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From: hrs@homxb.UUCP (H.SILBIGER)
Newsgroups: net.micro.pc
Subject: Re: More on WordPerfect, TROFF, and DIF
Message-ID: <1084@homxb.UUCP>
Date: Thu, 2-Jan-86 19:31:43 EST
Article-I.D.: homxb.1084
Posted: Thu Jan  2 19:31:43 1986
Date-Received: Fri, 3-Jan-86 05:33:23 EST
References: <488@imsvax.UUCP>, <25@cornell.UUCP>
Organization: AT&T Bell Labs, Holmdel NJ
Lines: 55


A historical note on the origins of Navy DIF.

In the early 80's the Navy discovered that it owned at least
17 different makes of word processors, none of which could
interchange documents.  They invited all known providers of
wp's to come to Washington, sat the ones that showed up together
in a room, and asked them to come up with a way to interchange
documents. The mfrs were also informed that in the future the Navy
would only procure (the gov't doesn't buy., it procures) from
suppliers that conformed to the interchange method.
All the attendees in the room had word processors that used
control codes for formatting.  They constructed a big table
where each listed the control codes they used, and what
its function was.

The first thing they agreed on that only functions everyone
used would be supported.  Next they looked at those functions
for which evryone used the same control code.  Those were accepted.
Next they all agreed on a code for all other functions for which
there was no common code.

It is obvious that the result is the least common denominator of
the capabalities of those wordprocessors.  The Navy did not
care, they felt they would be better off if they could
communicate at all.  The National Bureau of Standards also
was involved in the process.  These common control codes
are now being added into the appropriate ANSI and ISO
standards. The Federal Govt is also adopting the DIF standard.

It is clear that something better is needed for document interchange
than DIF, and there is an international standards activity in
process in ISO and CCITT.  The ISO work (in TC97/SC18) is
called "Text Structures."  It is an interchange standard which
is based on defining the logical and layout structures of a
document. It will be able to handle (theoretically) any kind
of coded content. The current version supports only character
coded information , but raster scan graphics
(Facsimile, which the CCITT version already supports), vector
graphics (CGM), are being worked on.  Almost any kind of
compound document (which the CCITT calls mixed-mode) will
potentially be able to be interchanged.  It is expected
that this work will reach Draft International Standard status
by the middle of the year. The ISO number is 8613.
The US committee responsible for this work is ANSC X3V1.

All layout in the ISO standard is positional by rectangular
coordinates, with the origin in the upper left hand corner
of the (virtual) page.

The DIF work should thus be seen as a stop-gap measure to
achieve some limited degree of interchange. It is not
easily extensible, and cannot support compound documents.

Herman Silbiger  ihnp4!homxb!hrs