Trace the Dining Philosopher problem and write the flow of s.pdf
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The document explains the dining philosopher problem and details the flow of states for philosophers 2, 3, and 5 during their eating attempts. It outlines the use of semaphores for mutual exclusion and synchronization, defining procedures for taking and dropping chopsticks, along with the conditions under which philosophers can eat. The initial state of all philosophers is set to thinking, and the state changes are to be tracked whenever one philosopher's state changes.
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![Trace the Dining Philosopher problem and write the flow of states using table below. If
philosophers 2, 3 and 5 try to eat. Write the states of all philosophers whenever there is a change
in
one philosopher state.
Semaphore me= 1; /* for mutual exclusion */
Semaphore s[5], all initially 0; /* for synchronization */
pflag[5]: {THINK, HUNGRY, EAT}, initially THINK; /* philosopher flag */
procedure philosopher(i) //starts here
{
while TRUE do
{
THINKING;
take_chopsticks(i);
EATING;
drop_chopsticks(i);
}
}
procedure take_chopsticks(i)
{
P(me); /* critical section */
pflag[i] = HUNGRY;
test[i];
V(me); /* end critical section */
P(s[i]) /* Eat if enabled */
}
void test(i) /* Let phil[i] eat, if waiting */
{
if ( pflag[i] == HUNGRY && pflag[i-1] != EAT && pflag[i+1] != EAT)then
{
pflag[i] = EAT;
V(s[i])
}
}
void drop_chopsticks(int i)
{
P(me); /* critical section */
pflag[i]=THINKING;
test(i-1); /* Let phil. on left eat if possible */
test(i+1); /* Let phil. on right eat if possible */](https://image.slidesharecdn.com/tracethediningphilosopherproblemandwritetheflowofs-230319100420-7bfa6319/85/Trace-the-Dining-Philosopher-problem-and-write-the-flow-of-s-pdf-1-320.jpg)
![V(me); /* up critical section */
}
Write the change in state of philosophers [T,E,H]. Initially all are in the thinking state [T].](https://image.slidesharecdn.com/tracethediningphilosopherproblemandwritetheflowofs-230319100420-7bfa6319/85/Trace-the-Dining-Philosopher-problem-and-write-the-flow-of-s-pdf-2-320.jpg)
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Trace the Dining Philosopher problem and write the flow of s.pdf
- 1. Trace the Dining Philosopher problem and write the flow of states using table below. If philosophers 2, 3 and 5 try to eat. Write the states of all philosophers whenever there is a change in one philosopher state. Semaphore me= 1; /* for mutual exclusion */ Semaphore s[5], all initially 0; /* for synchronization */ pflag[5]: {THINK, HUNGRY, EAT}, initially THINK; /* philosopher flag */ procedure philosopher(i) //starts here { while TRUE do { THINKING; take_chopsticks(i); EATING; drop_chopsticks(i); } } procedure take_chopsticks(i) { P(me); /* critical section */ pflag[i] = HUNGRY; test[i]; V(me); /* end critical section */ P(s[i]) /* Eat if enabled */ } void test(i) /* Let phil[i] eat, if waiting */ { if ( pflag[i] == HUNGRY && pflag[i-1] != EAT && pflag[i+1] != EAT)then { pflag[i] = EAT; V(s[i]) } } void drop_chopsticks(int i) { P(me); /* critical section */ pflag[i]=THINKING; test(i-1); /* Let phil. on left eat if possible */ test(i+1); /* Let phil. on right eat if possible */
- 2. V(me); /* up critical section */ } Write the change in state of philosophers [T,E,H]. Initially all are in the thinking state [T].