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

6 votes

1 answer

331

deadlock
If ‘m’ processes share ‘n’ resources of the same type, the maximum need of each process does not exceed ‘n’ and the sum of all their maximum needs is always less than ‘m+n’. In this case: (a) Deadlock can never occur (b) Deadlock may occur (c) Deadlock has to occur (d) None

If ‘m’ processes share ‘n’ resources of the same type, the maximum need of each process doesnot exceed ‘n’ and the sum of all their maximum needs is always le...

harshit agarwal

2.1k views

harshit agarwal asked Dec 17, 2016

0 votes

1 answer

332

Made easy booklet- Synchronisation: What are possible outcomes?
Please help in part b) What are the potential outcomes? Answer:

Please help in part b) What are the potential outcomes?Answer:

agoh

381 views

agoh asked Dec 11, 2016

3 votes

4 answers

333

If there is deadlock possible, is it correct to conclude that progress and bounded wait will be violated?

My doubt is as follows: If deadlock is there, processes will be busy waiting in wait loop. So, decision on which process enters C.S. is not made in finite time. Hence, is...

agoh

1.1k views

agoh asked Dec 11, 2016

6 votes

1 answer

334

GATE CSE 1989 | Question: 11b
Consider the following precedence graph $(\text{Fig}.6)$ of processes where a node denotes a process and a directed edge from node $P_{i}$ to node $P_{j}$ implies; that $P_{i}$ must complete before $P_{j}$ commences. Implement the graph using FORK and JOIN constructs. The actual computation done by a process may be indicated by a comment line.

Consider the following precedence graph $(\text{Fig}.6)$ of processes where a node denotes a process and a directed edge from node $P_{i}$ to node $P_{j}$ implies; that $...

makhdoom ghaya

2.5k views

makhdoom ghaya asked Dec 9, 2016

4 votes

1 answer

335

MadeEasy Test Series: Operating System - Process Synchronization
question :

question :

dd

1.4k views

dd asked Dec 5, 2016

0 votes

1 answer

336

[Strong/Weak Semaphore] Operating system Chapter -5 William Stallings 7th Edition
How the processes are removed from the Semaphore suspended queue?Is it implementation dependent or is it FIFO always?If not FIFO then how starvation will be handled.I got this doubt while reading following ... Priority based/SJf..etc ,then it will neither be strong semaphore nor weak semaphore?# Please clarify

How the processes are removed from the Semaphore suspended queue?Is it implementation dependent or is it FIFO always?If not FIFO then how starvation will be handled.I got...

rahul sharma 5

3.4k views

rahul sharma 5 asked Dec 4, 2016

1 votes

4 answers

337

Suppose that an operating system provides two functions
Suppose that an operating system provides two functions, block_queue() which puts the calling process on the blocked queue, and wakeup_queue(P)which moves process P to the runnable queue if it is currently on the ... the Following statement is true? it prints P0P1 alternatively always. It prints P1P0 alternatively always Deadlock possible None

Suppose that an operating system provides two functions, block_queue() which puts the calling process on the blocked queue, and wakeup_queue(P)which moves process P to th...

Akriti sood

832 views

Akriti sood asked Dec 4, 2016

1 votes

1 answer

338

MadeEasy Test Series: Operating System - Process Synchronization
#plz check???

#plz check???

Hradesh patel

691 views

Hradesh patel asked Nov 29, 2016

12 votes

1 answer

339

progress and deadlock
Is is true that...If there is deadlock then system can not progress?

Is is true that...If there is deadlock then system can not progress?

vaishali jhalani

4.9k views

vaishali jhalani asked Nov 26, 2016

2 votes

0 answers

340

GATE CSE 1990 | Question: 9a
Assume that an instruction test-and-set (TS) has been provided in a machine whose function is as follows: 'the left most bit of the one byte operand is checked and accordingly the condition code (CC) is set to $1$ or $0$. After checking and setting the condition code, implement a critical region using this instruction.

Assume that an instruction test-and-set (TS) has been provided in a machine whose function is as follows: 'the left most bit of the one byte operand is checked and accord...

makhdoom ghaya

894 views

makhdoom ghaya asked Nov 24, 2016

7 votes

2 answers

341

OS Synchronization
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 } 5 What is the minimum and maximum possible value of count after the completion of the program? (a) 1, 40 (b) 2, 40 (c) 3, 40 (d) 4, 40

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 }5...

target2017

4.3k views

target2017 asked Nov 23, 2016

30 votes

2 answers

342

GATE CSE 1990 | Question: 2-iii
Match the pairs:$\begin{array}{|ll|ll|}\hline (a) & \text{Critical region} & (p) & \text{Hoare's monitor} \\ (b) & \text{Wait/Signal} & (q) & \text{Mutual exclusion} \\ (c) & \text{Working Set} & (r) & \text{Principle of locality} \\ (d) & \text{Deadlock} & (s) & \text{Circular Wait} \\\hline \end{array}$

Match the pairs:$$\begin{array}{|ll|ll|}\hline (a) & \text{Critical region} & (p) & \text{Hoare's monitor} \\ (b) & \text{Wait/Signal} & (q) & \text{Mutual exclusion} \\ ...

makhdoom ghaya

6.1k views

makhdoom ghaya asked Nov 18, 2016

22 votes

1 answer

343

GATE CSE 1990 | Question: 1-vii
Semaphore operations are atomic because they are implemented within the OS _________.

Semaphore operations are atomic because they are implemented within the OS _________.

makhdoom ghaya

7.8k views

makhdoom ghaya asked Nov 18, 2016

13 votes

1 answer

344

GATE CSE 1987 | Question: 8a
Consider the following proposal to the "readers and writers problem." Shared variables and semaphores: aw, ar, rw, rr : interger; mutex, reading, writing: semaphore: initial values of variables and states of semaphores: ar=rr=aw ... group of readers make waiting writers starve? Can writers starve readers? Explain in two sentences why the solution is incorrect.

Consider the following proposal to the "readers and writers problem."Shared variables and semaphores:aw, ar, rw, rr : interger; mutex, reading, writing: semaphore: initia...

makhdoom ghaya

3.1k views

makhdoom ghaya asked Nov 14, 2016

24 votes

1 answer

345

GATE CSE 1987 | Question: 1-xvi
A critical region is One which is enclosed by a pair of $P$ and $V$ operations on semaphores. A program segment that has not been proved bug-free. A program segment that often causes unexpected system crashes. A program segment where shared resources are accessed.

A critical region isOne which is enclosed by a pair of $P$ and $V$ operations on semaphores.A program segment that has not been proved bug-free.A program segment that oft...

makhdoom ghaya

5.2k views

makhdoom ghaya asked Nov 8, 2016

2 votes

1 answer

346

difference among Critical Section ,Mutual Exclusion and Semaphore
difference in following: [i] mutual exclusion [ii] critical section [iii] semaphore

difference in following: [i] mutual exclusion [ii] critical section [iii] semaphore

LavTheRawkstar

1.7k views

LavTheRawkstar asked Nov 4, 2016

0 votes

0 answers

347

process synchoronozation and semaphores
The Semaphore variable full, empty and mutex are initialized to 0, n and 1 respectively. Process P1 repeatedly adds one item at a time to a buffer of size n, and process P2 repeatedly removes one item at a time from the same buffer using the programs given below. In the ... (c) P(empty), V(full), P(empty), V(full) (d) P(empty), V(full), P(full), V(empty)

The Semaphore variable full, empty and mutex are initialized to 0, n and 1 respectively. Process P1 repeatedly adds one item at a time to a buffer of size n, and process ...

Lone Wolf

382 views

Lone Wolf asked Oct 27, 2016

5 votes

2 answers

348

operating system process synchronization
var occupied var blocked Enter Region: { If (occupied) { blocked= blocked +1 sleep ( ); } else occupied= 1; } // (critical section) Exit Region: { occupied= 0 If (blocked) { wakeup (process); blocked= blocked - 1; } } Now consider the following statements ... of the above statements are False? (a) Only 1 (b) 1 & 2 (c) 1 & 3 (d) none of the above

var occupied var blocked Enter Region: { If (occupied) { blocked= blocked +1 sleep ( ); } else occupied= 1; } // (critical section) Exit Region: { occupied= 0 If (block...

Lone Wolf

1.0k views

Lone Wolf asked Oct 27, 2016

0 votes

1 answer

349

Which of the following statements is/are true?
The Operations P(S) & V(S) needs to be atomic. A process exiting the CS will call V(S) Busy-Wait' solutions to the Critical Section are typically implemented using machine instructions that execute in the Kernel mode All of ... the above process to enter the critical section) will never be able to run. Are my points incorrect? Please advice.

The Operations P(S) & V(S) needs to be atomic.A process exiting the CS will call V(S)‘Busy-Wait’ solutions to the Critical Section are typically implemented using mac...

rickeshjohn

3.3k views

rickeshjohn asked Oct 22, 2016

0 votes

1 answer

350

#self made
In lock variable mechanism of the following modified code , if we execute the code then can mutul exclusion be satisfied.?? 1. Load Ri , M[lock] 2. cmp Ri, # 0 3. store # 1,M[lock] 4. JZ to step 1 CS 5. store # 0, M[lock]

In lock variable mechanism of the following modified code , if we execute the code then can mutul exclusion be satisfied.??1. Load Ri , M[lock]2. cmp Ri, # 03. store # ...

Aman Jha

348 views

Aman Jha asked Oct 21, 2016

3 votes

2 answers

351

Self Doubt
Q : Each process Pi , i = 1 to 9 executes the following code : while (TRUE) { P(mutex); Critical section ; V(mutex); } The process P10 executes the following code : while(TRUE) { V(mutex); critical section ; P(mutex); } Initial value of binary semaphore "mutex" = ... at any instant of time? a) 2 b) 3 c) 9 d) 10 e) 1 Plz explain in details which one is true out of these options.

Q : Each process Pi , i = 1 to 9 executes the following code : while (TRUE) { P(mutex); Critical section ; V(mutex);}The process P10 executes the foll...

Habibkhan

2.9k views

Habibkhan asked Oct 16, 2016

5 votes

3 answers

352

Two process critical section software solution
// a software solution for critical section problem bool flag[2]; int turn; void process(int id) { while(true) { flag[id] = true; while(turn != id) { while(flag[1-id]); turn = id; } < Critical Section > ... return 0; } Which of the following is false ? Mutual exclusion is satisfied. Progress is satisfied. Bounded waiting is satisfied. None.

// a software solution for critical section problem bool flag ; int turn; void process(int id) { while(true) { flag[id] = true; while(turn != id) { while(flag[1-id]); tur...

dd

2.6k views

dd asked Oct 14, 2016

3 votes

1 answer

353

OS Synchronization
In process synchronozation , when we can say progress is satisfied and when progress not satisfied? Explain with example. (Donot give just definition, need clear difference when progress is satisfied and when not satisfied)

In process synchronozation , when we can say progress is satisfied and when progress not satisfied?Explain with example.(Donot give just definition, need clear difference...

srestha

1.3k views

srestha asked Oct 14, 2016

0 votes

2 answers

354

Doubt in some basic things synchronisation
I have some fundamental doubts regarding the conditions which need to be followed for a correct synchronisation solution i.e. about mutual exclusion , progress and bounded wait. I m asking these. Plz address to these doubts but give a ... for the fact whether the bounded wait condition is satisfied or not? Also plz support your answer with proper reason..

I have some fundamental doubts regarding the conditions which need to be followed for a correct synchronisation solution i.e. about mutual exclusion , progress and bounde...

Habibkhan

1.3k views

Habibkhan asked Oct 14, 2016

1 votes

2 answers

355

synchronization reader's writer's problem.
int readers_count = 0; semaphore mutex = 1; // binary semaphore semaphore db = 1; // binary semaphore void reader() { while(TRUE) { x. down(mutex); //or wait(mutex) or P(mutex) readers_count = readers_count + 1; y. if(readers_count ... and writers are allowed in the database at the same time. c. There is possibility of deadlock. d. None of the above.

int readers_count = 0; semaphore mutex = 1; // binary semaphore semaphore db = 1; // binary semaphore void reader() { while(TRUE) { x. down(mutex); //or wait(mutex) or P(...

dd

2.3k views

dd asked Oct 11, 2016

1 votes

1 answer

356

pthreads
Suppose you have an array A of 4 numbers and you have 2 threads. how will you perform a cumulative sum of numbers and store it in array B using parallel computation and synchronization. (B[1]=A[1], B[2]=A[1] + A[2],.. so on

Suppose you have an array A of 4 numbers and you have 2 threads. how will you perform a cumulative sum of numbers and store it in array B using parallel computation and ...

.

457 views

. asked Oct 10, 2016

0 votes

1 answer

357

process sychronization
What is spinlock? What are the advantages of having spinlock?

What is spinlock?What are the advantages of having spinlock?

vaishali jhalani

588 views

vaishali jhalani asked Oct 7, 2016

0 votes

0 answers

358

process synchronisation
What is the difference between MUTEX and Binary Semaphores.

What is the difference between MUTEX and Binary Semaphores.

vaishali jhalani

580 views

vaishali jhalani asked Oct 7, 2016

11 votes

1 answer

359

Difference between Dekkers and Peterson solutions to Critical Section Problem
Dekkers Algorithm flag[0]=true; while(flag[1]==true) { if(turn!=0) { flag[0]=false; while(turn!=0); flag[0]=true; } } // CS turn=1; flag[0]=false; Peterson Algorithm flag[0]=true; turn=1; ... [1]==true&&turn==1); // CS flag[0]=false Account on the Mutual Exclusion Bound Waiting Deadlock and Starvation Progress

Dekkers Algorithmflag[0]=true; while(flag ==true) { if(turn!=0) { flag[0]=false; while(turn!=0); flag[0]=true; } } // CS turn=1; flag[0]=false;Peterson Algorithm flag[0]=...

pC

11.8k views

pC asked Oct 6, 2016

2 votes

2 answers

360

critical section

vaishali jhalani

1.1k views

vaishali jhalani asked Oct 5, 2016

tags	tag:apple
author	user:martin
title	title:apple
content	content:apple
exclude	-tag:apple
force match	+apple
views	views:100
score	score:10
answers	answers:2
is accepted	isaccepted:true
is closed	isclosed:true