Which of the following is NOT a valid deadlock prevention scheme?

20002025

Which of the following is NOT a valid deadlock prevention scheme?

  1. A.

    Release all resources before requesting a new resource

  2. B.

    Number the resources uniquely and never request a lower numbered resource than the last one requested.

  3. C.

    Never request a resource after releasing any resource

  4. D.

    Request and all required resources be allocated before execution.

Attempted by 70 students.

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Correct answer: C

Deadlock prevention strategies work by eliminating at least one of Coffman's four necessary conditions for a deadlock to occur: Mutual Exclusion, Hold and Wait, No Preemption, and Circular Wait.

Option 3 does not break any of these conditions, nor does it structurally prevent loops in resource allocation graph cycles. In fact, a process is perfectly free to request new resources after releasing old ones without inducing a deadlock, provided it follows a valid protocol while holding them. This statement is simply an arbitrary operational restriction that provides no safety guarantees.

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