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

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31

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 52 (Page No. 260 - 261)
Write a program that simulates a toy paging system that uses the $\text{WSClock}$ algorithm. The system is a toy in that we will assume there are no write references (not very realistic), and process ... references. Explain what is needed to extend the program to handle a page reference stream that also includes writes.

Write a program that simulates a toy paging system that uses the $\text{WSClock}$ algorithm. The system is a toy in that we will assume there are no write references (not...

admin

390 views

admin asked Oct 26, 2019

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32

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 51 (Page No. 260)
Write a program that simulates a paging system using the aging algorithm. The number of page frames is a parameter. The sequence of page references should be read from a file. For a given input file, plot the number of page faults per $1000$ memory references as a function of the number of page frames available.

Write a program that simulates a paging system using the aging algorithm. The number of page frames is a parameter. The sequence of page references should be read from a ...

admin

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admin asked Oct 26, 2019

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33

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 47 (Page No. 259 - 260)
We consider a program which has the two segments shown below consisting of instructions in segment $0,$ and read/write data in segment $1.$ Segment $0$ has read/execute protection, and segment $1$ has just read/write protection. The ... $1,$ page $4,$ offset $28$ Jump to location in segment $1,$ page $3,$ offset $32$

We consider a program which has the two segments shown below consisting of instructions in segment $0,$ and read/write data in segment $1.$ Segment $0$ has read/execute p...

admin

779 views

admin asked Oct 26, 2019

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0 answers

34

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 44 (Page No. 259)
A machine-language instruction to load a $32-bit$ word into a register contains the $32-bit$ address of the word to be loaded. What is the maximum number of page faults this instruction can cause?

A machine-language instruction to load a $32-bit$ word into a register contains the $32-bit$ address of the word to be loaded. What is the maximum number of page faults t...

admin

316 views

admin asked Oct 26, 2019

1 votes

1 answer

35

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 42 (Page No. 259)
It has been observed that the number of instructions executed between page faults is directly proportional to the number of page frames allocated to a program. If the available memory is doubled, the mean interval between page faults ... page faults, how long would it take to run if twice as much memory were available?

It has been observed that the number of instructions executed between page faults is directly proportional to the number of page frames allocated to a program. If the ava...

admin

642 views

admin asked Oct 26, 2019

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0 answers

36

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 39 (Page No. 259)
You have been hired by a cloud computing company that deploys thousands of servers at each of its data centers. They have recently heard that it would be worthwhile to handle a page fault at server A by reading ... local disk drive. How could that be done? Under what conditions would the approach be worthwhile? Be feasible?

You have been hired by a cloud computing company that deploys thousands of servers at each of its data centers. They have recently heard that it would be worthwhile to ha...

admin

277 views

admin asked Oct 26, 2019

1 votes

2 answers

37

Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 13 (Page No. 255)
If an instruction takes $1\: nsec$ and a page fault takes an additional $n\: nsec,$ give a formula for the effective instruction time if page faults occur every $k$ instructions.

If an instruction takes $1\: nsec$ and a page fault takes an additional $n\: nsec,$ give a formula for the effective instruction time if page faults occur every $k$ instr...

admin

1.7k views

admin asked Oct 26, 2019

3 votes

1 answer

38

Self Doubt on Page Fault
To calculate EMAT in case of page fault we used: EMAT= page fault rate*(page fault service time) + (1-page fault rate)*(memory access time) My doubt is: In case of NO PAGE FAULT, why we considered only one memory access time . Why ... considered (VA -> PA time) + memory access time. Then why not we consider address translation time in questions involving only pagefault?

To calculate EMAT in case of page fault we used:EMAT= page fault rate*(page fault service time) + (1-page fault rate)*(memory access time)My doubt is:In case of NO PAGE ...

tp21

1.1k views

tp21 asked Sep 22, 2019

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1 answer

39

Made Easy Test Series:Operating System-Page Fault
Consider a system using demand paging architecture it takes $3ms.$ to service page fault if either empty frame is available or replaced page is not to be modified takes $10ms.$ if replaced page is modified. Main Memory access time ... time. The maximum acceptable page fault rate to get effective memory access time not more than $4ms.$ is_________(%)

Consider a system using demand paging architectureit takes $3ms.$ to service page fault if either empty frame is available or replaced page is not to be modifiedtakes $10...

srestha

700 views

srestha asked May 15, 2019

2 votes

0 answers

40

Vani Question Bank:Operating System

Hirak

259 views

Hirak asked May 9, 2019

0 votes

1 answer

41

Galvin Edition 9 Exercise 9 Question 21 (Page No. 453)
Consider the following page reference string: $7, 2, 3, 1, 2, 5, 3, 4, 6, 7, 7, 1, 0, 5, 4, 6, 2, 3, 0 , 1.$ Assuming demand paging with three frames, how many page faults would occur for the following replacement algorithms ? $•$ $LRU$ $replacement$ $•$ $FIFO$ $replacement$ $•$ $Optimal$ $replacement$

Consider the following page reference string:$7, 2, 3, 1, 2, 5, 3, 4, 6, 7, 7, 1, 0, 5, 4, 6, 2, 3, 0 , 1.$Assuming demand paging with three frames, how many page faults ...

akash.dinkar12

4.5k views

akash.dinkar12 asked Mar 21, 2019

1 votes

0 answers

42

Galvin Edition 9 Exercise 9 Question 20 (Page No. 453)
When a page fault occurs, the process requesting the page must block while waiting for the page to be brought from disk into physical memory. Assume that there exists a process with five user-level threads and that the mapping of user ... page fault-that is, would they also have to wait for the faulting page to be brought into memory? Explain.

When a page fault occurs, the process requesting the page must block while waiting for the page to be brought from disk into physical memory. Assume that there exists a p...

akash.dinkar12

851 views

akash.dinkar12 asked Mar 21, 2019

0 votes

1 answer

43

Galvin Edition 9 Exercise 9 Question 19 (Page No. 453)
Assume that we have a demand-paged memory. The page table is held in registers. It takes $8$ milliseconds to service a page fault if an empty frame is available or if the replaced page is not modified and $20$ milliseconds ... time. What is the maximum acceptable page-fault rate for an effective access time of no more than $200$ nanoseconds ?

Assume that we have a demand-paged memory. The page table is held in registers. It takes $8$ milliseconds to service a page fault if an empty frame is available or if the...

akash.dinkar12

305 views

akash.dinkar12 asked Mar 21, 2019

0 votes

1 answer

44

Test series
Consider a system with main memory access time is 150ns and page fault service time is 5 microsecond if one-page fault generated for every 10^3 memory access then what is effective memory access time(in ns)?? The answer given is 154.85 and the answer I am getting is 4850.15 please verify someone

Consider a system with main memory access time is 150ns and page fault service time is 5 microsecond if one-page fault generated for every 10^3 memory access then what i...

saif

355 views

saif asked Jan 31, 2019

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0 answers

45

Made Easy
Shouldnt we take 1 instead of 1-P ?? As it should be sequential access???

Shouldnt we take 1 instead of 1-P ?? As it should be sequential access???

anjali007

299 views

anjali007 asked Jan 23, 2019

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0 answers

46

UPPCL AE 2018:57
Consider the following $\text{C}$ function executed in an $\text{OS}$ with paging where the page size is $4$ kilobytes. Further, assume that the system employs a $32-$ entry direct mapped $\text{TLB}$ int *alloc_and_init() { int counter, value = 0, size = 2048; int ... of the program, what is the number of $\text{TLB}$ misses during the execution of the for loop? $2048$ $2$ $0$ $1$

Consider the following $\text{C}$ function executed in an $\text{OS}$ with paging where the page size is $4$ kilobytes. Further, assume that the system employs a $32-$ en...

admin

275 views

admin asked Jan 5, 2019

0 votes

1 answer

47

Effective memory access time
Suppose: TLB lookup time = 20 ns TLB hit ratio = 80% Memory access time = 75 ns Swap page time = 500,000 ns 50% of pages are dirty OS uses a single level page table What is the effective access time (EAT) if we assume the page fault rate is 10%? Assume the cost toupdate the TLB, the page table, and the frame table (if needed) is negligible.

Suppose: TLB lookup time = 20 nsTLB hit ratio = 80%Memory access time = 75 nsSwap page time = 500,000 ns50% of pages are dirtyOS uses a single level page tableWhat is the...

Hardik Vagadia

1.4k views

Hardik Vagadia asked Jan 3, 2019

0 votes

1 answer

48

UGC NET CSE | December 2018 | Part 2 | Question: 72
Suppose for a process $P$, reference to pages in order are $1, 2, 4, 5, 2, 1, 2, 4$. Assume that main memory can accomodate $3$ pages and the main memory has already $1$ and $2$ in the order $1$ ... Replacement Algorithm is used then the number of page faults that occur to complete the execution of process $P$ is $4$ $3$ $5$ $6$

Suppose for a process $P$, reference to pages in order are $1, 2, 4, 5, 2, 1, 2, 4$. Assume that main memory can accomodate $3$ pages and the main me...

Arjun

2.3k views

Arjun asked Jan 2, 2019

5 votes

1 answer

49

GATE Overflow | Mock GATE | Test 1 | Question: 64
Consider the $2$ dimensional array $A$: int A[][]=new int[100][100]; where $A[0][0]$ is at location $800$ in a paged memory system with pages of size $800 bytes$. Each int type needs 4 bytes and A is stored in row-major order. A small process that ... other $2$ are initially empty? for (int i=0;i<100;i++) for (int j=0;j<100; j++) A[j][i]=1;

Consider the $2$ dimensional array $A$:int A[][]=new int[100][100];where $A[0][0]$ is at location $800$ in a paged memory system with pages of size $800 bytes$. Each int ...

Ruturaj Mohanty

1.3k views

Ruturaj Mohanty asked Dec 27, 2018

2 votes

0 answers

50

Self doubt on EMAT
For page fault Some where I see EMAT=page fault (page fault service time) +(1-page fault)(memory access time) BUT somewhere it's like EMAT=page fault (page fault service time + memory access time) +(1-page fault)(memory access time) Which one is correct and why this difference?

For page fault Some where I seeEMAT=page fault (page fault service time) +(1-page fault)(memory access time)BUT somewhere it's likeEMAT=page fault (page fault service tim...

Rishav Kumar Singh

513 views

Rishav Kumar Singh asked Dec 26, 2018

0 votes

0 answers

51

Self Doubt [Effective memory access time]
Page fault rate = p Main memory access time = m Page fault service time = PS EMAT = (1-p) (m) + (p) (PS + m) OR EMAT = (1-p) (m) + (p) (PS) which one is right ...if page fault occurs should we consider [ Page fault service time + MM ] OR [ Page fault service time only ]

Page fault rate = pMain memory access time = mPage fault service time = PSEMAT = (1-p) (m) + (p) (PS + m)OREMAT = (1-p) (m) + (p) (PS)which one is right ...if page fault...

jatin khachane 1

622 views

jatin khachane 1 asked Dec 15, 2018

2 votes

1 answer

52

MadeEasy Subject Test 2019: Operating System - Virtual Memory

jatin khachane 1

498 views

jatin khachane 1 asked Dec 13, 2018

0 votes

0 answers

53

OS EMAT vs AMAT
In Page Fault and Demand Paging concept what is the difference between Effective Memory access time and average memory access time? The formulae are known but i am confused with the concept.

In Page Fault and Demand Paging concept what is the difference between Effective Memory access time and average memory access time?The formulae are known but i am confuse...

Shamim Ahmed

894 views

Shamim Ahmed asked Dec 9, 2018

0 votes

0 answers

54

Page Size v/s Page fault
I studied from book william stalling ,it was written there if we increase the size of page then pagefault first increases and then when pagesize become size of process then pagefault decreases. Can someone explain with an example why this happens?

I studied from book william stalling ,it was written there if we increase the size of page then pagefault first increases and then when pagesize become size of process th...

garvit_vijai

413 views

garvit_vijai asked Dec 8, 2018

0 votes

1 answer

55

Galvin #page fault service time #memory management #disk access

gourav94240

1.5k views

gourav94240 asked Oct 19, 2018

2 votes

4 answers

56

ISI2016-PCB-CS-3
Consider the following extract from a program, written in a C-like language, that computes the transpose of a matrix. for (i=0; i<N; i++) for (j=0; j<N; j++) B[i,j]=A[i,j]; $A$ and $B$ are $N \times N$ matrices with floating point entries ... Each of $A$ and $B$ is stored starting from the beginning of a page None of the pages allocated to $A$ and $B$ are initially in memory.

Consider the following extract from a program, written in a C-like language, that computes the transpose of a matrix.for (i=0; i<N; i++) for (j=0; j<N; j++) B[i,j]=A[i,j]...

go_editor

943 views

go_editor asked Sep 18, 2018

0 votes

1 answer

57

Page Fault Doubt
https://gateoverflow.in/2122/gate2011-20-ugcnet-june2013-ii-48 in the solution why memory access is not considered along with page fault service time when a page fault occurs? Because after page fault the page has to be brought into the memory which needs memory access

https://gateoverflow.in/2122/gate2011-20-ugcnet-june2013-ii-48in the solution why memory access is not considered along with page fault service time when a page fault occ...

aditi19

363 views

aditi19 asked Sep 13, 2018

2 votes

1 answer

58

MadeEasy Test Series: Operating System - Page Replacement
Consider a demand paged memory system, page table is held in registers. It takes 800 nsec to service a page fault if empty page is available or replaced page is not modified and 950 nsec if the replaced page is modified, ... modified 85% of time and page faultrate is 20% then average memory access time is ________. (Upto 1 decimal place)

Consider a demand paged memory system, page table is held in registers. It takes 800 nsec to service a page fault if empty page is available or replaced page is not modif...

jhaanuj2108

2.5k views

jhaanuj2108 asked Aug 14, 2018

0 votes

1 answer

59

EMAT in case of page fault
I have read that EMAT when the page fault occurs is =p(PS+MA)+(1-p)(MA) p is the probability of page fault i-p is the probability that page is present in Main Memory PS is the Page fault service time MA is the memory access time but according to me first it ... which is going to take one Memory access So,EMAT should be equals=p(MA+PS+MA)+(1-p)(MA+MA). why it is not so??

I have read that EMAT when the page fault occurs is =p(PS+MA)+(1-p)(MA)p is the probability of page faulti-p is the probability that page is present in Main MemoryPS is t...

CHIRAG CHAWLA

1.6k views

CHIRAG CHAWLA asked Aug 11, 2018

0 votes

1 answer

60

UGC NET CSE | July 2018 | Part 2 | Question: 58
Consider a virtual page reference string 1, 2, 3, 2, 4, 2, 5, 2, 3, 4. Suppose LRU page replacement algorithm is implemented with 3 page frames in main memory. Then the number of page faults are _____ 5 7 9 10

Consider a virtual page reference string 1, 2, 3, 2, 4, 2, 5, 2, 3, 4. Suppose LRU page replacement algorithm is implemented with 3 page frames in main memory. Then the n...

Pooja Khatri

3.4k views

Pooja Khatri asked Jul 13, 2018

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