sentence: while it is most common for the fn key processing to happen directly in the keyboard micro-controller , offering no knowledge to the main computer of whether the fn key was pressed , some manufacturers , like lenovo , performs this mapping in bios running on the main cpu , allowing remapping the fn key by modifying the bios interrupt handler ; and apple , in which the fn key is mappable and serves other uses too , as triggering the dictation function by pressing the fn key twice .