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Key Rollover
Key rollover is the ability of a computer keyboard to correctly handle several simultaneous keystrokes. A keyboard with ''n''-key rollover (NKRO) can correctly detect input from each key on the keyboard at the same time, regardless of how many other keys are also being pressed. Keyboards that lack full rollover will register an incorrect keystroke when certain combinations of keys are pressed simultaneously. Rollover has applications for stenotype, electronic music keyboards, gaming, and touch-typing generally. Keyboard usage During normal typing on a conventional computer keyboard, only one key is usually pressed at any given time, then released before the next key is pressed. However, this is not always the case. When using modifier keys such as Shift or Control, the user intentionally holds the modifier key(s) while pressing and releasing another key. * Rapid typists may also sometimes inadvertently press a key before releasing the previous one. Certain unusual forms of keyboa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, interaction via teleprinter-style keyboards have been the main input method for computers since the 1970s, supplemented by the computer mouse since the 1980s. Keyboard keys (buttons) typically have a set of characters engraved or printed on them, and each press of a key typically corresponds to a single written symbol. However, producing some symbols may require pressing and holding several keys simultaneously or in sequence. While most keys produce characters (letters, numbers or symbols), other keys (such as the escape key) can prompt the computer to execute system commands. In a modern computer, the interpretation of key presses is generally left to the software: the information sent to the computer, the scan code, tells it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Interface Device
A human interface device or HID is a type of computer device usually used by humans that takes input from humans and gives output to humans. The term "HID" most commonly refers to the USB-HID specification. The term was coined by Mike Van Flandern of Microsoft when he proposed that the USB committee create a Human Input Device class working group. The working group was renamed as the Human Interface Device class at the suggestion of Tom Schmidt of DEC because the proposed standard supported bi-directional communication. HID standard The HID standard was adopted primarily to enable innovation in PC input devices and to simplify the process of installing such devices. Prior to the introduction of the HID concept, devices usually conformed to strictly defined protocols for mouse, keyboards and joysticks; for example, the standard mouse protocol at the time supported relative X- and Y-axis data and binary input for up to two buttons, with no legacy support. All hardware i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charlieplexing
Charlieplexing (also known as tristate multiplexing, reduced pin-count LED multiplexing, complementary LED drive and crossplexing) is a technique for driving a multiplexed display in which relatively few I/O pins on a microcontroller are used e.g. to drive an array of LEDs. The method uses the tri-state logic capabilities of microcontrollers in order to gain efficiency over traditional multiplexing. Although it is more efficient in its use of I/O, there are issues that cause it to be more complicated to design and render it difficult for larger displays. These issues include duty cycle, current requirements and the forward voltages of the LEDs. As with any multiplexing, there is a requirement to cycle through the in-use LEDs rapidly so that the persistence of the human eye perceives the display to be lit as a whole. Multiplexing can generally be seen by a strobing effect and skewing if the eye's focal point is moved past the display rapidly. Origin The Charlieplexing te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Console Emulator
A video game console emulator is a type of emulator that allows a computing device to emulate a video game console's hardware and play its games on the emulating platform. More often than not, emulators carry additional features that surpass the limitations of the original hardware, such as broader controller compatibility, timescale control, greater performance, clearer quality, easier access to memory modifications (like GameShark), one-click cheat codes, and unlocking of gameplay features. Emulators are also a useful tool in the development process of homebrew demos and the creation of new games for older, discontinued, or rare consoles. The code and data of a game are typically supplied to the emulator by means of a ROM file (a copy of game cartridge data) or an ISO image (a copy of optical media), which are created by either specialized tools for game cartridges, or regular optical drives reading the data. Most games retain their copyright despite the increasing time-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Key Mapping
Key or The Key may refer to: Common meanings * Key (cryptography), a piece of information that controls the operation of a cryptography algorithm * Key (lock), device used to control access to places or facilities restricted by a lock * Key (map), a guide to a map's symbology * Key (music), a group of pitches in a piece * Key, on a typewriter or computer keyboard * Answer key, a list of answers to a test Geography * Cay, also spelled key, a small, low-elevation, sandy island formed on the surface of a coral reef United States * Key, Alabama * Key, Ohio * Key, West Virginia * Keys, Oklahoma * Florida Keys, an archipelago of about 1,700 islands in the southeast United States Elsewhere * Rural Municipality of Keys No. 303, Saskatchewan, Canada * Key, Iran, a village in Isfahan Province, Iran * Key Island, Tasmania, Australia * The Key, New Zealand, a locality in Southland, New Zealand Arts and media Films * ''The Key'' (1934 film), a 1934 film directed by Michael Curtiz * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyboard Technology
The technology of computer keyboards includes many elements. Among the more important of these is the switch technology that they use. Computer alphanumeric keyboards typically have 80 to 110 durable switches, generally one for each key. The choice of switch technology affects key response (the positive feedback that a key has been pressed) and pre-travel (the distance needed to push the key to enter a character reliably). Virtual keyboards on touch screens have no physical switches and provide audio and haptic feedback instead. Some newer keyboard models use hybrids of various technologies to achieve greater cost savings or better ergonomics. The modern keyboard also includes a control processor and indicator lights to provide feedback to the user (and to the central processor) about what state the keyboard is in. Plug and play technology means that its 'out of the box' layout can be notified to the system, making the keyboard immediately ready to use without need for furth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyboard Matrix (music)
A keyboard matrix circuit is a design used in most electronic musical keyboards and computer keyboards in which the key switches are connected by a grid of wires, similar to a diode matrix. For example, 16 wires arranged in 8 rows and 8 columns can connect 64 keys—sufficient for a full five octaves of range (61 notes). By scanning these crossings, a keyboard controller can determine which keys are currently pressed. Description Without a matrix circuit, a 61-key keyboard for a synthesizer, electronic organ, or digital piano would require 62 wires to connect (one for each note, and a ground)—an awkwardly thick bundle of wiring. With a matrix circuit, any of 61 notes can be determined with only 16 wires. This is drawn schematically as a matrix of 8 columns and 8 rows of wires, with a switch at every intersection. The keyboard controller scans the columns. If a key has been pressed, the controller scans the rows—and in a manner analogous to the board game Battleship, the contr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Touch Typing
Touch typing (also called blind typing, or touch keyboarding) is a style of typing. Although the phrase refers to typing without using the sense of sight to find the keys—specifically, a touch typist will know their location on the keyboard through muscle memory—the term is often used to refer to a specific form of touch typing that involves placing the eight fingers in a horizontal row along the middle of the keyboard (the ''home row'') and having them reach for specific other keys. (Under this usage, typists who do not look at the keyboard but do not use home row either are referred to as hybrid typists.) Both two-handed touch typing and one-handed touch typing are possible. Frank Edward McGurrin, a court stenographer from Salt Lake City, Utah who taught typing classes, reportedly invented home row touch typing in 1888. On a standard QWERTY keyboard for English speakers the home row keys are: "ASDF" for the left hand and "JKL;" for the right hand. Most modern computer keyb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English (language)
English is a West Germanic language of the Indo-European language family, with its earliest forms spoken by the inhabitants of early medieval England. It is named after the Angles, one of the ancient Germanic peoples that migrated to the island of Great Britain. Existing on a dialect continuum with Scots, and then closest related to the Low Saxon and Frisian languages, English is genealogically West Germanic. However, its vocabulary is also distinctively influenced by dialects of France (about 29% of Modern English words) and Latin (also about 29%), plus some grammar and a small amount of core vocabulary influenced by Old Norse (a North Germanic language). Speakers of English are called Anglophones. The earliest forms of English, collectively known as Old English, evolved from a group of West Germanic ( Ingvaeonic) dialects brought to Great Britain by Anglo-Saxon settlers in the 5th century and further mutated by Norse-speaking Viking settlers starting in the 8th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ctrl-Alt-Delete
Control-Alt-Delete (often abbreviated to Ctrl+Alt+Del, also known as the "three-finger salute" or "Security Keys") is a computer keyboard command on IBM PC compatible computers, invoked by pressing the Delete key while holding the Control and Alt keys: . The function of the key combination differs depending on the context but it generally interrupts or facilitates interrupting a function. For instance, in pre-boot environment (before an operating system starts) or in DOS, Windows 3.0 and earlier versions of Windows or OS/2, the key combination reboots the computer. Starting with Windows 95, the key combination invokes a task manager or security related component that facilitates ending a Windows session or killing a frozen application. History The soft reboot function via keyboard was originally designed by David Bradley. Bradley, as the chief engineer of the IBM PC project and developer of the machine's ROM-BIOS, had originally used , but found it was too easy to bum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyboard Matrix (music)
A keyboard matrix circuit is a design used in most electronic musical keyboards and computer keyboards in which the key switches are connected by a grid of wires, similar to a diode matrix. For example, 16 wires arranged in 8 rows and 8 columns can connect 64 keys—sufficient for a full five octaves of range (61 notes). By scanning these crossings, a keyboard controller can determine which keys are currently pressed. Description Without a matrix circuit, a 61-key keyboard for a synthesizer, electronic organ, or digital piano would require 62 wires to connect (one for each note, and a ground)—an awkwardly thick bundle of wiring. With a matrix circuit, any of 61 notes can be determined with only 16 wires. This is drawn schematically as a matrix of 8 columns and 8 rows of wires, with a switch at every intersection. The keyboard controller scans the columns. If a key has been pressed, the controller scans the rows—and in a manner analogous to the board game Battleship, the contr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
