Question 1

All unsafe states are___________

Accepted Answer

Unsafe states are not necessarily deadlocks, but they indicate a condition where the possibility of a deadlock exists if further precautions are not taken. An unsafe state leads to a situation where there is a potential for processes to get stuck waiting for resources, but it does not guarantee a deadlock.

Question 2

If no cycle exists in the resource allocation graph___________

Accepted Answer

If no cycle exists in the resource allocation graph, it indicates that there are no circular dependencies among processes for resources, which means the system can allocate resources in such a way that it can avoid deadlocks, thus being in a safe state.

Question 3

The resource allocation graph is not applicable to a resource allocation system

Accepted Answer

The resource allocation graph is specifically designed for systems with a single instance of each resource type. When there are multiple instances of a resource type, the graph cannot accurately represent the allocation state and potential deadlock situations, making it not applicable.

Question 4

The data structures available in the Banker's algorithm are___________

Accepted Answer

The Banker's algorithm uses all of the mentioned data structures: available, need, and allocation, to manage resources and avoid deadlocks.

Question 5

The content of the matrix Need is

Accepted Answer

The content of the matrix Need is calculated as max - allocation, which represents the maximum demand of each resource by each process minus the amount currently allocated to each process.

Question 6

The wait-for graph is a deadlock detection algorithm that is applicable when

Accepted Answer

The wait-for graph is specifically designed for scenarios where all resources have a single instance. In such graphs, nodes represent processes, and an edge from one process to another indicates that the first process is waiting for a resource held by the second process. This method is not directly applicable for resources with multiple instances, as the graph does not capture the complexity of multiple instances being held and requested.

Question 7

An edge from process Pi to Pj in a wait for graph indicates that___________

Accepted Answer

An edge from process Pi to Pj in a wait-for graph indicates that Pi is waiting for Pj to release a resource that Pi needs. This is used to represent resource allocation and waiting conditions in a system.

Question 8

If the wait for graph contains a cycle

Accepted Answer

A wait for graph is used to represent the allocation of resources and process requests in a system. If the wait for graph contains a cycle, it means that there is a set of processes each of which is waiting for a resource held by another process in the set. This situation indicates a deadlock because none of the processes can proceed until one of them releases a resource, which will not happen since each process is waiting for another resource to be released first.

Question 9

If deadlocks occur frequently, the detection algorithm must be invoked___________

Accepted Answer

If deadlocks occur frequently, the detection algorithm must be invoked frequently to identify and resolve them in a timely manner.

Question 10

What is the disadvantage of invoking the detection algorithm for every request?

Accepted Answer

The answer of What is the disadvantage of invoking the...

Question 11

A deadlock eventually cripples system throughput and will cause the CPU utilization to___________

Accepted Answer

Deadlock causes the system to halt progress on certain tasks, leading to underutilization of the CPU as it cannot proceed with the tasks at hand, causing CPU utilization to drop.

Question 12

Every time a request for allocation cannot be granted immediately, the detection algorithm is invoked. This will help identify

Accepted Answer

The detection algorithm is designed to identify the set of processes that have been deadlocked, not necessarily the specific process that caused it or a so-called "deadlock queue."

Question 13

A computer system has 6 tape drives, with 'n' processes competing for them. Each process may need 3 tape drives. The maximum value of 'n' for which the system is guaranteed to be deadlock free is?

Accepted Answer

To ensure the system is deadlock-free, each process must be able to obtain up to 3 tape drives. If there are 2 processes, each can potentially obtain 3 drives, using all 6 drives without causing a deadlock. However, with more than 2 processes, it's possible for each process to hold 2 drives without any being able to obtain a third, leading to a deadlock. Therefore, the maximum number of processes (n) for a deadlock-free system is 2.

Question 14

A system has 3 processes sharing 4 resources. If each process needs a maximum of 2 units then, deadlock___________

Accepted Answer

The system has 4 resources and each process needs a maximum of 2 units. So, the total number of units needed by all the processes is 2 * 3 = 6 units. Since the system has 4 resources, there is no way that all the processes can get the resources they need at the same time. Therefore, deadlock can never occur.

Question 15

'm' processes share 'n' resources of the same type. The maximum need of each process doesn't exceed 'n' and the sum of all their maximum needs is always less than m+n. In this setup, deadlock___________

Accepted Answer

Given the conditions, there's always at least one resource available for a process, preventing a deadlock situation.

Question 16

A deadlock can be broken by

Accepted Answer

Abort one or more processes to break the circular wait is a common strategy for handling deadlocks. By aborting a process, the system can break the cycle of processes waiting on each other, thus resolving the deadlock situation.

Question 17

The two ways of aborting processes and eliminating deadlocks are___________

Accepted Answer

The answer of The two ways of aborting processes and...

Question 18

Those processes should be aborted on occurrence of a deadlock, the termination of which?

Accepted Answer

The process that incurs the minimum cost should be aborted to resolve a deadlock, minimizing the impact on the system.

Question 19

The process to be aborted is chosen on the basis of the following factors?

Accepted Answer

The process to be aborted can be chosen based on various factors including its priority, whether it is interactive or batch, and how long it has been computing. These criteria help in making a decision that aims to minimize the impact of the abortion on the system's performance and user experience.

Question 20

Cost factors for process termination include___________

Accepted Answer

The amount of time a deadlocked process has consumed is a relevant cost factor for deciding whether to terminate it, as it reflects the investment already made in the process.

Quiz 14: Deadlock and Resource Allocation in Computer Systems