Notably, ThinkPads did not include Windows keys on any of their keyboards until 2006, which meant that though the left Control key was displaced by the Fn key, neither it nor the left Alt key needed to be made smaller. IBM designers chose this arrangement at least in part because it allowed the laptop's ThinkLight to be turned on in the dark simply by feeling for the keys in two of the keyboard's corners. This arrangement is currently unique to ThinkPads amongst all laptops shipped with Windows, but it is one that has been in place since the modern ThinkPad product line was introduced by IBM in 1992. This usually means that the Control key is reduced in size, but allows it to remain in the lowest-left position on the keyboard.Ĭonversely, Lenovo currently arrange keyboards on their ThinkPad computers with the Fn key as the lowest-left, making Control the second-from-left on the bottom row.
The majority of portable computer manufacturers today (including HP, Dell, and Samsung) currently place the Fn key between the left Control key and the left Windows key, making it the second key from the left on the bottom row of the keyboard. Because the Control key is most frequently associated with OS and application shortcuts (such as Control+S to save a document, or Control+Shift+Escape to launch the Task Manager in modern versions of Microsoft Windows), altering its size and placement is often regarded as inconvenient for users accustomed to the larger left Control key on IBM PC-style keyboards commonly used for desktop computers.
There is not yet an agreed-upon standard for the placement of the Fn key, although most manufacturers have elected to place it alongside a shrunken and/or displaced left Control key. In addition to being mapped to standard keyboard keys like Scroll Lock and Num Lock, the Fn key combinations may also be mapped to control system interfaces to change the LCD brightness, VGA output, or speaker volume on most laptop computers. 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.
However, because the operating system has no notion of the Fn key, the key can not normally be remapped in software, unlike all other standard keyboard keys. This allows the keyboard to directly emulate a full-sized keyboard, so the operating system can use standard keymaps designed for a full-sized keyboard. The Fn key is a form of meta-modifier key, in that it causes the operating system to see altered scancodes when other keys on the keyboard are pressed. For a standard modifier key, the microcontroller inside the keyboard sends a scancode for the modifier itself, which is then interpreted by the operating system and combined with other simultaneous key-presses.
Characters in blue are accessed through the Fn key, but functions on the top row can be accessed without Fn key in Mac OS X.įn is a modifier key, and works like other modifiers keys, such as Ctrl, Shift, Alt and AltGr. This 78-key UK layout is taken from the Apple iBook.