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Date: Wed, 26 Mar 1997 05:45:40 -0800 (PST)
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From: mark thompson <thompson@tgsoft.com>
To: brian@shift.lan.awfulhak.org
CC: hackers@freefall.freebsd.org
In-reply-to: message from Brian Somers on Tue, 25 Mar 1997 14:09:38 +0000
Subject: Re: Backspace = ^H
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   From: Brian Somers <brian@shift.lan.awfulhak.org>
   Date: Tue, 25 Mar 1997 14:09:38 +0000

   > In reply to Brian Somers who wrote:
   > > > In reply to Brian Somers who wrote:
   > > > 
   > > > *SIGH*, why does this come up again and again??
   > > 
   > > 'cos it doesn't make sense (*stir* *stir* *stir*).
   > 
   > Yes it does :)
   > 
   > > > > The DEL key would send whatever the Backspace key doesn't.
   > > > > 
   > > > > (I'd prefer BS=^?, DEL=^h)
   > > > 
   > > > BS = BACKSPACE = 0x08
   > > > DEL = DELETE = 0x7f
   > > > 
   > > > Why on earth should they be reversed contradicting their names ??
   > > 
   > > So that emacs' help system can work.  Why would reversing them
   > > contradict their names ?
   > 
   > Change emacs ??
   > 
   > Because "back space" in ascii parlour is 0x08, and "delete" is 0x7f
   > thats why....go check an ascii chart...

   Yep - it just occurred to me to look at an ascii chart.

This appealing to the ascii chart is getting rather silly. On some of
the old teletypes 'BS' backed the print head up so you could overtype
(ie. back-space). Since it was a printing process, the previous
character was not deleted, merely overstruck.

The <delete> key, by contrast, punched out all 7 data channels on a
paper tape (it was originally called <rubout>). Many systems ignored
rubouts (so you could wipeout mispunched characters). Others took them as
an interrupt character. I believe older unices defaultly did that.

Back in those days, DEC, at least, was pretty consistent in using
<delete> to mean 'delete the previous typein'. Others used BS to mean
roughly the same.

Since unix is nice enough to let you pick, why do we need to argue?

-mark