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, perform 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.