Analyze the resource-allocation graph below. Which option is the corresponding…
2025
Analyze the resource-allocation graph below.
Which option is the corresponding wait-for graph?
Attempted by 128 students.
Show answer & explanation
Correct answer: the first option
In a wait-for graph, resource nodes are removed. For every pair Pi -> Rk and Rk -> Pj draw a process edge Pi -> Pj.
From the given resource-allocation graph:
P1 requests R1, and R1 is allocated to P3, so add P1 -> P3.
P3 requests R3, and R3 is allocated to P2, so add P3 -> P2.
P3 requests R4, and R4 is allocated to P5, so add P3 -> P5.
P3 requests R6, and R6 is allocated to P4 and P5, so add P3 -> P4 and keep P3 -> P5.
P4 requests R5, and R5 is allocated to P1, so add P4 -> P1.
The first option is the one that keeps only process nodes and matches these wait edges with the correct directions.