FW: PLUG: OT: AD\/:ETC - Good training for mouse-challenged *nixpeople

[Bill Campbell]

On Mon, Dec 19, 2005, Kenneth Brody wrote:
>Quoting Bill Campbell (Mon, 19 Dec 2005 09:42:40 -0800):
>[...]
>> Scripsit for the Model 16/6000 Xenix machines was a very
>> different beast than the TRSDOS version, and, IHMO, not as easy
>> to use since it had to run on dumb terminals as opposed to a
>> single user machine with memory mapped video and no issues with
>> serial communications (it used ctrl-s for something which would
>> stop a serial line dead in its tracks :-).
>[...]
>
>Then there was the printer (I forget the make/model) which would freeze
>up a terminal when hung off the terminal's local printer port, because
>it used Ctrl-S for the "underline on" code.

This was always one of the major issues when trying to do pass
through printing to terminals.  The printer manufacturers by and
large didn't have a clue about serial communications or terminal
control codes.  One job I worked on used some Really Cheap(tm)
terminals that had a multi-character printer-off control code,
and passwd the code through to the printer until the last
character was received by the terminal.  This caused a Panasonic
24 pin dot-matrix printer to go into 6 inches per line mode which
sorta messed up the output.  I had to do some major workarounds
in my accounting system's printer control codes, storing the
printer initialization string, and resending it to reinitialize
the printer whenever sending the printer-on codes.  Naturally the
printer reset caused it to lose track of where it was on the page
so automatic form feeds were out of the question.

As a general rule pass-through printing works best on terminals
that use ANSI escape sequences for printer-on and printer-off.
Mannesman Talley made (makes) a line of printers where all the
printer control codes are ANSI as well so there's no chance of
conflict with the terminal control.  HP PC uses reasonable ESC
sequences as well to avoid conflicts.

I always thought that it would nice to have a black box that went
between the computer, the terminal and the printer that would
take care of the printer-on/off codes so the terminal never saw
them.  The size limitation would be size of a parallel printer
connection.

Then there was the WordStar diamond, that used the xon/xoff keys
for cursor control or some such.

The worst though is all the Windows programmers that think that a
single ESC character is a command when ESC was designed to
indicate the start of a command sequence (which is why FilePro
uses ESC-ESC to save.

Bill
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