fetchFromMemory(address);

}

pageTable = fetch(); page = pageTable.get();

if page { return fetch(page.address); } else { return fetchFromDisk(); }

; cost Effective access time between cache / memory:

0.95 * 20ns + 0.05 * (20ns + 500ns)
    = 45ns

To fetch page table: 45ns If hit, to fetch data: 45ns If fault, to fetch data: 0.01ms

; pseudocode ; under the assumption that we check the cache first data = fetchFromCache(address);

if data { return data; } else { pageTable = fetchFromMemory(); page = pageTable.get();

if page {
    return fetchFromMemory(page.address);
} else {
    return fetchFromDisk(page.address);
}

}

; cost Final EAT: 20ns + 0.05 * ( 500ns + 0.99 * 500ns + 0.01 * 0.01ms )