Question

With respect to deadlocks in an operating system, which of the following
statements is/are FALSE?

• A. Banker’s algorithm is used to prevent deadlocks
• B. Deadlock formation can be prevented by ensuring that the hold and wait condition is not allowed
• C. An assignment edge in a resource allocation graph is marked from a process to a resource
• D. A safe state guarantees that all processes can finish without formation of a deadlock

Hint:

Banker's algorithm is deadlock avoidance not prevention, and assignment edges in a resource allocation graph go from resource to process, not process to resource; these two claims are false.

Answer 1

The Correct Option is A, C

Step 1: Evaluate the claim that Banker's algorithm is used to prevent deadlocks. Banker's algorithm is a classic deadlock avoidance algorithm, it dynamically checks, before granting each resource request, whether the resulting state is safe. It does not statically deny one of the four necessary conditions the way prevention techniques do, so calling it a prevention technique is FALSE.

Step 2: Evaluate the claim that deadlock formation can be prevented by disallowing the hold-and-wait condition. Hold-and-wait is one of the four necessary conditions for deadlock (Mutual Exclusion, Hold and Wait, No Preemption, Circular Wait). Removing any one of these conditions prevents deadlock, so forbidding hold-and-wait (for example, requiring a process to request all resources at once) is a valid prevention technique. This statement is TRUE.

Step 3: Evaluate the claim about assignment edges. In a resource allocation graph, an edge from a process to a resource is a request edge; an assignment edge goes the other way, from a resource to a process already holding it. So this statement has the direction reversed and is FALSE.

Step 4: Evaluate the claim about safe states. This is exactly the textbook definition: a safe state has at least one ordering (safe sequence) of processes in which each process's remaining resource needs can be satisfied, guaranteeing no deadlock. This statement is TRUE.

Step 5: The FALSE statements are the Banker's algorithm claim and the assignment edge claim, options A and C.

\[ \boxed{\text{Options A and C are FALSE}} \]