can be used to avoid a race condition.  --&gt; find a way to prevent one process from accessing some shared data, while another process is already using it
class of safety problems that deal with using a shared resource, and characterizing behaviors in which two processes never access the shared resource at the same time.
The lady in question, Professor Samantha Van der Feldt, flunked you because instead of studying like the rest of us, you sent her love letters.