[GreenKeys] Slashed zero on Teletypes

[David Christ]

Actually that’s way modern.  According to the entry on slashed zero in wikipedia, slashed zero can be found as early as the 12th and 13 centuries.  Their authority is: 
	• Cajori, Florian (1928–29), A History of Mathematical Notations, Chicago, IL: Open Court Pub.; op. cit., New York: Dover Publications, 1993, ISBN 0-486-67766-4.

IBM of course did its own thing in those days.  Paid no attention to common practices and few standards.  Surprised that they didn’t insist their equipment run on only 25 Hz or 400 Hz power.

David K0LUM

On May 20, 2015, at 12:00 AM, WA5CAB--- via GreenKeys <greenkeys at mailman.qth.net> wrote:

> IBM was 'way behind the times.  I have either two or three TG-7's (M15 KSR with series governed AC motors) with Slash-Zero.  So the practice dates at least back to WW-II.
> 
> In a message dated 05/19/2015 18:28:05 PM Central Daylight Time, coryheisterkamp at gmail.com writes: 
>> That's been my experience as well; IBM went with the slashed letter O while the rest of the industry went with slashed zero. What's interesting is I have two Model 33's here, each with their own variation. Wish I knew where these were originally used... -C
>> 
>> 
>> On May 19, 2015, at 4:40 PM, David Christ wrote:
>> 
>> >Norwegian and Danish use a slashed O similar to a slashed zero.  Not with a horizontal bar.  One of three additional vowels in their alphabet.  Effectively an O umlaut.
>> >
>> >As for slashed O, I can’t cite a reference but IBM core dumps started out as one and zero.  So when alphabetic characters showed up the O was slashed for differentiation from zero in output.  Teleprinter output was mainly for text so that is probably why a slashed zero was used.
>> >
>> >This is based on memories from over 50 years ago so I am quite willing to be corrected.
>> >
>> >David K0LUM
>> >
> 
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