Recent questions and answers in Operating System - GATE Overflow

+71 votes

6 answers

1

GATE2006-61
The atomic fetch-and-set $x, y$ instruction unconditionally sets the memory location $x$ to $1$ and fetches the old value of $x$ in $y$ without allowing any intervening access to the memory location $x$. Consider the following implementation of $P$ and $V$ ... -set, a pair of normal load/store can be used The implementation of $V$ is wrong The code does not implement a binary semaphore

answered 1 day ago in Operating System by RRR | 9.8k views

+8 votes

2 answers

2

ISRO2007-43
On a system using non-preemptive scheduling, processes with expected run times of 5, 18, 9 and 12 are in the ready queue. In what order should they be run to minimize wait time? 5, 12, 9, 18 5, 9, 12, 18 12, 18, 9, 5 9, 12, 18, 5

answered 2 days ago in Operating System by Nbhardwaj | 5.8k views

+21 votes

3 answers

3

GATE1998-25-a
Free disk space can be used to keep track of using a free list or a bit map. Disk addresses require $d$ bits. For a disk with $B$ blocks, $F$ of which are free, state the condition under which the free list uses less space than the bit map.

answered 5 days ago in Operating System by Mohnish | 1.7k views

+41 votes

8 answers

4

GATE2009-30
Consider a system with $4$ types of resources $R1$ ($3$ units), $R2$ ($2$ units), $R3$ ($3$ units), $R4$ ($2$ units). A non-preemptive resource allocation policy is used. At any given instance, a request is not entertained if it cannot be completely ... any deadlock Only $P1$ and $P2$ will be in deadlock Only $P1$ and $P3$ will be in deadlock All three processes will be in deadlock

answered 5 days ago in Operating System by Asim Siddiqui 4 Active | 10.4k views

0 votes

1 answer

5

Galvin Edition 9 Exercise 5 Question 6 (Page No. 243)
Illustrate how a binary semaphore can be used to implement mutual exclusion among n processes.

answered 6 days ago in Operating System by krish71 | 33 views

+12 votes

4 answers

6

#OS #MULTILEVEL FEEDBACK QUEUE
Consider a system which has a CPU bound process,which require the burst time of 40 seconds.The multilevel Feed Back Queue scheduling algorithm is used and the queue time quantum '2' seconds and in each level it is incremented by '5' seconds.Then how many times the process ... on which queue the process will terminate the execution? (a) 5,4 (b) 4,5 (c) 3,4 (d) 4,3

answered May 19 in Operating System by bhupendrakumar | 2.5k views

+1 vote

7 answers

7

Conceptual question: What is the difference between program and process?
Conceptual question: What is the difference between program and process? any simple ,clear answer plz..

answered May 18 in Operating System by DIBAKAR MAJEE Active | 577 views

+6 votes

3 answers

8

Which of the following process scheduling algorithm may lead to starvation?
Which of the following process scheduling algorithm may lead to starvation (1)SJF (2)SRTF (3)Priority(without preemption) (4)Priority(with preemption) a)1,2,3 b)1,2,4 c)1,3,4 d)1,2,3,4 e)1,3 f)1,4

answered May 18 in Operating System by DIBAKAR MAJEE Active | 7.2k views

0 votes

2 answers

9

UGCNET-July-2018-II: 60
In which of the following scheduling criteria, context switching will never take place? ROUND ROBIN Preemptive SJF Non-preemptive SJF Preemptive priority

answered May 17 in Operating System by Nbhardwaj | 308 views

+4 votes

2 answers

10

Difference between deadloack & spinlock

answered May 17 in Operating System by Asim Siddiqui 4 Active | 2.5k views

+62 votes

12 answers

11

GATE2015-1-46
Consider a uniprocessor system executing three tasks $T_{1}, T_{2}$ and $T_{3}$ each of which is composed of an infinite sequence of jobs (or instances) which arrive periodically at intervals of $3$, $7$ and $20$ milliseconds, ... the 1st millisecond and task preemptions are allowed, the first instance of $T_{3}$ completes its execution at the end of_____________________milliseconds.

answered May 15 in Operating System by Asim Siddiqui 4 Active | 12.7k views

+19 votes

2 answers

12

GATE2008-66
A process executes the following code for(i=0; i<n; i++) fork(); The total number of child processes created is $n$ $2^n-1$ $2^n$ $2^{n+1} - 1$

answered May 15 in Operating System by IITB2020 | 3.6k views

0 votes

1 answer

13

Galvin Edition 9 Exercise 6 Question 19 (Page No. 309)
Which of the following scheduling algorithms could result in starvation ? $a. First-come$, $first-served$ $b. Shortest$ $job$ $first$ $c. Round$ $robin$ $d. Priority$

answered May 14 in Operating System by Jay Singh 1 | 28 views

+34 votes

5 answers

14

GATE1992-12-b
Let the page reference and the working set window be $c\ c\ d\ b\ c\ e\ c\ e\ a\ d\ $ and $4$, respectively. The initial working set at time $t=0$ contains the pages $\{a,d,e\}$, where $a$ was referenced at time $t=0$ ... referenced at time $t=-2$. Determine the total number of page faults and the average number of page frames used by computing the working set at each reference.

answered May 13 in Operating System by Mohnish | 3.3k views

+1 vote

1 answer

15

IES 2018 - Round robin, FCFS, SJF comparison
Consider the following set of processes First Come First Serve (FCFS), non preemptive Shortest Job First (SJF) and Round Robin (RR) (quantum = 10 ms). Scheduling Algorithms for this process set would imply which of the following features? 1. The SJF policy results in less than ... below. (a) 1, 2 and 3 (b) 1 and 2 only (c) 1 and 3 only (d) 2 and 3 only

answered May 12 in Operating System by bharti0420 | 195 views

+1 vote

1 answer

16

page replacement algorithm

answered May 12 in Operating System by Himanshu Kumar Gupta Junior | 563 views

+1 vote

4 answers

17

'm' processes share 'n' resources of same type. The maximum need of each process does not exceed 'n' and the sum all their maximum needs is always less than m+n. In this setup deadlock can occur or not?

answered May 11 in Operating System by shi_van_i24 | 6.3k views

+1 vote

3 answers

18

Self doubt
Virtual memory increases context switching overhead ? Why why not ?

answered May 11 in Operating System by Harshitkmr | 120 views

+5 votes

5 answers

19

Deadlock
Consider two processes P1 and P2, each needed 3 resources 1, 2 and 3 in a database. If each processes ask them in any order, then the number of ways possible in which system is guaranteed to be deadlock free ________. Given answer is 6. I am getting 12.

answered May 11 in Operating System by Vikramaditya19 | 1.6k views

+3 votes

2 answers

20

Round Robin Scheduling
Consider a System using Round Robin scheduling with 10 Processes all arriving at the time 0. Each Process is associated with 20 identical Request. Each Process request consumes 20 ms of CPU time after which it spends 10 ms of time on I/O,thereafter ... ii. Response time of the 1st Request of the last Process. iii. Response time of the subsequent request of any process.

answered May 10 in Operating System by Harshitkmr | 640 views

0 votes

2 answers

21

Andrew S. Tanenbaum (OS) Edition 4 Exercise 2 Question 40 (Page No. 177)
Round-robin schedulers normally maintain a list of all runnable processes, with each process occurring exactly once in the list. What would happen if a process occurred twice in the list? Can you think of any reason for allowing this?

answered May 10 in Operating System by Jay Singh 1 | 94 views

0 votes

1 answer

22

SELF DOUBT OS MADEEASY TEST SERIES
CONSIDER A SYSTEM USING PAGING AND SEGMENTATION .THE VIRTUAL ADDRESS SPACE CONSIST OF UP TO 8 SEGMENTS AND EACH SEGMENT IS 229 BYTE long the hardware pages each segment into 28 B pages Q: HOW MANY BITS IN THE VIRTUAL ADDRESS SPECIFY THE PAGE NUMBER? A)4 bits b)5 bits c)16 bits d)21 bits

answered May 10 in Operating System by Antaroop | 389 views

+21 votes

4 answers

23

GATE2002-1.22
Which of the following scheduling algorithms is non-preemptive? Round Robin First-In First-Out Multilevel Queue Scheduling Multilevel Queue Scheduling with Feedback

answered May 8 in Operating System by eajaz alam | 2.1k views

+16 votes

4 answers

24

GATE2004-46
Consider the following set of processes, with the arrival times and the CPU-burst times gives in milliseconds. ... time for these processes with the preemptive shortest remaining processing time first (SRPT) algorithm? $5.50$ $5.75$ $6.00$ $6.25$

answered May 8 in Operating System by eajaz alam | 2.4k views

+1 vote

1 answer

25

NIELIT 2016 DEC Scientist B (CS) - Section B: 56
Consider a system with $m$ resources of same type being shared by $n$ processes. Resources can be requested and released by processes only one at a time. The system is deadlock free if and only if The sum of all max needs is $< m+n$ The sum of all max needs is $>m+n$ Both of above None

answered May 7 in Operating System by abhishek tiwary Active | 37 views

0 votes

1 answer

26

NIELIT 2016 DEC Scientist B (CS) - Section B: 51
A process that is based on IPC mechanism which executes on different systems and can communicate with other processes using message based communication is called _______. Local Procedure Call Remote Procedure Call Inter Process Communication Remote Machine Invocation

answered May 7 in Operating System by abhishek tiwary Active | 30 views

0 votes

1 answer

27

NIELIT 2016 DEC Scientist B (IT) - Section B: 50
Which of the following statements about semaphores is true? $P$ and $V$ operations should be indivisible operations. A semaphore implementation should guarantee that threads do not suffer indefinite postponement. If several threads attempt a $P(S)$ operation simultaneously, only one thread should be allowed to proceed. All of the above.

answered May 7 in Operating System by abhishek tiwary Active | 31 views

0 votes

2 answers

28

UGCNET-Jan2017-II: 36
There are three processes $P_{1}, P_{2}$ and $P_{3}$ sharing a semaphore for synchronizing a variable. Initial value of semaphore is one. Assume that negative value of semaphore tells us how many processes are waiting in queue. Processes access the semaphore in ... exits critical section $P1$ exits critical section The final value of semaphore will be : $0$ $1$ $-1$ $-2$

answered May 7 in Operating System by Mohit Kumar 6 Active | 15 views

0 votes

2 answers

29

UGCNET-Jan2017-II: 38
Match the following w.r.t Input/Output management : ...

answered May 7 in Operating System by Mohit Kumar 6 Active | 26 views

0 votes

3 answers

30

UGCNET-Jan2017-II: 39
Which of the following scheduling algorithms may cause starvation ? First-come-first-served Round Robin Priority Shortest process next Shortest remaining time first a, c and e c, d and e b, d and e b, c and d

answered May 7 in Operating System by Mohit Kumar 6 Active | 17 views

0 votes

2 answers

31

UGCNET-Jan2017-II: 37
In a paging system, it takes $30$ ns to search translation Look-a-side Buffer (TLB) and $90$ ns to access the main memory. If the TLB hit ratio is $70\%$, the effective memory access time is : $48$ ns $147$ns $120$ns $84$ns

answered May 7 in Operating System by Mohit Kumar 6 Active | 17 views

+153 votes

10 answers

32

GATE2008-67
A processor uses $36$ bit physical address and $32$ bit virtual addresses, with a page frame size of $4$ Kbytes. Each page table entry is of size $4$ bytes. A three level page table is used for virtual to physical address translation, where the virtual address is used as follows: ... page tables are respectively $\text{20,20,20}$ $\text{24,24,24}$ $\text{24,24,20}$ $\text{25,25,24}$

answered May 4 in Operating System by Gaurav Yadav Junior | 30.1k views

0 votes

2 answers

33

Andrew S. Tanenbaum (OS) Edition 4 Exercise 2 Question 50 (Page No. 178)
A soft real-time system has four periodic events with periods of $50, 100, 200,$ and $250$ msec each. Suppose that the four events require $35, 20, 10,$ and $x$ msec of CPU time, respectively. What is the largest value of $x$ for which the system is schedulable?

answered May 4 in Operating System by DIBAKAR MAJEE Active | 141 views

0 votes

2 answers

34

Andrew S. Tanenbaum (OS) Edition 4 Exercise 2 Question 39 (Page No. 177)
Consider the following piece of C code: void main( ) { fork( ); fork( ); exit( ); } How many child processes are created upon execution of this program?

answered May 4 in Operating System by DIBAKAR MAJEE Active | 169 views

+4 votes

3 answers

35

Which of the following algorithm leads convoy effect?
Which of the following algorithm leads convoy effect? FCFS SJF Priority scheduling All of the above

answered May 2 in Operating System by Deepakk Poonia (Dee) Boss | 1.5k views

0 votes

1 answer

36

UGC NET DEC 2018 Paper 2 Q-88

answered May 2 in Operating System by saloni pande | 420 views

+74 votes

6 answers

37

GATE2016-1-50
Consider the following proposed solution for the critical section problem. There are $n$ processes : $P_0....P_{n-1}$. In the code, function $\text{pmax}$ returns an integer not smaller than any of its arguments .For all $i,t[i]$ is ... can be in the critical section at any time The bounded wait condition is satisfied The progress condition is satisfied It cannot cause a deadlock

answered May 1 in Operating System by Gaurav Yadav Junior | 15.3k views

+40 votes

4 answers

38

GATE2009-51
A hard disk has $63$ sectors per track, $10$ platters each with $2$ recording surfaces and $1000$ cylinders. The address of a sector is given as a triple $\langle c, h, s \rangle$, where $c$ is the cylinder number, $h$ is the surface number and $s$ is ... $\langle 400, 16, 29 \rangle$ corresponds to sector number: $505035$ $505036$ $505037$ $505038$

answered Apr 29 in Operating System by MRINMOY_HALDER Active | 7.1k views

+55 votes

6 answers

39

GATE2013-29
Consider a hard disk with $16$ recording surfaces $(0-15)$ having 16384 cylinders $(0-16383)$ and each cylinder contains $64$ sectors $(0-63)$. Data storage capacity in each sector is $512$ bytes. Data are organized cylinder-wise and the addressing format is < ... the cylinder number of the last sector of the file, if it is stored in a contiguous manner? $1281$ $1282$ $1283$ $1284$

answered Apr 29 in Operating System by MRINMOY_HALDER Active | 10.1k views

+1 vote

1 answer

40

Topic: virtual memory.
Suppose the average page fault service time is 20 milliseconds and memory access time is 200 nanoseconds. Assuming we wish to have less than 10% degradation in memory access when a page fault occurs estimate the value of the fault rate must be less than.

answered Apr 28 in Operating System by Raju2021 | 70 views

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