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Re: handling older ISO-646 displays

1992-02-06 12:18:56
You wrote:

:   One thing that has frankly never been very clear to me is why
: none of the Europeans who are unhappy about the large installed
: base of ISO-646 variants has built a conversion lookup table into
: their MTA that sends the data across the wire as ISO-8859-1
: and converts it to the local ISO-646 variant if necessary at
: display time.  The number of glyphs is small enough to fit in
: a static array lookup table even on a small machine.  Since the
: size is quite small, the performance shouldn't be noticable
: -- especially since most of the ISO-646 equipment is video
: terminals connected via RS-232-like serial lines.

Actually, there is such a generic (not e-mail specific) feature
in AT&T's MNLS package for SVR4. There's a streams module (named
'kbd') that is pushed on tty streams. It uses lookup tables to
convert various national ISO 646-based character sets as well as
various 8 bit ones (i.e., CP 850, CP 437, DEC MCS etc) into
"internal" character sets (the internal ones are what the programs
see). The most common internal character set is ISO 8859/1, although
a program can work with up to four at the same time by using EUC
(Extended UNIX Code), which is an ISO 2022 based switching
mechanism.

I've used it several times and it works just fine. The performance
degradation is, as you say, not noticeable.

Robert Claeson                  Internet: 
robert(_at_)sys(_dot_)sweden(_dot_)dg(_dot_)com
Data General AB                           robert(_at_)sys(_dot_)dg(_dot_)se
Box 28                          Tel: +46 (0)8-92 55 00
S-164 93 KISTA, Sweden          Fax: +46 (0)8-751 36 22

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