From: Jony Rosenne (rosennej@qsm.co.il)
Date: Tue Aug 02 2005 - 04:44:02 CDT
> -----Original Message-----
> From: unicode-bounce@unicode.org
> [mailto:unicode-bounce@unicode.org] On Behalf Of Gregg Reynolds
> Sent: Tuesday, August 02, 2005 6:16 AM
> To: Kenneth Whistler
> Cc: unicode@unicode.org
> Subject: Re: Jumping Cursor. Was: Right-to-Left Punctuation Problem
>
>
> > Visual order Arabic and Hebrew implementations on computers were
> > probably "invented" in the 70's, and saw fairly widespread use
> > in that timeframe on mainframes and later in the 80's on PC's. A
> > lot of that work was done by IBM. An inherent bidirectionality
>
> I figured it was IBM, but I would have guessed the 60's. Now the
> question is, why would one go for an MSD encoding design? My
> speculation is that, as computation was expensive in those days, they
> didn't want to mess with the math routines, and the encoding was
> probably motivated primarily by number crunching (Banks, etc.) rather
> than text processing.
Visual order for Hebrew ("inverted") was used in the 1950's on "unit
record", i.e. punched cards. Arabic was more complicated, because of
shaping, and I am not qualified to discuss it, but I believe it was around
at about the same time.
When PDP's became common in the 70's everybody did his own version of
Hebrew, there were about 8 of them, all visual, some inverted and some not.
The main determinant was whether the application required just Hebrew or
both Hebrew and English.
The IBM 3270 had a button to determine whether the screen should be right to
left or left to right, and a way to reverse numbers and English text during
data entry.
The IBM 5250 used non-inverted visual order.
An important landmark was the article ARABIC WORD PROCESSING by Joe Becker
of Xerox, Communications of the ACM, July 1987, Volume 30 Number 7.
"Recently developed word processing software can correctly format the
cursive, interacting letters of the Arabic script. Moreover, new layout
procedures can automatically intermix right-to-left Arabic writing with
left-to-right text in European or other languages."
Jony
>
> > algorithm was invented at Xerox PARC in the 80's, I think, although
> > others might have had an earlier hand in it. It was implemented
> > on the Xerox Star system in that timeframe. You can see it
> > discussed in Joe Becker's 1984 Scientific American article, for
> > example. And that was the immediate precursor of Arabic and Hebrew
> > support on the Macintosh, as well as the inspiration for the
> > Unicode bidirectional algorithm.
> >
> > [Some historians on the list can, no doubt, nail this stuff down
> > more precisely...]
>
> That would be very interesting. I hope they do.
>
Jony
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