Modifier keys

Info from following URLs:
  http://en.wikipedia.org/wiki/Computer_keyboard

  http://en.wikipedia.org/wiki/Windows_Key
  http://en.wikipedia.org/wiki/AltGr_key
  http://en.wikipedia.org/wiki/Space-cadet_keyboard

    I was surfing the Web last night on my Eee PC and thought that it would be easier to use the PgUp and PgDn keys if I could remap the Menu key as a Fn key. After searching around, I found info on xmodmap but could not understand what the Super-L and Hyper-L keys were.

    Did some "research" on our ubiquitous keyboard and decided to share the following info below, which will hopefully help in my quest to remap the keys later on :)

    This is a photo of my Fujitsu T4010 keyboard. I will be using the bottom row of keys to explain the special modifier keys. A modifier key when pressed in conjunction with another key, will perform a special operation (for example, Control-Alt-Delete) but rarely performs any function when pressed by itself.

(Bottom row, from left to right)

Key	Description
Ctrl (left)	ConTRoL key. A commonly used modifier key, so no elaboration here.
Fn	FunctioN key. This key is usually found on laptop keyboards and is used for various functions like adjusting volume, brightness, etc.
Win	WINdows key.  Pressing and releasing it by itself opens the Start Menu in Windows, which can be invoked using Ctrl-Esc also.
Alt (left)	ALTernate key. Commonly used to call up the application menu, eg. Alt-F to call up the File menu. The F10 key can be used to invoke the application menu as well.
Spacebar	Not a modifier key, but the longest one on all keyboards :P
AltGr	ALTernate GRaphic key. On most keyboards, this functions as another Alt key. Used primarily to type characters unusual to the locale of the keyboard layout. If a key has a 3rd symbol on it, then AltGr can often be used to type it. As those using US keyboards increasingly needed the specific functionality of AltGr when typing non-English text, Windows began to allow all keystroke combinations involving AltGr to be typed by using Ctrl+Alt in its place.
Menu	Also known as the Application key. Its primary function is to launch a context menu with the keyboard rather than with the usual right mouse button. This functionality can be invoked with the Shift-F10 shortcut also.
Ctrl (right)	Typically, each keyboard will have 2 Ctrl keys, 2 Alt keys and 2 Win keys.

    This, is a Space-cadet keyboard used on MIT Lisp machines and designed by Tom Knight, which inspired several still-current jargon terms in the field of computer science and influenced the design of Emacs, a feature-rich text-editor popular with technically proficient computer users and computer programmers.

    It is said that with the combination of the Control, Meta, Hyper and Super keys, it was possible to type out over 8000 different characters on the Space-cadet keyboard, allowing users to type very complicated mathematical text. Many users were actually willing to memorise the command meanings of that many characters if it reduced typing time (this attitude shaped the interface of Emacs).

    The reason for showing this is that some keys in xmodmap are apparently linked to these, especially the Meta, Hyper and Super keys (on the left and right sides of the bottom row).

 

Key	Description
Hyper	Not much info on this, except that it is a modifier key.
Super	This key is typically identified today with the Windows key or Apple logo key, although these may also be identified with the Meta key.
Meta	Sun keyboards continue to include it, marked as a solid diamond. May be considered equivalent to the Macintosh's command key. Emulated with Alt or Windows key on modern keyboards.
Compose	The Compose key is not on the Space-cadet keyboard, but it's worth mentioning. Also known as the "Multi-key" on X Window System. A key designated to signal the software to interpret the subsequent keystrokes as a combination in order to produce a character not found on the keyboard.

(^ v ^)