1.) Resource Allocation Graph

Example of a Resource Allocation Graph


Resource Allocation Graph With A Deadlock


Resource Allocation Graph With A Cycle But No Deadlock


Resource-Allocation Graph For Deadlock Avoidance


Unsafe State In Resource-Allocation Graph


Resource-Allocation Graph and Wait-for Graph


Resource-Allocation Graph
● Process


● Resource Type with 4 instances


● Pi requests instance of Rj


● Pi is holding an instance of Rj


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QUESTION:
=>How would you know if there's a DEADLOCK based on the resource allocation graph?

ANSWER:
If graph contains no cycles => no deadlock.
If graph contains a cycle
=> if only one instance per resource type, then deadlock (meaning if the cycle goes on a single path, it will result to a DEALOCK).
=> if several instances per resource type, possibility of deadlock (meaning if the resource allocation graph has several cycles it has a POSSIBILITY for DEADLOCK).