MadeEasy Test Series: Operating System - Process Synchronization

Question

Comments

how mutual exclusion is satisfied ??? at a time three process can enter in critical section.i think answer is wrong.

---

How will three processes enter the CS?

---

it's my mistake i didn't see p(s3).option (d) is correct .

Answer 1

Yes given answer is correct ...

Now we can see value of S3 semaphore is 3 ,S2 is 2 and that of S1 is 1..

Whe process P1 or P2 or P3 enters ...the All can do DOWN on S3 and are allowed to do DOWN on S2....but again

value of S2 is 2 ...so any 2 Process are allowed to do DOWN ..hence one Process will go into Queue ..now  2 process which has done DOWN on S2 will be able to to DOWN on S1...but S1 has value 1 so only one can do DOWN and other will go into Queue..

So any how...in CS only one process is allowed....so MUTEX is gurantee... here if one doesnt want to go to CS it will not affect others decision to go to CS so ..progress is there..

Bounded WAIT... when we do DOWN on semaphore a process my get into QUEUE ..so even few process are blocked then also Due to First come First out Service of QUEUE ..every process has equal share to access the CS so bounded Wait is also there.

Comments

why have u assumed that after blocking a process they went into the queue?

Is it a rule?@SHUBHAM SHASTRI