[mod.computers.vax] Ultrix and parity

BART@HDETUD53.BITNET (Bart Zorn) (03/17/87)

Subject:        Ultrix and parity settings for terminals

I am currently involved in implementing a 600 port Ungerman Bass network
and doing so, believe it or not, I sometimes find my self being confronted
with a Unix system. BSD 4.2 or Gould's UTX/32 and now even ULTRIX-32.

I was very surprised to see that Digital's own ULTRIX doesn't know about the
existence of VT200 and equivalents, at least when such a terminal behaves
like one. Ultrix's login prompts with characters which have some sort of
parity set and that results in a lot of multinational characters on my
screen.

This experience leads to my question:
Has anybody ever heard of equipment and/or software which uses parity bits
whith asynchronous communication techniques in a useful way?
I know of terminals that display some error symbol when a parity error
is detected, but I have never seen anything which does a retransmit or
something like that.

If there is no such equipment and software, can anybody tell me why parity
is still being used?


Bart Zorn               (BART@HDETUD53.BITNET)
Delft University of Technology
Faculty of Electrical Engineering