Search results for operating-system+process-synchronization / GATE Overflow for GATE CSE

112 votes

7 answers

1

GATE CSE 2016 Set 1 | Question: 50
Consider the following proposed solution for the critical section problem. There are $n$ processes : $P_0....P_{n-1}$. In the code, function $\text{pmax}$ ... in the critical section at any time The bounded wait condition is satisfied The progress condition is satisfied It cannot cause a deadlock

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 inte...

Sandeep Singh

47.5k views

Sandeep Singh asked Feb 12, 2016

106 votes

8 answers

2

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

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...

gatecse

30.0k views

gatecse asked Sep 26, 2014

122 votes

7 answers

3

GATE CSE 2017 Set 1 | Question: 27
A multithreaded program $P$ executes with $x$ number of threads and uses $y$ number of locks for ensuring mutual exclusion while operating on shared memory locations. All locks in the program are non-reentrant, i.e., if a thread holds a lock $l$, then it cannot re-acquire lock $l$ without releasing ... $x = 1, y = 2$ $x = 2, y = 1$ $x = 2, y = 2$ $x = 1, y = 1$

A multithreaded program $P$ executes with $x$ number of threads and uses $y$ number of locks for ensuring mutual exclusion while operating on shared memory locations. All...

Arjun

33.3k views

Arjun asked Feb 14, 2017

57 votes

10 answers

4

GATE CSE 2007 | Question: 58
Two processes, $P1$ and $P2$, need to access a critical section of code. Consider the following synchronization construct used by the processes: /* P1 */ while (true) { wants1 = true; while (wants2 == true); /* Critical ... waiting. It requires that processes enter the critical section in strict alteration. It does not prevent deadlocks, but ensures mutual exclusion.

Two processes, $P1$ and $P2$, need to access a critical section of code. Consider the following synchronization construct used by the processes:/* P1 */ while (true) { wa...

Kathleen

27.7k views

Kathleen asked Sep 21, 2014

51 votes

14 answers

5

GATE CSE 1997 | Question: 6.8
Each Process $P_i, i = 1\ldots 9$ is coded as follows repeat P(mutex) {Critical section} V(mutex) forever The code for $P_{10}$ is identical except it uses V(mutex) in place of P(mutex). What is the largest number of processes that can be inside the critical section at any moment? $1$ $2$ $3$ None

Each Process $P_i, i = 1\ldots 9$ is coded as followsrepeat P(mutex) {Critical section} V(mutex) foreverThe code for $P_{10}$ is identical except it uses V(mutex) in plac...

Kathleen

25.1k views

Kathleen asked Sep 29, 2014

115 votes

6 answers

6

GATE CSE 2013 | Question: 39
A certain computation generates two arrays a and b such that $a[i] = f(i)$ for $0 \leq i < n$ and $b[i] = g(a[i])$ for $0 \leq i < n$. Suppose this computation is decomposed into two concurrent processes $X$ and $Y$ such that $X$ computes the array $a$ and $Y$ computes the ... EntryY(R, S) { V(S); P(R); } ExitX(R, S) { V(R); P(S); } EntryY(R, S) { V(S); P(R); }

A certain computation generates two arrays a and b such that $a[i] = f(i)$ for $0 \leq i < n$ and $b[i] = g(a[i])$ for $0 \leq i < n$. Suppose this computation is decompo...

Arjun

28.4k views

Arjun asked Sep 24, 2014

61 votes

6 answers

7

GATE CSE 2010 | Question: 45
The following program consists of $3$ concurrent processes and $3$ binary semaphores. The semaphores are initialized as $S0=1, S1=0$ and $S2=0.$ ... $P0$ print '$0$'? At least twice Exactly twice Exactly thrice Exactly once

The following program consists of $3$ concurrent processes and $3$ binary semaphores. The semaphores are initialized as $S0=1, S1=0$ and $S2=0.$$$\begin{array}{|l|l|}\hli...

go_editor

26.2k views

go_editor asked Sep 30, 2014

75 votes

11 answers

8

GATE IT 2005 | Question: 41
Given below is a program which when executed spawns two concurrent processes : semaphore $X : = 0 ;$ /* Process now forks into concurrent processes $P1$ & $P2$ ... (II) are true. (I) is true but (II) is false. (II) is true but (I) is false Both (I) and (II) are false

Given below is a program which when executed spawns two concurrent processes :semaphore $X : = 0 ;$/* Process now forks into concurrent processes $P1$ & $P2$ */$\begin{ar...

Ishrat Jahan

24.0k views

Ishrat Jahan asked Nov 3, 2014

61 votes

9 answers

9

GATE CSE 2013 | Question: 34
A shared variable $x$, initialized to zero, is operated on by four concurrent processes $W, X, Y, Z$ as follows. Each of the processes $W$ and $X$ reads $x$ from memory, increments by one, stores it to memory, and then terminates. Each of the ... initialized to two. What is the maximum possible value of $x$ after all processes complete execution? $-2$ $-1$ $1$ $2$

A shared variable $x$, initialized to zero, is operated on by four concurrent processes $W, X, Y, Z$ as follows. Each of the processes $W$ and $X$ reads $x$ from memory, ...

Arjun

22.7k views

Arjun asked Sep 24, 2014

104 votes

6 answers

10

GATE CSE 2006 | Question: 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 $x$ ... a pair of normal load/store can be used The implementation of $V$ is wrong The code does not implement a binary semaphore

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 a...

Rucha Shelke

27.7k views

Rucha Shelke asked Sep 26, 2014

69 votes

6 answers

11

GATE CSE 2015 Set 3 | Question: 10
Two processes $X$ and $Y$ ... proposed solution guarantees mutual exclusion and prevents deadlock The proposed solution fails to prevent deadlock and fails to guarantee mutual exclusion

Two processes $X$ and $Y$ need to access a critical section. Consider the following synchronization construct used by both the processes$$\begin{array}{|l|l|}\hline \text...

go_editor

20.8k views

go_editor asked Feb 14, 2015

59 votes

5 answers

12

GATE CSE 2001 | Question: 2.22
Consider Peterson's algorithm for mutual exclusion between two concurrent processes i and j. The program executed by process is shown below. repeat flag[i] = true; turn = j; while (P) do no-op; Enter critical section, perform actions, then exit critical section Flag[i] = ... i flag[j] = true and turn = j flag[i] = true and turn = j flag[i] = true and turn = i

Consider Peterson's algorithm for mutual exclusion between two concurrent processes i and j. The program executed by process is shown below.repeat flag[i] = true; turn = ...

Kathleen

27.0k views

Kathleen asked Sep 14, 2014

45 votes

5 answers

13

GATE CSE 2010 | Question: 23
Consider the methods used by processes $P1$ and $P2$ for accessing their critical sections whenever needed, as given below. The initial values of shared boolean variables $S1$ and $S2$ ... ? Mutual exclusion but not progress Progress but not mutual exclusion Neither mutual exclusion nor progress Both mutual exclusion and progress

Consider the methods used by processes $P1$ and $P2$ for accessing their critical sections whenever needed, as given below. The initial values of shared boolean variables...

go_editor

17.9k views

go_editor asked Sep 29, 2014

26 votes

5 answers

14

GATE CSE 1992 | Question: 02,x, ISRO2015-35
At a particular time of computation, the value of a counting semaphore is $7$. Then $20$ $P$ operations and $15$ $V$ operations were completed on this semaphore. The resulting value of the semaphore is : $42$ $2$ $7$ $12$

At a particular time of computation, the value of a counting semaphore is $7$. Then $20$ $P$ operations and $15$ $V$ operations were completed on this semaphore. The resu...

Kathleen

23.9k views

Kathleen asked Sep 12, 2014

55 votes

7 answers

15

GATE CSE 2003 | Question: 81
Suppose we want to synchronize two concurrent processes $P$ and $Q$ using binary semaphores $S$ and $T$. The code for the processes $P$ and $Q$ ... $1$ $V(S)$ at $W, V(T)$ at $X, P(S)$ at $Y, P(T)$ at $Z, S$ and $T$ initially $1$

Suppose we want to synchronize two concurrent processes $P$ and $Q$ using binary semaphores $S$ and $T$. The code for the processes $P$ and $Q$ is shown below.$$\begin{ar...

go_editor

15.1k views

go_editor asked Apr 24, 2016

61 votes

13 answers

16

GATE CSE 2009 | Question: 33
The enter_CS() and leave_CS() functions to implement critical section of a process are realized using test-and-set instruction as follows: void enter_CS(X) { while(test-and-set(X)); } void leave_CS(X) { X = 0; } In the above solution, $X$ is a memory location ... at the same time Which of the above statements are TRUE? (I) only (I) and (II) (II) and (III) (IV) only

The enter_CS() and leave_CS() functions to implement critical section of a process are realized using test-and-set instruction as follows:void enter_CS(X) { while(test-an...

Kathleen

25.0k views

Kathleen asked Sep 22, 2014

21 votes

4 answers

17

GATE CSE 2021 Set 1 | Question: 46
Consider the following pseudocode, where $\textsf{S}$ is a semaphore initialized to $5$ in line $\#2$ and $\textsf{counter}$ is a shared variable initialized to $0$ in line $\#1$. Assume that the increment operation in line $\#7$ ... is $0$ after all the threads successfully complete the execution of $\textsf{parop}$ There is a deadlock involving all the threads

Consider the following pseudocode, where $\textsf{S}$ is a semaphore initialized to $5$ in line $\#2$ and $\textsf{counter}$ is a shared variable initialized to $0$ in li...

Arjun

13.5k views

Arjun asked Feb 18, 2021

33 votes

5 answers

18

GATE CSE 1996 | Question: 2.19
A solution to the Dining Philosophers Problem which avoids deadlock is to ensure that all philosophers pick up the left fork before the right fork ensure that all philosophers pick up the right fork before the left fork ensure that one particular ... the right fork, and that all other philosophers pick up the right fork before the left fork None of the above

A solution to the Dining Philosophers Problem which avoids deadlock is toensure that all philosophers pick up the left fork before the right forkensure that all philosoph...

Kathleen

11.1k views

Kathleen asked Oct 9, 2014

42 votes

5 answers

19

GATE IT 2008 | Question: 53
The following is a code with two threads, producer and consumer, that can run in parallel. Further, $S$ and $Q$ are binary semaphores quipped with the standard $P$ and $V$ operations. semaphore S = 1, Q = 0; integer x; producer: ... lost Values generated and stored in '$x$' by the producer will always be consumed before the producer can generate a new value

The following is a code with two threads, producer and consumer, that can run in parallel. Further, $S$ and $Q$ are binary semaphores quipped with the standard $P$ and $V...

Ishrat Jahan

9.8k views

Ishrat Jahan asked Oct 28, 2014

42 votes

8 answers

20

GATE CSE 2016 Set 2 | Question: 48
Consider the following two-process synchronization solution. ... synchronization solution. This solution violates mutual exclusion requirement. This solution violates progress requirement. This solution violates bounded wait requirement.

Consider the following two-process synchronization solution.$$\begin{array}{l|l}\hline \text{PROCESS 0 } & \text{Process 1 }\\ \\ \text{Entry: loop while (turn == 1);...

Akash Kanase

15.1k views

Akash Kanase asked Feb 12, 2016

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