Corvettes and Frigates.

Future?

Which navies around the world still operate Corvettes, and do they not all employ Frigates of varying sizes?  

Since the second world-war (1939-45) many navies have developed greatly with many advances in missile systems over guns and sonar. Meanwhile there has also been many new advances in the gathering of electronic intelligence and systems for counter attack.

What is the differences between a Frigate and a Corvette?
Has it more to do with their role in the theatre of warfare.

Today some navies, if they are not just called defense forces employ the Corvette for inshore patrol, with a bit of a punch. While the Frigate is more of a real warship, missiles, air defenses, Helicopter facility and torpedo tubes.