Recent questions tagged page-fault / GATE Overflow for GATE CSE

1 votes

2 answers

61

ISRO2018-20
Determine the number of page faults when references to pages occur in the order - $1, 2, 4, 5, 2, 1, 2, 4$. Assume that the main memory can accommodate $3$ pages and the main memory already has the pages $1$ and $2$, with page $1$ having brought earlier than page $2$. (assume LRU i.e. Least-Recently-Used algorithm is applied) $3$ $4$ $5$ None of the above

Determine the number of page faults when references to pages occur in the order - $1, 2, 4, 5, 2, 1, 2, 4$. Assume that the main memory can accommodate $3$ pages and the ...

Arjun

1.0k views

Arjun asked Apr 22, 2018

2 votes

1 answer

62

My doubt on TLB and page fault
First read this whole thing what I am writing below: Case 1: If we have to access unit address in memory using TLB and we assume that no page fault occurs then, EMAT=p( T+M )+( 1-p ) (T+M+M) T=TLB access time, M= ... if there page fault occurs then how does the last calculated EMAT here affects the first Estimated memory access time which we have calculated using TLB?

First read this whole thing what I am writing below:Case 1: If we have to access unit address in memory using TLB and we assume that no page fault occurs then,EMAT=p( T+M...

Akash Kumar Roy

2.6k views

Akash Kumar Roy asked Apr 5, 2018

0 votes

0 answers

63

Gate_2018_model_Paper
There is any difference or same these two statement? 1. Page fault service time is 10ms. 2. The Time to service a page fault is on average 10ms.

There is any difference or same these two statement?1. Page fault service time is 10ms.2. The Time to service a page fault is on average 10ms.

Harikesh Kumar

266 views

Harikesh Kumar asked Feb 3, 2018

1 votes

1 answer

64

page replacemment policy
A system uses optimal policy for a page replacement. It has 4 page frames with no pages loaded to begin with. Consider the following scenario Case-1: System first accesses 200 distinct pages in sequential order and then access same 200 distinct ... access same 200 distinct page in reverse order. The difference in the number of faults occurred in both case are _________.

A system uses optimal policy for a page replacement. It has 4 page frames with no pages loaded to begin with. Consider the following scenarioCase-1: System first accesses...

_anu

374 views

_anu asked Jan 24, 2018

3 votes

2 answers

65

VirtualGate2018-I-64
Suppose a $32 K 8 K$ matrix A with $1$-byte elements is stored in row major order in virtual memory. Assume that only the program in question occupies space in physical memory. Program $1$ for (i = 0; i < 32768; i++) for (j = 0; j < 8192; j++) A[i ... faults would program $2$ experience if the physical memory can store only $1$ page? $(A) 8M$ $(B) 16M$ $(C) 32M$ $(D) 64M$

Suppose a $32 K×8 K$ matrix A with $1$-byte elements is stored in row major order in virtual memory. Assume that only the program in question occupies space in physical ...

Avdhesh Singh Rana

1.1k views

Avdhesh Singh Rana asked Jan 23, 2018

1 votes

1 answer

66

CO Page fault
How this is 20000? the array is in RMO and we are accessing like CMO then for each entry there should be PF.

How this is 20000? the array is in RMO and we are accessing like CMO then for each entry there should be PF.

Ashwin Kulkarni

586 views

Ashwin Kulkarni asked Jan 19, 2018

3 votes

1 answer

67

LRU page replacement policy
Self doubt: What is the rule or keyb point we should keep in mind while solving problems on LRU page replacement algorithm? Please explain with examples.

Self doubt:What is the rule or keyb point we should keep in mind while solving problems on LRU page replacement algorithm? Please explain with examples.

Sona Barman

470 views

Sona Barman asked Jan 18, 2018

1 votes

1 answer

68

Page Replacement
Could anyone give an example.

Could anyone give an example.

dragonball

390 views

dragonball asked Jan 12, 2018

3 votes

1 answer

69

ace test series
Can anyone explain the answer?

Can anyone explain the answer?

rasto mapp

602 views

rasto mapp asked Jan 11, 2018

3 votes

1 answer

70

gatebook-os
Consider a virtual memory system running on a RISC CPU. Page tables are not locked in memory and may be swapped to disk. An 1w (load word) instruction reads one data word from memory; the address is the sum of value in a register and an immediate constant ... In the worst case how many page faults could be generated as a result of the fetch, decode, and execution of an 1w instruction?

Consider a virtual memory system running on a RISC CPU. Page tables are not locked in memory and may be swapped to disk. An 1w (load word) instruction reads one data word...

rishi71662data4

2.3k views

rishi71662data4 asked Dec 21, 2017

3 votes

1 answer

71

Effective memory access time

Parshu gate

1.1k views

Parshu gate asked Nov 28, 2017

1 votes

0 answers

72

Operating Systems Concepts Page fault using LRU
if you have 10 Frames and using LRU how many page fault will be there in both below: for (int j = 0; j < 100; j++) for (int i = 0; i < 100; i++) A[i][j] = A[i][j] + A[j][i]; for (int i = 0; i < 100; i++) for (int j = 0; j < 100; j++) A[i][j] = A[i][j] + A[j][i];

if you have 10 Frames and using LRU how many page fault will be there in both below: for (int j = 0; j < 100; j++) for (int i = 0; i < 100; i++) A[i][j] = A[i][j] + A[j]...

ashu0316

391 views

ashu0316 asked Nov 13, 2017

0 votes

1 answer

73

UGC NET CSE | December 2009 | Part 2 | Question: 37
A page fault (A) is an error specific page. (B) is an access to the page not currently in memory. (C) occur when a page program occur in a page memory. (D) page used in the previous page reference

A page fault(A) is an error specific page.(B) is an access to the page not currently in memory.(C) occur when a page program occur in a page memory.(D) page used in the p...

rishu_darkshadow

560 views

rishu_darkshadow asked Sep 17, 2017

8 votes

2 answers

74

OS:- Page fault service time vs Effective memory access time
I got some doubt while solving previous year questions:- Since While calculating EMAT and question involves page fault service time,we use formulae:- p*s+(1-p)*m ,taken from Galvin p is page fault rate s is page fault service time m ... sense. So why in first reference/doubt we are not using 2m instead of m in case of NOT a page fault?

I got some doubt while solving previous year questions:-Since While calculating EMAT and question involves page fault service time,we use formulae:-p*s+(1-p)*m ,taken fro...

rahul sharma 5

12.9k views

rahul sharma 5 asked Aug 29, 2017

0 votes

1 answer

75

Self Doubt in Page fault
Small doubt, We know that, when a page fault(required page is missing in main memory) occurs, the respective process will be blocked (Process is removed from Main memory. Does the page table of this process is removed from main memory?? If so, once ... Page Table has to be loaded back.(If it is removed once a process is blocked). Is my understanding correct? Please help me

Small doubt,We know that, when a page fault(required page is missing in main memory) occurs, the respective process will be blocked (Process is removed from Main memory. ...

AnilGoudar

306 views

AnilGoudar asked Apr 30, 2017

2 votes

1 answer

76

Virtual Memory
Consider the following passage to answer questions from Q. Nos. 1 to 6 : Virtual Memory is a technique that allows the execution of processes that may not be completely in the memory. In this system of over-allocation, while a user process is executing, a page fault ... reference string for four frames ? (A) 09 page faults (B) 10 page faults (C) 14 page faults (D) 12 page faults

Consider the following passage to answer questions from Q. Nos. 1 to 6 :Virtual Memory is a technique that allows the execution of processes that maynot be completely in ...

Beyonder

4.3k views

Beyonder asked Mar 14, 2017

1 votes

0 answers

77

Virtual Gate Test Series: Operating System - Page Replacement
Consider the two-dimensional array A$:$ int A[ ] [ ] = new int[100][100]; where A[0][0] is at location 200 in a paged memory system with pages of size 200. A small process that manipulates the matrix resides in page 0 (locations 0 to 199). ... other two are initially empty? for(int j=0;j<100;j++) for(int i=0;i<100;i++) A[i][j]=0;

Consider the two-dimensional array A$:$int A[ ] [ ] = new int[100][100]; where A[0][0] is at location 200 in a paged memory system with pages of size 200. A small process...

Samujjal Das

551 views

Samujjal Das asked Jan 24, 2017

1 votes

2 answers

78

TestBook Test Series
Consider the following information about a hypothetical organization. Assume the cache is physically addressed TLB:hit rate is 95%,access time is 1 cycle Cache: hit rate is 90%,access time is 1 cycle When TLB and cache both get miss,page fault rate is 1% ... cycles Page table is always kept in main memory. Compute the average memory access time? 1 cycle 2 cycle 3 cycle 4 cycle

Consider the following information about a hypothetical organization.Assume the cache is physically addressedTLB:hit rate is 95%,access time is 1 cycleCache: hit rate is ...

vnc

667 views

vnc asked Jan 11, 2017

2 votes

2 answers

79

Page Fault with Optimal
I am getting 11 as pagefault , but the solution says 9. What i am missing?

I am getting 11 as pagefault , but the solution says 9. What i am missing?

vishwa ratna

478 views

vishwa ratna asked Jan 2, 2017

2 votes

0 answers

80

Page Replacement Algorithm #Virtualgate
A.11 B.12 C.13 D.14 Couldn't visualize how counter is assigned and how page is exactly replaced based on counter.Visual representation would be helpful rather than just ans!

A.11B.12C.13D.14Couldn't visualize how counter is assigned and how page is exactly replaced based on counter.Visual representation would be helpful rather than just ans!

Prajwal Bhat

986 views

Prajwal Bhat asked Dec 27, 2016

2 votes

0 answers

81

Page fault in reverse order
Which of the page replacement algorithm has the property that if we traverse the reference string from start to end or from end to start,the number of page faults will be same?

Which of the page replacement algorithm has the property that if we traverse the reference string from start to end or from end to start,the number of page faults will be...

rahul sharma 5

1.6k views

rahul sharma 5 asked Dec 5, 2016

6 votes

2 answers

82

Probability of a Page being Dirty
A demand paging system has page fault service time as 125 time units if page is not dirty and 400 times units of page fault service time if it is a dirty page. Memory access time is 10 time units. The probability of a page fault is 0.3. In ... P. It is observed that average access time is 50 time units. Then, the value of P is ______? [upto four decimal places]

A demand paging system has page fault service time as 125 time units if page is not dirty and 400 times units of page fault service time if it is a dirty page. Memory acc...

User007

2.0k views

User007 asked Nov 14, 2016

4 votes

1 answer

83

(Hamacher, pg.255, question 5.20)
1024x1024 array of 32-bit numbers is to be normalized as follows. For each column the largest element is found and all elements of the column are divided by this maximum value. Assume that each page in the virtual memory consists of 4Kbytes and that 1Mbytes of the ... it takes 2 ns to do a comparison, 20 ns to do a divide and 100 ns to do a load/store to memory.

1024x1024 array of 32-bit numbers is to be normalized as follows. For each column the largest element is found and all elements of the column are divided by this maximum ...

sushmita

2.6k views

sushmita asked Oct 29, 2016

1 votes

2 answers

84

UGC NET CSE | August 2016 | Part 3 | Question: 52
Consider the following page reference string : $1, 2, 3, 4, 2, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6$ Which of the following options, gives the correct number of page faults related to LRU, FIFO, and optimal page replacement algorithms ... $10, 14, 8$ $8, 10, 7$ $7, 10, 8$ $7, 10, 7$

Consider the following page reference string :$1, 2, 3, 4, 2, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6$ Which of the following options, gives the correct number of pag...

makhdoom ghaya

2.5k views

makhdoom ghaya asked Oct 4, 2016

1 votes

1 answer

85

optimal page replacement problem

resilientknight

767 views

resilientknight asked Sep 3, 2016

0 votes

1 answer

86

standrard co question with a bit of confusion
Considering hierarchical method,is my this equation correct? Assuming tlb access time as 0 ns EMAT = 300 [memory access time] + 0.2*(300*2)[2 level page table] + 0.2 * (500) Average instruction execution time = Emat + 200. = 720 ns.

Considering hierarchical method,is my this equation correct?Assuming tlb access time as 0 nsEMAT = 300 [memory access time] + 0.2*(300*2)[2 level page table] + 0.2 * (500...

resilientknight

393 views

resilientknight asked Sep 3, 2016

0 votes

1 answer

87

confusing question? use hierarchical or simultenous
if i use hierarchical system then the equation : 50 = 10 + 0.3(p*400 + (1-p)*125)... is correct?

if i use hierarchical system then the equation : 50 = 10 + 0.3(p*400 + (1-p)*125)... is correct?

resilientknight

423 views

resilientknight asked Sep 3, 2016

3 votes

1 answer

88

UGC NET CSE | June 2016 | Part 2 | Question: 36
Consider the reference string: 0 1 2 3 0 1 4 0 1 2 3 4 If FIFO page replacement algorithm is used, then the number of page faults with three page frames and four page frames are ____ and ___ respectively. 10, 9 9, 9 10, 10 9, 10

Consider the reference string:0 1 2 3 0 1 4 0 1 2 3 4If FIFO page replacement algorithm is used, then the number of page faults with three page frames and four page frame...

go_editor

8.1k views

go_editor asked Aug 16, 2016

1 votes

2 answers

89

UGC NET CSE | December 2015 | Part 2 | Question: 27
Suppose that the number of instructions executed between page fault is directly proportional to the number of page frames allocated to a program. If the available memory is doubled, the mean interval between the page faults is also doubled. Further, ... how long would it take to run twice as much memory were available? 60 sec 30 sec 45 sec 10 sec

Suppose that the number of instructions executed between page fault is directly proportional to the number of page frames allocated to a program. If the available memory ...

go_editor

6.1k views

go_editor asked Aug 8, 2016

1 votes

2 answers

90

UGC NET CSE | September 2013 | Part 3 | Question: 23
Match the following $:$ ... $\text{(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)}$

Match the following $:$$\begin{array}{} \text{(a)} & \text{Dangling pointer} & \text{(i)} & \text{Buffer replacement policy} \\ \text{(b)} & \text{Page fault} & \text{(...

go_editor

1.4k views

go_editor asked Jul 22, 2016

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