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From: brian@shift.lan.awfulhak.org (Brian Somers)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Backspace = ^H
Date: 25 Mar 1997 10:21:57 GMT
Organization: Awfulhak Ltd.
Lines: 65
Message-ID: <5h8905$lj1@ui-gate.utell.co.uk>
References: <5h2c01$4i2@reader.seed.net.tw>
<5h6e83$1mk@ui-gate.utell.co.uk> <E7KvDC.ILE@nemesis.lonestar.org>
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In article <E7KvDC.ILE@nemesis.lonestar.org>,
uhclem@nemesis.lonestar.org (Frank Durda IV) writes:
> Brian Somers (brian@shift.lan.awfulhak.org) wrote:
>: What's the argument for BS=^h ?
>
>: Surely everyone agrees that since the dawn of time, dumb terminals
>: have sent ^? for the BS key.
>
> Only if you bought them from DEC after 1979, circa VT100.
>
> I've got (or had) a Beehive, ADM-3, Teleray 1060, Teleray 11M, ACT-V,
> a genuine DEC VT50, DEC VT52, DEC LA36 (DECwriter II), DEC LA120
> (DECwriter III), a GE Terminet KSR printer, Radio Shack DT-1, and a
> Wyse 75 (aka DT-100) AND ALL of these produce 0x08 when you hit the
> backspace key, just like the Teletype ASR33/35/37s all did,
> the original DUMB terminals. So did the Singer terminals and a dozen
> brands long forgotten. Few, if any, had an option for changing what
> code the backspace key produced away from 0x08.
>
> Even Hayes AT-compatible modems recognize 0x08 as a backspace by default,
> not ^?.
>
> Sending ^? for as a substitute for backspace came along much later in
> isolated equipment and as such is incompatible.
>
> That's why in the ASCII chart 0x08 is called BACKSPACE. :-)
>
> Frank Durda IV <uhclem@nemesis.lonestar.org>|"The Knights who say "LETNi"
> or uhclem%nemesis@rwsystr.nkn.net | demand... A SEGMENT REGISTER!!!"
> |"A what?"
> or ...letni!rwsys!nemesis!uhclem |"LETNi! LETNi! LETNi!" - 1983
>
I didn't realize this (any dumb terminals I've seen have been vt100,
vt200 and vt220s, and looking in /etc/termcap (on 2.2) we've got
19 occurences of ^h and 1 of ^? :(
Still, I prefer the ^? idea, mainly for emacs reasons (are there
*any* other reasons?), but it's a pain in the ass getting syscons
& X to work like this on every machine.
The interresting "inconsistency" here is that the default erase
character is ^? and the default keyboard maps send ^? from
the DEL key - implying that it's "normal" to press DEL to rubout :(
Then, to compound matters, the default .profile comes with an
stty erase ^h (implying that someone decided it wasn't normal after
all but didn't want to disturb the status-quo too much) !
I think we should have no stty in any .profile, and either of the
following:
* The Backspace key sending ^? and a default stty erase char of ^?
* The Backspace key sending ^h and a default stty erase char of ^h
The DEL key would send whatever the Backspace key doesn't.
(I'd prefer BS=^?, DEL=^h)
Anything that deviates from the "default" needs to be stty'd in
a .profile somewhere.
--
Brian <brian@awfulhak.demon.co.uk> <brian@freebsd.org>
<http://www.awfulhak.demon.co.uk>
Don't _EVER_ lose your sense of humour !