Re: Terminal Emulation

From: Michael Everson (everson@indigo.ie)
Date: Fri Oct 30 1998 - 06:22:02 EST


Ar 12:42 -0800 1998-10-29, scríobh Frank da Cruz:

>Again, the rationale is not simply that they would be nice to have (and
>they would be, for many reasons not related to terminal emulation). It
>is that certain terminals already include a selection of single-cell hex
>byte pictures; some terminals have as many as 32 of them.

Um, Frank, why did I make 256 of them then? >:-(

>If we are to include the graphic characters of such terminals in Unicode,
>then we would have to include these hex byte pictures. But then it seems a
>shame to include some byte values but not others. Why not include them all?
>
>On the other hand, if we conclude that hex byte pictures are not needed at
>all, then we can not fully emulate the terminals that have them.

Surely the ordinary user is not expected to deal with hex-byte representations.

>When putting together this table, it occurred to me that when debugging
>Unicode data streams (e.g. in a Unicode-based line monitor or protocol
>analyzer), it would be good to be able to show the presence of a character
>that is "guaranteed not be a Unicode character at all". There will be a
>strong temptation to use it as an escape, and debuggers will want to show
>this.

Users will need to "show invisibles". Whether they need to do that with
special UCS characters designed for that purpose and for no other is the
question.

>I agree. I, personally, can live without the rest and life will go on. But
>before we decide to dismiss the ideas in this proposal, recall the original
>motivation: to stop the proliferation of incompatible encodings for the same
>glyphs. More and more Windows-based terminal emulators are coming on the
>market all the time. Each has has to include its own custom font, encoding
>the same glyphs at different code points.

It would be nice to know what the actual manufacturers want. Are any of
them members of the Unicode Consortium?

>I think we now can agree that
>terminal emulation is not dead and will not die any time soon. Therefore my
>hope is that there can be a standard encoding to follow, and regular
>off-the-shelf fonts can be used -- both for the emulators themselves, and
>for applications that will interoperate with the emulators via copy-paste or
>any other means.

OK, but the UCS will be used for a long long long long time. Probably
longer than terminal emulation.

--
Michael Everson, Everson Gunn Teoranta ** http://www.indigo.ie/egt
15 Port Chaeimhghein Íochtarach; Baile Átha Cliath 2; Éire/Ireland
Guthán: +353 1 478-2597 ** Facsa: +353 1 478-2597 (by arrangement)
27 Páirc an Fhéithlinn;  Baile an Bhóthair;  Co. Átha Cliath; Éire



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