Control key
The control button labeled Ctrl, in Switzerland and on English keyboards with Ctrl for Control, is a key to invoke additional functions: Ctrl or Ctrl
On standard PC keyboards it is located on the far left in the bottom row of keys directly below the Shift key ( Shift key ), and usually a second time at the bottom right next to the arrow keys. Most applications do not distinguish between left and right key press, computer games, however, made use of.
It is sometimes in Germany colloquially the key as the " string " - "Strong" - or even " Strange" button called, but more often are the single letter " S", " t", " r", " g" instead of the word "Control" pronounced. In Switzerland Ctrl commonly referred to as "Control" very, rarely spelled out.
Operation
The Control key is not usually used alone, but usually results in combination with another key from a command or calls a program function (except in newer versions of Windows - but by default switched off - the possibility to rediscover by pressing the mouse pointer ). So you can, for example, Ctrl C to copy text and paste it with Ctrl V ( copy and paste) without having to use the mouse. The advantage here is that you will not be disturbed while writing, because you do not have an extra reach for the mouse. The Alt and Alt Gr key are more, computer historically somewhat newer keys that work on this principle.
Pressing the control key together with another key leads PCs to the fact that the ASCII equivalent of the second key with 1Fhex ( 00011111bin ) is bitwise ANDed. This causes the sixth to eighth bits of the ASCII code of the corresponding key, and are cut off as a return value the result is a number, which one of the first odierungen ASCII-C 32, that is, a certain control function corresponds.
Each of the ASCII uppercase letters are assigned to a function whose code is less accurate than the 64 code of the character. Lowercase activate the same functions as the corresponding uppercase letters, only by their code is not 64, but 96 deducted because they have different codes of lowercase and uppercase letters for each 32.
Today, most of these control functions are no longer for the control of devices, but also for the control of various software packages are used by keyboard shortcuts.
Common combinations of the control key
Many programs include the ability to trigger functions on the keyboard instead of the mouse and menus. In the menus often is the right of each function, as it can be executed faster using a keyboard shortcut. Depending on the program, the combinations may differ, however.
History
In older PC types (original IBM PC, IBM XT, IBM AT), and many non- personal computers, for example, Commodore 64, Atari ST, Apple II, and many Unix machines, you will find the key above the shift key either to the left of "A" or left of the " Q". The English name is Ctrl or Control.
On old computer architectures the Ctrl key was used to generate the first 32 codes (000 to 031) in the ASCII table, the so-called control characters. These 32 non-printing characters corresponded to the output devices (originally were the most Telegraph ) no symbolic representations, but devices controlling functions such as BEL (Bell, octal code: \ 007, Ctrl G), what the bell of the instrument (now a beep ) sound can, LF ( line feed, Eng Line Feed, octal code. \ 012 Ctrl J), which produces a line feed, BS (backspace, octal code: \ 010, Ctrl H ), which moves the print head back one step to the left, etc.