no, its not firmware and whatever. its because 1 gb=1024 mb, 1 mb=1024 kb, and 1 kb=1024 bytes. therefore, 1 gb = 1,073,741,824 bytes. however, when apple advertises their ipod as having 30 gb, they say 1 gb = 1000 mb, 1 mb = 1000 kb, and 1 kb = 1000 bytes, or that 1 gb = 1,000,000,000 bytes. so in actuality, 30 gb would be 32,212,254,720 bytes, and apple is only giving you 30,000,000,000 bytes, and you lose 2,212,254,720 bytes, or 2.06032 gb. if you check your capacity, it will say something like 27.9 gb or so, because they is the actual number of gb, not apples smaller ones.
and now i sound like a fucking nerd, but i looked it up on their website to see why i was getting screwed out of 2 gigs.