Resource allocation graph

1. What is Resource Allocation Graph explain?
2. What are the components of Resource Allocation Graph?
3. What are the edges of Resource Allocation Graph?
4. What does a knot and cycle in a Resource Allocation Graph indicate?
5. What is deadlock in C?
6. What is Banker's algorithm in OS?
7. Is no cycle exist in the Resource Allocation Graph?
8. What is resource allocation in operating system?
9. How many vertices are there in Resource Allocation Graph?
10. What is allocation edge?
11. How can wait for graph be obtained from the resource allocation graph?
12. Does a deadlock imply a knot?
13. What is meant by multithreading?
14. What is circular wait?
15. What is SQL deadlock?

What is Resource Allocation Graph explain?

The resource allocation graph is the pictorial representation of the state of a system. As its name suggests, the resource allocation graph is the complete information about all the processes which are holding some resources or waiting for some resources.

What are the components of Resource Allocation Graph?

Resource Allocation Graph (RAG) is a graph that represents the state of a system pictorially. There are two components of RAG- Vertices and Edges.

What are the edges of Resource Allocation Graph?

The Resource Allocation graph mainly consists of a set of vertices V and a set of Edges E. This graph mainly contains all the information related to the processes that are holding some resources and also contains the information of the processes that are waiting for some more resources in the system.

What does a knot and cycle in a Resource Allocation Graph indicate?

Deadlock detection: We have seen that a cycle in a resource-allocation graph may mean that there is a deadlock. ... If a resource-allocation graph is expedient, a knot is a sufficient condition for deadlock.

What is deadlock in C?

Deadlock in operating system is a situation which occurs when a process or thread enters a waiting state because a resource requested is being held by another waiting process, which in turn is waiting for another resource held by another waiting process.

What is Banker's algorithm in OS?

The banker's algorithm is a resource allocation and deadlock avoidance algorithm that tests for safety by simulating the allocation for predetermined maximum possible amounts of all resources, then makes an “s-state” check to test for possible activities, before deciding whether allocation should be allowed to continue ...

Is no cycle exist in the Resource Allocation Graph?

If no cycle exists in the resource allocation graph, there is no deadlock. If there is a cycle in the graph and each resource has only one instance, then there is deadlock. In this case, a cycle is a necessary and sufficient condition for deadlock.

What is resource allocation in operating system?

In computing, resource allocation is necessary for any application to be run on the system. When the user opens any program this will be counted as a process, and therefore requires the computer to allocate certain resources for it to be able to run.

How many vertices are there in Resource Allocation Graph?

According to the number of instances that may exist in the system, there are two types of resource vertices, i.e., single instance and multiple instances.

What is allocation edge?

An allocation edge, R_j --> P_i, means that the process P_i has been allocated the resource R_j. A cycle in a Resource Allocation Graph suggests that there might be circular wait in the system, i.e. deadlock. However, this may happen without deadlock being present.

How can wait for graph be obtained from the resource allocation graph?

A wait-for graph can be constructed from a resource-allocation graph by eliminating the resources and collapsing the associated edges, as shown in the figure below. An arc from Pi to Pj in a wait-for graph indicates that process Pi is waiting for a resource that process Pj is currently holding.

Does a deadlock imply a knot?

Theorem: In a general resource graph: a cycle is a necessary condition for deadlock. if the graph is expedient, a knot is a sufficient condition for a deadlock.

What is meant by multithreading?

Multithreading is a model of program execution that allows for multiple threads to be created within a process, executing independently but concurrently sharing process resources. Depending on the hardware, threads can run fully parallel if they are distributed to their own CPU core.

What is circular wait?

Circular waiting happens when one process is waiting for the resource, which is held by the second process, which is also waiting for the resource held by the third process etc. A deadlock occurrence can be detected by the resource scheduler. It's important to prevent a deadlock before it can occur.

What is SQL deadlock?

In terms of SQL Server, a deadlock occurs when two (or more) processes lock the separate resource. Under these circumstances, each process cannot continue and begins to wait for others to release the resource. ... The killed process is called the deadlock victim.