IBM 1620 invalid character symbol

Ken Whistler via Unicode unicode at
Tue Sep 26 10:45:19 CDT 2017


Yeah, I know. My point was that by examining the physical typewriter 
keys (the striking head on the typebar, not the images on the keypads), 
one could see what could be generated *by* overstriking. I think 
Philippe's suggestion that it was simply an overstrike of "X" with an 
"I" is probably the simplest explanation for the actual operation. And 
the typeset manuals just grabbed some type that looked similar. Note 
that the typewriters in question didn't have a vertical bar or 
backslash, apparently.

But adding an annotation for similar-looking symbols that could be used 
for this is, I agree, probably better than looking for a proposal to 
encode some new symbol for this oddball construction.

If it really is an overstrike, then technically, it could probably also 
be represented as the sequence <0058, 20D2>, just to represent the data.


On 9/25/2017 11:34 PM, Leo Broukhis wrote:
> If it was implemented as an overprint, either )^H|^H( or \^H|^H/ and 
> was intended to signify an invalid character
> (for example, in the text part of core dumps, where a period is used 
> by hexdump -C), then there would not be a physical key to generate it.

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