The answer for the question below is \"it is not safe\", can you please explain

Question

The answer for the question below is "it is not safe", can you please explain the steps for this problem.

Thank you.

Suppose that there are ten resources available to three processes. At time 0, the following data is collected. The table indicates the process, the maximum number of resources needed by the process, and the number of resources currently owned by each process. Which of the following correctly characterizes this state?

Process

Maximum Needs

Currently Owned

P0

10

5

P1

3

1

P2

6

2

The answer is "it is not safe"

Process

Maximum Needs

Currently Owned

P0

10

5

P1

3

1

P2

6

2

Explanation / Answer

Total resources are 10.

The current available resource is 10- 5 -2 -1 = 2

P0 needs 5 more resources to complete as it owned 5 and max need is 10. At this point 5 more resources cannot be assigned to P0 so it has to wait.

P1 needs 2 more resource to complete (as max need is 3 and currently owned 1). Available resources are 2. So it is allocated 2 resources and it completes its execution and after that it releases all the resources.

Then the total free resources available will be 2+(resource owned by P1) = 2+ 1= 3

P2 needs 4 more resources to complete as it owned 2 and max need is 6. At this point 4 more resources cannot be assigned to P2 as only 3 resources are available, so it has to wait.

Now the current situation is Available resources : 3

P0 needs 5 more resources to complete; P1 has completed its execution; P2 needs 4 more resources to complete

So P0 and P2 has to wait indefinite time for completion which would eventually create a deadlock situation.

Hence the state is not safe.

Hope this explanation helps. Thanks.

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