System Software and Operating System – Previous Year Questions
336 questions from past UGC NET Paper 2 – Computer Science papers, each with the correct answer. Open any question for its explanation.
- Match List – I with List – II. List I: (A) LRU (B) Demand cleaning (C) Long term scheduling (D) Medium term scheduling List II: (I) Page not referenced for the longest time is replaced (II) Page is written to secondary…
- Three processes arrive as follows: Process Arrival Time Burst Time P0 0 ms 7 ms P1 1 ms 3 ms P2 2 ms 7 ms The preemptive shortest-job-first (SJF) scheduling algorithm is used, with scheduling decisions made only at a pr…
- Three processes arrive as follows: Process Arrival Time Burst Time P0 0 ms 7 ms P1 1 ms 3 ms P2 2 ms 7 ms The preemptive shortest-job-first (SJF) scheduling algorithm is used, with scheduling decisions made only at a pr…
- For the following set of processes scheduled using FCFS policy, determine the average waiting time. Assume that the processes arrived in the order P1, P2, P3, P4. Process Burst Time (ms) P1 8 P2 15 P3 10 P4 7
- Which of the following statements are true? (A) Shortest remaining time first scheduling may cause starvation. (B) Preemptive scheduling may cause starvation. (C) Round robin is better than FCFS in terms of response tim…
- An OS follows round robin scheduling with a time quantum of 4 ms. Assuming that the CPU is free now and there are 20 processes waiting in the ready queue, what is the maximum amount of time that a process waits before g…
- If an operating system does not allow a child process to exist when the parent process has been terminated, this phenomenon is called:
- Consider the following 3 processes, with the length of the CPU burst time given in milliseconds: Process Arrival Time Burst Time P1 0 8 P2 1 4 P3 2 9 What is the average waiting time for these processes if they are sche…
- Assuming that the system call fork() never fails, consider the following C programs P1 and P2 executed on a UNIX/Linux system. P1 P2 int main() { fork(); fork(); fork(); printf("Happy\n"); } int main() { fork(); printf(…
- Consider the following four processes with the arrival time and length of CPU burst given in milliseconds: Process Arrival Time Burst Time P1 0 8 P2 1 4 P3 2 9 P4 3 5 Using the preemptive shortest job first (SJF / SRTF)…
- Which module gives control of the CPU to the process selected by the short-term scheduler?
- A fair share scheduler computes the priority of a process based on which of the following? (1) Processor utilization by the individual process. (2) Weight assigned to the user/group. (3) Processor utilization by the use…
- Which of the following CPU scheduling algorithms may cause starvation of a process? (1) First-Come-First-Served (2) Round Robin (3) Priority scheduling (4) Shortest-Process-Next (5) Shortest-Remaining-Time-First
- A scheduling algorithm assigns a process's priority proportional to how long it has been waiting; every process starts at priority zero (the lowest), and the scheduler re-evaluates all priorities and picks the next proc…
- Which of the following statements are CORRECT? (A) A process always checks the state of the currently executing process to enter its critical section. (B) Spin locks use busy waiting. (C) Periodically testing a variable…
- At a particular time of computation, the value of a counting semaphore is 7. Then 20 P operations and 'x' V operations were performed on this semaphore. If the final value of the semaphore is 5, what is x?
- Match List I with List II: List I: (A) Critical region (B) Wait/Signal (C) Working set (D) Deadlock List II: (I) Hoare's monitor (II) Mutual exclusion (III) Principle of locality (IV) Circular wait Choose the correct ma…
- At a particular time of computation, the value of a counting semaphore is 7. Then 20 P operations and 'x' V operations were performed on this semaphore. If the final value of the semaphore is 5, what is x?
- Match List I with List II: List I: (A) Critical region (B) Wait/Signal (C) Working set (D) Deadlock List II: (I) Hoare's monitor (II) Mutual exclusion (III) Principle of locality (IV) Circular wait Choose the correct ma…
- In the design protocol of the critical section problem, each process must ask permission to enter the critical section in …… code; it then executes in the critical section; once it finishes executing in the critical sec…
- Consider a system with five processes P0 through P4 and three resource types A, B and C, with 7, 2 and 6 total instances respectively. At time T0 the system state is: Process Allocation (A,B,C) Request (A,B,C) P0 0 1 0…
- The Bounded Buffer problem is also known as the ________.
- Two atomic operations permissible on semaphores are ________ and ________.
- Three processes share a single counting semaphore S whose initial value is 1. All three execute wait(S) one after another, in the order P2, P1, P3. After this, P2 exits its critical section by executing signal(S), and t…
- In the UNIX operating system, when a process creates a child process using the fork() system call, which of the following is genuinely shared between the parent and child process, rather than being copied?
- A system has 12 instances of a resource R shared among four processes. The maximum need and current allocation of each process are: Process Max Need Current Allocation P1 8 3 P2 9 4 P3 5 2 P4 3 1 With reference to the c…
- Given 4 GB (≈ 4.3 × 10⁹ bytes) of virtual address space and a page size of 4 KB (= 4 × 10³ bytes), with each page table entry 5 bytes: how many virtual pages would this imply, and what is the size of the whole page tabl…
- An address in main memory is called:
- A table T with 17 rows and 1024 columns is stored in memory. T[i][j] and the variable temp are 32-bit floating-point values; memory is word-addressable (1 word = 1 element) and temp is kept in a processor register (no m…
- Using the same table T (17 rows × 1024 columns, 32-bit word-addressable entries, 16 page frames of 1024 words each, LRU) and the same column-averaging program as above, now consider T stored in column-major format. How…