From: Eric Scace (eric@scace.org)
Date: Thu Dec 18 2003 - 10:57:22 EST
The logical "not" glyph got into EBCDIC because the concept was needed in computer programming. An example is the instruction
that if A does not equal B, then do something. IBM picked up the glyph and incorporated it into its punch card systems.
In the late 1970s the C programming language was one of the first to use the glyph "!" to mean logical "not"; e.g., "!=". This
was a response to the use of mechanisms other than punch cards to enter program instructions (keyboards and CRTs, teletypewriters,
etc). Earlier keyboard languages used a different workaround; e.g., "<>" for "not equal".
(Apologies if this duplicates earlier information; I'm jumping into the thread rather late.)
-- Eric Scace
-----Original Message-----
From: unicode-bounce@unicode.org [mailto:unicode-bounce@unicode.org]On
Behalf Of John Cowan
Sent: 2003 December 18 09:31
To: Arcane Jill
Cc: unicode@unicode.org
Subject: Re: American English translation of character names
Arcane Jill scripsit:
> For example, U+00AC (NOT
> SIGN) is something that most people I know would describe in terms like
> "oh - you know - that character to the left of 'one' on a keyboard, if
> you press shift".
On the standard U.S. keyboard, that gesture generates ~.
If I turn on the U.S.-International keyboard, then RightAlt-\ gives me the
NOT SIGN, where \ is the rightmost key in the QWERTYUIOP row.
> (And even then, the usual response is "Oh that one -
> I've never used it. What's it for?". Curiously, to a mathematician,
> tilde, overscore and prime are used in various contexts to mean "not
> sign"; wheras to a programmer, exclamation mark and tilde could mean
> "not sign".
In this case, it's logicians who use U+00AC for "not", or at least
some of them. It got into EBCDIC, I don't know exactly how, and from
there into ISO 8859-1.
> Curiously, [the BBC] never had the same problem
> with the name of the letter P.
In the New York City subway system (of underground trains, that is,
not underground pedestrian tunnels!), this letter has been consistently
avoided since 1967, when the system of distinguishing trains by letter
or number was instituted. The only other letters never used are I
and O (presumably to avoid confusion with 1 and 0, though 0 has never
been used either), and Y. Why Y is a mystery to me: perhaps there has
simply never been a need for it.
-- The Imperials are decadent, 300 pound John Cowan <jcowan@reutershealth.com> free-range chickens (except they have http://www.reutershealth.com teeth, arms instead of wings and http://www.ccil.org/~cowan dinosaurlike tails). --Elyse Grasso
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