BSCS Bachelor of Science in Computer Science: Operating Systems Concepts 4

Question 1

A semaphore initialized to 1 and used to protect a critical section is called a:

Accepted Answer

Binary semaphore (mutex semaphore)

Answer

A binary semaphore (or mutex semaphore) takes only values 0 and 1 and is used to enforce mutual exclusion in a critical section.

Question 2

What is the main advantage of using a microkernel architecture over a monolithic kernel?

Accepted Answer

Greater reliability because services run in isolated user-space processes

Answer

In a microkernel, OS services run as user-space servers, so a failing component cannot crash the entire kernel, improving fault isolation.

Question 3

In a multi-level feedback queue (MLFQ) scheduler, a process that uses its entire time quantum is typically:

Accepted Answer

Moved to a lower-priority queue

Answer

CPU-bound processes that exhaust their time quantum are demoted to lower-priority queues so interactive, I/O-bound jobs remain responsive.

Question 4

The concept of 'copy-on-write' (COW) after fork() means that:

Accepted Answer

Child and parent share pages until one of them writes, triggering a private copy

Answer

COW defers page duplication until a write occurs, so processes that exec() immediately after fork() never copy the parent's data, saving memory and time.

Question 5

Which condition is NOT one of the four necessary conditions for deadlock?

Accepted Answer

Preemption

Answer

Preemption (the ability to forcibly take a resource from a process) is actually a condition whose absence enables deadlock, not one of the four necessary conditions.

BSCS - Bachelor of Science in Computer Science Practice Test

BSCS - Bachelor of Science in Computer Science Practice Test

BSCS Bachelor of Science in Computer Science: Operating Systems Concepts 4