[TUHS] Word erase?

Larry McVoy lm at mcvoy.com
Tue Apr 9 01:40:07 AEST 2024


On Mon, Apr 08, 2024 at 09:18:41AM -0600, arnold at skeeve.com wrote:
> Dan Cross <crossd at gmail.com> wrote:
> 
> > I wonder if anyone can shed any light on the timing and rationale for
> > the introduction of ???word erase??? functionality to the kernel terminal
> > driver. My surface skim earlier leads me to believe it came to Unix
> > with 4BSD, but it was not reincorporated into 8th Edition or later,
> > nor did it make it to Plan 9 (which did incorporate ^U for the "line
> > kill" command).  TOPS-20 supports it via the familiar ^W, but I'm not
> > sure about other PDP-10 OSes (Lars?).  Multics does not support it.
> > VMS does not support it.
> >
> > What was the proximal inspiration?  The early terminal drivers seem to
> > use the Multics command editing suite (`#` for erase/backspace, `@`
> > for line kill), though at some point that changed, one presumes as
> > TTYs fell out of favor and display terminals came to the fore.
> >
> >         - Dan C.
> 
> My memory jibes with this -- through V7 defaults were # and @, and BSD
> changed to ^H / DEL and ^U.  ^W was a BSD thing, probably inspired by
> TOPS-10.
> 
> There was a patch on USENET that added ^T to print the load average that
> we put into the vax at Georgia Tech.  A professor who'd come to us from MIT
> saw it and was surprised tht we could do it on Unix. :-)

I loved and hated ^T.  Logged into a 4MB Vax 780 running 4.x BSD
with 40-50 other students, the only thing that was responsive was ^T.
I really wonder how much slower that Vax was because we were all hitting
^T wondering when our compile would be done.

It was around then that I bought a 128K floppy only CP/M machine.  
Slower than the Vax but it was all mine and unshared.  I got way
more work done on that machine.


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