NationMaster - Encyclopedia: Break key

The break key is a special key on computer keyboards that no longer has a well-defined purpose. Its origins go back to telegraph practices. Image File history File links Key_break. ... Image File history File links Key_break. ... A computer keyboard is a peripheral partially modeled after the typewriter keyboard. ...

A standard telegraph key has a built-in knife switch that can be used to short the key's contacts. When the key was not in use, that switch was kept closed, so that a signal was continually sent. If that steady-state signal was interrupted, it indicated one of two things: either the operator was about to start transmitting, or something else had happened to break the connection — such as hostiles cutting the telegraph line. Optical Telegraf of Claude Chappe on the Litermont near Nalbach, Germany Telegraph and telegram redirect here. ...

As the teletype came into use, a key was created that would temporarily interrupt the communications line, allowing this practice to continue. When this occurred, the receiving teletype mechanism would activate but not print characters (it was typing the non-printing "DEL" character repeatedly). The noise got the operator's attention. A teleprinter (teletypewriter, teletype or TTY) is a now largely obsolete electro-mechanical typewriter which can be used to communicate typed messages from point to point through a simple electrical communications channel, often just a pair of wires. ...

Time-sharing computers connected to modems could recognize the break because the "DEL" characters received had "bad parity". This was usually used to generate an interrupt and allow login or stop a running program. Alternate uses: see Timesharing Time-sharing is an approach to interactive computing in which a single computer is used to provide apparently simultaneous interactive general-purpose computing to multiple users by sharing processor time. ... A modem (from modulate and demodulate) is a device that modulates an analogue carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... Look up Parity in Wiktionary, the free dictionary Parity is a concept of equality of status or functional equivalence. ... In computing, an interrupt is an asynchronous signal from hardware or software indicating the need for attention. ...

On personal computers, the Break key is used in different ways by different programs, but usually involves some sense of changing the interaction with the computer, such as switching between multiple login sessions, terminating a program, or interrupting a modem connection.

On a BBC Micro computer, the Break key generated an interrupt which would normally cause a warm restart of the computer. By holding Control and pressing break, a cold restart is triggered. If a DFS ROM is installed, holding Shift and pressing break will cause the computer to search for and load a file called !boot on the floppy disk in drive 0. The BBC Micro, affectionately known as the Beeb, was an early home computer. ...

On the Sinclair ZX80, ZX81 and ZX Spectrum computers, the Break key is accessed by pressing Shift and Space.^{[dubious — see talk page]} The Spectrum+ and later computers have a dedicated Break key that emulates this keypress. It does not trigger an interrupt but will halt any running BASIC program, or terminate the loading or saving of data to cassette tape. An interrupted BASIC program can usually be resumed with the CONTINUE command. The Sinclair QL computer does not have a break key, but pressing Control and Space has the same effect. The Sinclair ZX80 was a home computer brought to market in 1980 by Sinclair Research of Cambridge, England. ... The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the followup to the companys ZX80. ... The ZX Spectrum is a home computer released in the United Kingdom in 1982 by Sinclair Research Ltd. ... A Sinclair QL The Sinclair QL (for Quantum Leap), was a personal computer launched by Sinclair Research in January 1984, as the successor to the ZX Spectrum. ...

On many modern PCs, Pause interrupts screen output by BIOS until another key is pressed. This is effective during boot in text mode and in a DOS box in Windows safe mode with 50 lines. This functionality had been there with the very first PCs, except that before the introduction of 101 keys keyboards (previous keyboards did not have a pause key), one had to press Ctrl + Num Lock instead, a combination that even on modern PCs with modern keyboards still does exactly the same as the 'Pause' key. Apple Macintoshes like the iMac Core Duo are personal computers. ... BIOS, in computing, stands for Basic Input/Output System also incorrectly known as Basic Integrated Operating System. ... An Internet payphone loading Windows XP In computing, booting is a bootstrapping process that starts operating systems when the user turns on a computer system. ... A text mode program communicates with the user by only displaying text and possibly a limited set of predefined semi-graphical characters, which allow the drawing of rudimentary boxes around portions of text, either to highlight the content or to simulate widget or control interface objects found in GUI programs. ... â€¹ The template below has been proposed for deletion. ... Microsoft Windows is the name of several families of proprietary software operating systems by Microsoft. ...

In programming, especially old DOS-style BASIC, Pascal and C++, Break is used (in conjunction with Control key) to stop program execution. In addition to this, Linux and variants, as well as many DOS programs, treat this combination the same as Ctrl+C. Finally, the combination can be used to stop a batch file, which is highly useful on older DOS machines that ran batch scripts on boot up. BASIC (Beginners All-purpose Symbolic Instruction Code) is a family of high-level programming languages. ... Pascal is an imperative computer programming language, developed in 1970 by Niklaus Wirth as a language particularly suitable for structured programming. ... C++ (pronounced see plus plus, IPA: ) is a general-purpose, high-level programming language with low-level facilities. ... A Control key (marked Ctrl) on a modern Windows keyboard In computing, a Control key is a key, which when pressed in conjunction with another key, will perform a special operation. ... Linux (IPA pronunciation: ) is a Unix-like computer operating system family that uses the Linux kernel. ...

On modern keyboards, the break key is usually labeled Pause/Break. On many games this was the key to pause the game. In most Windows environments, the key combination Windows key+Pause brings up the system properties. A Windows key on a black laptop keyboard The Windows key or Windows logo key (in short WinKey, or rarely Flag key) is a keyboard key originally introduced for the Windows 95 operating system. ...

Compact and notebook keyboards often have the Pause/Break key mapped to a function command. As a result, pressing Ctrl+Pause in a notebook computer may require the user to press something else, such as Ctrl+Fn+F11.

See also

Categories: Accuracy disputes | Computer keys | Out-of-band management SysRq or SysReq (short for System Request) is a key on keyboards for PCs that has no standard use. ... Scroll lock is a key (with an associated status light) on most modern computer keyboards. ... Num Lock is a key on the numeric keypad of most keyboards, used to switch that pad between number entry and arrow keys. ... A computer keyboard is a peripheral partially modeled after the typewriter keyboard. ... It has been suggested that this article or section be merged with Combining character. ... The compose key and compose LED on a Sun Type 5c keyboard is the second-last key on the bottom row On some computer systems, a compose key is a key which is designated to signal the software to interpret the next keystrokes as a combination in order to produce... 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. ... A Control key (marked Ctrl) on a modern Windows keyboard In computing, a Control key is a key, which when pressed in conjunction with another key, will perform a special operation. ... The shift key on a modern Windows keyboard The shift key is a modifier key on a keyboard, used to type capital letters and other alternate upper characters. ... The Alt key on a modern Windows keyboard The Alt key on an IBM PC keyboard is the key located immediately to either side of the Space bar, used to change (alternate) the function of other pressed keys. ... The Option key The Option key, known to latent PC users as Alt key, is a modifier key present on Apple keyboards. ... This article or section does not cite its references or sources. ... AltGr is a modifier key on PC keyboards used to type many characters, primarily ones that are unusual for the locale of the keyboard layout, such as foreign currency symbols and accented letters. ... The Command key The Command key, known as the open-Apple key in documentation previous to the Apple Macintosh family of computers, is a modifier key present on Apple keyboards. ... The Meta key was a special key on old MIT computer keyboards. ... The Massachusetts Institute of Technology (MIT) is a private, coeducational research university located in Cambridge, Massachusetts. ... A Windows key on a black laptop keyboard The Windows key or Windows logo key (in short WinKey, or rarely Flag key) is a keyboard key originally introduced for the Windows 95 operating system. ... Fn key can also refer to the function keys on a computer keyboard. ... Computers and other typing devices offer many different keyboard layouts for inputting data in different languages. ... Lock is a function that locks part of the keyboard keys depending on the lock settings selected. ... Scroll lock is a key (with an associated status light) on most modern computer keyboards. ... Num Lock is a key on the numeric keypad of most keyboards, used to switch that pad between number entry and arrow keys. ... The caps lock on a modern Windows keyboard. ... Arrow keys Arrow keys are buttons on a computer keyboard that move the cursor in a specified direction. ... The page scroll keys among other keys The page scroll keys are two keys commonly found on computer keyboards, the page up key and the page down key. ... The home key among other keys The home key is a key commonly found on computer keyboards. ... The end key among other keys The end key is a key commonly found on computer keyboards. ... Originally, carriage return was the term for the key, lever, or mechanism on a typewriter that would cause the cylinder on which the paper was held (the carriage) to return to the left side of the paper after a line of text had been typed, and would often move it... The enter key (or return key) causes a form or dialog box to operate its default function, which is typically to finish an entry and begin the obviously desired process. ... Backspace is the keyboard key that originally pushed the typewriter head one position backwards, and in modern computer displays moves the cursor one position backwards and deletes the preceding character. ... The Insert key (often abbreviated to INS) commonly found on keyboards is mostly used to switch between the two main modes of entering text on a computer. ... The user pressing the delete key on a Macintosh On computer keyboards, the delete key (sometimes shortened Del), should, during normal text editing, discard the character at the cursors position, moving all following characters one position back towards the freed place. ... This article is about the use of the term Tab in computing. ... A computer keyboard Space bar is a key on an alphanumeric keyboard in the form of a horizontal bar in the lowermost row, significantly wider than other keys. ... SysRq or SysReq (short for System Request) is a key on keyboards for PCs that has no standard use. ... A 102-key PC US English keyboard layout with the print screen key marked in red. ... A computer keyboard. ... In computing, the Menu key is a key found on Windows-oriented computer keyboards. ... This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... A 102-key PC US English keyboard layout with the function keys in orange. ... Power management keys placed in the top row, with the keys at that place and below moved down one row. ... Language input keys are keys designed to translate letters entered by users, usually found in Japanese and Korean keyboards, for use with input method editor. ...