Delete character
Encyclopedia
In computing, a delete character
(, sometimes also called rubout) is the last character in the ASCII
repertoire, with the code 127
. Not a graphic character
, it denoted as
and has a graphic representation in Unicode
like all ASCII control character
s, while its meaning is a bit unclear.
There is no common method to input this character on modern keyboards, although in some environments (especially, Unix-like
systems) the key or combination of and in, for example, Notepad (software) may generate this code.
, since any character could be changed to all ones by punching holes everywhere. If a character was punched erroneously, punching out all seven bits caused this position to be ignored (or deleted). On VT100
compatible terminals, this is the character generated by the key labelled , usually called backspace on modern machines, and does not correspond to the PC "Delete" key.
operating systems are known to use it as erase
control character, i.e. to delete the previous character in the line mode. This, though, differs from its original function where this code replaced (physically) characters on a punched tape to be deleted.
DOS
/Windows
never used this character in any way, using the backspace
(0x08, or control-H) to delete the previous character. EGA/VGA fonts
, as fonts used by Win32 console
, usually have the "house" symbol ⌂ at 127 (0x7F) code point, see CP437 for details.
Character (computing)
In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language....
(, sometimes also called rubout) is the last character in the ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
repertoire, with the code 127
127 (number)
127 is the natural number following 126 and preceding 128.- In mathematics :*As a Mersenne prime, 127 is related to the perfect number 8128. 127 is also an exponent for the Mersenne prime 2127 - 1, making 127 a double Mersenne prime...
. Not a graphic character
Graphic character
In ISO/IEC 646 and related standards including ISO 8859 and Unicode, a graphic character is any character intended to be written, printed, or otherwise displayed in a form that can be read by humans...
, it denoted as
^? in caret notationCaret notation
Caret notation is a notation for unprintable control characters in ASCII encoding. The notation consists of a caret followed by a capital letter; this digraph stands for the ASCII code that has the numerical value equivalent to the letter's numerical value. For example the EOT character with a...
and has a graphic representation in Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
like all ASCII control character
Control character
In computing and telecommunication, a control character or non-printing character is a code point in a character set, that does not in itself represent a written symbol.It is in-band signaling in the context of character encoding....
s, while its meaning is a bit unclear.
There is no common method to input this character on modern keyboards, although in some environments (especially, Unix-like
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
systems) the key or combination of and in, for example, Notepad (software) may generate this code.
History
This code was originally used to mark deleted characters on punched tapePunched tape
Punched tape or paper tape is an obsolete form of data storage, consisting of a long strip of paper in which holes are punched to store data...
, since any character could be changed to all ones by punching holes everywhere. If a character was punched erroneously, punching out all seven bits caused this position to be ignored (or deleted). On VT100
VT100
The VT100 is a video terminal that was made by Digital Equipment Corporation . Its detailed attributes became the de facto standard for terminal emulators.-History:...
compatible terminals, this is the character generated by the key labelled , usually called backspace on modern machines, and does not correspond to the PC "Delete" key.
Current use
Unix-likeUnix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
operating systems are known to use it as erase
Stty
The Unix stty command is used for changing the settings of a Unix computer terminal. This command is used to change keystrokes, irregular character handling, and more. Stty gives a full set of features that are also available in ncurses for programmers but simplifies it by building it in to a...
control character, i.e. to delete the previous character in the line mode. This, though, differs from its original function where this code replaced (physically) characters on a punched tape to be deleted.
DOS
DOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
/Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
never used this character in any way, using the backspace
Backspace
Backspace is the keyboard key that originally pushed the typewriter carriage one position backwards, and in modern computer displays moves the cursor one position backwards, deletes the preceding character, and shifts back the text after it by one position....
(0x08, or control-H) to delete the previous character. EGA/VGA fonts
VGA compatible text mode
The implementation of computer monitor text mode on VGA compatible hardware is quite complex. Its use on PC compatible computers was widespread in 1980s–1990s , but persists today for some applications even on modern desktop computers...
, as fonts used by Win32 console
Win32 console
Win32 console is a text user interface implementation within the system of Windows API, which runs console applications. A Win32 console has a screen buffer and an input buffer, and is available both as a window or in text mode screen, with switching back and forth available via Alt-Enter...
, usually have the "house" symbol ⌂ at 127 (0x7F) code point, see CP437 for details.