Operating Systems · Concurrency and Synchronization
Official IIT answer key · IIT Kharagpur · Audited Aug 2026
GATE CSE 2014 Set 2 Q31 · MCQ · 2 marks
semaphore n = 0;
semaphore s = 1;
void producer()
{
while(true)
{
produce();
semWait(s);
addToBuffer();
semSignal(s);
semSignal(n);
}
}
void consumer()
{
while(true)
{
semWait(s);
semWait(n);
removeFromBuffer();
semSignal(s);
consume();
}
}
Which one of the following is TRUE?Key concept
No account needed
Sit 5 related Concurrency and SynchronizationPYQs as a guest. We'll score the set and show which traps cost marks — sign in only if you want to save the run.
Topic notes
Concurrency and Synchronization is consistently evaluated through rigorous interleaving analysis, semaphore tracing, and correctness verification of mutual exclusion algorithms. Over the years, GATE tests whether candidates can systematically trace race conditions, identify potential deadlocks from mismatched semaphore wait/signal orders, and compute the bounds or exact sets of possible shared variable values under non-atomic operations. Recent papers heavily favor Multi-Select Questions (MSQs) requiring complete enumeration of all valid execution traces and program outcomes.
Full Concurrency and Synchronization guide →Consider the procedure below for the *Producer-Consumer* problem which uses semaphores: semaphore n = 0; semaphore s = 1; void producer() while(true) produce(); semWait(s); addToBuffer(); semSignal(s); semSignal(n); void consumer() while(true) semWait(s); semWait(n); removeFromBuffer(); semSignal(s); consume(); Which one of the following is TRUE?
Topic-wise GATE CS PYQs with verified steps
Independent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.