Deadlocks - deadlock characterization, prevention, avoidance, detection and recovery methods - One Line Questions

1. A cycle in a Resource Allocation Graph with multiple instances of each resource type implies: — A necessary but not sufficient condition for deadlock.
2. Which of the following is a characteristic of the 'Circular Wait' condition for deadlock? — A set of processes {P0, P1, ..., Pn} exists such that P0 is waiting for a resource held by P1, P1 is waiting for a resource held by P2, ..., and Pn is waiting for a resource held by P0.
3. Which of the following is a characteristic of the 'Hold and Wait' condition for deadlock? — A process holds at least one resource and waits for another resource held by a different process.
4. What is the 'Mutual Exclusion' condition for deadlock? — At least one resource must be held in a non-sharable mode; otherwise, no deadlock can occur.
5. Which recovery strategy involves aborting all deadlocked processes? — Abort all deadlocked processes
6. When recovering from a deadlock by aborting a process, what is a common strategy to minimize cost? — Abort the process that has made the least progress.
7. Which of the following is a strategy for deadlock prevention by ensuring that once a process has started using a resource, it cannot be preempted? — Ensuring that processes are not allowed to hold resources indefinitely.
8. Which of the following is a deadlock detection algorithm that relies on checking for cycles in a graph? — Wait-for Graph Cycle Detection
9. Which deadlock avoidance algorithm dynamically examines the resource allocation state to ensure that there is never a state where a circular wait condition can occur? — Banker's Algorithm
10. Which of the following is a deadlock detection algorithm that uses a wait-for graph? — Cycle Detection Algorithm
11. The Banker's Algorithm is primarily used for: — Deadlock Avoidance
12. Which of the following is a deadlock prevention technique that involves ordering all resource types? — Disallow Circular Wait
13. Which deadlock prevention strategy involves ordering all resource types and requiring processes to request resources in increasing order of enumeration? — Disallowing Circular Wait
14. Which of the following is a method of deadlock prevention that involves ensuring that processes do not request resources in a circular manner? — Disallowing Circular Wait
15. Which of the following is a deadlock prevention strategy that requires a process to request all of its resources at one time? — Disallowing Hold and Wait
16. Which of the following is a characteristic of the 'No Preemption' condition for deadlock? — Resources can only be released voluntarily by the process holding them.
17. Which condition is violated by setting all resources to be shareable? — Mutual Exclusion
18. Which condition for deadlock is violated if a process can be forced to release its resources even if it is still using them? — No Preemption
19. If a process is preempted and its resources are taken away, which deadlock condition is being violated? — No Preemption
20. Which condition for deadlock is violated if a process releases all its resources before acquiring new ones? — Hold and Wait
21. Which of the following is a condition for deadlock that states that a process will not be preempted until it voluntarily releases the resource? — No Preemption
22. Which of the following conditions is NOT necessary for a deadlock to occur? — Progress
23. In deadlock prevention, which condition is violated by ensuring that every process requests all its resources before it starts execution? — Hold and Wait
24. Which condition for deadlock is violated if a process can be forced to relinquish resources it holds? — No Preemption
25. In deadlock avoidance, a 'safe state' guarantees that: — The system can allocate resources to each process in some sequence without causing deadlock.
26. When recovering from a deadlock by preempting resources, what is a critical consideration? — Preempting from a process that will not require the resource again.
27. What is the fundamental difference between deadlock prevention and deadlock avoidance? — Prevention actively prevents deadlock conditions, while avoidance dynamically checks for safe states.
28. Which deadlock recovery strategy involves choosing a process and preempting its resources until the deadlock is resolved? — Resource Preemption
29. Which method of deadlock recovery involves selecting a process and restarting it from a previous checkpoint? — Rollback
30. If a deadlock is detected, which of the following is NOT a common recovery strategy? — System reboot.
31. Which of the following is a condition that MUST hold for a deadlock to occur? — Mutual Exclusion
32. What is the 'Progress' condition, which is NOT necessary for deadlock, often related to? — Process scheduling and execution order
33. Which of the following is a method to recover from deadlock by selecting a victim process and aborting it? — Process Termination
34. In deadlock recovery, what is the process of 'Rollback'? — Restoring a process to a previously defined safe state.
35. In a Resource Allocation Graph, a cycle indicates: — A potential for deadlock, or an actual deadlock if there is only one instance per resource type.
36. In the Banker's Algorithm, what does the 'Max' matrix represent? — The maximum number of resources of each type that a process may request.
37. In the Banker's Algorithm, what does the 'Need' matrix represent? — The remaining resources of each type that a process may still request to complete its task.
38. When recovering from a deadlock by preempting resources, what is a common criterion for selecting a victim process? — The process that has the lowest priority.
39. In the Banker's Algorithm, if a process requests more resources than its maximum declared need, what is the consequence? — The request is denied, and the process may be terminated.
40. In the context of deadlock avoidance, what does the 'Available' vector represent in the Banker's Algorithm? — The number of instances of each resource type currently available for allocation.
41. A state is considered 'safe' in the Banker's Algorithm if: — The system can allocate resources to each process in some order and still avoid deadlock.
42. Which of the following is a disadvantage of deadlock prevention techniques? — They reduce resource utilization and system throughput.
43. What is the main challenge with deadlock detection algorithms? — They can be computationally expensive, especially with many processes and resources.
44. What is a potential disadvantage of using deadlock prevention methods? — They can significantly reduce the degree of concurrency and system utilization.
45. What is the primary goal of deadlock avoidance algorithms? — To prevent deadlocks by ensuring safe states.
46. What is the primary goal of deadlock detection algorithms? — To identify when a deadlock has occurred and take action.
47. What is the purpose of the 'Allocation' matrix in the Banker's Algorithm? — To track the resources currently held by each process.
48. Which of the following is a method for deadlock detection that involves maintaining a matrix of available resources and resource requests? — Algorithm based on available and allocation matrices
49. Which of the following is a common representation for detecting deadlocks in a system with multiple instances of each resource type? — Detection Algorithm using Available and Allocation Matrices
50. Which of the following is a method of deadlock detection that works by trying to find a sequence of process completions? — Detection Algorithm based on Available and Allocation Matrices
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