1-3. All memory references within a process are _____ that are dynamically

translated into _____ at run time. This means that a process may be

_____ such that it occupies different regions of main memory at

different times during the course of execution.

4-6. A process may be broken up into _____ and these need not be _____

in main memory during execution. The combination of dynamic

run-time _____ and the use of a page or segment table permits this.

7-10. If the preceding two characteristics are present, then it is _____ that

all of the pages or all of the segments of a process be _____ during

execution. If the piece that holds _____ and the piece that holds

_____ are in main memory, then at least for a time execution may

proceed.

11. The portion of a process that is actually in memory at any given time is

called the _____ of the process.

12-16. More _____ may be _____. Because we are only going to load

some of the pieces of any particular process, there is _____. This leads

to more efficient utilization of _____ because it is more likely that at

least one of the more numerous processes will be _____ at any

particular time.

17. It is possible for a process to be _____.

18. Because a process executes only in main memory, that memory is

referred to as ...

19. But a programmer or user perceives a potentially much larger memory -

that which is allocated on disk. This latter is referred to as...

20. When a processor spends most of its time swapping pieces rather than

executing instructions, this is known as...

21-22. When virtual memory is implemented via paging, what two bits must

be present in the page table entry for each page?

23-27. In principle, every virtual memory reference can cause two physical

memory accesses: one to _____, and one to _____. This would have

the effect of doubling the memory access time. To overcome this

problem, most virtual memory systems make use of a special _____

for _____, usually called a _____. It contains those page table entries

that have been most recently used.

28. If the desired page is not in main memory when it is needed to continue

execution, this is called a ...

Desire to...

29. ...decrease internal fragmentation.

30. ...decrease size of page tables

31. ...increase the number of pages available in main memory for a process

32. Physical characteristics (rotational) of most secondary memory devices.

33. Describe how a double page fault can occur for a single memory

reference.

34-35. Describe two programming techniques used in large programs that

tend to decrease the locality of reference within a process.

36. Demand paging

37. Prepaging

38-39. Choice of placement policy is an important issue for _____ but

relatively unimportant for _____.

40. What is frame locking? Where may it be used?

41. Select that page for which the time to next reference is the longest.

42. Replace that page that has not been referenced for the longest time.

43. Replace the page that has been in memory the longest.

44. Using a use bit, replace the first page whose use bit = 0, resetting that

bit to 0 for each page passed over.

45. If there are 10 pages in the set to be considered for replacement, what is

the maximum number of pages, under Clock, that may be scanned before

a page is found to be replaced.

46. In the modification of Clock using two bits (u - used; m - modified), there

are 4 possible combinations of u & m: 0,0; 0,1; 1,0; 1,1. Which

combination is chosen during step 1 of this algorithm?

47. Which is chosen during step 2 of the algorithm?

48. If Step 2 fails, Step 3 involves

a. A repetition of Step 1 only.

b. A repetition of Step 1, and Step 2 (if necessary).

49. How is it possible for a page to be unused, but modified?

50. Give a process a fixed number of pages within which to execute.

51. Allow the number of page frames allocated to a process to change over

the lifetime of a process.

52. Choose only among the resident pages of the process that generated the

page fault to find a page to replace.

53. Choose all unlocked pages in memory are candidates for replacement,

regardless of which process they belong to.

54. Of the 4 combinations of resident set management and scope of

replacement policies, which one is not possible?

55. The set of pages that a process is accessing over a period of time is

known as its ...

56. Monitor the _____ of each process.

57. Periodically _____ those pages that are not in its working set.

58. A process may execute only if ...

59. The past ...

60. A true measurement of the working set of each process ...

61. The optimal value of delta ...

62. What measurement may be used as an approximation for determining

whether or not the working set of a process is in main memory?

63. A problem with this approach is that during interlocality transitions, the

rapid succession of page faults causes _____ to swell.

64. An approach that attempts to deal with the phenomenon of interlocality

transition is the ...

65. A page is written out to secondary memory only when it is selected for

replacement.

66. Modified pages are written before page frames are needed, so that pages

can be written out in batches.

67-71. The load control policy is critical in effective memory management.

If _____ are resident at any one time, then there will be many

occasions when all processes will be blocked, and much time will be

spent _____. On the other hand, if _____ are resident, then, on

average, the size of the resident set of each process will be inadequate

and _____ will occur.