Recent questions tagged process-synchronization / GATE Overflow for GATE CSE

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181

MadeEasy Subject Test 2019: Operating System - Process Synchronization
In these type of questions “Will we NOT consider CONTEXT SWITCHING unless mentioned???” If context switching is ALLOWED, minimum value will be 8...Correct me if I’m wrong.

In these type of questions “Will we NOT consider CONTEXT SWITCHING unless mentioned???”If context switching is ALLOWED, minimum value will be 8...Correct me if I’m ...

Hopealways

445 views

Hopealways asked Dec 1, 2018

1 votes

1 answer

182

Semaphore
What happens if signal() is performed on a binary semaphore which is already set to 1. sem mutex = 1; signal(mutex) // cs

What happens if signal() is performed on a binary semaphore which is already set to 1.sem mutex = 1;signal(mutex)// cs

Shiv Gaur

572 views

Shiv Gaur asked Nov 30, 2018

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0 answers

183

ace academy test series

amitqy

992 views

amitqy asked Nov 21, 2018

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0 answers

184

Ace Test Series: Operating System - Process Synchronization And Semaphore
I think that statement iii is false , deadlock can arise in both semaphore as well as monitor (mutex)

I think that statement iii is false , deadlock can arise in both semaphore as well as monitor (mutex)

Magma

722 views

Magma asked Nov 19, 2018

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1 answer

185

Abraham Silberasch Galvin operating system Book chapter 5 process synchronization
The first known correct software solution to the critical-section problem for two processes was developed by Dekker. The two processes, P0 and P1, share the following variables: boolean flag[2]; /* initially false */ int turn; ... critical section */ turn = j; flag[i] = false; /* remainder section */ } while (true);

The first known correct software solution to the critical-section problemfor two processes was developed by Dekker. The two processes, P0 andP1, share the following varia...

Chetan Warke

3.1k views

Chetan Warke asked Nov 17, 2018

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186

Readers-writers problem
In Reader-writer problem, if a Writer is writing some data, can other reader reads the data at the same time? If no, this is the code present in Galvin how does it taking care of above situation Writer's process: do { wait(rw mutex); . . . /* writing is performed ... / . . . wait(mutex); read count--; if (read count == 0) signal(rw mutex); signal(mutex); } while (true);

In Reader-writer problem, if a Writer is writing some data, can other reader reads the data at the same time?If no, this is the code present in Galvin how does it taking ...

Swapnil Naik

1.2k views

Swapnil Naik asked Nov 16, 2018

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1 answer

187

Doubt Counting Semaphore
Assume Counting Semaphore N=8. On performing 10 down() operations by 10 different processes , first 8 will be successful and last two processes will be suspended. Does this mean that the first 8 processes can enter in the CS at the same time? In other words, does counting semaphore can let multiple processes access the CS at the same time?

Assume Counting Semaphore N=8.On performing 10 down() operations by 10 different processes , first 8 will be successful and last two processes will be suspended.Does this...

Shaijal Tripathi

1.0k views

Shaijal Tripathi asked Nov 7, 2018

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1 answer

188

MadeEasy Test Series: Operating System - Process Synchronization
What is the main reason for RACE condition while synchronzing the process? A)The two processes trying to update the variable at same time. B) More than one process entering into the critical section at same time. C)Mutual Exclusion condition not satisfies. D)All of the above

What is the main reason for RACE condition while synchronzing the process?A)The two processes trying to update the variable at same time.B) More than one process entering...

Parth Shah

1.2k views

Parth Shah asked Oct 31, 2018

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0 answers

189

Testbook Test Series: Operating System - Process Synchronization

monty

408 views

monty asked Oct 30, 2018

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0 answers

190

Self Doubt
Let X is an Binary Semaphore with waiting Queue in FIFO order. P1 P2 repeat forever V(X); Compute ; P(X); repeat forever P(X); Compute ; V(X); P1 P2 repeat forever V(X); Compute ; V(X); repeat forever P(X); Compute ; V(X); In which case Starvation for P2 is possible??

Let X is an Binary Semaphore with waiting Queue in FIFO order.P1P2repeat forever V(X); Compute ; P(X); repea...

jatin khachane 1

693 views

jatin khachane 1 asked Oct 29, 2018

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0 answers

191

Gate Practice
Please explain the question given below.

Please explain the question given below.

Abhisek Saha

487 views

Abhisek Saha asked Oct 26, 2018

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0 answers

192

Operating Systems
To check that a mutual exclusion algorithm is not free from deadlock,is it necessary to check if the entire processes in the system are in deadlock- If there are 5 processes in the system- P0,P1,P2,P3,P4 and if we have to prove that the ... definitely in deadlock- This means it is not necessary for all processes in the system to be in deadlock to say deadlock has occurred?

To check that a mutual exclusion algorithm is not free from deadlock,is it necessary to check if the entire processes in the system are in deadlock-If there are 5 proces...

skywalker_19

287 views

skywalker_19 asked Oct 23, 2018

3 votes

1 answer

193

MadeEasy_OS_test
Here it is given that the load and store are atomic. So , I Am assuming that Thread 1 uses following machine code to increment x by 3. $(I)LOAD\,R_i\,M[X]$ $(II)ADDI\,R_i,3$ $(III)STORE\,R_i,M[X]$ And thread 2 uses below machine code for ... value comes to be 30, please let me know. I see I can get minimum value 30 only when the increment of x and assignment both are atomic.

Here it is given that the load and store are atomic.So , I Am assuming that Thread 1 uses following machine code to increment x by 3.$(I)LOAD\,R_i\,M[X]$$(II)ADDI\,R_i,3$...

Ayush Upadhyaya

966 views

Ayush Upadhyaya asked Oct 23, 2018

0 votes

1 answer

194

Acebook
Consider the following code: co-begin-end X=2; co begin X=X+3; X=X+1; co end The final possible values of 'X' are: a)3,5 b)3,4,5 c)3,5,6 d)5,3,2

Consider the following code:co-begin-end X=2; co begin X=X+3; X=X+1; co endThe final possible values of 'X' are:a)3,5b)3,4,5c)3,5,6d)5,3,2

abhishek1995_cse

444 views

abhishek1995_cse asked Oct 18, 2018

1 votes

0 answers

195

Semaphore
Will it causing deadlock? How do we fixed it? P1: P2: Wait(S); Wait(Q); Wait(Q); Wait(S); ........ ............. Signal(S); Signal(Q); Signal(Q); Signal(S);

Will it causing deadlock? How do we fixed it?P1: P2: Wait(S); Wait(Q); Wait(Q); Wait(S); ........ ............. Signal(S); Signal(Q); Signal(Q); Signal(S);

srestha

1.1k views

srestha asked Oct 4, 2018

2 votes

2 answers

196

Test Series : Checking Bounded Waiting
How does option B ensure Bounded Waiting? Process A can keep on entering the CS while process B tries to enter the CS but keeps on spinning over Wait(P). I mean if there is no context switch from A to B then A can keep on visiting the CS as many times as possible(no bound on the no. of times it enters) making B to wait.

How does option B ensure Bounded Waiting?Process A can keep on entering the CS while process B tries to enter the CS but keeps on spinning over Wait(P). I mean if there i...

MiNiPanda

2.6k views

MiNiPanda asked Oct 1, 2018

3 votes

0 answers

197

#OS Usergate Process Synchronisation
Any implementation of a critical section requires the use of an indivisible machine- instruction ,such as test-and-set? Is the above statement True or False?

Any implementation of a critical section requires the use of an indivisible machine- instruction ,such as test-and-set?Is the above statement True or False?

iarnav

760 views

iarnav asked Sep 28, 2018

0 votes

1 answer

198

MadeEasy Test Series: Operating System - Process Synchronization

debanjan sarkar

621 views

debanjan sarkar asked Sep 23, 2018

0 votes

0 answers

199

Dining Philosopher problem-Doubt
Consider the below code as a solution to dining philosopher problem #define N 5 /* number of philosophers */ #define LEFT (i+N−1)%N /* number of i's left neighbor */ #define RIGHT (i+1)%N /* number of i's right neighbor */ #define THINKING ... forks each be available to P1 and P3 at the same time? Please help. The code is taken from Andre Tanenbaum as a reference.

Consider the below code as a solution to dining philosopher problem #define N 5 /* number of philosophers */ #define LEFT (i+N−1)%N /* number of i’s left neighbor */ ...

Ayush Upadhyaya

1.0k views

Ayush Upadhyaya asked Sep 21, 2018

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200

Test and Set Lock(TSL)
In case of TSL we are aware of the following instructions: 1. TSL LOCK, Ro 2. CMP Ro, #0 3. JNZ step1 Now, the initial value of LOCK is 0 If process Po comes and executes line 1 and if it gets preempted, then Ro = 0 and LOCK = 1 Now, If process P1 ... able to enter the CS...right? So, in this way, Po and P1 both will get stuck...right? and so is there a chance of deadlock?

In case of TSL we are aware of the following instructions: 1. TSL LOCK, Ro 2. CMP Ro, #0 3. JNZ step1 Now, the initial value of LOCK is 0 If process Po...

garvit_vijai

1.4k views

garvit_vijai asked Sep 20, 2018

1 votes

0 answers

201

doubt - synchronization
what is difference between in both question...? it is totally look same just difference in variable. https://gateoverflow.in/1256/gate2007-58 https://gateoverflow.in/8405/gate2015-3-10

what is difference between in both question...? it is totally look same just difference in variable.https://gateoverflow.in/1256/gate2007-58 https://gateoverflow.in/8405...

bhavnakumrawat5

582 views

bhavnakumrawat5 asked Sep 17, 2018

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0 answers

202

Galvin Operating system
Can someone explain me the code of TSL in process synchronization from Operating Systems Concepts by Galvin?

Can someone explain me the code of TSL in process synchronization from Operating Systems Concepts by Galvin?

vikas999

198 views

vikas999 asked Aug 17, 2018

0 votes

1 answer

203

Monitors Process Synchronization
Is Monitors concept not in GATE 2019 ?

Is Monitors concept not in GATE 2019 ?

Harsh Kumar

970 views

Harsh Kumar asked Aug 17, 2018

4 votes

2 answers

204

#OS process synchronization
What happens if we run the following program? int main() { int sem; sem = screate(1); //Semaphore is created and is initialized to 1 fork (); Wait(sem); printf(―Gate ―); Signal(sem); return 0; } (A) Starvation occurs (B) Deadlock occurs (C) Both processes enter critical section simultaneously (D) ―Gate Gate―will be the output

What happens if we run the following program?int main(){int sem;sem = screate(1); //Semaphore is created and is initialized to 1fork ();Wait(sem);printf(―Gate ―);Sign...

Rackson

828 views

Rackson asked Aug 4, 2018

0 votes

0 answers

205

#OS Gate 2001 Peterson Algorithm Question Doubt (user gate)
Original question - here 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 ... option b) will allow both Pi and Pj into CS. May you guys please explain, how option c) is answer!

Original question - here Consider Peterson's algorithm for mutual exclusion between two concurrent processes i and j. The program executed by process is shown below.repea...

iarnav

1.7k views

iarnav asked Aug 1, 2018

0 votes

1 answer

206

#OS Reader Writer User Gate 2000 Doubt
Original Question - https://gateoverflow.in/691/gate2000-20 a. Fill in the boxes below to get a solution for the reader-writer problem, using a single binary semaphore, mutex (initialized to 1) and busy waiting. Write the box numbers (1, 2 and 3), and ... = R - 1; ///// This is Critical Section, right//// signal (mutex); } Also, how starvation is happening?

Original Question - https://gateoverflow.in/691/gate2000-20 a. Fill in the boxes below to get a solution for the reader-writer problem, using a single binary semaphore, m...

iarnav

1.1k views

iarnav asked Jul 30, 2018

0 votes

0 answers

207

#OS #GATE2016 UserGate 2016 Barrier Synchronisation Question Doubt,
Original question - Click here My question is how deadlock is possible in that question. I've read the discussion and folks are saying that this below line is not an atomic execution, fair enough!! And more than one process can have same t ... then P1 will have t[1] = 1. So, how two processes has same t[i] value at any time?

Original question - Click hereMy question is how deadlock is possible in that question. I've read the discussion and folks are saying that this below line is not an atom...

iarnav

754 views

iarnav asked Jul 28, 2018

0 votes

1 answer

208

#OS [Process Synchronisation} Self Doubt in Bakery Algorithm's Code.
Clear Algorithm photo - here Please see page 1 - here Page 2 - here Page 3 here My question is that when P0 didn't get stuck at line 11 on page 3 then won't it go and execute for loop? i.e make ++p and p ... at line 11 while as while loop will break and P2 also goes into CS? Basically, how is the for loop working, here?

Clear Algorithm photo - herePlease see page 1 - herePage 2 - here Page 3 hereMy question is that when P0 didn't get stuck at line 11 on page 3 then won't it go and execut...

iarnav

2.2k views

iarnav asked Jul 27, 2018

0 votes

1 answer

209

Semaphore
Given two semaphore n and s Now given 2 situation Situation 1) The producer will be able to add an item to the buffer, but consumer can never consume it Situation 2) Consumer succeeds in acquiring semaphore s, when buffer is empty What will be initial value of n and s to fulfill these two condition separately? (U can describe the situation with few words)

Given two semaphore n and sNow given 2 situationSituation 1) The producer will be able to add an item to the buffer, but consumer can never consume itSituation 2) Consume...

srestha

670 views

srestha asked Jul 26, 2018

0 votes

0 answers

210

#OS #Semaphores Producer Consumer Problem Self Doubt.
I know, that both P and C can go and fall into sleeping state in case of preemption and this can be solved via Semaphores. Now, my doubt is that integer bit that will be set by the P and being sent to C and C will see the semaphore bit ... ? Basically, both P and C can send this integer bit or only P can send this to C to wake him up? Thank you!

I know, that both P and C can go and fall into sleeping state in case of preemption and this can be solved via Semaphores. Now, my doubt is that integer bit that will be ...

iarnav

524 views

iarnav asked Jul 22, 2018

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