Question

A system has 12 magnetic tape drives and 3 processes: P0, P1, and P2. Process P0 requires 10 tape drives, P1 requires 4, and P2 requires 9 tape drives.

Maximum needs (process-wise: P0 through P2 from top to bottom):
10
4
9
Currently allocated (process-wise):
5
2
2
Which of the following sequences is a safe sequence?

a) P0, P1, P2
b) P1, P2, P0
c) P2, P0, P1
d) P1, P0, P2

Answer 1

To determine the safe sequence, we can use the Banker's Algorithm. Analyzing the given sequences, the safe sequence is P2, P0, P1.

Step-by-step explanation:

To determine the safe sequence, we can use the Banker's Algorithm. In this case, we have a system with 12 tape drives and 3 processes: P0, P1, and P2. The maximum needs of each process and the currently allocated tape drives are given. Let's check each sequence to see if it is safe:

1. Sequence a) P0, P1, P2: P0 requires 10 tape drives but there are only 9 available (2 tape drives are allocated to P1 and 5 are allocated to P2), so this sequence is not safe.
2. Sequence b) P1, P2, P0: P1 requires 4 tape drives and there are 13 available, so this sequence is safe. After P1 completes, 8 tape drives are available for P2 and P2 requires 9. Therefore, this sequence is not safe.
3. Sequence c) P2, P0, P1: P2 requires 9 tape drives and there are 9 available, so this sequence is safe. After P2 completes, 18 tape drives are available for P0 and P0 requires 10. Therefore, this sequence is safe.
4. Sequence d) P1, P0, P2: P1 requires 4 tape drives and there are 13 available, so this sequence is safe. After P1 completes, 8 tape drives are available for P0 and P0 requires 10. Therefore, this sequence is not safe.

Based on our analysis, the safe sequence is Sequence c) P2, P0, P1.