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, e ...
, 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 layout
A keyboard layout is any specific physical, visual or functional arrangement of the keys, legends, or key-meaning associations (respectively) of a computer keyboard, mobile phone, or other computer-controlled typographic keyboard.
is the actua ...
s 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
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...
will close the
active window
A window manager is system software that controls the placement and appearance of windows within a windowing system in a graphical user interface. Most window managers are designed to help provide a desktop environment. They work in conjunction ...
; 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
Jef Raskin (born Jeff Raskin; March 9, 1943 – February 26, 2005) was an American human–computer interface expert best known for conceiving and starting the Macintosh project at Apple in the late 1970s.
Early life and education
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
Apple Inc. has designed and released dozens of keyboard models since the introduction of the Apple II in 1977. The current models in use are dual-mode (Bluetooth and USB) keyboards with integrated batteries: Magic Keyboard (silver only), and M ...
.
* (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
Amiga is a family of personal computers introduced by Commodore in 1985. The original model is one of a number of mid-1980s computers with 16- or 32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphi ...
computers, are usually handled equivalently. Under the Linux operating system, the desktop environment
KDE
KDE is an international free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-known products include the ...
calls this key
Meta
Meta (from the Greek μετά, '' meta'', meaning "after" or "beyond") is a prefix meaning "more comprehensive" or "transcending".
In modern nomenclature, ''meta''- can also serve as a prefix meaning self-referential, as a field of study or ende ...
, while
GNOME
A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its characte ...
calls this key, neutrally,
Super. (This is a bit confusing, since the original
space-cadet keyboard
The space-cadet keyboard is a keyboard designed by John L. Kulp in 1978 and used on Lisp machines at Massachusetts Institute of Technology (MIT), which inspired several still-current jargon terms in the field of computer science and influenced th ...
and the
X Window System
The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems.
X provides the basic framework for a GUI environment: drawing and moving windows on the display device and interacting wit ...
recognize a "" modifier distinct from "".)
The Sinclair
ZX Spectrum
The ZX Spectrum () is an 8-bit computing, 8-bit home computer that was developed by Sinclair Research. It was released in the United Kingdom on 23 April 1982, and became Britain's best-selling microcomputer.
Referred to during development as t ...
has a Symbol Shift key in addition to Caps Shift. This was used to access additional punctuation and keywords.
The
MSX 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 Expert, made by Gradiente Eletrônica (to date best known as a game console and Hi-Fi equipment company) was the second and last MSX home computer launched in the Brazilian market, in the mid-1980s.
It was presented to the public at th5th ...
, 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
The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness ...
and other Commodore computers had the Commodore key at the bottom left of the keyboard.
Compact keyboards, such as those used in
laptop
A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...
s, often have a
Fn key
The key, short form for ''function,'' is a modifier key on many keyboards, especially on laptops, used in a compact layout to combine keys which are usually kept separate. It is typically found on laptops due to their keyboard size restrictions. ...
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
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
space-cadet keyboard
The space-cadet keyboard is a keyboard designed by John L. Kulp in 1978 and used on Lisp machines at Massachusetts Institute of Technology (MIT), which inspired several still-current jargon terms in the field of computer science and influenced th ...
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
A diacritic (also diacritical mark, diacritical point, diacritical sign, or accent) is a glyph added to a letter or to a basic glyph. The term derives from the Ancient Greek (, "distinguishing"), from (, "to distinguish"). The word ''diacriti ...
modifications of the standard Latin-letter keys. In fact, the standard British
keyboard layout
A keyboard layout is any specific physical, visual or functional arrangement of the keys, legends, or key-meaning associations (respectively) of a computer keyboard, mobile phone, or other computer-controlled typographic keyboard.
is the actua ...
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 t ...
s. The
AltGr
AltGr (also Alt Graph) is a modifier key found on many computer keyboards (rather than a second Alt key found on US keyboards). It is primarily used to type characters that are not widely used in the territory where sold, such as foreign c ...
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
A compose key (sometimes called multi key) is a key on a computer keyboard that indicates that the following (usually 2 or more) keystrokes trigger the insertion of an alternate character, typically a precomposed character or a symbol.
For insta ...
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
In computing, a bucky bit is a bit in a binary representation of a character that is set by pressing on a keyboard modifier key other than the shift key.
Overview
Setting a bucky bit changes the output character. A bucky bit allows the user to ty ...
*
Control character
In computing and telecommunication, a control Character (computing), character or non-printing character (NPC) is a code point (a number) in a character encoding, character set, that does not represent a written symbol. They are used as in-band ...
*
Function key
A function key is a key on a computer or terminal keyboard that can be programmed so as to cause an operating system command interpreter or application program to perform certain actions, a form of soft key. On some keyboards/computers, function ...
*
Keyboard layout
A keyboard layout is any specific physical, visual or functional arrangement of the keys, legends, or key-meaning associations (respectively) of a computer keyboard, mobile phone, or other computer-controlled typographic keyboard.
is the actua ...
*
Space-cadet keyboard
The space-cadet keyboard is a keyboard designed by John L. Kulp in 1978 and used on Lisp machines at Massachusetts Institute of Technology (MIT), which inspired several still-current jargon terms in the field of computer science and influenced th ...
*
Table of keyboard shortcuts
In computing, a keyboard shortcut is a sequence or combination of keystrokes on a computer keyboard which invokes commands in software.
Most keyboard shortcuts require the user to press a single key or a sequence of keys one after the other. Ot ...
*
Emacs pinky
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, se ...
-
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, cumula ...
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, s ...
users.
References
External links
Bucky bits in the Jargon file
{{DEFAULTSORT:Modifier Key
Computer keys
User interface techniques
de:Tastenkombination#Hilfstasten für Tastenkombinationen