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The keyboard for IBM PC-compatible computers is standardized. However, during the more than 30 years of PC architecture being frequently updated, many keyboard layout variations have been developed.
A well-known class of IBM PC keyboards is the Model M. Introduced in 1984 and manufactured by IBM, Lexmark, Maxi-Switch and Unicomp, the vast majority of Model M keyboards feature a buckling spring key design and many have fully swappable keycaps.
The PC keyboard changed over the years, often at the launch of new IBM PC versions.
Name | Keys | Description | Image | |
---|---|---|---|---|
Model F (PC/XT) | 83 | Original left-hand side function key (F key) columns, F1 through F10; electronically incompatible with PC/AT keyboard types | Introduced with original IBM PC August 1981. | |
Model F (PC/AT) | 84 | Additional SysRq (system request) key; numerical block clearly separated from main keyboard; added indicator LEDs for Caps/Scroll/Num lock | Introduced August 1984. | |
Model M (Enhanced) | Additional navigation and control keys; 12 F keys in separate row along top, grouped F1–4, F5–8, and F9–12. Early models of Enhanced keyboard (notably those manufactured by Northgate Ltd.) maintained the layout with function keys on the left side, arranged in two columns of six pairs. This layout was more efficient for touch typists but was superseded in the marketplace by that with F-keys along the top. PS/2 released April 1987. There are different versions of the Enhanced keyboard layout: | |||
101 | standard US layout | Introduced April 1986. [1] | ||
102 | European layouts | Introduced April 1986. | ||
103 | Korean layout | |||
104 | Brazilian ABNT NBR 10346 variant 2 (alphanumeric portion) and 10347 (numeric portion).
| |||
106 | Japanese JIS layout
| |||
Windows [2] | Additional Windows key (×2) and Menu key added (one Windows key to the right of the left control key, the other and the Menu key to the left of the right control key). [2] [3] Introduced in the Microsoft Natural keyboard for use with the Windows 95 operating system. [4] Most modern PCs, whether supplied with Microsoft Windows or not, are now delivered with this layout. [5] Like the Enhanced layout, there are regional variants of the Windows keyboard layout: [5] | |||
104 | standard US layout (as above) | |||
105 | European layouts [5] (as above) | |||
106 | Korean layout (as above) | |||
107 | Brazilian ABNT NBR 10346 variant 2 (alphanumeric portion) and 10347 (numeric), as above | |||
109 | Japanese layout (as above) |
Esc | F1 | F2 | F3 | F4 | F5 | F6 | F7 | F8 | F9 | F10 | F11 | F12 | PrtScn/ SysRq | Scroll Lock | Pause/ Break | |||||||||
Insert | Home | PgUp | Num Lock | ∕ | ∗ | − | ||||||||||||||||||
Delete | End | PgDn | 7 | 8 | 9 | + | ||||||||||||||||||
4 | 5 | 6 | ||||||||||||||||||||||
↑ | 1 | 2 | 3 | Enter | ||||||||||||||||||||
← | ↓ | → | 0 Ins | . Del |
Common additions to the standard layouts include additional power management keys, volume controls, media player controls (e.g. "Play/Pause", "Previous track", "Next track) and miscellaneous user-configurable shortcuts for email client, World Wide Web browser, etc.
The IBM PC layout, particularly the Model M, has been extremely influential, and today most keyboards use some variant of it. This has caused problems for applications developed with alternative layouts, which require keys that are in awkward positions on the Model M layout – often requiring the pinkie to operate – and thus require remapping for comfortable use. [6] One notable example is the escape key, used by the vi editor: on the ADM-3A terminal this was located where the Tab key is on the IBM PC, but on the IBM PC the Escape key is in the corner; this is typically solved by remapping Caps Lock to Escape. [6] Another example is the Emacs editor, which makes extensive use of modifier keys, and uses the Control key more than the meta key (IBM PC instead has the Alt key) – these date to the Knight keyboard, which had the Control key on the inside of the Meta key, opposite to the Model M, where it is on the outside of the Alt key; and to the space-cadet keyboard, where the four bucky bit keys (Control, Meta, Super, Hyper) are in a row, allowing easy chording to press several, unlike on the Model M layout. This results in the "Emacs pinky" problem. [7]
Although PC Magazine praised most aspects of the 1981 IBM PC keyboard's hardware design, it questioned "how IBM, that ultimate pro of keyboard manufacture, could put the left-hand shift key at the awkward reach they did". [8] The magazine reported in 1982 that it received more letters to its "Wish List" column asking for the ability to determine the status of the three lock keys than on any other topic. [9] Byte columnist Jerry Pournelle described the keyboard as "infuriatingly excellent". He praised its feel but complained that the Shift and other keys' locations were "enough to make a saint weep", and denounced the trend of PC compatible computers to emulate the layout but not the feel. [10] He reported that the layout "nearly drove" science-fiction editor Jim Baen "crazy", and that "many of [Baen's] authors refused to work with that keyboard" so could not submit manuscripts in a compatible format. [11] The magazine's official review was more sanguine. It praised the keyboard as "bar none, the best ... on any microcomputer" and described the unusual Shift key locations as "minor [problems] compared to some of the gigantic mistakes made on almost every other microcomputer keyboard". [12]
"I wasn't thrilled with the placement of [the left Shift and Return] keys, either", IBM's Don Estridge stated in 1983. He defended the layout, however, stating that "every place you pick to put them is not a good place for somebody ... there's no consensus", and claimed that "if we were to change it now we would be in hot water". [13]
The PC keyboard with its various keys has a long history of evolution reaching back to teletypewriters. In addition to the 'old' standard keys, the PC keyboard has accumulated several special keys over the years. Some of the additions have been inspired by the opportunity or requirement for improving user productivity with general office application software, while other slightly more general keyboard additions have become the factory standards after being introduced by certain operating system or GUI software vendors such as Microsoft.
System | Connector | Image | Pinout | Transmission Protocol | Command Strings |
---|---|---|---|---|---|
PC (Type 1) [19] | 5-pin DIN (DIN 41524) | 1 CLK 2 DATA | 2 start bits, 8 data bits, make/break bit (keydown/keyup), 1 stop bit keyboard reset via pin 3 to ground | Not supported | |
XT (Type 2) [20] | 1 CLK 2 DATA | 2 start bits, 8 data bits, make/break bit (keydown/keyup), 1 stop bit keyboard reset via sequence on DATA and CLK lines | |||
AT | 1 CLK 2 DATA | 1 start bit, 8 data, 1 parity (odd), 1 stop bit keyboard reset via command string | Supported | ||
PS/2 "PS/2 port" | 6-pin Mini-DIN (DIN 45322) | 1 DATA 2 N/C (or MOUSE DATA) | |||
Later PC compatibles | 4-pin USB Type A connector | 1 +5V 2 Data − | sync field plus 8-bit bytes as packets (HANDSHAKE, TOKEN, DATA, Special packets), least-significant bit first. |
Scroll Lock is a lock key on most IBM-compatible computer keyboards. Depending on the operating system, it may be used for different purposes, and applications may assign functions to the key or change their behavior depending on its toggling state. The key is not frequently used, and therefore some reduced or specialized keyboards lack Scroll Lock altogether.
In computing and telecommunications, an escape character is a character that invokes an alternative interpretation on the following characters in a character sequence. An escape character is a particular case of metacharacters. Generally, the judgement of whether something is an escape character or not depends on the context.
In computing, a modifier key is a special key on a computer keyboard 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 ⇧ Shift, Alt, or Ctrl keys alone does not (generally) trigger any action from the computer. They are commonly used in defined sequences of keys with another keys to trigger a specific action. These sequences are called keyboard shortcuts.
In computing, a Control keyCtrl is a modifier key which, when pressed in conjunction with another key, performs a special operation. Similarly to the Shift key, the Control key rarely performs any function when pressed by itself. The Control key is located on or near the bottom left side of most keyboards, with many featuring an additional one at the bottom right.
The QWERTZQWERTZU, or QWERTZUIOP keyboard is a typewriter and keyboard layout widely used in Central and Southeast Europe. The name comes from the first six letters at the top left of the keyboard:.
A function key is a key on a computer or terminal keyboard that can be programmed to cause the operating system or an application program to perform certain actions, a form of soft key. On some keyboards/computers, function keys may have default actions, accessible on power-on.
The Windows key is a keyboard key which was originally introduced on Microsoft's Natural Keyboard in 1994. Windows 95 used it to bring up the start menu and it then became a standard key on PC keyboards. Ctrl+Esc performs the same function, in case the keyboard lacks this key.
AltGr is a modifier key found on many computer keyboards. It is primarily used to type special characters and symbols that are not widely used in the territory where sold, such as foreign currency symbols, typographic marks and accented letters. On a typical Windows-compatible PC keyboard, the AltGr key, when present, takes the place of the right-hand Alt key. The key at this location will operate as AltGr if a keyboard layout using AltGr is chosen in the operating system, regardless of what is engraved on the key. In macOS, the Option key has functions similar to the AltGr key.
The Alt keyAlt on a computer keyboard is used to change (alternate) the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing A will type the letter 'a', but holding down the Alt key while pressing A will cause the computer to perform an Alt+A function, which varies from program to program. The international standard ISO/IEC 9995-2 calls it Alternate key. The key is located on either side of the space bar, but in non-US PC keyboard layouts, rather than a second Alt key, there is an 'Alt Gr' key to the right of the space bar. Both placements are in accordance with ISO/IEC 9995-2. With some keyboard mappings, the right Alt key can be reconfigured to function as an AltGr key although not engraved as such.
Common User Access (CUA) is a standard for user interfaces to operating systems and computer programs. It was developed by IBM and first published in 1987 as part of their Systems Application Architecture. Used originally in the MVS/ESA, VM/CMS, OS/400, OS/2 and Microsoft Windows operating systems, parts of the CUA standard are now implemented in programs for other operating systems, including variants of Unix. It is also used by Java AWT and Swing.
The Fn key, short form for function, is a modifier key on many keyboards, especially external keyboards, and is not available for mobile devices. For use in a compact layout, combine keys which are normally kept separate. It-Alt + FN is typically found on laptops due to their keyboard size restrictions. It is also found on many full-sized "multimedia" keyboards as the F-Lock key. It is mainly for the purpose of changing display or audio settings quickly, such as brightness, contrast, or volume, and is held down in conjunction with the Caps Lock to change the settings.
On personal computers with numeric keypads that use Microsoft operating systems, such as Windows, many characters that do not have a dedicated key combination on the keyboard may nevertheless be entered using the Alt code. This is done by pressing and holding the Alt key, then typing a number on the keyboard's numeric keypad that identifies the character and then releasing Alt.
In computing, a keyboard shortcut is a sequence or combination of keystrokes on a computer keyboard which invokes commands in software.
Language input keys, which are usually found on Japanese and Korean keyboards, are keys designed to translate letters using an input method editor (IME). On non-Japanese or Korean keyboard layouts using an IME, these functions can usually be reproduced via hotkeys, though not always directly corresponding to the behavior of these keys.
Unicode input is method to add a specific Unicode character to a computer file; it is a common way to input characters not directly supported by a physical keyboard. Characters can be entered either by selecting them from a display, by typing a certain sequence of keys on a physical keyboard, or by drawing the symbol by hand on touch-sensitive screen. In contrast to ASCII's 96 element character set, Unicode encodes hundreds of thousands of graphemes (characters) from almost all of the world's written languages and many other signs and symbols besides.
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, interaction via teleprinter-style keyboards have been the main input method for computers since the 1970s, supplemented by the computer mouse since the 1980s.
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.
The German keyboard layout is family of QWERTZ keyboard layouts commonly used in Austria and Germany. It is based on one defined in a former edition of the German standard DIN 2137–2. The current edition DIN 2137-1:2012-06 standardizes it as the first (basic) one of three layouts, calling it "T1".
The delete key is a button on most computer keyboards which is typically used to delete either the character ahead of or beneath the cursor, or the currently-selected object. The key is sometimes referred to as the "forward delete" key. This is because the backspace key also deletes characters, but to the left of the cursor. On many keyboards, such as most Apple keyboards, the key with the backspace function is also labelled "delete".