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    commit f210ea26c444607980d5de17ed7d4e62bb813631
    parent 8306568bd0b9d082c58ad897b4562ffe6822e585
    Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
    Date:   Thu, 24 Jul 2014 19:56:58 +0200

    Add info about Backspace and Delete to the FAQ

    Diffstat:
    MFAQ | 58++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    1 file changed, 58 insertions(+), 0 deletions(-)
    diff --git a/FAQ b/FAQ
    @@ -98,3 +98,61 @@ If you want to compile st for OpenBSD you have to remove -lrt from config.mk, an
     st will compile without any loss of functionality, because all the functions are
     included in libc on this platform.

    +## Backspace key does not work
    +
    +This is an issue that was discussed in suckless mailing list
    +<http://lists.suckless.org/dev/1404/20697.html>:
    +
    +	Well, I am going to comment why I want to change the behaviour
    +	of this key. When ascii was defined in 1968 communication
    +	with computers were done using punched cards, or hardcopy
    +	terminals (basically a typewritter machine connected with
    +	the computer using a serial port). Due to this, ascii defines
    +	DELETE as 7F, because in the puched cards, it means all the
    +	holes of the card punched, so it is a kind of 'phisical
    +	delete'. In the same way, BACKSPACE key was a non destructive
    +	back space, as in typewriter machines.  So, if you wanted
    +	to delete a character, you had to BACKSPACE and then DELETE.
    +	Other use of BACKSPACE was accented characters, for example
    +	'a BACKSPACE `'. The VT100 had no BACKSPACE key, it was
    +	generated using the CONTROL key as another control character
    +	(CONTROL key sets to 0 b7 b6 b5, so it converts H (code
    +	0x48) into BACKSPACE (code 0x08)), but it had a DELETE key
    +	in a similar position where BACKSPACE key is located today
    +	in common PC keyboards. All the terminal emulators emulated
    +	correctly the difference between these keys, and backspace
    +	key generated a BACKSPACE (^H) and delete key generated a
    +	DELETE (^?).
    +
    +	But the problem arised when Linus Torvald wrote Linux, and
    +	he did that the virtual terminal (the terminal emulator
    +	integrated in the kernel) returns a DELETE when backspace
    +	was pressed, due to the fact of the key in that position
    +	in VT100 was a delete key. This created a lot of problems
    +	(you can see it in [1] and [2]), and how Linux became the
    +	king, a lot of terminal emulators today generate a DELETE
    +	when backspace key is pressed in order to avoid problems
    +	with linux. It causes that the only way of generating a
    +	BACKSPACE in these systems is using CONTROL + H. I also
    +	think that emacs had an important point here because CONTROL
    +	+ H prefix is used in emacs in some commands (help commands).
    +
    +	From point of view of the kernel, you can change the key
    +	for deleting a previous character with stty erase. When you
    +	connect a real terminal into a machine you describe the
    +	type of terminal, so getty configure the correct value of
    +	stty erase for this terminal, but in the case of terminal
    +	emulators you don't have any getty that can set the correct
    +	value of stty erase, so you always get the default value.
    +	So it means that in case of changing the value of the
    +	backspace keyboard, you have to add a 'stty erase ^H' into
    +	your profile. Of course, other solution can be that st
    +	itself modify the value of stty erase.  I have usually the
    +	inverse problem, when I connect with non Unix machines, and
    +	I have to press control + h to get a BACKSPACE, or the
    +	inverse, when a user connects to my unix machines from a
    +	different system with a correct backspace key.
    +
    +	[1] http://www.ibb.net/~anne/keyboard.html
    +	[2] http://www.tldp.org/HOWTO/Keyboard-and-Console-HOWTO-5.html
    +