Question

Given below are two statements :
one is labelled as
Assertion (A) and the other is labelled as
Reason (R).
Assertion (A) :
Preemptive scheduling can lead to race conditions in critical section.
Reason (R) :
Preemption allows multiple processes to access shared data simultaneously.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

In a non-preemptive environment, a process stays in its critical section until it finishes. In a preemptive environment, the OS can "kick" it out mid-calculation, which is why we need Mutexes!

Answer 1

The Correct Option is C

To evaluate these statements, we must analyze how preemptive scheduling interacts with process synchronization and critical sections. 1. Analyzing Assertion (A): Preemptive scheduling allows the operating system to interrupt a currently running process to assign the CPU to another process. If a process is interrupted while it is inside a critical section (modifying shared data) and another process is scheduled that accesses the same shared data, a race condition occurs. Thus, Assertion (A) is correct. 2. Analyzing Reason (R): Preemption does not allow multiple processes to access shared data "simultaneously" on a single-core system; it allows them to access it concurrently via interleaving. More importantly, the goal of synchronization primitives (like semaphores or mutexes) is specifically to prevent such simultaneous access. The reason race conditions occur is due to the interruption and subsequent inconsistent state of data, not because the OS intentionally allows simultaneous access to shared variables. Therefore, Reason (R) is incorrect. 3. Final Conclusion: Since the assertion is a true statement about the risks of preemptive kernels, but the reason provides a fundamentally incorrect description of how data access is managed, Option (3) is the most appropriate.