Process Synchronization Gate 1994

Question

KINDLY SOMEONE POINT OUT MY MISTAKE. I FEEL PAREND ,PARBEGIN CONSTRUCTS CAN BE USED FOR S1 AND S2. BUT ONE SOLUTION BOOK IS SHOWING DIFFERENT PRECEDENCE GRAPH.THERE IT IS EVEN SAID WE CANT USE PARBEG ,PAREND 

HERE IS MY PRECEDENCE GRAPH

I AM VERY CONFUSED OVER THIS.PLEASE HELP ME. I FEEL S1 AND S2 CAN BE CONCURRENT AS THEY DEAL WITH DIFFERENT VARIABLE. THEN WE SHOULD BE ABLE TO USE PARBEG AND PAREND FOR THEM .PLZZ HELP  AND RECTIFY ME

Answer 1

i think this is the right answer . can u plz post a copy of the solution provided,. what they have told u about the answer. ??

Comments

 actulay i am not having the book now.It was my friends.but the book was  published by ACE publications 27 years solution.but i had copied it from the book.i will post it sometime..plz help me

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sorry  for late reply .i wanted to make sure about the graph. the solution given in that ACE publication is 

please help me out . i cant make out the reason for their precedence graph . they mentioned that if this graph is to be implemented using parbeg and parend binary semaphore would be needed  which is i feel true for this graph but why will such graph occur ?? i am very confused

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on thing i want to tell u ANI just don't worry seeing any answer from test series or booklet . there question are ambigous ans many time wrong . just stick to the question the gate question will never be not well defined . they are always well defined. so my opinion is u are right . may be they have taken it in sequence . or may be i am wrong . but i think the solution is wrong. just believe in the concept not in the answer.

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thank you ravi. you are correct.

.bdw while solving this problem i felt whenever there would be any loop i.e (for,while, if )  the resulting true subcodes or false codes can't be executed paralelly . am i correct in saying that ?

if i go by that then this question was wrong .coz if i put  use  semaphore in their graph or even mine    then S6 would wait for S3 and S5 while S5 would wait for S3 through S3 hence even the last call to if that would be false next can't be jumped directly and hence a(i) would be wrong as it would be incremented again .

i hope i am able to clear out my doubt else i would post it as a question