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Re: backspace in wscons console sends ^H to processes
First of all, as another comment - it wasn't really a DEC vs. anyone
else with regards to BS vs DEL. DG for example also used DEL (and there
But using DEL pretty much just comes naturally from the teletype, so if
anyone wants to argue that BS would be more natural than DEL really
needs to go back and look at a teletype, and see that it's clearly not
the case there.
And I guess this reply isn't really as much a comment directly to you,
Michael, as a general followup on the topic. But it had to come somewhere...
On 2021-07-19 23:34, Michael van Elst wrote:
bqt%update.uu.se@localhost (Johnny Billquist) writes:
No idea why they decided on using BS.
With teletypes you couldn't "backspace", a DEL would usually print
something like a black rectangle or echo the previous character.
You can get something similar with 'stty -echoe echoprt' (unless
you have a too modern shell that resets the terminal driver).
IBM didn't use teletypes. Or at least not uses using ASCII. And DEL is
an ASCII character. My point was really that IBM using BS on the PC did
not come from their mainframe world, since they didn't even use ASCII on
And the teletype itself don't print anything when you send a DEL. DEL
was sometimes used as a filler character, if you didn't use NUL.
Any kind of echoing when a DEL was sent to a computer was done by the
computer echoing back the previous character or whatever.
But anyway. The big point is that teletypes actually just had a key
labelled "rubout". That key did send a DEL character, though.
So obviously, it was pretty natural for any systems back in that day to
adopt this by interpreting the DEL character as the user had pressed
rubout, and when the user pressed rubout, he was most likely wanting to
rub out the character he just typed.
When other terminals came around, the convention of using DEL to
indicate that you wanted to rub out characters were already established
from the teletype, and it was pretty natural to just continue doing the
The notion of "backspacing" and then overwriting the input probably
comes from video displays. And there I only remember the use of
BS to erase the last character and move the cursor left while DEL
was erasing the character under the cursor and shift the remainder
of the line.
Yes, using BS most likely came with some manufacturers when video
terminals started showing up. But it also meant breaking with an already
well established convention.
Very unfortunate, if you ask me, and it continues to be an issue to this
day. But before IBM did that on the PC, it was a bit uncommon to see BS
used for this. But since then, it has become very predominant.
I still change my systems back to using DEL everywhere, because I prefer
this. But each one to his own. I don't feel a need to mess others up
just because I disagree with them. Others obviously feel different about
The original VT100 also chose to have a Backspace and a Delete key
next to each other.
Yes. And DEC software used BS as a sort of complement to TAB sometimes.
So BS was also still possible to have on VT200 and newer terminals, if
you ran them in VT100-compatible mode.
But I also always configure things around so that that key sends DEL
everywhere I am.
The majority of all systems nowadays seem to agree on using BS
(0x08) for the Backarrow key. USB uses BS, PS/2 uses DEL, but
which is older? :)
I'd say the teletype beats them all. :-)
RedHat once tried to force everything to use DEL, but it probably
didn't work out as the patches are gone. Forcing everything to use
BS is probably as futile.
Agreed. Just let people use whatever they prefer. (Even going back to
the Unix # and @ if they really want to.)
I have a theory that only emacs users nowadays want it to send DEL
so that they can use BS for "Help".
Well, anyone using some other operating systems might also want things
N.B. The original VT100 also had a linefeed key. Now try to imagine
how the world would look like if Richard Stallman had been a Wordstar
lover where LF (Ctrl-J) was the help function.
Emacs tried, when possible, to use keys which did have some natural
association with the function. Thus ^H for HELP actually is sortof
proper. ^J is not.
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt%softjar.se@localhost || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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