April 1999
SW204: SOFTWARE AND FILES DESIGN

QUESTION 3

Total Marks: 20 Marks

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SAMPLE STUDENT'S SOLUTIONS
for Question 3

 
(a) There are three techniques which may be used to achieve virtual memory management. One of these techniques is pagination.
(i) Name the two other techniques which may be used to achieve pagination. [2]
(ii) Discuss four characteristics of the techniques named in part (i).

 

 [8]
(b) Using the Banker’s Algorithm, determine whether the situations described below are in a safe or an unsafe state. In both cases, show how your answer was derived.
(i) A system with a total of 12 tape drives. [6]
 
Process Maximum drive needed Drive allocated
P0 10 5
P1 4 2
P2 9 2

 
(ii) A system with the following resources:
  • A: 10 units
  • B: 5 units
  • C: 7 units
 [4]
 
Process Allocation Maximum
  A B C A B C
P0 0 1 0 7 5 3
P1 2 0 0 3 2 2
P2 3 0 2 9 0 2
P3 2 1 1 2 2 2
P4 0 0 2 4 3 3