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?

Consider the following policies for preventing deadlock in a system with mutually exclusive resources. I. Processes should acquire all their resources at the beginning of execution. If any resource is not available, all resources acquired so far are released II. The resources are numbered uniquely, and processes are allowed to request for resources only in increasing resource numbers III. The resources are numbered uniquely, and processes are allowed to request for resources only in decreasing resource numbers IV. The resources are numbered uniquely. A process is allowed to request only for a resource with resource number larger than its currently held resources Which of the above policies can be used for preventing deadlock?

A

Any one of I and III but not II or IV

B

Any one of I, III, and IV but not II

C

Any one of II and III but not I or IV

D

Any one of I, II, III and IV

A system has n resources R0,…,Rn-1, and k processes P0,…..Pk-1. The implementation of the resource request logic of each process Pi. is as follows: if (i%2 == 0) { if (i

In a system, there are three types of resources and four processes that execute concurrently. At the outset, the processes have declared their maximum resource requirements using a matrix named Max as given below. For example, Max[ ] is the maximum number of instances of that would require. The number of instances of the resources allocated to the various processes at any given state is given by a matrix named Allocation. Consider a state of the system with the Allocation matrix as shown below, and in which 3 instances of E and 3 instances of F are the only resources available. Allocation E F G P0 1 0 1 P1 1 1 2 P2 1 0 3 P3 2 0 0 Max E F G P0 4 3 1 P1 2 1 4 P2 1 3 3 P3 5 4 1 From the perspective of deadlock avoidance, which one of the following is true?

A

The system is in safe state.

B

The system is not in state, but would be if one more instance of E were available

C

The system is not in safe state, but would be safe if one more instance of F were available

D

The system is not in state, but would be if one more instance of G were available

The conditions regarding selection from a list of suitable candidates to be called for interview after a written examination for appointment of management-level persons to a multi-national company providing accounting services and sales are mentioned below. Candidates: a) Must have a Bachelor's degree in Basic Science with 65% or more marks or BE with 55% or more marks. b) Must have passed the examination with 70% or more marks. c) Age must be between 25 to 30 years as of 1/4/18. d) Must have 3 years of experience in an Accounting Institution and must have a Diploma in Accounting with 60% or more marks. e) Must be currently getting CTC of Rs. 6 lakh or more per annum. If the candidate: 1) If he fulfills all the other conditions other than A above, he will be designated as Junior Accountant. 2) If he fulfills all the other conditions other than (d) and (e) above, he can be designated as Trainee-Accountant. If he fulfills all the above conditions including 5 years of experience, he can be designated as a Senior Accountant. He can be designated as Manager (Accounts) if he fulfills all the above criteria including educational qualifications of CA/ ICWA/ MBA (Finance). Study all the above information and answer the following question. Varun has passed the CA exam and has a bachelor's degree in basic science and a diploma in accountancy, having scored 75% or more in the written examination during his entire career and also in the written examination. His age is 27 years and with 4 years of experience in Accountancy, he has a CTC salary of 18 lakhs per annum. To which of the following positions can he be referred? Select from the given options.

A

Manager (Accounts)

B

Trainee-Accountant

C

Junior Accountant

D

Senior-Accountant

Consider the following statements regarding life time of any normally terminating process in an operating system. (I) The process must be in RUNNING state at least once during its execution. (II) The process must be in RUNNING state at least twice during its execution. (III) The process must be in WAITING state at least once during its execution. (IV) The process must be in READY state at least once during its execution. Which of the above statements are correct?

A

I and III

B

I only

C

I, III, and IV

D

I and II

An operating system uses the Banker’s algorithm 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 0 0 1 8 4 3 P1 3 2 0 6 2 0 P2 2 1 1 3 3 3 There are 3 units of type X, 2 units of type Y and 2 units 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: REQ1: P0 requests 0 units of X, 0 units of Y and 2 units of Z REQ2: P1 requests 2 units of X, 0 units of Y and 0 units of Z Which one of the following is TRUE?

A

Only REQ1 can be permitted

B

Only REQ2 can be permitted.

C

Both REQ1 and REQ2 can be permitted

D

Neither REQ1 nor REQ2 can be permitted

Consider a computer system with multiple shared resource types, with one instance per resource type. Each instance can be owned by only one process at a time. Owning and freeing of resources are done by holding a global lock (L). The following scheme is used to own a resource instance: function OWNRESOURCES(Resource R) Acquire lock L / / a global lock if R is available then Acquire R Release lock L else if R is owned by another process P then Terminate P, after releasing all resources owned by P Acquire R Restart P Release lock L end if end if end function Which of the following choice(s) about the above scheme is/are correct?

A

The scheme may lead to starvation.

B

The scheme may lead to live-lock.

C

The scheme ensures that deadlocks will not occur.

D

The scheme violates the mutual exclusion property.

Consider four processes P, Q, R, and S scheduled on a CPU as per round-robin algorithm with a time quantum of 4 units. The processes arrive in the order P, Q, R, S, all at time t = 0. There is exactly one context switch from S to Q, exactly one context switch from R to Q, and exactly two context switches from Q to R. There is no context switch from S to P. Switching to a ready process after the termination of another process is also considered a context switch. Which one of the following is NOT possible as CPU burst time (in time units) of these processes?

A

P = 4, Q = 10, R = 6, S = 2

B

P = 2, Q = 9, R = 5, S = 1

C

P = 4, Q = 12, R = 5, S = 4

D

P = 3, Q = 7, R = 7, S = 3

Two processes X and Y need to access a critical section. Consider the following synchronization construct used by both the processes Process ? /* other code for process ? */ while(true) { varP = true; while(varQ == true) { /* Critical Section */ varP = false; } } /* other code for process ?? */ Process ? /* other code for process ? */ while(true) { varQ = true; while(varP == true) { /* Critical Section */ varQ = false; } } /* other code for process ? */ Here, varP and varQ are shared variables and both are initialized to false. Which one of the following statements is true?

A

The proposed solution prevents deadlock but fails to guarantee mutual exclusion

B

The proposed solution guarantees mutual exclusion but fails to prevent deadlock

C

The proposed solution guarantees mutual exclusion and prevents deadlock

D

The proposed solution fails to prevent deadlock and fails to guarantee mutual exclusion

A certain computation generates two arrays a and b such that a[i]=f(i) for 0 ≤ i < n and b[i] = g (a[i] ) for 0 ≤ i < n. Suppose this computation is decomposed into two concurrent processes X and Y such that X computes the array a and Y computes the array b. The processes employ two binary semaphores R and S, both initialized to zero. The array a is shared by the two processes. The structures of the processes are shown below. Process X: private i; for (i=0; i

A

ExitX(R, S) {

P(R);

V(S);

}

EntryY(R, S) {

P(S);

V(R);

}

B

ExitX(R, S) {

V(R);

V(S);

}

EntryY(R, S) {

P(R);

P(S);

}

C

ExitX(R, S) {

P(S);

V(R);

}

EntryY(R, S) {

V(S);

P(R);

}

D

ExitX(R, S) {

V(R);

P(S);

}

EntryY(R, S) {

V(S);

P(R);

}

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