MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Deadlock Avoidance

Consider 3 co...

Question

Consider 3 concurrent processes X, Y & Z which request resources in the order given in options. There are total 5 resources $R_{1}$ to $R_{5}$ . If process do not get resource, it waits till it becomes available. Once process completes, it release all resources it has. Which of the following guarantees deadlock free operation?

Open in App

Solution

Option (A)

If all processes start concurrently. X can wait for $R_{5}$ which is taken by Z, Y wait for $R_{2}$ which is taken by X & Z waits for $R_{1}$
$∴$ Its a deadlock.
Option (B) & (D) also may lead to deadlock.
In option (C), the resource request sequence is in ordered sequence
$∴$ Its deadlock free.

Suggest Corrections

thumbs-up

0

Similar questions

Q. A system has m resources:

R_{0}, R_{1} . . . . . R_{m - 1}

& n concurrent processes

P_{0}, P_{1} . . . P_{n - 1}

. The implementation of resource request logic of each process

P_{i}

, is as follows

{{Request R}_{[(t m o d m)]}

{Request R}_{[(t - 2) m o d m]}

}

If first resource is not available, process waits till it becomes available & then only request next.
Which of the following statement is TRUE?

Q. There are resources in system, n processes & k is the requirement of each process. Which of the following condition must be satisfied so that deadlock free operation is guaranteed with minimum number of resources?

Q. A single processor system has three resource types X, Y and Z, which are shared by three processes. There are 5 units of each resource type. Consider the following scenario, where the column alloc denotes the number of units of each resource type allocated to each process, and the column request denotes the number of units of each resource type requested by a process in order to complete execution. Which of these processes will finish LAST?

alloc request
P0 121 103
P1 201 012
P2 221 120

Q. A system has n resources

R_{0}, R_{1}, . . . . R_{1}

, and k processes

P_{0}, P_{1}, . . . . P_{k - 1}

. The implementation of the resource request logic of each process

P_{i}

, is as follows:
if (i%2 = =0) {
if (i < n) request

R_{i}

;
if (i + 2 < n) request

R_{i + 2}

;
}
else {
if (i < n) request

R_{n - 1}

;
if (i +2< n) request

R_{n - 1 - 2}

;

In which one of the following situations is a deadlock possible?

Q. An operating system uses the Banker's alogrithm, for deadlock avoidance when managing the allocation of three resource types X, Y, and Z to three processes P0, P1, and P2. The table given below presents the current system state. Here, the Allocation matrix shows the current number of resources of each type allocated to each process and the Max matrix shows the maximum number of resources of each type required by each process during its execution.

	Allocation	Max
	X Y Z	X Y Z
P0 P1 P2	0 0 1 3 2 0 2 1 1	8 4 3 6 2 0 3 3 3

There are 3 units of type X, 2 units of type Y and 2 uits of type Z still available. The system is currently in a safe state. Consider the following independent requests for additional resources in the current state :
REQ 1: P0 requests 0 units of X, 0 units of Y and 2 units of Z
REQ 2: P1 requests 2 units of X, 0 units of Y and 0 units of Z

Which one of the following is TRUE?

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Deadlock Avoidance

OTHER

Watch in App

explore_more_icon

Explore more

Deadlock Avoidance

Join BYJU'S Learning Program

CrossIcon