Define thrashing in an operating system.
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Correct answer: (A) Excessive swapping of pages in and out of memory
CIL MT · Computer Science
Operating Systems Previous Year Questions
21 Operating Systems (Computer Science) questions asked in CIL MT previous year papers, each with the correct answer and explanation. Read them free on UTpaper, or attempt the full papers as timed online tests.
- 21 questions
- Official answer key
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Other Computer Science topics
In the context of algorithm design and analysis, which of the following represents the initial step in the design process?
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Correct answer: (B) Define the problem clearly and specify the input output
What does the read() system call in an operating system do?
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Correct answer: (B) Copies data from kernel space to user space, possibly after reading from device buffers
In SRTF (Shortest Remaining Time First) scheduling, which process is selected next?
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Correct answer: (C) One with the shortest remaining burst time
Which of the following options about non-preemptive scheduling is incorrect?
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Correct answer: (D) Round Robin is classified as a non-preemptive scheduling algorithm.
Consider a Mealy machine designed to process a sequence representing the presence of mineral samples ('M') and non-mineral samples ('N') during a geological survey. The machine outputs 'A' when the current sample is 'M' and the previous sample was 'N', otherwise it outputs 'B'. Which description below correctly reflects the machine's output behavior?
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Correct answer: (A) It produces output based on both the current input and the previous state.
What is the division of the main memory in Fixed Partitioning in memory management of operating system?
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Correct answer: (C) Made at boot time and remain unchanged in size and number.
Which of the following Windows API functions is used to write data to a file?
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Correct answer: (B) WriteFile()
What will happen if a process with a higher priority arrives in the ready queue in preemptive scheduling algorithm?
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Correct answer: (C) The currently running process is immediately removed from the CPU.
In a memory system with fixed-sized partitions, each holding one process (as in IBM OS/360 MFT).
Which statement is correct?
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Correct answer: (B) Multiprogramming limited; internal fragmentation possible
Which of the following is an application of compiler technology?
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Correct answer: (C) Code optimization
Which of the following problem cannot be solved using greedy approach?
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Correct answer: (A) 0-1 knapsack
Match the following.
List-1: A. Moves suspended process to secondary storage, B. Loads the processes into memory for execution, C. Moves one of the processes to Running state, D. Allocates CPU to a process
List-2: I. Short-Term Scheduler, II. Dispatcher, III. Medium-Term Scheduler, IV. Long-Term Scheduler
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Correct answer: (A) A – III, B – IV, C – I, D – II
Given the Burst Time (BT) of 4 processes P1, P2, P3 and P4 as BT(t1, t2, t3, t4) = (4, 8, 6, 7), smoothening factor (α) = 0.5, and T1 = 10, what will be the burst time of process P5 for Shortest Job First scheduling, using the technique of exponential averaging?
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Correct answer: (A) 6.875 unit time
Let each process Pᵢ, i=1 to 7 executes the following code.
repeat
P(mutex);
CS
V(mutex);
forever
The process P₈ executes the following code:
repeat
V(mutex);
CS
V(mutex);
forever
What is the maximum number of processes that can be present in the critical section at any point of time? Given that the initial value of binary semaphore variable "mutex" is 1.
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Correct answer: (B) 8
Consider the following segment of codes related to process creation. How many times the message "child process created" will be printed?
#include <stdio.h>
void main(){
fork(); fork(); fork();
printf("child process created");
}
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Correct answer: (C) 8
The working set model is used in memory management to implement the concept of:
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Correct answer: (A) Principle of locality
Consider the Unix i-node which uses 12 direct DBAs, 1 single indirect, 1 double indirect, 1 triple indirect. The disk block address requires 32 bits and disk block size is 1 KB. What is the maximum file size?
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Correct answer: (C) 16 GB
Page fault occurs when ________.
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Correct answer: (C) The page is not in main memory
Consider a system with page fault service time (S) = 100 ns, main memory access time (M) = 20 ns, and page fault rate (P) = 65%. Calculate the effective memory access time.
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Correct answer: (D) 72 ns
Which scheduling algorithm gives a minimum average waiting time?
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Correct answer: (C) SJF
How to use these CIL MT Computer Science questions
Every question here was asked in a real CIL MT paper; the paper and shift are shown on the card, and the number opens the question on its own page. Try each one before tapping Show answer, then attempt the full CIL MT papers as timed tests to check your speed under exam conditions.