UGC NET CSE | June 2010 | Part 2 | Question: 39

Question

In order to allow only one process to enter its critical section, binary semaphore are initialized to

• A. $0$
• B. $1$ 
• C. $2$
• D. $3$

Answer 1

In order to allow only one process to enter its critical section,generaly  we will take semaphore value as 1 as when it will enter in critical section it will down the semaphore value to zero so that no other process is able to down ,further the value of semaphore .

 (b) option ans.

Answer 2

i think ans should be 1 .
when a process want to enter critical section it decrements value by 1 .
Now value becomes to zero. if another process try to enter critical section it goes to waiting queue.
 2 & 3 can not be possible value for binary semaphore it can contain only 0 & 1 possible value