Chapter 29

Question 1

What are 2 techniques for the recovery of deadlock

Answer 1

1. Process termination

2. Resource preemption

Question 2

How deadlock detection works

Answer 2

Allow system to enter a deadlock state. There is detection algorithm to detect deadlock. If deadlock found then recovery of system.

Question 3

What algorithm used for deadlock detection in single instance resource type

Answer 3

Wait-for graph

Question 4

What are types of nodes in resource allocation graph

Answer 4

Processes and resource

Question 5

What is available data structure in bankers algorithm

Answer 5

It tells available instances of resources

Question 6

What are 3 possibilities of invoking deadlock detection algorithm

Answer 6

1. Run deadlock detection algorithm every time request can not be granted immediately. It is very expensive.
2. Monitor CPU utilization and when it lowers to some watermark then run detection algorithm
3. Run detection algorithm arbitrarily

Question 7

What are 2 ways in Process termination

Answer 7

1. kill all processes in deadlock

2. kill processes one by one and check if system came out of deadlock or not

Question 8

What is resource preemption

Answer 8

Take resources from process so deadlock break

Question 9

What is rollback in resource preemption

Answer 9

Process return to some safe state, restart process from that state.

Question 10

What are 3 main issues in resource preemption

Answer 10

1. Selecting a victim
2. Rollback
3. Starvation