How are the wait/signal operations for monitor different from those for semaphores?

Question

I heard the term "worker thread" and other types of threads such as "system thread" and "user thread".
For me a thread is nothing but a lite weight process and multi-threaded design is chosen for a software development when there are multiple task in the application/system and those tasks can be executed independently.
I want to know when these different terms are used like worker thread, user thread and system thread ?

Answer 1

If a process in a monitor signal and no task is waiting on the condition variable, the signal is lost. So this allows easier program design. Whereas in semaphores, every operation affects the value of the semaphore, so the wait and signal operations should be perfectly balanced in the program.