Programming-for-Output-Problems
October 6, 2023Computer-Organization
October 6, 2023Operating-Systems
| Question 9 |
Consider the following snapshot of a system running n concurrent processes. Process i is holding Xi instances of a resource R, 1 ≤ i ≤ n. Assume that all instances of R are currently in use. Further, for all i, process i can place a request for at most Yi additional instances of R while holding the Xi instances it already has. Of the n processes, there are exactly two processes p and q such that Yp = Yq = 0. Which one of the following conditions guarantees that no other process apart from p and q can complete execution?
| Min (Xp, Xq) ≥ Min {Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q} | |
| Xp + Xq < Max {Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q} | |
| Min (Xp, Xq) ≤ Max {Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q} | |
| Xp + Xq < Min {Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q} |
Question 9 Explanation:
{P1, P2, …, Pn}
Pi holds Xi instances.
Pi can request additional Yi instances.
Given two process p & q such that their additional requests are zero.
Yp = Yq = 0
{Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q} means that out of ‘n’ processes, we are left with (n-2) process (except p&q), i.e., Yk indicates additional request of all the processes (n-2) except p & q.
For p & q to complete first, accordingly
Xp + Xq < Min {Yk}
Option D is correct.
There are exactly two process p and q which do not need any additional instances of resources.
So, p and q will complete their execution and will release Xp and Xq instances of resources.
Now to guarantee that no other process apart from p and q can complete execution, the no. of instances of resources available must be less than the minimum no. of instances of resources required by any other process, i.e.,
Xp + Xq < Min {Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q}.
Pi holds Xi instances.
Pi can request additional Yi instances.
Given two process p & q such that their additional requests are zero.
Yp = Yq = 0
{Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q} means that out of ‘n’ processes, we are left with (n-2) process (except p&q), i.e., Yk indicates additional request of all the processes (n-2) except p & q.
For p & q to complete first, accordingly
Xp + Xq < Min {Yk}
Option D is correct.
There are exactly two process p and q which do not need any additional instances of resources.
So, p and q will complete their execution and will release Xp and Xq instances of resources.
Now to guarantee that no other process apart from p and q can complete execution, the no. of instances of resources available must be less than the minimum no. of instances of resources required by any other process, i.e.,
Xp + Xq < Min {Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q}.
Correct Answer: D
Question 9 Explanation:
{P1, P2, …, Pn}
Pi holds Xi instances.
Pi can request additional Yi instances.
Given two process p & q such that their additional requests are zero.
Yp = Yq = 0
{Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q} means that out of ‘n’ processes, we are left with (n-2) process (except p&q), i.e., Yk indicates additional request of all the processes (n-2) except p & q.
For p & q to complete first, accordingly
Xp + Xq < Min {Yk}
Option D is correct.
There are exactly two process p and q which do not need any additional instances of resources.
So, p and q will complete their execution and will release Xp and Xq instances of resources.
Now to guarantee that no other process apart from p and q can complete execution, the no. of instances of resources available must be less than the minimum no. of instances of resources required by any other process, i.e.,
Xp + Xq < Min {Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q}.
Pi holds Xi instances.
Pi can request additional Yi instances.
Given two process p & q such that their additional requests are zero.
Yp = Yq = 0
{Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q} means that out of ‘n’ processes, we are left with (n-2) process (except p&q), i.e., Yk indicates additional request of all the processes (n-2) except p & q.
For p & q to complete first, accordingly
Xp + Xq < Min {Yk}
Option D is correct.
There are exactly two process p and q which do not need any additional instances of resources.
So, p and q will complete their execution and will release Xp and Xq instances of resources.
Now to guarantee that no other process apart from p and q can complete execution, the no. of instances of resources available must be less than the minimum no. of instances of resources required by any other process, i.e.,
Xp + Xq < Min {Yk | 1 ≤ k ≤ n, k ≠ p, k ≠ q}.
Subscribe
Login
0 Comments