GO Classes DPP | OS | RESOURCE ALLOCATION

Answer 1

$$
\begin{gathered}
n(2-1)<4 \\
n(1)<4 \\
n<4
\end{gathered}
$$

This means the system is guaranteed to be deadlock-free if the number of processes $n$ is $\mathbf{3}$ or fewer.

• A. THE SYSTEM IS GUARANTEED TO BE DEADLOCK-FREE IF $N=3$ : TRUE. As calculated, $n=3$ satisfies the condition $n<4$. Even in the worst-case scenario where each of the $3$ processes holds $1$ resource $($Total $= 3)$, there is still $1$ resource left in the pool to satisfy any process's request for a second copy.
   
• B. THE SYSTEM IS GUARANTEED TO BE DEADLOCK-FREE IF $N=4$ : FALSE. If $n=4$ , it is possible for each process to hold $1$ resource. At this point, all 4 resources are exhausted. Each process will then wait for a second resource that will never become available. This is a deadlock state.
   
• C. THE MAXIMUM NUMBER OF PROCESSES THE SYSTEM CAN SUPPORT WITHOUT ANY POSSIBILITY OF DEADLOCK IS $\mathbf{3}$: TRUE. This is the direct result of our inequality $n<4$. If $n$ increases to $4$, the "guarantee" of being deadlock-free disappears.
   
• D. IF $N=5$, A DEADLOCK IS CERTAIN TO OCCUR: FALSE. In GATE questions, "certain to occur" is a very strong claim. While deadlock is possible if $n=5$, it is not certain. If one process finishes its execution and releases its resources before the others hit their peak demand, the system can still complete all tasks without deadlocking.

Comments

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Answer 2

For Single resource type, with:

• m total instances

• n processes

• Each process needs at most k instances

Then, The system is guaranteed deadlock-free if:

                    m ≥ n ( k − 1 ) + 1

here m=4 , k=2 so n<=3 So A and C are True