Free Deadlocks lessonsDeadlocks · Stage 0 · What a deadlock is · Step 2
Resource-allocation graphs
Draw who holds and who wants what, and learn when a cycle in the picture means deadlock. About 13 minutes.
A resource-allocation graph has a cycle, and every resource has several instances. What can you conclude?
- AThere might be a deadlock; the cycle isn't enough to prove it
- BThere is definitely a deadlock
- CThere is definitely no deadlock
Show the answer
There might be a deadlock; the cycle isn't enough to prove it. A process outside the cycle may release an instance that unwinds it.
4 questions on this idea
Short questions that apply the idea to new cases: trace it, work out a number, put steps in order. A wrong answer explains itself.
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