Single Instance of Each Resource Type

Q2. What happens when a Single Instance of Each Resource Type is present?

Ans.

Maintain wait for graph

Node are processes

P_i → P_j,

if P_i is waiting for P_j.

Invoke an algorithm that searches for cycle in the graph. If there is a cycle, there exists a deadlock.

An algorithm to detect a cycle in the graph requires an order of n² operations, where n=number of vertices or processes in the graph.

Figure: Resource Allocation Graph

Note:

• Process(P) to Resource(R) is a Request.
• Request (R) to Process (P) is a Assignment.

Figure: Wait for Graph