That is weird, I've always used dad. I've never heard anyone call their dad "sir" outside of films.
Dad. However if he asks me a yes or no question I better not be caught saying yeah or naw. It's yes, sir. No, sir.
What do you call your iPhone or iPod?
What do you call your Mac?
What do you call your iPhone?
What do you call your Time Machine disk?
What do you call your iPod?