Editing IBM PC keyboard (section)

==Keyboard layouts==
The PC keyboard changed over the years, often at the launch of new [[IBM PC]] versions.
{| class="wikitable"
! scope="col" | Name !! Keys !! Description !! Image
|-
| [[Model F keyboard|Model F]] ([[IBM Personal Computer XT|PC/XT]])
| {{0}}83
| Original left-hand side [[function key]] (F key) columns, F1 through F10; electronically [[computer compatibility|incompatible]] with PC/AT keyboard types
| [[File:IBM Model F XT.png|frameless|upright=0.65|alt= 83-key PC/XT keyboard]] Introduced with original [[IBM PC]] August 1981.
|-
| [[Model F keyboard|Model F]] ([[IBM Personal Computer/AT|PC/AT]])
| {{0}}84
| Additional {{key press|SysRq}} ([[system request]]) key; numerical block clearly separated from main keyboard; added indicator [[LED]]s for Caps/Scroll/Num lock
| [[File:AT keyboard original layout.png|frameless|upright=0.65|alt= 84-key PC/AT keyboard]] Introduced August 1984.
|-
| rowspan="6" | [[Model M keyboard |Model M]] (Enhanced)
| style="border-right:none" |
| style="border-left:none" colspan= "3" | Additional navigation and control keys; dedicated cursor control block with inverted T for arrow keys to left of numeric pad. 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  This layout was more efficient for touch typists but was superseded in the marketplace by that with F-keys along the top.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
* double-width Return key (spanning [[ISO 9995#Physical division and reference grid |C12]] and [[ISO 9995#Physical division and reference grid|C13]]) with a 1.5-width key at [[ISO 9995#Physical division and reference grid|D13]] 
* double-width Backspace key (spanning [[ISO 9995#Physical division and reference grid |E13]] and [[ISO 9995#Physical division and reference grid|E14]])
| [[File:IBM Model M.png|frameless|upright=0.65|alt= 101-key Enhanced keyboard]] Introduced April 1986.<ref>IBM. ''[http://www-01.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/8/877/ENUSZG86-4008/  IBM Enhanced Keyboard for the Personal Computer Announcement Letter]''. 1986-04-18.</ref>
|-
| <span id= "102-key-model">102</span>
| European layouts
* different shaped Return key (spanning 1.5-width [[ISO 9995#Physical division and reference grid|D13]] and [[ISO 9995#Physical division and reference grid|C13]]) with the U.S. [[ISO 9995#Physical division and reference grid |D13]] at [[ISO 9995#Physical division and reference grid|C12]] and single width
* double-width Backspace key (spanning [[ISO 9995#Physical division and reference grid |E13]] and [[ISO 9995#Physical division and reference grid|E14]])
* additional 1 key to the right of the Left Shift key ([[ISO 9995#Physical division and reference grid|B00]])
| [[File:102-key Model M.jpg|frameless|upright=0.65|alt= 102-key Enhanced keyboard]] Introduced April 1986.
|-
| 103
| Korean layout
* different shaped Return key (spanning 1.5-width [[ISO 9995#Physical division and reference grid|D13]] and [[ISO 9995#Physical division and reference grid|C13]]) with the U.S. [[ISO 9995#Physical division and reference grid |D13]] at [[ISO 9995#Physical division and reference grid|C12]] and single width
* double-width Backspace key (spanning [[ISO 9995#Physical division and reference grid |E13]] and [[ISO 9995#Physical division and reference grid|E14]])
* additional 2 keys: one to the left ([[ISO 9995#Physical division and reference grid|A03]]) and one to the right ([[ISO 9995#Physical division and reference grid|A07]]) of the space bar; both [[language input keys]]
|
|-
| 104
| Brazilian [[ABNT]] NBR 10346 variant 2 (alphanumeric portion) and 10347 (numeric portion).
* different shaped Return key (spanning 1.5-width [[ISO 9995#Physical division and reference grid|D13]] and [[ISO 9995#Physical division and reference grid|C13]]) with the U.S. [[ISO 9995#Physical division and reference grid |D13]] at [[ISO 9995#Physical division and reference grid|C12]] and single width
* double-width Backspace key (spanning [[ISO 9995#Physical division and reference grid |E13]] and [[ISO 9995#Physical division and reference grid|E14]])
* additional 3 keys: one to the right of the Left Shift key ([[ISO 9995#Physical division and reference grid |B00]]), one to the left of the Right Shift key ([[ISO 9995#Physical division and reference grid |B11]]), and one on the numeric keypad above Enter ([[ISO 9995#Physical division and reference grid|C54]])
| [[File:Brazilian 104-key ABNT2 keyboard.jpg|frameless|upright= 0.65|alt=104-key Windows keyboard]]
|-
| 106
| Japanese JIS layout
* different shaped Return key (spanning 1.5-width [[ISO 9995#Physical division and reference grid|D13]] and [[ISO 9995#Physical division and reference grid|C13]]) with the U.S. [[ISO 9995#Physical division and reference grid |D13]] at [[ISO 9995#Physical division and reference grid|C12]] and single width
* single-width Backspace key (at [[ISO 9995#Physical division and reference grid|E14]])
* additional 5 keys: one to the left ([[ISO 9995#Physical division and reference grid|A03]]) of the space bar, two to the right ([[ISO 9995#Physical division and reference grid |A06]] and [[ISO 9995#Physical division and reference grid|A07]]) of the space bar, one to the left of the Right Shift key ([[ISO 9995#Physical division and reference grid |B11]]), and one to the left of the Backspace key ([[ISO 9995#Physical division and reference grid|E13]]); three of which are [[language input keys]]
* the key at [[ISO 9995#Physical division and reference grid |E00]] is another [[language input key]] but exists on the 101-key U.S. layout
| [[File:Compaq Enhanced III.jpg|frameless|upright=0.65|alt=106-key Enhanced keyboard]]
|-
| rowspan="6" | Windows<ref name= "Ivens1998">{{cite book |page= 165 |title=Using Microsoft Windows 95|first=Kathy|last= Ivens |edition=4th |publisher= Que |year=1998|isbn= 978-0-78971573-9}}</ref>
| style="border-right:none" |
| style="border-left:none" colspan="3" | 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).<ref name= "Ivens1998"/><ref>{{cite book|title= Upgrading and Repairing PCs |volume=1|series=The Scott Mueller library series|first= Scott |last=Mueller |edition= 10th |publisher=Que|year=1998|isbn= 978-0-78971636-1|page= 450}}</ref>  Introduced in the [[Microsoft Natural keyboard]] for use with the [[Windows 95]] operating system.<ref>{{cite magazine|first= Cate T.|last= Corcoran |magazine= [[InfoWorld]] |title= Microsoft keyboard ships |page= 36 |date=1994-09-05}}</ref> Most modern PCs, whether supplied with [[Microsoft Windows]] or not, are now delivered with this layout.<ref name= "Mueller2011">{{cite book|pages= 1115–16|title= Upgrading and Repairing PCs|first=Scott|last= Mueller |edition=20th|publisher= Que |year=2011|isbn= 978-0-13268218-3}}</ref>  Like the Enhanced layout, there are regional variants of the Windows keyboard layout:<ref name= "Mueller2011"/>
|-
| 104
| standard US layout (as above)
| [[File:Unicomp keyboard.jpg|frameless|upright=0.65|alt= Modern 104-key Windows keyboard]]
|-
| 105
| European layouts<ref name= "Mueller2011"/> (as above)
| [[File:Cherry keyboard 105 keys.jpg|frameless|upright=0.65|alt=105-key Windows keyboard]]
|-
| 106
| Korean layout (as above)
| [[File:Korean 106-key keyboard.jpg|frameless|upright= 0.65|alt=Modern 106-key Windows keyboard]]
|-
| 107
| Brazilian [[ABNT]] NBR 10346 variant 2 (alphanumeric portion) and 10347 (numeric), as above
| [[File:Brazilian 107-key ABNT2 Windows keyboard.jpg|frameless|upright=0.65|alt=Modern 107-key Windows keyboard]]
|-
| 109
| Japanese layout (as above)
| 
|}


Common additions to the standard layouts include additional [[power management keys]], volume controls, [[Media control symbols|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.<ref name=xahlee>{{cite web
|url=http://xahlee.info/kbd/keyboard_hardware_and_key_choices.html |title= History of Emacs ＆ vi Keys (Keyboard Influence on Keybinding Design) | first =Xah | last = Lee}}</ref> One notable example is the [[escape key]], used by the [[Vi (text editor)|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.<ref name= xahlee /> Another example is the [[Emacs]] editor, which makes extensive use of [[modifier key]]s, 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.<ref>{{cite web|url= http://xahlee.org/emacs/emacs_pinky.html |title=How To Avoid The Emacs Pinky Problem | first = Xah | last = Lee |access-date= 2009-11-08}}</ref>