re: French ISO
Fre is short for Free, not French (which is typically abreviated to FRA anyway)
So what is meant by 'Free'? Not zero dollars; instead it means 'release' build (vs 'debug' build, which is also known as 'checked').
in short the difference between release(free) and debug(checked), is that in release the compiler has optimized the code (typically for speed), and in debug there is typically lot's of extra debugging info and code (making it big and slow)
Biting the hand that feeds IT
