In computing, a keyboard is a peripheral partially modeled after the typewriter keyboard. The Microwriter is a hand-held portable word-processor with an innovative chording keyboard. Douglas Noël Adams (11 March 1952 &ndash 11 May 2001 was an English author comic Radio dramatist A keyset or chorded keyboard (also called a chord keyboard or chording keyboard) is a computer input device that allows the user to enter characters Computing is usually defined like the activity of using and developing Computer technology Computer hardware and software. For an account of the words periphery and peripheral as they are used in biology sociology politics computer hardware and other fields see the A typewriter is a mechanical or Electromechanical device with a set of "keys" that when pressed cause characters to be printed on a medium
Physically, a keyboard is an arrangement of buttons, or keys. A push-button (often simply " button " or " pushbutton " is a simple Switch mechanism for controlling some aspect of a Machine A keyboard typically has characters engraved or printed on the keys; in most cases, each press of a key corresponds to a single written symbol. Engraving is the practice of incising a design onto a hard usually flat surface by cutting grooves into it Printing is a process for reproducing text and image typically with ink on Paper using a printing press The musical instrument is spelled Cymbal. A symbol is something --- such as an object, Picture, written word a sound a piece However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence; other keys do not produce any symbol, but instead affect the operation of the computer or the keyboard itself. See input method editor.
A majority of all keyboard keys produce letters, numbers or signs (characters) that are appropriate for the operator's language. A letter is an element in an Alphabetic system of writing such as the Greek alphabet and its descendants A number is an Abstract object, tokens of which are Symbols used in Counting and measuring. A sign is an entity which signifies another entity A natural sign is an entity which bears a causal relation to the signified entity as thunder is a sign of storm For other uses see Character. In Computer and machine-based Telecommunications terminology a character is a unit of A language is a dynamic set of visual auditory or tactile Symbols of Communication and the elements used to manipulate them Other keys can produce actions when pressed, and other actions are available by the simultaneous pressing of more than one action key.
There exists a large number of different arrangements of symbols on keys. QWERTY keyboardjpg|thumb|right|300px|QWERTY keyboard on a Laptop of 2007]]A keyboard layout is any specific mechanical, visual, or functional These different keyboard layouts arise mainly because different people need easy access to different symbols; typically, this is because they are writing in different languages, but specialized keyboard layouts for mathematics, accounting, and computer programming also exist. QWERTY keyboardjpg|thumb|right|300px|QWERTY keyboard on a Laptop of 2007]]A keyboard layout is any specific mechanical, visual, or functional
Most of the more common keyboard layouts (QWERTY-based and similar) were designed in the era of the mechanical typewriters, so their ergonomics had to be slightly compromised in order to tackle some of the technical limitations of the typewriters. QWERTY (ˈkwɜː(rti is the most common modern-day Keyboard layout on English-language computer and Typewriter keyboards It takes its The letters were attached to levers that needed to move freely; because jamming would result if commonly used letters were placed too close to one another, Christopher Sholes invented the QWERTY layout. Christopher Latham Sholes ( February 14, 1819 - February 17, 1890) was an American Inventor who invented the first However, with the advent of modern electronics, this is no longer an issue. QWERTY layouts and their brethren had been a de facto standard for decades prior to the introduction of the very first computer keyboard, and were primarily adopted for electronic keyboards for this reason. Alternative layouts do exist, the best known of which is Dvorak; however, these are not in widespread use. The Dvorak Simplified Keyboard (ˈdvɔræk or) is a Keyboard layout patented in 1936 by Dr
The number of keys on a keyboard varies from the standard of 101 keys introduced in the late 1980s to the 104-key Windows keyboards and all the way up to 130 keys or more, with many of the additional keys being symbol-less programmable keys that can simulate multiple functions such as starting a web browser or e-mail client. Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. A web browser is a software application which enables a user to display and interact with text images videos music games and other information typically located on a An e-mail client, aka Mail User Agent (MUA aka e-mail reader is a frontend Computer program used to manage E-mail. There also were "Internet keyboards," sold in the late 1990s, that replaced the function keys with pre-programmed internet shortcuts. Pressing the shortcut keys would launch a browser to go to that website. A keyboard shortcut (or accelerator key, shortcut key, hot key, key binding, keybinding, key combo, etc
There are several different ways of connecting a keyboard which have evolved over the years. These include the standard AT (DIN-5) connector commonly found on pre-80486 motherboards, which was eventually replaced by the PS/2 and USB connection. A DIN connector is a connector that was originally standardized by the Deutsches Institut für Normung (DIN the German national standards organization The PS/2 connector is used for connecting some keyboards and mice to a PC compatible computer system Prior to the iMac line of systems, Apple Computer used ADB, a proprietary system, for its keyboard connector. Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics Apple Desktop Bus (or ADB) is an obsolete bit-serial Computer bus connecting low-speed devices to computers
Wireless keyboards have become popular for their increased user freedom. Wireless communication is the transfer of information over a distance without the use of electrical conductors or " Wires quot However, a wireless keyboard needs batteries to work and may pose a security problem due to the risk of eavesdropping. Eavesdropping is the act of surreptitiously listening to a private conversation 
A wireless keyboard often includes a required combination transmitter and receiver unit that attaches to the computer's keyboard port (see Connection types above). The wireless aspect is achieved either by radio frequency (RF) or by infrared (IR) signals sent and received from both the keyboard and the unit attached to the computer. Radio frequency ( RF) is a Frequency or rate of Oscillation within the range of about 3 Hz to 300 GHz Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of A wireless keyboard may use an industry standard RF, called Bluetooth. Bluetooth is a wireless protocol utilizing short-range communications technology facilitating data transmission over short distances from fixed and/or mobile devices creating wireless With Bluetooth, the transceiver may be built into the computer.
Keys on older IBM keyboards were made with a "buckling spring" mechanism, in which a coil spring under the key buckles under pressure from the user's finger, pressing a rubber dome, whose inside is coated with conductive graphite, which connects two leads below, completing a circuit. There are many types of keyboard, usually differentiated by the Switch technology employed in their operation This produces a clicking sound, and a "positive" feel of feedback, so that the typist knows when the key is fully pressed. Keys on most modern keyboards are made with a so-called "dome switch" mechanism, without the buckling spring. There are many types of keyboard, usually differentiated by the Switch technology employed in their operation In Computing, a keyboard is an Input device partially modelled after the typewriter keyboard which uses an arrangement of buttons or keys Many typists prefer the buckling spring board, which is still manufactured. 
A specialty keyboard is a standard keyboard with software keyboard shortcuts marked on color-coded keys. They help users to learn and use the keyboard shortcuts for particular software applications. A keyboard shortcut (or accelerator key, shortcut key, hot key, key binding, keybinding, key combo, etc It is very popular with videographers who have to spend hours editing their raw video. Videography refers to the process of capturing moving Images on Electronic media (e The keyboard helps to increase the speed of their work. It is also starting to catch on in other applications, such as graphic designers using Photoshop keyboards, audio editors using audio editing keyboards, etc. A graphic designer (also known as a graphic artist and communication designer) is a professional within the Graphic design and Graphic arts industry A digital audio editor is a computer application for Audio editing, i There is no reason why other applications such as word processing and email programs cannot take advantage of specialty keyboards' shortcut keycaps. Word processing is the creation of documents using a Word processor. Electronic mail, often abbreviated to e-mail, email, or originally eMail, is a Store-and-forward method of writing sending receiving
A standard keyboard is physically quite large, as each key must remain large enough to be easily pressed by fingers. Other types of keyboards have been proposed for small portable equipment where a standard keyboard is too large. One way to reduce the size of the keyboard is to reduce the number of keys and use chording keyer, i. A keyset or chorded keyboard (also called a chord keyboard or chording keyboard) is a computer input device that allows the user to enter characters A keyer is a device for signaling by hand by way of pressing one or more switches e. pressing several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. A keyset or chorded keyboard (also called a chord keyboard or chording keyboard) is a computer input device that allows the user to enter characters Other two-handed alternatives more akin to a game controller, such as the AlphaGrip, are also used as a way to input data and text. A game controller is an Input device used to control a Video game. The AlphaGrip is a hand-held Computer keyboard and game controller that is being marketed as an alternative to the traditional design
Another way to reduce the size of a keyboard is to use smaller buttons and pack them closer together. Such keyboards, often called a "thumbboard" (thumbing) are used in some personal digital assistants such as the Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO. A thumb keyboard, or a thumbboard is a type of keyboard commonly found on PDAs Mobile phones and PDA phones which has a familiar layout to an The BlackBerry is a Wireless Handheld device introduced in 1999 as a two-way pager In Personal computers Ultra-Mobile PC (often abbreviated UMPC) is a small Form factor (a standard size and shape for Tablet PCs and subnotebook/ OQO is a US computer hardware company the manufacturer of Subnotebook, handheld computers named the OQO model 02 and OQO model e2
Multimedia keyboards offer special keys for accessing music, web, and other oft-used programs. They also usually have other convenient controls, such as a mute button, volume buttons or knob, and standby (sleep) button. The MUTE Network (or MUTE-net) is a Peer-to-peer and Friend-to-friend File sharing network developed with anonymity in mind KNOB is a commercial Radio station in Healdsburg California, broadcasting to the Santa Rosa California area on 96
Some gaming keyboards offer extra function keys which can be programmed with keystroke macros. A personal computer Game (also known as a computer game or simply PC game) is a Video game played on a Personal computer, rather For example, ctrl+shift+y could be a keystroke that is frequently used in a certain computer game. But it is a physically awkward (or, at least, annoying) combination for the hands to reach for repeatedly. It may be very useful to assign that keystroke combination to one function key. Some keyboards (Such as the Logitech G11 or G15) have a keypad full of "G keys" to the left of the QWERTY keyboard for this purpose. The Logitech G11 is a keyboard produced by Logitech designed specifically for gamers The Logitech G15 is a keyboard produced by Logitech designed specifically for gamers The keystroke macros can be reprogrammed at will.
The development of these keyboards was spurred by gaming, but the concept can also be very convenient in non-gaming applications, such as office work. Any keystroke combination that is awkward or annoying but frequently needed can be replaced with a "G key". The meaning of the "G key" press can automatically change depending on which application has focus, thus extending the number of macros available given a certain limited number of G keys. In Computing, the focus indicates the component of the Graphical user interface which is currently selected to receive input
A relatively new type of keyboard, the I-Tech Virtual Laser Keyboard, works by projecting an image of a full-size keyboard onto a surface. A projection keyboard is a Virtual keyboard that can be projected and touched on any surface Sensors in the projection unit identify which key is being "pressed" and relay the signals to a computer or personal digital assistant. A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument
As explained above, the QWERTY layout was a legacy from mechanical typewriters. In contrast, some keyboard layouts are specifically designed for speed. The most common is the Dvorak layout; more recently, hobbyists have designed other layouts in an attempt to improve on Dvorak and to be easier to learn for existing QWERTY users. The Dvorak Simplified Keyboard (ˈdvɔræk or) is a Keyboard layout patented in 1936 by Dr The fastest keyboard so far is the stenotype — some people who use a stenotype type faster than 300 words per minute. A stenotype or shorthand machine is a specialized Chorded keyboard or Typewriter used by Stenographers for Shorthand use Words per minute, commonly abbreviated wpm, is a measure of input or output speed
It is possible to limit or eliminate the use of computer keyboards with the introduction of alternative methods not based in keystrokes, such as optical character recognition (OCR), speech recognition and pointing-device text input.
Optical character recognition (OCR) is preferable to rekeying for converting existing text that is already written down but not in machine-readable format (for example, a Linotype-composed book from the 1940s). Optical character recognition, usually abbreviated to OCR, is the Mechanical or electronic translation of Images of handwritten typewritten The Linotype machine (pronounced "Line-O-Type") is a "line casting" machine used in Printing. In other words, to convert the text from an image to editable text (that is, a string of character codes), a person could re-type it, or a computer could look at the image and deduce what each character is. For other uses see Character. In Computer and machine-based Telecommunications terminology a character is a unit of OCR technology has already reached an impressive state (for example, Google Book Search) and promises more for the future. Google Book Search is a tool from Google that searches the full text of books that Google scans OCRs, and stores in its digital database
Speech recognition converts speech into machine-readable text (that is, a string of character codes). Speech recognition (also known as automatic speech recognition or computer speech recognition) converts spoken words to machine-readable input (for example to keypresses The technology has already reached an impressive state and is already implemented in various software products. Modern Speech recognition software enables a single Computer user to speak text and/or commands to the computer largely but not entirely bypassing the use For certain uses (e. g. , transcription of medical or legal dictation; journalism; writing essays or novels) it is starting to replace the keyboard; however, it does not threaten to replace keyboards entirely anytime soon. It can, however, interpret commands (for example, "close window" or "undo that") in addition to text. Therefore, it has theoretical potential to replace keyboards entirely (whereas OCR replaces them only for a certain kind of task).
There is a class of hardware or software accessories enabling users to enter text efficiently using a pointing device, in contexts where using a physical keyboard would be inappropriate or impossible. A pointing device is an Input interface (specifically a Human interface device) that allows a user to input spatial (ie continuous and multi-dimensional data These accessories typically present characters on a display, in a layout that provides fast access to the more frequently used characters or character combinations. Popular examples of this kind of input are Graffiti, Dasher and on-screen virtual keyboards. Graffiti is the Handwriting recognition software used in PDAs based on the Palm OS. Dasher is a Computer accessibility tool which enables users to write without using a keyboard, by entering text on a screen using a Pointing device A virtual keyboard is a software and/or hardware component that allows a user to enter characters
FITALY (http://www.FITALY.com) is a stylus/one-finger keyboard that can yield 50+ WPM. The key is to stare at the keyboard, not the screen (as in traditional touch typing). No memorization of layout is required. It is engineered for rapid text input (e. g. , some 85% of English words are visible at the center of the keyboard). It is available for many mobile and laptop devices.
In principle, computer keyboard designs are governed by the ISO/IEC 9995 international standard. ISO/IEC 9995 (less formally "ISO 9995" is an ISO standard defining layouts of computer keyboards
While the IBM PC keyboard was hardly the first electronic keyboard, it does merit particular mention, if only for its ubiquity. The IBM PC keyboard and its derivative Computer keyboards are standardized The original IBM PC/XT had 83 keys; the AT keyboard had 84 (adding a SysRq key and separating keys into sections, also changing the communication protocol). Next came the "Enhanced" 101 keys (which duplicated the cursor movement keys from the numeric pad, added the function key row along the top and increased their number from 10 to 12, made other minor changes, and included an often-maligned control-key/caps-lock placement swap). The above-mentioned 104 keys were obtained by adding three "windows" keys. The internationally common 102/105 key keyboards have a smaller 'left shift' key and an additional key with some more symbols between that and the letter to its right (usually Z or Y). 
In normal usage, the keyboard is used to type text into a word processor, text editor, or any other textbox. A text editor is a type of program used for editing plain Text files Text editors are often provided with Operating systems or software development
In a modern computer the interpretation of keypresses is generally left to the software. A modern keyboard distinguishes each physical key from every other and report all keypresses to the controlling software. This flexibility is not often taken advantage of and it usually does not matter, for example, whether the left or right shift key is held down in conjunction with another character, even though they are coded as completely separate keys.
The term keystroke refers to the simple act of pressing a button on a keyboard that is connected to some form of digital computer. A computer is a Machine that manipulates data according to a list of instructions. The term is also frequently used to mean a keystroke combination (several keys pressed at once, for example, ctrl+shift+spacebar) used as a keyboard shortcut (also known as a shortcut key or other names). A keyboard shortcut (or accelerator key, shortcut key, hot key, key binding, keybinding, key combo, etc
Nefarious programs may log keystrokes and thereby capture such sensitive information as operating system passwords and credit card numbers. Keystroke logging (often called keylogging) is a method of capturing and recording user keystrokes
A keyboard is also used to type commands in a computer. One famous example on the PC is the Control-Alt-Delete combination. Control-Alt-Delete (often abbreviated to Ctrl-Alt-Del, also known as the "three-finger salute" is a computer keyboard command on PC compatible systems On most versions of Microsoft Windows, this command brings up a window (such as the Task Manager on Windows NT based versions of Windows) which allows users to manage currently-running processes, shut down the machine, and other functions. Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. A task manager is a program used to provide information about the processes and programs running on a Computer, as well as the general status of the computer Windows NT is a family of Operating systems produced by Microsoft, the first version of which was released in July 1993 Under Linux, MS-DOS and some older versions of Windows, the command performs either a "cold" or "warm" reboot. Linux (commonly pronounced ˈlɪnəks MS-DOS (short for M icro' s' oft D isk O perating S ystem is an Operating system commercialized by Microsoft. ReBoot is a Canadian CGI - animated action-adventure Television series that originally aired from 1994 to 2001
A keyboard is one of the primary methods of control in computer games. A personal computer Game (also known as a computer game or simply PC game) is a Video game played on a Personal computer, rather For instance, the arrow keys or a group of letters resembling the pattern of the arrow keys, like WASD, can be used for movement of a game character. Cursor movement keys or arrow keys are buttons on a Computer keyboard that are either programmed or designated to move the cursor in a specified direction In many games, keys can be configured to the user's preferences. Alphabet keys are also sometimes used to perform actions starting with that letter. (e. g. pressing j to jump, r to reload or c to crouch). As explained earlier, gaming keyboards can expedite awkward or frequently used keystroke combinations.
Some low-quality keyboards suffer problems with rollover (that is, when multiple keys are pressed in quick succession); some types of keyboard circuitry will register a maximum number of keys at one time. Rollover is the ability of a Computer keyboard to correctly handle several simultaneous keystrokes This is undesirable for games (designed for multiple keypresses, e. A game is a structured activity, usually undertaken for Enjoyment and sometimes also used as an Educational tool g. casting a spell while holding down keys to run) and undesirable for extremely fast typing (hitting new keys before the fingers can release previous keys). A common side effect of this shortcoming is called "phantom key blocking": on some keyboards, pressing three keys simultaneously sometimes resulted in a 4th keypress being registered. Modern keyboards prevent this from happening by blocking the 3rd key in certain key combinations, but while this prevents phantom input, it also means that when two keys are depressed simultaneously, many of the other keys on the keyboard will not respond until one of the two depressed keys is lifted. With better keyboards designs, this seldom happens in office programs, but it remains a problem in games even on expensive keyboards, due to wildly different and/or configurable key/command layouts in different games.
Computer input devices, including keyboards, are a good example where a bit more capital investment up front can more than pay for itself over time by reducing future costs. For example, buying an ergonomic keyboard (one with the QWERTY field divided into two sections angled away from each other) may cost $20 more up front, but if it keeps repetitive strain injury at a subclinical level rather than allowing it to progress to a level of clinical dysfunction, then it has paid for itself many times over by obviating future medical costs, user discomfort or annoyance, partial disability, etc. A repetitive strain injury (RSI also called cumulative trauma disorder ( CTD) occupational overuse syndrome, or work related upper limb disorder In Medicine, a subclinical infection refers to an inapparent asymptomatic Infection, or an infection that has such a mild course that it does not alert the Patient The same can be said of keyboards with programmable hot keys that obviate awkward keystroke combinations.
Some experts believe that the use of any keyboard may cause serious injury (that is, carpal tunnel syndrome or other repetitive strain injury) to hands, wrists, arms, neck or back. Carpal tunnel syndrome (CTS or median neuropathy at the wrist is a medical condition in which the Median nerve is compressed at the Wrist, leading A repetitive strain injury (RSI also called cumulative trauma disorder ( CTD) occupational overuse syndrome, or work related upper limb disorder Ways to reduce the risks of injuries can be done by:
Other types of keyboards function in a similar manner, the main differences being how the individual key-switches work. For more on this subject refer to the article on keyboard technology. There are many types of keyboard, usually differentiated by the Switch technology employed in their operation
Certain key presses are special, namely Ctrl-Alt-Delete and SysRq, but what makes them special is a function of software. Control-Alt-Delete (often abbreviated to Ctrl-Alt-Del, also known as the "three-finger salute" is a computer keyboard command on PC compatible systems System request (often abbreviated SysRq or Sys Req) is a key on keyboards for PCs that has no standard use In the PC architecture, the keyboard controller (the component in the computer that receives the make and break codes) sends the computer's CPU a hardware interrupt whenever a key is pressed or released. In Computing, an interrupt is an asynchronous signal from hardware indicating the need for attention or a synchronous event in software indicating the need for a change The CPU's interrupt routine which handles these interrupts usually just places the key's code in a queue, to be handled later by other code when it gets around to it, then returns to whatever the computer was doing before. The special keys cause the interrupt routine to take a different "emergency" exit instead. This more trusted route is much harder to intercept.
Sometimes it is helpful to customize the layout of a keyboard by remapping the keys. When you remap a key, you tell the computer a new meaning for the pressing of that key. Keyboard remapping is supported at a driver-level configurable within the operating system, or as add-ons to the existing programs.
For Windows, Microsoft provides a free downloadable tool called Microsoft Keyboard Layout Creator, and there are several other software programs for this purpose:
For European (AZERTY etc) and other layouts see Keyboard layout
References regarding problems with keypresses in short succession: