"As far as" and "as long as" can be treated like idioms. "As far as" means "Regarding [a topic]" Example: As far as your safety is concerned, you cannot run away! OR Regarding your safety, you cannot run away! "As long as" means "while" Example: As long as I know the truth, you cannot run away! OR While I know the truth, you cannot run away! Hope that helps! :-)

Yes sure, they are totally different. You can use as far as in the context "As far as I remember (if I remember correctly) Regarding to As long as, you can say: I can sing it as long as I have a voice (you will be able to sing the song if you still have a voice) That's it :)