Delete character

In computing, the delete character (sometimes also called rubout ) is the last character in the ASCII directory, with the code 127 ( decimal ). [1] Not a graphic character but a control character , it is denoted as ^?in caret notationand has a graphic representation of Unicode (as all ASCII control characters graphic representations).

Most modern keyboards do not have a key to input the Delete character. In Unix-like systems the key or combination of and can be used to express the Delete character. Products like Notepad can also generate this character with the same key presses.← BackspaceControl← Backspace

History

This code was originally used to mark the characters on punched tape , since any character could be changed to everywhere by punching holes everywhere. If a character was punched erroneously, punching out all seven bits caused this position to be ignored or deleted, a computer version of fluid correction . [2] [3] In hexadecimal , this is 7F to 7-bit rubout, and FF to 8-bit rubout. For teleprinters like the Teletype Model 33 , lines have been terminated by the three characters CR , LF , and rubout, with the rubout allowing time for the print mechanism to move to the left margin. On VT100delete, which transmits to delete character (octal 177, hexadecimal 7F) to the host system. [4] [5] On VT510 compatible terminals, this is the character generated by the key labeled ?, usually called backspace on modern machines, and does not correspond to the PC “Delete” key. [6]

Current use

Unix-like operating systems are known to use the erase control character, ie to delete the previous character in the line mode . This, though, differs from its original function when this code is replaced.

DOS / Windows never used this character in any way, using the backspace (0x08, or control-H) to delete the previous character. EGA / VGA fonts , used by Win32 console , usually have the “house” symbol at 127 (0x7F) dot code, see Code page 437 for details. HOWEVER, ict legacy can be seen in Some applications distributed as share of the Windows operating system: as an example, chording Controland in Microsoft Notepad will output the delete character.← Backspace

See also

  • Eight Ones

References

  1. Jump up^ definition of the rubout character 7F hex
  2. Jump up^ Robert C. Martin (2011). The Clean Coder: Code of Conduct for Professional Programmers . Pearson Education . ISBN  9780132542883 .
  3. Jump up^ LaFarr (18 August 2006). ” ” Paper Tape “First Machinable I / O” .
  4. Jump up^ “VT100 Family of Video Terminals” . vt100.net.
  5. Jump up^ “VT100 User Guide- Chapter 3 – Table 3-4 Function Key Codes” . vt100.net.
  6. Jump up^ “VT510 Video Terminal Programmer Information – Chapter 8 – Keyboard Processing” . vt100.net.

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