> There is a difference between blocking and non-blocking Not really. "Blocking" means "tell the scheduler to mark the process idle until operation finishes",

> There is a difference between blocking and non-blocking Not really. "Blocking" means "tell the scheduler to mark the process idle until operation finishes", while "non-blocking" means "don't mark the process but flip a semaphore bit when operation finishes". The point of view of the OS the difference is just which bit to flip.