Process Synchronization

PROCESS SYNCHRONIZATION SONALI C. UDIT-SYBSc-IT 2008-09

INTRODUCTION ,[object Object],[object Object],[object Object]

CRITICAL SECTION ,[object Object],[object Object],[object Object],[object Object]

CRITICAL SECTION ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Cont… Entry section exit section GENERAL STRUCTURE OF A TYPICAL PROCESS Pi

CRITICAL SECTION ,[object Object],[object Object],[object Object],[object Object],Cont…

TWO-PROCESS SOLUTION ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

TWO-PROCESS SOLUTION -Algorithm 1 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Do{ Critical section remainder section }while(1) For Process P i while (turn != i); Turn = j;

TWO-PROCESS SOLUTION -Algorithm 2 ,[object Object],[object Object],[object Object],[object Object],do { flag[i] = true; // declare your own interest while (flag[ j]) ; //wait if the other guy is interested critical section flag [i] = false; // declare that you lost interest remainder section // allows other guy to enter } while (1);

[object Object],[object Object],[object Object],[object Object],TWO-PROCESS SOLUTION -Algorithm 2

[object Object],TWO-PROCESS SOLUTION -Algorithm 3 For Process P i do { flag [i] = true; // declare your interest to enter turn = j; // assume it is the other’s turn-give PJ a chance while (flag [ j ] and turn == j) ; critical section flag [i] = false; remainder section } while (1);

[object Object],[object Object],[object Object],TWO-PROCESS SOLUTION -Algorithm 3

MULTIPLE-PROCESS SOLUTIONS - Bakery Algorithm ,[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],MULTIPLE-PROCESS SOLUTIONS - Bakery Algorithm

[object Object],MULTIPLE-PROCESS SOLUTIONS - Bakery Algorithm

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],do { /* Has four states: choosing, scanning, CS, remainder section */ critical section /* no longer a candidate for CS entry */ remainder section } while (1); number[i] = 0;

SEMAPHORSES ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

SEMAPHORSES ,[object Object],Definition-Wait wait(S) { while(S<=0) ; //no-op S--; } Definition-signal Signal(S) { S++; }

[object Object],struct semaphore { int count; queueType queue; } void wait(semaphore s) { s.count--; if (s.count < 0) { place this process in s.queue; block this process } } void signal(semaphore s) { s.count++; if (s.count <= 0) { remove a process P from s.queue; place process P on ready list; } }

SEMAPHORES -Two Type ,[object Object],[object Object],[object Object]

SEMAPHORES -Binary Semaphores ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Process Synchronization

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to Process Synchronization

Similar to Process Synchronization (20)

More from Sonali Chauhan

More from Sonali Chauhan (20)

Recently uploaded

Recently uploaded (20)

Process Synchronization