IBM 1620 invalid character symbol

William_J_G Overington via Unicode unicode at
Tue Sep 26 08:56:04 CDT 2017

A digit with a bar over the top is used to express the common logarithm of a number that is both greater than zero and also less than one.
William Overington
Tuesday 26 September 2017
----Original message----
>From : unicode at
Date : 2017/09/26 - 14:34 (GMTST)
To : duerst at
Cc : unicode at, john.w.kennedy at, leob at
Subject : Re: IBM 1620 invalid character symbol
But what is interesting is the use of negative digits (-1 to -9, with the minus sign above the digit; I've not seen a case of minus 0, not needed apparently by the described operations)
How do you encode these negative decimal digits in Unicode ? with a macron diacritic ?
2017-09-26 15:20 GMT+02:00 Martin J. Dürst via Unicode <unicode at>:
On 2017/09/26 22:03, John W Kennedy via Unicode wrote:
I don’t know what your snippet is from, but the normally authoritative IBM manual, A26-5706-3, IBM 1620 CPU Model 1 (July, 1965) displays what is clearly the Cyrillic letter. Whether it should be regarded as that, or as a distinct character, is another question. See
What page?
Regards,   Martin.
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