Replying to a message of Cindy Haglund to Roger Nelson:

 CH> Okay for a shock. One clue's answer was "Chad" las in hanging chad.
 CH> Now I know what that is so please, no need to explain.

 CH> But why DO they call the little punch out dot a chad? Where did that
 CH> come from?

Back in the days of teletypes, messages were prepared on paper tape and
then transmitted.  There were several different systems of code patterns but
AFAIK all used the same kind of tape - about an inch wide, with room for 5
holes across to represent characters.  The systems I worked with used the
Baudot code (from which came 'baud,' which is incorrectly used to describe
modem speeds - which are bits per second, not bauds per second - a baud
being a complete character), which IIRC had 2 start bits, 5 character bits and
a stop bit.  There were several others, none of which were compatible with
any other system; the Friden Corp. had one such proprietary code for its equipment.

I digress.  Anyhow, when those tapes were punched, lots of tiny, round pieces of
paper were left over, and they were called 'chad,' I've no idea why.  The 'chad box'
on the teletype(s) had to be emptied regularly.  Toss a burn bag full of chad (which
was slightly oily) into the incinerator and you had a 'chad bomb' that could and did
send a flame out the top of a forty foot chimney.  The word continued to be used
when keypunches came into vogue, except that keypunch 'chad' was rectangular,
something over twice the size of a teletype 'chad' and made of card stock instead
of paper.

Somebody invented 'chadless' paper tape.  Instead of punching holes in the tape it
punched something like a 'c' - leaving part of the hole unpunched.  Since the paper
tape readers used mechanical fingers to read the tape they'd go through the 'hole'
and read it just fine.  Unfortunately the 'chadless' tape didn't work well with the
optical readers that came out shortly before paper tape went away in the early 1970s
or thereabouts.

Incidentally, the original 'ASCII Art' was done on teletypes.  Somewhere around here
I have a picture of John F Kennedy done on a teletype.  I had - and may still have -
the paper tape that produces a pretty good rendition of the 'Madonna and
Child' painting.
Unfortunately I don't have a teletype.

--- FleetStreet 1.19+