In
computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...
, a modifier key is a special key (or combination) on a
computer keyboard
A computer keyboard is a peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches. Replacing early punched cards and paper tape technology ...
that temporarily modifies the normal action of another key when pressed together. By themselves, modifier keys usually do nothing; that is, pressing any of the , , or keys alone does not (generally) trigger any action from the computer.
For example, in most
keyboard layouts the Shift key combination will produce a capital letter "A" instead of the default lower-case letter "a" (unless in
Caps lock or
Shift lock mode). A combination of in
Microsoft Windows will close the
active window; in this instance, Alt is the modifier key. In contrast, pressing just or will probably do nothing unless assigned a specific function in a particular program (for example, activating input aids or the toolbar of the active window in Windows).
User interface
In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine f ...
expert
Jef Raskin coined the term "
quasimode" to describe the state a computer enters into when a modifier key is pressed.
Modifier keys on personal computers
The most common are:
*
* (Control)
* (Alternate) – also labelled on
Apple keyboards.
* (Alternate Graphic)
* – Meta key, found on MIT, Symbolics, and Sun Microsystems keyboards.
* – Super key, found on MIT, Symbolics, Linux, and BSD keyboards.
* (Windows logo) – found on Windows keyboards.
* – Command key, found on Apple keyboards. On older keyboards labelled (Apple logo).
* (Function) – often present on small-layout keyboards, or keyboard where the top row of function keys have multimedia functions like controlling volume attached.
The (Sun) Meta key, Windows key, (Apple) Cmd key, and the analogous "Amiga key"() on
Amiga computers, are usually handled equivalently. Under the Linux operating system, the desktop environment
KDE calls this key
Meta, while
GNOME calls this key, neutrally,
Super
Super may refer to:
Computing
* SUPER (computer program), or Simplified Universal Player Encoder & Renderer, a video converter / player
* Super (computer science), a keyword in object-oriented programming languages
* Super key (keyboard butt ...
. (This is a bit confusing, since the original
space-cadet keyboard and the
X Window System recognize a "" modifier distinct from "".)
The Sinclair
ZX Spectrum has a Symbol Shift key in addition to Caps Shift. This was used to access additional punctuation and keywords.
The
MSX
MSX is a standardized home computer architecture, announced by Microsoft and ASCII Corporation on June 16, 1983. It was initially conceived by Microsoft as a product for the Eastern sector, and jointly marketed by Kazuhiko Nishi, then vice-p ...
computer keyboard, besides Shift and Control, also included two special modifier keys, Code and Graph. In some models, as in the Brazilian
Gradiente Expert, the Code and Graph keys are labelled "" and "" (Left and Right Graphics). They are used to select special graphic symbols and extended characters.
Likewise, the
Commodore 64 and other Commodore computers had the Commodore key at the bottom left of the keyboard.
Compact keyboards, such as those used in
laptops, often have a
Fn key to save space by combining two functions that are normally on separate keys. On laptops, pressing plus one of the function keys, e.g., F2, often control hardware functions. Keyboards that lack a dedicated numeric keypad may mimic its functionality by combining the Fn key with other keys.
The
MIT space-cadet keyboard had additional Top, Front, Super and Hyper modifier keys. Combined with standard modifiers, it could enter as many as 8,000 different characters.
Accented characters
Some non-English language keyboards have special keys to produce
accented modifications of the standard Latin-letter keys. In fact, the standard British
keyboard layout includes an accent key on the top-left corner to produce àèìòù, although this is a two step procedure, with the user pressing the accent key, releasing, then pressing the letter key. These kinds of keys are called
dead key
A dead key is a special kind of modifier key on a mechanical typewriter, or computer keyboard, that is typically used to attach a specific diacritic to a base letter. The dead key does not generate a (complete) character by itself, but modifies th ...
s. The
AltGr modifier produces the áéíóú sequence, or in conjunction with the Shift key, ÁÉÍÓÚ. Keyboards of some languages simply include the accented characters on their own keys. Some keyboards also have a
Compose key for typing accented and other special characters. By pressing , and then two other keys, something similar to a combination of the glyphs of the two previous keys will appear on the screen.
Dual-role keys
It is possible to use (with some utility software) one key both as a normal key and as a modifier.
For example, you can use the both as a normal Space bar and as a Shift. Intuitively, it will act as a standard Space when you want a whitespace, and a Shift when you want it to act as a shift. I.e. when you simply press and release it, it is the usual space, but when you press other keys, say , and , while holding down the , then they will be treated as plus X, Y and Z.
The above example is known as "SandS", standing for "Space and Shift" in Japan. But any number of any combinations are possible.
To press shift+space in the previous example, you need in addition to a space/shift dual role key, one of (a) another space/shift key, (b) a usual shift, or (c) a usual space key.
See also
*
Bucky bit
*
Control character
*
Function key
*
Keyboard layout
*
Space-cadet keyboard
*
Table of keyboard shortcuts
*
Emacs pinky -
repetitive strain injury
A repetitive strain injury (RSI) is an injury to part of the musculoskeletal or nervous system caused by repetitive use, vibrations, compression or long periods in a fixed position. Other common names include repetitive stress disorders, cumu ...
developed by too much use of control key, notably for
Emacs
Emacs , originally named EMACS (an acronym for "Editor MACroS"), is a family of text editors that are characterized by their extensibility. The manual for the most widely used variant, GNU Emacs, describes it as "the extensible, customizable, ...
users.
References
External links
Bucky bits in the Jargon file
{{DEFAULTSORT:Modifier Key
Computer keys
User interface techniques
de:Tastenkombination#Hilfstasten für Tastenkombinationen