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Recent questions and answers in Operating System

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1

Fork() system call.
main(){ int i,n; for(int i=0;i<n;i++){ fork(); printf("*"); } } How many times ‘*’ will be printed? The answer is not 2^n ? why?

kickassakash answered in Operating System 1 day ago

by kickassakash

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1 vote

3 answers

2

Unacademy AIMT question on Fork()
Given the following piece of code : Main() { Int child = fork(); Int c = 5; if (child == 5) { C + = 5; } Else { Child = fork(); C + = 5; } } What are the different values of the variable c? First of all checking child == ... a pseudocode as some of the syntaxes are wrong. Also I am getting the answer as 10,10,10. Given answer is 20,10,15. Can someone please check?

Ujjal roy answered in Operating System 5 days ago

395 views

1 vote

1 answer

3

Operating Systems Galvin
Does Waiting Time and Response TIme remains the same in Preemptive Scheduling Algorithm???

Bharat Bhushan answered in Operating System 6 days ago

by Bharat Bhushan

78 views

1 vote

1 answer

4

#Operating system question #cpu scheduling
Consider arrival time and execution time for the following process:- P.id A.T B.T 1 2 5 2 7 9 3 8 3 4 10 4 Assume, each context switch requires 1ms time (excluding first and last context switch).then solve it using SRTF(shortest remaining time first)

Harsh Saini_1 answered in Operating System Mar 14

by Harsh Saini_1

157 views

2 votes

2 answers

5

GATE CSE 2023 | Question: 13
Which one or more of the following options guarantee that a computer system will transition from user mode to kernel mode? Function Call malloc Call Page Fault System Call

Bharat Bhushan answered in Operating System Mar 8

by Bharat Bhushan

1.4k views

0 votes

1 answer

6

Madeeasy workbook, chapter: Memory management
Consider a k-level paging system along with a TLB. A TLB takes 10ns, and a memory takes 100ns on average. The hit ratio of TLB is equal to 0.8. If it is known that the average memory access time is 70ns, then the value of k is?

wizard_2004 answered in Operating System Mar 4

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1 vote

1 answer

7

Gateforum Test Series: Operating System - Io Handling
Shouldn’t the answer be A but D is provided as an answer

Gate Shark answered in Operating System Mar 4

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2 answers

8

Galvin Edition 9 Exercise 8 Question 3 (Page No. 390)
Why are page sizes always powers of 2 ?

wizard_2004 answered in Operating System Mar 2

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1 answer

9

Galvin Edition 9 Exercise 8 Question 20 (Page No. 392)
Assuming a $1$ $KB$ page size, what are the page numbers and offsets for the following address references (provided as decimal numbers): $a. 3085$ $b. 42095$ $c. 215201$ $d. 650000$ $e. 2000001$

Gate Shark answered in Operating System Feb 27

162 views

9 votes

3 answers

10

GATE CSE 2023 | Question: 17
Which one or more of the following $\text{CPU}$ scheduling algorithms can potentially cause starvation? First-in First-Out Round Robin Priority Scheduling Shortest Job First

aaaakash001 answered in Operating System Feb 22

3.0k views

1 vote

2 answers

11

GATE CSE 2023 | Question: 48
Consider a computer system with $57$-bit virtual addressing using multi-level tree-structured page tables with $\mathrm{L}$ levels for virtual to physical address translation. The page size is $4 \mathrm{~KB}(1 \mathrm{~KB}=1024 \mathrm{~B})$ and a page table entry at any of the levels occupies $8$ bytes. The value of $\mathrm{L}$ is ______________.

Kabir5454 answered in Operating System Feb 19

1.0k views

3 votes

1 answer

12

GATE CSE 2023 | Question: 28
Consider the two functions $\textsf{incr}$ and $\textsf{decr}$ shown below. incr(){ decr(){ wait(s); wait(s); X = X+1; X = X-1; signal(s); signal(s); } } There are $5$ threads each invoking $\textsf{incr}$ once, and $3$ threads each ... of the following choices corresponds to the minimum possible values of $\text{V1, V2},$ respectively? $15,7$ $7,7$ $12,7$ $12,8$

amichopra answered in Operating System Feb 16

1.2k views

2 votes

1 answer

13

GATE CSE 2023 | Question: 12
Which one or more of the following need to be saved on a context switch from one thread $\text{(T1)}$ of a process to another thread $\text{(T2)}$ of the same process? Page table base register Stack pointer Program counter General purpose registers

himanshu2021 answered in Operating System Feb 15

by himanshu2021

1.4k views

2 votes

1 answer

14

GATE CSE 2023 | Question: 47
Consider the following two-dimensional array $\text{D}$ in the $\text{C}$ programming language, which is stored in row-major order: int D[128][128]; Demand paging is used for allocating memory and each physical page frame holds $512$ elements of the ... j++) D[j][i] *= 10; The number of page faults generated during the execution of this code snippet is _______________.

admin asked in Operating System Feb 15

by admin

1.2k views

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0 answers

15

Andrew S. Tanenbaum - Modern Operating Systems
Measurements of a certain system have shown that the average process runs for a time T before blocking on I/O. A process switch requires a time S, which is effectively wasted (overhead). For round-robin scheduling with quantum Q, giv e a formula for the CPU efficiency for each of the ... ) Q = ∞ (b) Q > T (c) S < Q < T (d) Q = S (e) Q nearly 0

arjunwkb asked in Operating System Feb 15

110 views

1 vote

1 answer

16

GATE CSE 2023 | Memory Based Question: 20
Which of the following option guarantee that a computer system transit from user mode to kernel mode malloc call system call function call page fault closed

mansi_003 answered in Operating System Feb 13

482 views

0 votes

1 answer

17

GATE CSE 2023 | Memory Based Question: 19
incr() { wait(s) x = x+1 signal(s) } decr() { wait(s) x = x-1 signal(s) } Shared integer variable $\mathrm{x}$ initialized with $10.$ There are five threads which are calling incr() and there are three threads which are calling decr() ... $s=2$ minimum possible value of $\mathrm{x}$ is $\mathrm{V}_2$ $15,8$ $12,8$ $15,7$ $12,7$ closed

Singhpal answered in Operating System Feb 9

397 views

1 vote

0 answers

18

Difference between Convoy effect, starvation, deadlock
Difference between Convoy effect, starvation and deadlock I have shared my understanding on convoy effect, starvation and deadlock. Please correct me if I am wrong. Let us assume P1 burst time is 20 seconds and P2 is having Burst time is ... serviced by CPU. But in convoy effect and starvation at least one of P1 and P2 will be serviced by CPU.

Nandhakumar asked in Operating System Feb 7

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0 answers

19

GATE 2023 question
In which of the given operations, will a user level to kernel level switch, surely happen? Page Fault System Call Subroutine Call Malloc() closed

Souvik33 asked in Operating System Feb 6

165 views

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0 answers

20

GATE CSE 2023 | Memory Based Question: 18
In general which of the following CPU scheduling algorithms suffers from starvation? SJF FCFS Round robin Priority closed

GO Classes asked in Operating System Feb 6

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1 answer

21

OS Self doubt(Memory management)
] Our CPU is currently idle and the current time is labeled time 0. Four processes arrive to the ready queue at the following times and with the following required run time: See image for Ariival time and Process info Simulate ... decision, and calculate the turnaround time for each process. Also calculate the average turnaround time for each scheduling algorithm.

dmacop71 answered in Operating System Feb 3

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1 answer

22

consider 16tb disk that uses 4kb block and free list method. how many block address can be stored in a block

Shubhodeep answered in Operating System Jan 26

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1 answer

23

Operating System
In Dining philosopher's problem, there are 8 number of diners and X number of chopsticks. What is the minimum value of X which ensures that therewill be no deadlock Note: Even number philosopher takes left fork first and odd number philosopher takes right fork first.

anshikasingh08 answered in Operating System Jan 25

by anshikasingh08

163 views

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2 answers

24

Operating System(Process)
A process executes the following segment of code: int main(){ fork(); fork() && fork(); } The number of new processes created is

abhinowKatore answered in Operating System Jan 24

by abhinowKatore

94 views

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1 answer

25

operating system
Can somebody please show atleast one example where a synchromnisation mechanism " DOESNOT GUARANTEE BOUNDED WAITING BUT STILL IT GUARANTEES STARVATION FREEDOM " I am not able to find one .. MY LOGIC : If Bounded waiting is not guaranteed , ... SURELY SUFFER FROM STARVATION ??? Please correct me if I am wrong in understanding of definitions of Bounded waiting,starvation.

Joey answered in Operating System Jan 23

by Joey

258 views

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1 answer

26

OS
By default the memory address starts with 0. But they have considered from 1. What should I consider when nothing is mentioned?

nabeelchashoo answered in Operating System Jan 22

by nabeelchashoo

69 views

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2 answers

27

#self doubt
In round-robin if one process finishes its time quantum and at the same time another process enters the system so which one will enter the ready queue first?

akash_chauhan answered in Operating System Jan 19

by akash_chauhan

340 views

0 votes

1 answer

28

Fork() | OS
int doWork(){ fork(); fork(); printf("Hello world!\n"); } int main() { doWork(); printf("Hello world!\n"); exit(0); }

abhinowKatore asked in Operating System Jan 13

by abhinowKatore

343 views

0 votes

2 answers

29

Applied test series
We know that the paging scheme suffers from internal fragmentation. S1 : If the CPU attempts to access the unused portion of the last page, the valid/invalid bits will block such accesses. S2 : A possible solution to handle the internal fragmentation issue is to use multiple page sizes. can anyone plz explain me this ? we have to select from s1 and s2 which is correct

shikhar500 asked in Operating System Jan 8

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1 answer

30

Operating System
When a page is referred for the first time, then it will be counted in page fault or not?. E.g page reference 1,2,3,4,2,1. LRU is used with 3 frames(initially empty).

Overflow04 asked in Operating System Jan 7

145 views

2 votes

1 answer

31

No of page levels involved?
Consider a virtual memory system where, physical memory = 4GB page size = 4KB, page table entry size = 4B and 45-bit virtual address. Assume every page table exactly fits into a single page. If page table entry size is 4B then how many levels of page tables would be required.

h4kr asked in Operating System Jan 2

by h4kr

149 views

1 vote

1 answer

32

#Self doubt
Since Dealock --> No Progress then Does Progess --> No Deadlock bcoz contrapositive should be true.

yuvrajeyes asked in Operating System Dec 31, 2022

80 views

0 votes

1 answer

33

Operating System
How c came into picture.

Overflow04 asked in Operating System Dec 31, 2022

90 views

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0 answers

34

Multi Level Feedback Queue(UNIX-SVR3)
Consider the following set of processes, and schedule them using the Multi-levelf eedback queue CPU scheduling algorithm as used in UNIX SVR3. P's CB AT Base Priority P1 2 0 60 P2 1. 1 60 P3 3. 2 60 Also prepare a gantt chart for the following..

rdxrohit asked in Operating System Dec 31, 2022

108 views

2 votes

2 answers

35

Self Doubt
Can Safe state in DeadLock Avoidance Mechanism always guarantee No DeadLock??

Sunnidhya Roy asked in Operating System Dec 31, 2022

by Sunnidhya Roy

142 views

0 votes

0 answers

36

Operating System
What is the relationship between paging and virtual memory? A Virtual memory came before paging B When pages are created in disks, it is called a virtual memory? C Virtual memory can never be implemented without paging D Both have the same concepts

rayhanrjt asked in Operating System Dec 29, 2022

62 views

2 votes

1 answer

37

What is the solution?
I think the answer must be 500200ns

h4kr asked in Operating System Dec 29, 2022

by h4kr

89 views

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