Re: BS in rxvt+ncurses

[Philip Hands <phil@hands.com>]

Remco Blaakmeer <remco@blaakmeer.student.utwente.nl> wrote:
> I started using PCs when the only choice for me was MS-DOS with probably
> MS-Windows 3.0 on it. Things were easy back then. The 'Backspace' key did
> 'Backspace' and the 'Delete' key did 'Delete', just like the letters on
> the keys said.
> 
> A year ago I started using Linux and all of a sudden I got confronted with
> people who strongly believe that the 'Backspace' key should do 'Delete'.
> This is very, very confusing to me. Why don't you just let the keys do
> what is written on them? I don't want the 'A' key to generate a 'B' and I
> don't want my 'Backspace' key to do 'Delete'. I have a 'Delete' key for
> that.
> 
> I just want to be able to use both the 'Backspace' key and the 'Delete'
> key on any VC, xterm or rxvt and I want them to do just what I expect them
> to do, which is the same as what they do in MS-DOS.
> 
> Now, if I am seeing it totally wrong, then please explain it to me.

OK, you are not seeing it totally wrong, just a little bit wrong.

I would say that what you actually want to see is, that when you press the 
<--- key that it performs a Delete-Char-Left action (as in DOS), and when you 
press the DEL key it performs a Delete-Current-Char action.

I agree absolutely with this.

Where we differ is about whether it is important for the <--- key to generate 
a BS (ASCII 08) character and the DEL key to generate a DEL (ASCII 0x7F) 
character.  Most of the time it makes no difference to either of us what these 
two keys generate, as long as the required action takes place.

When does it make a difference:

  1) when using broken software that takes no notice of stty or terminfo
     settings

  This is a bug and should be fixed in _that_ software

  2) when attaching to a Linux system from a terminal emulator that cannot be
     set that way we want

  This is a bit of a pain, but can be handled by setting stty and terminfo as
  required to match your terminal emulator.  It is also the main cause of grief
  about this problem IMHO, since the people that have this problem are quite
  often the least able to fix it.

  3) when attaching from Linux systems to either other Linux systems, or other
     Unix systems.
  
  It makes life a lot easier if all the systems you are likely to talk to use
  the same standard mapping, regardless of what that standard is.

  This is my main reason for wanting the <--- == DEL setting to be standard,
  because it already is in Unixland (apart from SysV which you can override
  with stty), and so adding systems to a mixed environment is more likely to
  fit in if this is the default.  This is the source of most of the flames,
  since a lot of people have only ever used various SysV systems (and there's
  no shame in that), and so think that the standard Unix mapping is <---==BS

  4) when attaching from Linux to non-Unix hosts.

  This is a real problem, because mainframes etc, tend to be rather attached
  to their key settings, but there are other solutions on a case by case basis
  (i.e. tn3270/x3270 for mainframes)

Here are a few related pros and cons.

<--- == BS, but we must decide on one or the other as the installation default.

<--- == BS sounds right.  IMHO this is just silly.

<--- == DEL is different from DOS.  This to is just silly

<--- == DEL gives us an extra usable key on the main keyboard, since it 
differentiates between <--- and ^H

<--- == DEL is standard in Linux-land at the moment (very strong argument for 
keeping it that way IMHO)

<--- == BS allows the uninitiated easier use from DOS/Windows telnet's and the 
like (this needs a HOWTO to explain how to do the configuration, but is 
probably the strongest argument for the BS setting)

In conclusion, I'd say <--- == DEL gets to be the default setting on three 
grounds:

 1) Inertia
 2) Emacs (more inertia and extra functionality)
 3) Ease of reversing the decision by local admins.

We need to make point 3 a reality of course ;-)

I hope that is a fairly even handed summary, but please tell me if there is a 
decent technical reason for making <--- == BS the default.

Cheers, Phil.



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