IBM 1620 invalid character symbol

Philippe Verdy via Unicode unicode at unicode.org
Tue Sep 26 02:55:46 CDT 2017


I think it was simpler: "X^H|"

2017-09-26 8:34 GMT+02:00 Leo Broukhis via Unicode <unicode at unicode.org>:

> The glyph there looks more like U+1D219 Greek vocal notation symbol-51:
> http://shapecatcher.com/unicode/info/119321
> than a Ж.
>
> 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.
>
>
>
>
>
> On Mon, Sep 25, 2017 at 10:48 PM, Ken Whistler via Unicode <
> unicode at unicode.org> wrote:
>
>> The 1620 manual accessed from the Wiki page shows the same information
>> but with a different glyph (which looks more like the capital zhe, and is
>> presumably the source of the glyph cited in the Wiki page itself). See:
>>
>> http://www.bitsavers.org/pdf/ibm/1620/A26-5706-3_IBM_1620_CP
>> U_Model_1_Jul65.pdf
>>
>> p. 52 of the document (56/99 of the pdf).
>>
>> So there was some significant glyph variation in the 1620 documentation.
>> My guess is that the invalid character tofu was implemented as an overprint
>> symbol on the 1620 console typewriter (since the overlines and the
>> strikethroughs clearly were). The whole system was basically using only a
>> 50-character character set. But to verify exactly what was going on,
>> somebody would presumably have to examine the physical keys of a 1620
>> console typewriter to see what they could generate on paper.
>>
>> I'm guessing the Computer History Museum ( http://www.computerhistory.org
>> / ) would have one sitting around.
>>
>> --Ken
>>
>>
>>
>> On 9/25/2017 9:48 PM, Leo Broukhis via Unicode wrote:
>>
>>> Wikipedia (https://en.wikipedia.org/wiki/IBM_1620#Invalid_character)
>>> describes the "invalid character" symbol (see attachment) as a Cyrillic Ж
>>> which it obviously is not.
>>>
>>> But what is it? Does it deserve encoding, or is it a glyph variation of
>>> an existing codepoint?
>>>
>>>
>>
>
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