What is the difference between a semaphore and a critical region?

Question

The only thing I realized is

• Semaphore - a primitive way
• the critical area has a GUARD variable (the semaphore also does, but the name is not GUARD!)

??

so what's the difference?

Answer 1

Typically, a critical area is a place where, if there were two separate threads of execution, there would be a race condition or some other undesirable effect. Semaphores are one way to prevent two threads from being in a critical area at the same time.

Answer 2

GUARD 1 , n ( n) .

Answer 3

, ( ), , (CS) ( ) - , ,

Answer 4

" ":

• , undefined, .

• , , . . " ". Intel / CLI/STI.