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

1 votes

1 answer

241

MadeEasy Test Series: Operating System - Process Synchronization
Consider two processes P1 and P2 accessing shared variable x' and y' protected by two binary semaphores Sx and Sy respectively both initialized to 1. wait' and signal' denote the usual semaphore operators, where ... to do these operations again. Also both these process executing two simple statement which will take constant time.

Consider two processes P1 and P2 accessing shared variable ‘x’ and ‘y’ protected by two binary semaphores Sx and Sy respectively both initialized to 1. ‘wait’...

Hemant Parihar

1.5k views

Hemant Parihar asked Jan 18, 2018

1 votes

0 answers

242

Ace Test series: Operating System - Process Synchronization
I understand the Question Correctly. i know Mutual Exclusion ,But Can Anyone explain What is MUTUAL INCLUSION, ??

I understand the Question Correctly. i know Mutual Exclusion ,But Can Anyone explain What is MUTUAL INCLUSION, ??

Harsh Mehta

937 views

Harsh Mehta asked Jan 13, 2018

1 votes

1 answer

243

self doubt
Process P0:- Process P1 while(1) while(1) { { int[0]=True; int[1]=True; while(int[1]==True); while(int[0]=True); //CS// //CS// int[0]=False; int[1]=False; } } Initially, int[0]=int[1]=false; Will this algorithm satisfy progress and why?

Process P0:- Process P1while(1) ...

charul

330 views

charul asked Jan 4, 2018

1 votes

1 answer

244

Deadlock progress
Deadlock --> no progress Does progress ---> no deadlock...?

Deadlock no progressDoes progress - no deadlock...?

gari

574 views

gari asked Jan 3, 2018

3 votes

0 answers

245

OS critical section
Let 'n' processes competing to enter their critical sections and mutex be a global binary semaphore initialized to 1. The process is coded as follows: Signal(mutex); C.S; wait(mutex); Which of the following statements are TRUE? s1: This ... decision is not postponed indefinitely and there is no competition to enter as well. can we take this as progress? Please answer.

Let 'n' processes competing to enter their critical sections and mutex be a global binary semaphore initialized to 1. The process is coded as follows:Signal(mutex); C...

junk_mayavi

655 views

junk_mayavi asked Jan 2, 2018

1 votes

0 answers

246

Ace Test series: Operating System - Process Synchronization
When multiple processes in a typical IPC environment concurrent tries to update the value of a shared variable, it may result in I) Inconsistency in the value of a variable. II) Data loss III) Deadlock

When multiple processes in a typical IPC environment concurrent tries to update the value of a shared variable, it may result inI) Inconsistency in the value of a variabl...

Abhishek Kumar Singh

713 views

Abhishek Kumar Singh asked Dec 31, 2017

0 votes

0 answers

247

Process Synchronisation
Consider the following program: Const int n= 20 int Count= 0 Void GATE( ) { int i; for(i= 1 to n) Count= Count + 1; } Main ( ) { Par begin GATE( ); GATE( ); GATE( ); Par end } What is the minimum and maximum possible value of count after the completion of the program?

Consider the following program:Const int n= 20int Count= 0Void GATE( ){int i; for(i= 1 to n)Count= Count + 1;}Main ( ){Par beginGATE( );GATE( );GATE( );Par end}What is th...

ankitgupta.1729

697 views

ankitgupta.1729 asked Dec 14, 2017

0 votes

1 answer

248

Problem regarding mutual exclusion
Process P1 Process P2 P(S1) P(S1) P(S2) P(S2) Critical Section Critical Section V(S2) V(S1) V(S1) V(S2) In one of the Gateoverflow tests, this question was given and it was told that in the above case mutual exclusion is not ... section. As far as the order of unlocking, I dont see a problem there. Can someone please explain why mutual exclusion is not guaranteed?

Process P1Process P2P(S1)P(S1)P(S2)P(S2)Critical SectionCritical SectionV(S2)V(S1)V(S1)V(S2)In one of the Gateoverflow tests, this question was given and it was told that...

humblefool

912 views

humblefool asked Dec 13, 2017

1 votes

1 answer

249

Synchronization mechanism doubt
I read that one of the disadvantage of busy waiting solution to synchronization is that PRIORITY INVERSION can occur in it. My doubt is, does the priority inversion problem only occur in busy waiting solution or it can occur in without busy waiting solution too. Please explain. Thanks.

I read that one of the disadvantage of busy waiting solution to synchronization is that PRIORITY INVERSION can occur in it.My doubt is, does the priority inversion proble...

Mahendra Singh Kanya

845 views

Mahendra Singh Kanya asked Dec 11, 2017

1 votes

0 answers

250

Bounded Wait
Process Pi repeat flag[i] = true; while ( flag[j] ) do no-op; < critical - section > flag[i] = false; < remainder - section > until false; Note : "i" refer0s to current process and "j" refers to another process. How Bounded Wait is satisfied here?

Process Pi repeatflag[i] = true; while ( flag[j] ) do no-op; < critical - section flag[i] = false; < remainder - section until false; Note : "i" refer0s to current proc...

Shubhanshu

2.0k views

Shubhanshu asked Dec 7, 2017

1 votes

0 answers

251

Deadlock implies No Progress (in process synchronization) ?
Hi Guys, Deadlock implies no progress. This statement is mentioned at many places. But i just want to verify my reasoning with respect to Progress definition Progress If no process is executing in its critical section and some ... of Deadlock. If my reasoning is not complete or incorrect then please notify. It will be a great help.

Hi Guys,Deadlock implies no progress. This statement is mentioned at many places. But i just want to verify my reasoning with respect to Progress definition ProgressIf no...

Chhotu

832 views

Chhotu asked Dec 4, 2017

2 votes

2 answers

252

Process Synchronization
If there are n processes executing concurrently using binary semaphore S , (n-1) processes have the code do{ wait(S); <c.s> signal(s); <r.s> }while(1); the code for the n-th process i.e Pn is given by do{ signal(S); <c.s> signal(S); < ... (1); What is the max no. of processes that can be there in the critical section simultaneously? A. 2 B . 3 C. n-1 D. n

If there are n processes executing concurrently using binary semaphore S , (n-1) processes have the code do{ wait(S); <c.s signal(s); <r.s }while(1);the code for the n-th...

Kalpataru Bose

833 views

Kalpataru Bose asked Nov 27, 2017

2 votes

2 answers

253

Process Synchronization
If there are n processes executing concurrently using binary semaphore S , (n-1) processes have the code do{ wait(S); <c.s> signal(s); <r.s>}while(1); the code for the n-th process i.e Pn is given by do{ signal(S); <c.s> wait(S); <r. ... ; a) What is the max no. of processes that can be there in the critical section simultaneosly ? A. 2 B . 3 C. n-1 D. n

If there are n processes executing concurrently using binary semaphore S , (n-1) processes have the codedo{ wait(S);<c.s>signal(s);<r.s>...

Kalpataru Bose

730 views

Kalpataru Bose asked Nov 27, 2017

1 votes

1 answer

254

critical section
Consider the following code to access critical section do{ flag[j] = 1; turn = x; while(y); // Critical Section flag[z]=0; // Remainder Section } while(1); The values of x, y and z in the above code for which Mutual exclusion is guaranteed for two process i and j x=j; y=flag[j] ... =flag[i]&&turn=i; z=j x=j; y=flag[i]&&turn=i; z=j x=j; y=flag[j]&&turn=j; z=j

Consider the following code to access critical sectiondo{flag[j] = 1;turn = x;while(y);// Critical Sectionflag[z]=0;// Remainder Section} while(1);The values of x, y and ...

Parshu gate

3.1k views

Parshu gate asked Nov 27, 2017

2 votes

2 answers

255

Synchronisation OS
Should we consider bounded waiting if there is already a deadlock? I mean to say "If there is deadlock then surely not bounded waiting" is this statement true alway ? Some solutions follow this rule some solutions not. Thanks in advance :)

Should we consider bounded waiting if there is already a deadlock?I mean to say "If there is deadlock then surely not bounded waiting" is this statement true alway ?Some...

Ashwin Kulkarni

392 views

Ashwin Kulkarni asked Nov 26, 2017

1 votes

1 answer

256

Process Synchronization
If deadlock is possible ,how Bounded waiting is ensured? Progress is ensured. Right? If one process doesn't want to enter,it will not block other. Please explain me If I'm wrong.

If deadlock is possible ,how Bounded waiting is ensured? Progress is ensured. Right? If one process doesn't want to enter,it will not block other. Please explain me If I...

atul_21

387 views

atul_21 asked Nov 22, 2017

1 votes

0 answers

257

operating system

nikkey123

393 views

nikkey123 asked Nov 22, 2017

0 votes

0 answers

258

Synchronization

atul_21

315 views

atul_21 asked Nov 21, 2017

0 votes

1 answer

259

Process Synchronization
In a given synchronization construct, if there is no deadlock and no strict alternation between two process then is it always true that a process will starve ?

In a given synchronization construct, if there is no deadlock and no strict alternation between two process then is it always true that a process will starve ?

rishi71662data4

613 views

rishi71662data4 asked Nov 16, 2017

0 votes

1 answer

260

OS-question
if c has value =0 initially ....i am getting MAX=2 and minimum =-2..is it correct??

if c has value =0 initially ....i am getting MAX=2 and minimum =-2..is it correct??

SHUBHAM SHASTRI

1.0k views

SHUBHAM SHASTRI asked Nov 16, 2017

1 votes

1 answer

261

Process Synchronization
which of the following is true? it guarantees mutual exclusion. it is busy waiting solution. it does not guarantees progress. it guarantee bounded waiting. entry_section(int process) { int other = 1-process while (flag!=process); CS } exit_section(int process) { flag = other }

which of the following is true?it guarantees mutual exclusion.it is busy waiting solution.it does not guarantees progress.it guarantee bounded waiting.entry_section(int p...

hacker16

869 views

hacker16 asked Nov 9, 2017

3 votes

0 answers

262

Turn Variable
Turn is shared variable but the values are not shared. Explain?

Turn is shared variable but the values are not shared.Explain?

hacker16

488 views

hacker16 asked Nov 9, 2017

1 votes

3 answers

263

Bounded Waiting
how this solution does not satisfy bounded waiting? // initially turn = 0 while (turn != 0); turn = 1 CS turn = 0

how this solution does not satisfy bounded waiting?// initially turn = 0 while (turn != 0); turn = 1 CS turn = 0

hacker16

1.1k views

hacker16 asked Nov 9, 2017

2 votes

1 answer

264

Bounded Waiting
Bounded waiting does not allow: Starvation Busy Waiting A process to wait indefinitely for CS All of Above Ans - d) Explain Option 1 and 2 ?

Bounded waiting does not allow:StarvationBusy WaitingA process to wait indefinitely for CSAll of AboveAns - d)Explain Option 1 and 2 ?

hacker16

5.3k views

hacker16 asked Nov 9, 2017

2 votes

2 answers

265

Semaphores { Ace }
Pseudocode: Int x = 0 , y =20; Semaphores SX=1 , SY= 1; Parbegin Begin P(SX) , P(SY) ; X=X+1; V(SY), V(SX); End Begin P(SY) , P(SX) ; X=Y+2; V(SX), V(SY); End Parend Question: Final Values of X? I am getting 1, 22 and deadlock. How come answer is 22, 23 and deadlock possible??

Pseudocode:Int x = 0 , y =20;Semaphores SX=1 , SY= 1;ParbeginBegin P(SX) , P(SY) ; X=X+1; V(SY), V(SX); ...

vishwa ratna

678 views

vishwa ratna asked Nov 8, 2017

1 votes

1 answer

266

Ace Test Series: Operating System - Semaphore
It says as follows: Pseudocode Integer X = 0 , Y = 23 ; Semaphore mx = 1 , my = Null ; Codebegin Begin P(mx); x= x+1; V(my); End Begin P(my); x= y+1; V(mx); End Question: Possible final values of X?? I tried to find the values and i concluded that 1 and 24 could be the final values but solution says only 24 :( Any idea??

It says as follows:PseudocodeInteger X = 0 , Y = 23 ;Semaphore mx = 1 , my = Null ;Codebegin Begin P(mx); x= x+1; V(my); End...

vishwa ratna

987 views

vishwa ratna asked Nov 8, 2017

1 votes

2 answers

267

semaphores

Parshu gate

847 views

Parshu gate asked Nov 6, 2017

2 votes

1 answer

268

Deadlock
There are 5 processes and 10 instances of a Resource. If each process needs ‘P’ instances which is the minimum value of ‘P’ for the deadlock to occur? (a) 1 (b) 2 (c) 3 (d) 4

There are 5 processes and 10 instances of a Resource. If each process needs ‘P’ instances which is the minimum value of ‘P’ for the deadlock to occur?(a) 1 ...

NIKU

3.3k views

NIKU asked Oct 29, 2017

0 votes

3 answers

269

Process Synchronisation ( binary semaphores)
Consider the below program as two concurrent processes: Semaphore x:= 0; P1: repeat forever P2: repeat forever 1.V(x); 4. P(x); 2.Compute; 5.Compute; 3.P(x); 6.V(x); Consider the following statements about process P1 & P2: (1) ... chance to run , and it wil starve (THIS IS WHAT I THOUGHT THE ANSWER SHOULD BE , PLEASE COMMENT, IF I AM WRONG ANYWHERE)

Consider the below program as two concurrent processes:Semaphore x:= 0;P1: repeat forever P2: repeat forever1.V(x); ...

NIKU

1.0k views

NIKU asked Oct 28, 2017

0 votes

1 answer

270

Process Synchronisation
11. Consider the following program: Const int n= 10 int Count= 0 Void A( ) { int i; for(i= 1 to n) Count= Count + 1; } Main ( ) { Par begin A( ); A( ); A( ); A( ); Par end } What is the minimum and maximum possible value of count after the ... 40 (b) 2, 40 (c) 3, 40 (d) 4, 40 NOTE: I am not able to understand what does "par begin" and "par end" indicates

11. Consider the following program:Const int n= 10int Count= 0Void A( ){ int i;for(i= 1 to n)Count= Count + 1;}Main ( ){Par beginA( );A( );A( );A( );Par end}What is the m...

NIKU

609 views

NIKU asked Oct 28, 2017

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