On Mon, 13 Dec 2010, Chuck Guzis wrote:
  Another skill to be learned was the ability to
block-print neatly and
 legibly, differentiating "1" from "I", "0" from
"O", etc.  It was all
 uppercase, so that simplified things somewhat.  To this day, I still
 put a line through my "7", although I've dropped the stroke through
 my zero as most people find it to be confusing. 
A long time ago, there used to be some people who put slashes through the
letter 'o', to differentiate it from the numeral '0'.  Are they ALL dead
now?
One of MICROS~1's early attempts at OCR on their order forms gave examples
of how they wanted the letters formed, and included slashing the letter
'o'!
How many people still use the Palm "Grafitti" system?