Assume that there are three processes P1, P2, P3and P4 and four resources R1, R2, R3 and R4. The processes make the requests for resources in the following order:

• P1 requests R1
• P2 requests R2
• P3 requests R3
• P4 requests R4
• P1 requests R2
• P2 requests R3
• P3 requests R4
• P4 requests R1

Assume that there is only one instance of resources R1, R2, R3 and R4.

• Draw a resource allocation graph and find out if the above processes will deadlock or not?
• What are the four necessary conditions for a deadlock to happen?