From: Kenneth Whistler (firstname.lastname@example.org)
Date: Thu Dec 20 2007 - 13:41:40 CST
> On Thu, 20 Dec 2007, Karl Pentzlin wrote:
> > What is the use of the BROKEN BAR, especially contrastive to the
> > VERTICAL LINE?
> Both "not sign" and "broken bar" are included in ISO-8859-1
> so that the character set is the same as EBCDIC (cp037).
> Read about the history of these characters in ASCII, Latin-1,
> and EBCDIC in
> Coded character sets, history and development
> by Charles E. Mackenzie
> Reading, Mass., 1980
> ISBN 0-201-14460-3
And EBCDIC Code Page 37 was a deliberate consolidation of
most of the preexisting IBM "character sets" (= character
repertoires) into a single code page, so it incorporated
characters from "DP" (data processing) character sets,
as well as from the character sets that were tailored
for particular European languages.
As far as I can tell, the earliest IBM "character set"
(as defined by the IBM corporate registry) that these characters
appeared in was Character Set 00101 "USA DP 94".
Also keep in mind that IBM started as an office machinery
company, and only later evolved into computers and then
a software company. The early "character sets" were really
more in the nature of lists of characters on the print trains
of printing machinery.
I rather suspect that early on in the history of data
processing, some folks were thinking (and using the
machinery accordingly) that the (unbroken) vertical bar
could be used (with the underscore) to draw boxes, while
the broken bar and the logical not could be used to
write logical expressions.
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