Modifier key
Encyclopedia
In computing
, a modifier key is a special key on a computer keyboard
that modifies the normal action of another key when the two are pressed in combination.
For example, in Microsoft Windows
will close the program in the active window
; in this instance, Alt is the modifier key. In contrast, pressing just will probably do nothing unless assigned a specific function in a particular program. By themselves, modifier keys usually do nothing, that is, pressing Alt alone does not trigger any action from the computer.
User interface
expert Jef Raskin
coined the term "quasimode" to describe the state a computer enters into when a modifier key is pressed.
The (Sun) Meta key, Windows key, (Apple) Cmd key, and the analogous "Amiga key" on Amiga
computers, are usually handled equivalently. Under the GNU/Linux operating system, desktop environments such as KDE
and GNOME
call this key, neutrally, Super
. (This is a bit confusing, since the original space cadet keyboard and the X Window System
recognize a "Meta" modifier distinct from "Super".)
The Sinclair ZX Spectrum has a Symbol Shift key in addition to Caps Shift. This was used to access additional punctuation and keywords.
Compact keyboards, such as those used in laptop
s, 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.
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.
includes an accent key on the top-left corner to produce àèìòù, although this is a two step procedure, press the accent key and release, then the letter key. These kinds of keys are called dead key
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.
, it's the usual space, but when you press it together with other keys, say X, then it'll be treated as shift
+ X. It is known as "SandS", standing for "Space and Shift" in Japan, but there's no reason to limit to the combination of space and shift.
games, modifer keys such as Ctrl, Alt, Shift were often used extensively. For example, id Software
's original DOOM
series by default mapped the Ctrl key to fire a weapon, hold down Alt in conjunction with the arrow keys to strafe (move sideways), hold Shift and up or back arrow to run forwards and backwards. This kind of control scheme was copied by various game companies across multiple genres, including first-person shooters, fighting games, and others. With the introduction and standardization of the Windows key after Windows 95, this kind of control scheme became faulty because players could accidentally press the Windows key
while trying to press Ctrl or Alt, and this in turn could interfere with DOS games run on top of Windows via the Dos prompt. The addition of the Windows Key to keyboards may have been part of the reason why most current games have evolved their control schemes, and most first person shooters generally use the mouse in conjunction with a "Half-Life" style of control (W,A,S,D, Space, Shift, Ctrl) named apparently because it may have been the first widespread game to popularize such an interface, and because usage of the Alt button would nowadays heighten the risk of accidentally pressing the Windows Key. To cope with this problem, some newer games (like Doom 3
) disable the Windows Key
while in the game.
Computing
Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...
, a modifier key is a special key on a computer keyboard
Computer keyboard
In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...
that modifies the normal action of another key when the two are pressed in combination.
For example, in Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
will close the program in the active window
Active window
An active window is the currently focused window in the current window manager or explorer. Different window managers indicate the currently-active window in different ways and allow the user to switch between windows in different ways. For example, in Microsoft Windows, if both Notepad and...
; in this instance, Alt is the modifier key. In contrast, pressing just will probably do nothing unless assigned a specific function in a particular program. By themselves, modifier keys usually do nothing, that is, pressing Alt alone does not trigger any action from the computer.
User interface
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...
expert Jef Raskin
Jef Raskin
Jef Raskin was an American human-computer interface expert best known for starting the Macintosh project for Apple in the late 1970s.-Early years and education:...
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 "Opt" on Apple keyboards (Alternate Graphic) - Meta key, found on Sun Microsystems keyboards – found on Windows keyboards – Command key, found on Apple Macintosh keyboards. On older keyboards marked with the Apple logo. (Function) – present on small-layout keyboard, usually on notebooks.The (Sun) Meta key, Windows key, (Apple) Cmd key, and the analogous "Amiga key" on Amiga
Amiga
The Amiga is a family of personal computers that was sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities...
computers, are usually handled equivalently. Under the GNU/Linux operating system, desktop environments such as KDE
KDE
KDE is an international free software community producing an integrated set of cross-platform applications designed to run on Linux, FreeBSD, Microsoft Windows, Solaris and Mac OS X systems...
and GNOME
GNOME
GNOME is a desktop environment and graphical user interface that runs on top of a computer operating system. It is composed entirely of free and open source software...
call this key, neutrally, Super
Super key (keyboard button)
The Super key refers to several different keys throughout keyboard history. Originally the super key was a modifier key on the Space-cadet keyboard...
. (This is a bit confusing, since the original space cadet keyboard and the X Window System
X Window System
The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...
recognize a "Meta" modifier distinct from "Super".)
The Sinclair ZX Spectrum has a Symbol Shift key in addition to Caps Shift. This was used to access additional punctuation and keywords.
Compact keyboards, such as those used in laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...
s, often have a Fn key
Fn key
Fn, or '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, since a full-sized keyboard would be difficult to fit in a laptop chassis. It is also found in many full-sized...
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.
The MIT
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
space-cadet keyboard
Space-cadet keyboard
The space-cadet keyboard is a 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...
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 letter keys. In fact, the standard British keyboard layoutKeyboard layout
A keyboard layout is any specific mechanical, visual, or functional arrangement of the keys, legends, or key–meaning associations of a computer, typewriter, or other typographic keyboard....
includes an accent key on the top-left corner to produce àèìòù, although this is a two step procedure, press the accent key and release, then the letter key. These kinds of keys are called dead key
Dead key
A dead key is a special kind of a modifier key on a typewriter or computer keyboard that is typically used to attach a specific diacritic to a base letter. The dead key does not generate a character by itself but modifies the character generated by the key struck immediately after...
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
Compose key
A compose key, available on some computer keyboards, is a special kind of modifier key designated to signal the software to interpret the following sequence of two keystrokes as a combination in order to produce a character not found directly on the keyboard...
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.
Amphibious modifier key
There's attempts to make use of modifier keys in dual roles, so to say. For example, when you simply press space barSpace bar
thumb|250px|A [[computer keyboard]], Space Bar is on the bottom center of the keyboardThe space bar, spacebar, or space key, is a key on an alphanumeric keyboard in the form of a horizontal bar in the lowermost row, significantly wider than other keys. Its main purpose is to conveniently enter the...
, it's the usual space, but when you press it together with other keys, say X, then it'll be treated as shift
Shift key
The shift key is a modifier key on a keyboard, used to type capital letters and other alternate "upper" characters. There are typically two shift keys, on the left and right sides of the row below the home row...
+ X. It is known as "SandS", standing for "Space and Shift" in Japan, but there's no reason to limit to the combination of space and shift.
Gaming issue
In old, 1990s MS-DOSMS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
games, modifer keys such as Ctrl, Alt, Shift were often used extensively. For example, id Software
Id Software
Id Software is an American video game development company with its headquarters in Richardson, Texas. The company was founded in 1991 by four members of the computer company Softdisk: programmers John Carmack and John Romero, game designer Tom Hall, and artist Adrian Carmack...
's original DOOM
Doom
Doom may refer to:* dōm, the Anglo-Saxon word meaning "judgment", "law"** Doom book the Laws of King Aelfred, Legal Code of Alfred the Great, Code of Alfred 893* Doom , a painting that depicts the Last Judgment...
series by default mapped the Ctrl key to fire a weapon, hold down Alt in conjunction with the arrow keys to strafe (move sideways), hold Shift and up or back arrow to run forwards and backwards. This kind of control scheme was copied by various game companies across multiple genres, including first-person shooters, fighting games, and others. With the introduction and standardization of the Windows key after Windows 95, this kind of control scheme became faulty because players could accidentally press the Windows key
Windows key
The Windows logo key—also known as the Windows key, the home key, the meta key, the start key, MOD4, or the flag key —is a keyboard key which was originally introduced on the Microsoft Natural keyboard before the release of Windows 95. This key became a standard key on PC keyboards...
while trying to press Ctrl or Alt, and this in turn could interfere with DOS games run on top of Windows via the Dos prompt. The addition of the Windows Key to keyboards may have been part of the reason why most current games have evolved their control schemes, and most first person shooters generally use the mouse in conjunction with a "Half-Life" style of control (W,A,S,D, Space, Shift, Ctrl) named apparently because it may have been the first widespread game to popularize such an interface, and because usage of the Alt button would nowadays heighten the risk of accidentally pressing the Windows Key. To cope with this problem, some newer games (like Doom 3
Doom 3
Doom 3 is a science fiction horror video game developed by id Software and published by Activision. An example of the first-person shooter genre, Doom 3 was first released for Microsoft Windows on August 3, 2004. The game was later adapted for Linux, as well as being ported by Aspyr Media for Mac...
) disable the Windows Key
Windows key
The Windows logo key—also known as the Windows key, the home key, the meta key, the start key, MOD4, or the flag key —is a keyboard key which was originally introduced on the Microsoft Natural keyboard before the release of Windows 95. This key became a standard key on PC keyboards...
while in the game.
See also
- Control characterControl characterIn computing and telecommunication, a control character or non-printing character is a code point in a character set, that does not in itself represent a written symbol.It is in-band signaling in the context of character encoding....
- Function keyFunction keyA function key is a key on a computer or terminal keyboard which can be programmed so as to cause an operating system command interpreter or application program to perform certain actions...
- Keyboard layoutKeyboard layoutA keyboard layout is any specific mechanical, visual, or functional arrangement of the keys, legends, or key–meaning associations of a computer, typewriter, or other typographic keyboard....
- Space-cadet keyboardSpace-cadet keyboardThe space-cadet keyboard is a 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...
- EmacsEmacsEmacs is a class of text editors, usually characterized by their extensibility. GNU Emacs has over 1,000 commands. It also allows the user to combine these commands into macros to automate work.Development began in the mid-1970s and continues actively...
- Table of keyboard shortcutsTable of keyboard shortcutsIn computing, a keyboard shortcut is a sequence or combination of keystrokes on a computer keyboard which invokes commands in software.Some keyboard shortcuts require the user to press a single key or a sequence of keys one after the other. Other keyboard shortcuts require pressing and holding...