Sun type-4 keyboard offends

Brian Kantor brian at ucsd.edu
Thu Jun 8 13:43:09 AEST 1989


> ...DELete is the Unix [delete previous char] default....

Ah, another rank newcomer.  No, the original Unix defaults were # for
backspace and @ for linekill, with DEL being the interrupt key.  SysV
still comes that way from AT&T, but most of their .profiles seem to set ^H
as the backspace.

DELete didn't become the default BSD Unix backspace until someone (DEC?)
gave Berkeley a whole bunch of terminals that had this huge convenient
DELete key and this tiny little backspace key off in the function-key
wilderness.  The VT220 keyboard is arranged that way in homage to VMS.

VMS grew out of earlier paper-tape based operating systems in which the
RUBOUT (aka DELete) key was used to obliterate a bad character on the
paper tape.  It did NOT in fact delete the character in the input buffer,
but instead simply was discarded by the character input routine so that
you could physically backspace the paper tape and punch a RUBOUT over the
erroneous character, and it would pass unnoticed.  In some bizarre flight
of illogic, VMS adopted the RUBOUT key as the character delete, thus
giving it a whole new meaning.

For some reason, Berkeley also adopted the other VMS character definitions
whilst they were at it.  They choose to use ^U as line rubout, despite the
ASCII definition of ^X as CANcel and ^U as NAK (Negative AcKnowledge), and
^C (ETX, End of TeXt) for interrupt.

So much for ASCII as a standard.

Clearly in the world of 1200 bps modems there is a real advantage to not
using the DEL (RUBOUT) key for interrupt, since it is a common artifact of
line syncslips, but why would any community as virulently anti-VMS as the
Unix world is want to adopt the rest of the VMS bizarre keyboard editing
conventions?  Sun continues the farce.

Maybe if someone donates a whole bunch of terminals with no delete keys
and real nice backspace keys on them to Berkeley, the 4.4 release will
turn to the use of ^H (BS) as the default backspace key?

Brian

NB: of course VMS isn't alone in this: many other DEC-influenced operating
systems used similar keyboard editing characters: TOPS, CP/M, etc.



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