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Recent questions and answers in Operating System

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1

MadeEasy Test Series: Operating System - Process
Q. A process spends 25% of its time waiting for I/O to complete. if 3 process in memory at a time, then the probability of CPU utilized(assume all I/O process are overlapped) is...................... so here 2 solution plz check first one why not correct 1. 1 - [ (3C1 * ... (.75)^2 + (3C2 *(.25)^2* (.75) + (3C3 *(.25)^3* ) 2. 1 - [ (3C3 *(.25)^3* ) ]

ADITYARAJ answered in Operating System Mar 23

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1 answer

2

Paging
If Page size = Frame size is always true and offset in Logical address = offset in physical address holds Then how/why Logical address size can come different than physical address size?

Psy Duck answered in Operating System Mar 22

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1 vote

3 answers

3

GATE CSE 2024 | Set 1 | Question: 52
Consider a memory management system that uses a page size of $2 \mathrm{~KB}$. Assume that both the physical and virtual addresses start from $0$. Assume that the pages $0,1,2$, and $3$ ... $0$, respectively. The physical address (in decimal format) corresponding to the virtual address $2500$ (in decimal format) is ___________.

SarthakShastri answered in Operating System Mar 22

by SarthakShastri

1.7k views

105 votes

8 answers

4

GATE CSE 2012 | Question: 32
Fetch_And_Add(X,i) is an atomic Read-Modify-Write instruction that reads the value of memory location $X$, increments it by the value $i$, and returns the old value of $X$. It is used in the pseudocode shown below to implement ... take on a non-zero value when the lock is actually available works correctly but may starve some processes works correctly without starvation

shub2204 answered in Operating System Mar 22

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1 answer

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Three process P1, P2 and P3 arrive at time zero. Their total execution time is 10ms, 20ms, and 30ms respectively. They spent first 20% of their execution time in doing I/O, next 70% in CPU processing and the last 10% again doing I/O. For what percentage of time was the CPU free? Using SRTF algorithm

aman113 answered in Operating System Mar 21

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67 votes

5 answers

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GATE CSE 2001 | Question: 1.13
A CPU has two modes -- privileged and non-privileged. In order to change the mode from privileged to non-privileged a hardware interrupt is needed a software interrupt is needed a privileged instruction (which does not generate an interrupt) is needed a non-privileged instruction (which does not generate an interrupt) is needed

prasantkr.singh answered in Operating System Mar 19

by prasantkr.singh

21.8k views

30 votes

4 answers

7

GATE CSE 1996 | Question: 1.20, ISRO2008-56
Which of the following is an example of spooled device? A line printer used to print the output of a number of jobs A terminal used to enter input data to a running program A secondary storage device in a virtual memory system A graphic display device

prasantkr.singh answered in Operating System Mar 19

by prasantkr.singh

11.0k views

8 votes

6 answers

8

OS:- Round Robin scheduling
If we have only one process in ready queue with burst time "m", then how many context switching will happen using round robing scheduling with time quantum q ,where q<m.Assume that dispatching the process first time is not counted as a context switch.

prasantkr.singh answered in Operating System Mar 16

by prasantkr.singh

4.5k views

0 votes

1 answer

9

OS, Process Scheduling
Consider a uniprocessor system with n processes in the ready queue. Round robin scheduling with time quantum x is used for process scheduling. Assume each process requires kx seconds to complete and the context switch takes 0 seconds. At what time the first process will complete the execution? (assume all the variables as integers). A) nkx B) k(nx-1) C) k(nk+n) D) x(nk-n+1)

KraVLonE answered in Operating System Mar 15

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1 vote

1 answer

10

#OS-FORK Output
Q23. The following C program is executed on a Unix/Linux system: main() { int i=0; while (i<20) if (i%2==0) fork(); i++; return 0; } Calculate how many number of processes will be created after executing the above program. Options: 1.1023 2.Infinite 3.1024 4.2048

gateAspirant_X0 answered in Operating System Mar 4

by gateAspirant_X0

247 views

3 votes

2 answers

11

#OS Fork () tell the O/P?
A process executes the following segment of code : for(i = 1; i <= n; i++) fork (); fork (); The number of new processes created is

ADITYARAJ answered in Operating System Mar 2

1.9k views

0 votes

3 answers

12

#CPCB
How many helloWorld lines are printed by the program: #include <stdio.h> #include <stdlib.h> void myFunc() { if (fork() == 0) { fork(); printf(“helloWorld\n”); exit(0); } return ; } int main(){ printf(“helloWorld\n”); myFunc(); printf(“helloWorld\n”); return 1; }

amit166 answered in Operating System Mar 2

547 views

12 votes

3 answers

13

GATE CSE 2022 | Question: 16
Which of the following statements is/are $\text{TRUE}$ with respect to deadlocks? Circular wait is a necessary condition for the formation of deadlock. In a system where each resource has more than one instance, a cycle in its wait-for graph ... the resource-allocation graph of a system, if every edge is an assignment edge, then the system is not in deadlock state.

jvishal answered in Operating System Feb 29

12.1k views

1 vote

2 answers

14

UGC NET CSE | December 2004 | Part 2 | Question: 38
Remote computing system involves the use of timesharing systems and : Real time processing Batch processing Multiprocessing All of the above

ajayraho answered in Operating System Feb 29

1.6k views

0 votes

2 answers

15

UGC NET CSE | December 2004 | Part 2 | Question: 36
Semaphores are used to : Synchronise critical resources to prevent deadlock Synchronise critical resources to prevent contention Do I/o Facilitate memory management

ajayraho answered in Operating System Feb 29

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4 votes

2 answers

16

GATE CSE 2024 | Set 2 | Question: 54
Consider a $32$-bit system with $4 \mathrm{~KB}$ page size and page table entries of size $4$ bytes each. Assume $1 \mathrm{~KB}=2^{10}$ bytes. The OS uses a $2$-level page table for memory management, with the page table containing ... the maximum number of pages across the two levels of the page table of the process. The value of $\text{X+Y}$ is ___________.

rexritz answered in Operating System Feb 22

2.2k views

0 votes

2 answers

17

GATE CSE 2024 | Set 1 | Question: 47
Consider the following code snippet using the fork () and wait () system calls. Assume that the code compiles and runs correctly, and that the system calls run successfully without any errors. int $\mathrm{x}=3$; while $(\mathrm{x}>0)$ ... ("hello"); wait (NULL) ; X-- ; } The total number of times the printf statement is executed is __________.

Biswajit Kumar answered in Operating System Feb 18

by Biswajit Kumar

1.9k views

3 votes

3 answers

18

GATE CSE 2024 | Set 2 | Question: 27
Consider a single processor system with four processes $\text{A, B, C,}$ and $\text{D}$, represented as given below, where for each process the first value is its arrival time, and the second value is its $\text{CPU}$ ... $\mathrm{SRTF}=7, \mathrm{NP}-\mathrm{SJF}=7.5$ $\mathrm{SRTF}=7, \mathrm{NP}-\mathrm{SJF}=8.5$

Hira Thakur answered in Operating System Feb 18

2.0k views

0 votes

1 answer

19

Doubt on OS Syllabus (Galvin)
Hi, i'm starting my GATE journey and wanted to verify if these are the topics which should be learnt for GATE. The book is Operating Systems by Avi Silberschatz, Greg Gagne, and Peter Baer Galvin (9th Edition). Also have 10th edition but it seems to have rearranged a lot of topics and chapters.

TusharRana answered in Operating System Feb 18

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2 answers

20

GATE CSE 2024 | Set 1 | Question: 30
Consider the following two threads $\mathrm{T} 1$ and $\mathrm{T} 2$ that update two shared variables $\mathrm{a}$ and $\mathrm{b}$. Assume that initially $\mathrm{a}=\mathrm{b}=1$ ...

Hira Thakur answered in Operating System Feb 17

1.8k views

1 vote

1 answer

21

GATE CSE 2024 | Set 1 | Question: 14
Which of the following statements about threads is/are TRUE? Threads can only be implemented in kernel space Each thread has its own file descriptor table for open files All the threads belonging to a process share a common stack Threads belonging to a process are by default not protected from each other

phaniphani answered in Operating System Feb 16

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0 votes

2 answers

22

GATE CSE 2024 | Set 1 | Question: 44
Consider a $512$ GB hard disk with $32$ storage surfaces. There are $4096$ sectors per track and each sector holds $1024$ bytes of data. The number of cylinders in the hard disk is _________.

Hira Thakur answered in Operating System Feb 16

1.4k views

1 vote

1 answer

23

GATE CSE 2024 | Set 2 | Question: 15
Consider a process $\text{P}$ running on a $\text{CPU}$. Which one or more of the following events will always trigger a context switch by the $\text{OS}$ that results in process $\mathrm{P}$ moving to a non-running ... page fault An interrupt is raised by the disk to deliver data requested by some other process A timer interrupt is raised by the hardware

Sachin Mittal 1 answered in Operating System Feb 16

by Sachin Mittal 1

2.6k views

1 vote

1 answer

24

GATE CSE 2024 | Set 2 | Question: 36
Consider a multi-threaded program with two threads $\mathrm{T} 1$ and $\mathrm{T} 2$. The threads share two semaphores: $s1$ (initialized to $1$) and $s2$ (initialized to $0$). The threads also share a global variable $\mathrm{x}$ ( ... not print anything (deadlock) $\mathrm{T} 2$ runs first and prints $1, \mathrm{~T} 1$ does not print anything (deadlock)

Deepak Poonia answered in Operating System Feb 16

by Deepak Poonia

1.7k views

0 votes

1 answer

25

GATE CSE 2024 | Set 2 | Question: 14
Which of the following tasks is/are the responsibility/responsibilities of the memory management unit $\text{(MMU)}$ in a system with paging-based memory management? Allocate a new page table for a newly created process Translate a virtual address ... table Raise a trap when a process tries to write to a page marked with read-only permission in the page table

Sachin Mittal 1 answered in Operating System Feb 16

by Sachin Mittal 1

2.4k views

1 vote

1 answer

26

GATE CSE 2024 | Set 2 | Question: 43
Consider a disk with the following specifications: rotation speed of $6000$ RPM, average seek time of $5$ milliseconds, $500$ sectors/track, $512$-byte sectors. A file has content stored in $3000$ sectors located randomly on the disk. Assuming ... total time (in seconds, rounded off to $2$ decimal places) to read the entire file from the disk is ______________.

puspeshsrivastava answered in Operating System Feb 16

by puspeshsrivastava

1.5k views

1 vote

1 answer

27

GATE CSE 2024 | Set 1 | Question: 15
Which of the following process state transitions is/are NOT possible? Running to Ready Waiting to Running Ready to Waiting Running to Terminated

Hira Thakur answered in Operating System Feb 16

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1 answer

28

GATE 2024 CS set-1
If a process perform IO time first and then performing cpu, in that case process is going from ready state to wait state, is that true?

TusharRana answered in Operating System Feb 11

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0 answers

29

memory management
we have 8 pages (each side 32B) to store in physical memory of 2^32 bits how many bits are required to identify each page , according to me 3 bits are required but that is wrong plz explain why

SSR17 asked in Operating System Feb 8

by SSR17

186 views

7 votes

1 answer

30

GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 23
Consider the context switch of a CPU from the context of process P1 to that of process P2. Consider the following two events in the chronological order of the events during the context switch: E1: The stack pointer ... atomic hardware instruction. The relative ordering of E1 and E2 can vary from one context switch to the other.

Sachin Mittal 1 answered in Operating System Feb 8

by Sachin Mittal 1

475 views

58 votes

4 answers

31

GATE CSE 2013 | Question: 53
A computer uses $46\text{-bit}$ virtual address, $32\text{-bit}$ physical address, and a three-level paged page table organization. The page table base register stores the base address of the first-level table $\text{(T1)},$ which occupies exactly one ... to guarantee that no two synonyms map to different sets in the processor cache of this computer? $2$ $4$ $8$ $16$

iam.sahilpatra answered in Operating System Feb 7

by iam.sahilpatra

30.2k views

0 votes

1 answer

32

ACE OTS
A.330 B.388 C.279 D.389 Can someone please give detailed solution to this?

devBhaskar answered in Operating System Feb 6

180 views

2 votes

2 answers

33

GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 24
Consider a job A arrives at time $T=0$ and job length of $500 \mathrm{~ms}$. Job $B$ arrives at time $\mathrm{T}=100 \mathrm{~ms}$ with a length of $100 \mathrm{~ms}$. Considering the Shortest Remaining Time First Scheduler, what does ... for $100 \mathrm{~ms}$, then $B$ runs for $100 \mathrm{~ms}$, then A runs for $300 \mathrm{~ms}$

K1ngJok3r answered in Operating System Feb 6

356 views

9 votes

2 answers

34

GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 36
Assume a linear page table, with a 1-byte page-table entry. Assume physical and virtual address spaces of size 128 bytes with 32-byte pages. The page-table base register is set to physical address 16. The contents of ... What are the physical addresses that will get referred in fetch and execute of the above instruction? 10 42 102 70

mayajeet answered in Operating System Feb 6

561 views

2 votes

1 answer

35

GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 37
Suppose that an operating system provides two functions, block() which puts the calling process on the blocked queue, and wakeup(P) which moves process P to the ready queue if it is currently on the blocked queue. ... alternation printing ABABAB . A and B will always run forever with strick alternation printing BABABA . None of these

Prabhas answered in Operating System Feb 6

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29 votes

2 answers

36

GATE CSE 2022 | Question: 53
Consider two files systems $\text{A}$ and $\text{B}$, that use contiguous allocation and linked allocation, respectively. A file of size $100$ blocks is already stored in $\text{A}$ and also in $\text{B}$. Now, consider inserting a new block in the middle of ... $\text{B}$ are $n_{A}$ and $n_{B}$, respectively, then the value of $n_{A} + n_{B}$ is__________________.

Mahanth Yalla answered in Operating System Feb 2

by Mahanth Yalla

9.6k views

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0 answers

37

What is the difference between synchronous and asynchronous signals?
A process can receive two kinds of signals classified based on the source and reason. Synchronous are the one that are generated by illegal memory access or division by zero. Asynchronous are the one that ... exceptions? For example we have ZeroDivisionError or FileNotFoundError and all. Ref: Signal Handling from Galvin OS book

tbhaxor asked in Operating System Feb 1

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1 answer

38

Operating System
How much time is required to load a 64 KB program from a disk with an average seek time of 30 ms, a rotation time of 20 ms per rotation, a track size of 32 KB, and a page size of 2 KB. It is assumed that the pages are spread randomly around the disk. A. 1200 ms B. 1300 ms C. 1320 ms D. 1400 ms

jaydip74 asked in Operating System Jan 28

274 views

5 votes

1 answer

39

GO Classes Test Series 2024 | Mock GATE | Test 13 | Question: 20
Suppose we have a multi-level index file system, and this file system has $512$ Bytes blocks, inodes with $3$ direct, $1$ single-indirect, $2$ double-indirect, and $1$ triple-indirect pointer, and $64$-bit block ... inode requires the first single-indirect block number be used? $1536$ Bytes $1537$ Bytes $512$ Bytes $1500$ Bytes

GO Classes asked in Operating System Jan 28

547 views

5 votes

1 answer

40

GO Classes Test Series 2024 | Mock GATE | Test 13 | Question: 21
Consider a virtual memory system that uses paging. Virtual and physical addresses are both $32$ bits long, and the page size is $4 \textsf{KB}=2^{12}$ bytes. A process $\text{P}_1$ has the following page table. ... $\textsf{0x00003b65}$ $\textsf{0x00875b65}$ $\textsf{0x00875}$ Translation is not possible as per the given page table

GO Classes asked in Operating System Jan 28

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