Registry for terminal DA responses? - test-drb@ccmp.vtda.org

13 Jun 2005

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Subject: Re: Registry for terminal DA responses?
   From: msokolov at ivan.Harhan.ORG (Michael Sokolov)
   Date: Mon, 13 Jun 2005 05:32:27 +0000 (GMT)
     To: cctalk at classiccmp.org

Private parameters (what DEC used) do not guarantee interoperability:
vendor A can define ?1 to identify one of its products, but another vendor B
would have every right to define ?1 to identify one of *its* products. 
DEC published what they did.  Private in this sense was defiened in 
ISO/ANSI as undefined by them and available for implmentation if the 
VENDOR elects to have said functionality.  The ANSI defines were quite
limited and far for complete.

Then there were those vendors that use something else before ANSI 
and wished to continue with them for customer loyalty. 

That fragmented the market, ANSI/DEC compatable and NON ANSI/DEC compatable.

...
 DA (CSI c) is not a DECism, it's a feature of the
International Standard
ISO 6429.  Yes, of course there are terminals that don't care about ISO 6429
and implement their own completely different escape/control/whatever
sequences, but they are not relevant to this discussion.  I'm talking about
the standard mechanism for identifying a particular implementation of ISO
6429 among all others in the Universe. 
Who do you think was part of ANSI and supplied delagates and corperate 
support?

...
 The product I'm designing follows ISO 6429, which
is the successor to
ANSI X3.64 that you are referring to.  VT100 is one implementation of
the standard, mine will be another.  DEC is one manufacturer, HEC is
another. 
Actually VT100 predated that standard!  ANSI didnt get it out the 
door before VT100 was delieverd.

...
 My implementation of the standard will be very close to
DEC's, but not
identical.  I'm deliberately not writing an exact VTxxx emulator since
I want to do a few things differently.  The main area of difference is
character set handling.  I have made a proper implementation of ISO 2022,
whereas DEC has made some horrible kludges apparently to make it "user-
friendly" in their perverted sense.  I'm talking about the horrible mess
with multinational vs. national modes, keyboard variants and typewriter
vs. data processing keys, kludges that have no place in an ISO 2022
terminal. 
The DEC was was to keep their terminals compatable with prior version
that had existed since the mid 70s.  Or differently put, new terminals 
should not break the customer (they did sometimes anyway!)!

That was part one.  Part two of that is multinationalization was a POST
VT100 event.  By Time DEC started with Multinational products VT220
and some of the VT1xx vairents were out the door or about to.  The 
whole process of multinational products would over the next 10 years
undergo several variations to meet the market as it changed.

One thing to remember.  ANSI was always after the first product and
rarely covered all the varitions in the field.  And like it's IEEE 
and ISO cousins was subject to interpretation until the market 
forced everyone onto the same sheet of paper.

Allison