Dead button
The term dead key ( English dead key ) refers to a key on a keyboard that is after pressing does not produce letters feed and does not appear immediately, but a kind of "waiting mode" is activated. Only a further keystroke then generates a combined character (basic characters and diacritics - such as è, ĉ, ñ, ś or ů).
With the help of such key combinations, it is possible for the user to enter French-language letters such as é on a keyboard with a German keyboard layout , for example , without the corresponding keys having to be present on the keyboard.
origin
On mechanical typewriters, when a dead key is pressed, only the character is written on the sheet without moving the carriage. Next, any letter can be typed, which is then accentuated on the sheet. Entering in reverse order - as is customary in handwriting: first the letter and then the accent - was seldom used because the car would have to move back one character, which is technically more complex. On some Remington typewriters, however, this is circumvented with a type that appears one character further to the left.
For reasons of habit, the much more widespread system with dead keys was adopted on modern computer keyboards and is largely established today.
Examples
Swiss and Icelandic keyboards have the umlaut dead key ¨with which it is possible to enter umlauts in capital letters such as Ä, which are missing on these keyboards. Another example is the accent key ´with »´« and »` «(on German keyboards usually to the right of" ß "). If this key is pressed, nothing happens at first; if you then press, for example E, the character “é” is output.
Normally - and also prescribed in most input standards - the dead key (example:) ´and the subsequent pressure on the space bar results in the character itself (not with the apostrophe »'« or the minute sign »′« or the substitute character for both » '«To be confused).
On German keyboards, the circumflex (»^«) and the tilde (»~«) are often executed as dead keys. However, the tilde is dying out as a dead key on German keyboards, since hardly any keyboard driver lists it as a dead key. For mainly (for example) Spanish-speaking use or for Eastern European languages there are keyboards (or driver software ) with the respective specific dead keys.
Users who mainly program or who need special characters for other reasons like to use a keyboard layout without dead keys, since characters like "^" often have their own meaning and can otherwise only be entered with an additional space. This makes entering French texts, for example, considerably more complicated, but software source texts are easier to create.
A special dead key , especially common on Unix systems , is the Compose key .