I too am confused by what you're asking. If I have my BIOS setting to be function then the it require me to press <Fn> and the key to do their 'thing' and without they are just function (F1, F2, etc) keys. If I set it to multimedia then pressing F8(decrease volume icon), for example, will decrease the volume and pressing <Fn> and F8 will be like I pressed the F8 key for those few applications that actually use function keys.
Mini1: Vostro A90, Black, 2G, 1.3 Webcam, Bluetooth, 64G SuperTalent, OS X 10.6.4
Mini2: Mini9, Black, 2G, 0.3 Webcam, Bluetooth, 32G RunCore, OS X/Win 7, internal PCI-e SHDC Reader
Mini3: Mini10v. Black, 2G, Webcam, 640G HD, OS X 10.5.8/Win 7/Ubuntu [Hibernate w/NBI 0.8.3 RC4] Dropbox Referral