From: Erik Naggum <erik@naggum.no>
Organization: Naggum Software, Oslo, Norway
Date: 28 Jul 1992 01:49:19 +0200
Subject: Re: IBM DisplayWriter III(?)

[ Why was this crossposted to 9 newsgroups? ]

Rudy Chukran <chukran@austin.vnet.ibm.com> writes:
|
|   In article <1992Jul18.214951.16040@ccu.umanitoba.ca>, umthom61@ccu.umanitoba.ca (Adam Thompson) writes:
|   |> I've got someone with an old IBM DisplayWriter III (maybe II, dunno)
|   |>    Text deleted
|   |> I'd normally just hook it up, and write a software driver for it... no
|   |> problem.  Guess what?  IBM printers that old use 20ma current loops for
|   |> interfaces!
|   No problem?!!!   Dont expect to pump ASCII to these and expect readable
|   text to come out.   I helped write on layer of the driver for this machine.
|   It was hard in 1980.   It hasnt gotten any easier in 12 years.
|   These printers were quite stupid, even compared to an Epson graphic dot matrix.
|   A clue:  Do you know how to spell EBCDIC ? :-)

Please don't tell me you expect to have any printer (or any other
device) eat your files raw.  What's so difficult with one mapping table
or another?  People who are serious in this interface (and interchange)
game have one or more utilities to maintain and generate mapping tables
for any random character set or code format.

|   Actually I cant remember if the characters it took were EBCDIC or simply
|   a print wheel position code.  I do recall the Displaywriter stored its
|   text in EBCDIC.
|
|   Give it up.  Perhaps the Smithsonian might be interested:-)

Or call a consultant who knows what should and should not be expected
with peripherals that don't plainly say "I accept IBM PC Code Page 850,
and only IBM PC Code Page 850" on the front panel in large, friendly,
blinking neon letters.  (They do, of course, ignore any and all
reference literature and international standards regarding escape
sequences, no matter what purported character set they accept.  So we
have to make a mapping table between ANSI escape sequences for printers
(ISO 6429 has all the details), and whatever device your using.)

If you concentrate on making a mapping table from your favorite
application to some standard character set and/or escape sequence set,
you can make a mapping table from those standards to whatever the
device accepts.  Or better yet, describe the functions using unambiguous
names, and let the computer create those nasty tables directly if and
when you need them.

Seriously, we've had to do character set conversion and data format
conversion since the inception of the computer.  There should have been
a large number of wheels invented by now, yet many people seem to
approach the problem as if nobody in the known universe ever had to do
such conversions before them!

I maintain that a culture that does not let new members learn from the
past, collective experience, is doomed, and the software culture of
which the quoted message is indicative, is certainly heading for the
brink.

What makes me particularly depressed is that the quoted message is
posted from _inside_ IBM, where EBCDIC should've been a household word.
(I know, I called IBM Customer Service in Norway, and nobody knew what
"EBCDIC" was, but I was finally allowed to talk to the VM support group,
who knew.  Scary.)

Best regards,
</Erik>
--
Erik Naggum             |  ISO  8879 SGML     |
                        |  ISO 10744 HyTime   |
+47-295-0313            |  ISO 10646 UCS      |      Memento, terrigena.
<erik@naggum.no>        |  ISO  9899 C        |      Memento, vita brevis.
Newsgroups: comp.periphs