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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of John Cowan Sent: 2003 December 18 09:31 To: Arcane Jill Cc: [EMAIL PROTECTED] 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 <[EMAIL PROTECTED]> 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
