Re: Terminal Archaeology (was: MES)

From: Markus G. Kuhn (
Date: Wed Jul 02 1997 - 19:49:17 EDT

Jonathan Rosenne wrote on 1997-07-02 23:12 UTC:
> Even the VT 100 could display Hebrew. The visual bidi methods used by it
> were probably more complicated than the Unicode algorithm.

Sure? Is the exact model identifier "DEC VT100"? Or are you just talking
about one of the zillions of "VT100 compatible" terminals out there,
some of which certainly have bidi support as defined in ISO 6429.

I am the proud owner of a mostly functional DEC VT100 terminal including
the full documentation (probably built around 1979, the deflection
electronic is not the best any more, so the image geometry is somewhat
off, but otherwise still usable). It does definitely not support Hebrew,
in fact it does not even support German. All it supports is 7-bit ASCII
plus a DEC specific set of block graphic characters (including some that
are not even covered by Unicode). There were replacement character ROMs
available for some of the national ISO 646 variants of ASCII. My DEC
VT100 Programmer's Manual does at no place talk about a right-to-left

The DEC VT100 was a very popular terminal in its days, and it was
one of the first terminals that implemented the ESC sequences of a then
new ANSI standard (forgot the number, was withdrawn anyway) that is now
known as ISO 6429. The DEC VT100 implemented only a subset of ISO 6429,
and ISO 6429 has been extended by bidi control sequences long after the
VT100 was designed (1992 or so).

The VT100 terminal has long ago died out, except in the basements of
hardware collectors like myself, but the subset of ISO 6429 ESC sequences
that it implemented are still very widely used in numerous systems,
especially in the Unix and VMS world, where we still talk about VT100 or
ANSI terminal emulation.

ISO 6429 is also available freely from ECMA <> as
ECMA-48, by the way (as are many other standards like ISO 8859 and 2022).
They send you the paper version of the standard free of charge.


Markus G. Kuhn, Computer Science grad student, Purdue
University, Indiana, USA -- email:

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