> On Tue, 11 Jul 2000 21:55:18 -0800 (GMT-0800), Doug Ewell
> <email@example.com> wrote:
> >The problem would be just beginning for all the users of terminals
> >and terminal emulators that apparently rely on C1 control codes.
> Is there a (somewhat) reliable estimate how many such systems are in
> use today ?
> The only one I know is VMS and various VT2xx, VT3xx etc. terminals
> when set into "8-bit Controls" mode.
This is a common misconception. 8-bit controls mode applies in the
keyboard-to-host direction (e.g. for F keys, arrow keys, etc), not in
the host-to-terminal direction. The VT220 and above always accept
8-bit controls (unless they are set to a data length of 7 bits, in
which case they can't accept "bare" 8-bit graphic characters either).
8-bit controls are also used in other popular terminal families, such
as Televideo (today primarily used in the Stratus VOS market) and the
SNI 97801 in Germany. And of course C1 controls are also used IBM 3270
and 5250 datastreams.
As someone else pointed out in this thread, standards are good because
they don't change every five minutes. We can depend on them.
. Terminals such as the VT200 and above adhere to these well-
established and proven standards.
. Most terminal emulators (nowadays far more common than the actual
terminals they emulate) are based on the VT200 series (e.g. VT320),
and therefore adhere to the same standards.
. If you send a code in the 0x80-8x9f range to such a terminal or
emulator, it properly treats it as a control code. If it was
intended as a graphic character ("smart quote" or somesuch) the
result is a fractured screen, sometimes even a frozen session.
. The number of such emulators is probably 25% the installed base of
Windows 9x/NT/2000 PCs, which is not a small number (*). Plus
the installed base of xterms, plus the Macintosh-based emulators,
When we don't respect standards, we make our lives harder, not easier.
(*) The figure would be 100% except that the terminal emulators
distributed with Windows (Hyperterminal and Microsoft Telnet) do not
comply with ISO 2022. This is one of many reasons why there is such an
active market in 3rd-party communications software for Windows.
Before I leave my soapbox, let us all remember that we still rely
heavily on the terminal/host communication model, even if we don't
actually use a terminal or emulator. Email and netnews are based on
it. And for good reason. It's the only model of computer-based
communication that remains stable and is not application- or vendor-
specific. An email message such as this one will remain perfectly
legible 100 years from now, whereas most of the other forms avidly
discussed here will be consigned to the "legacy" trashheap before
your socks get holes.
This archive was generated by hypermail 2.1.2 : Tue Jul 10 2001 - 17:21:05 EDT