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+\centerline{\bf BCS Displays Group}
+\medskip
+\noindent
+The programme for the BCS Displays Group meeting
+held at the Rutherford Appleton Laboratory ({\sc ral}) on
+October 26th sounded rather close to what I would from the
+BCS Electronic Publishing Group. The meeting was rather
+grandly titled `Interactive Documents: Today and Tomorrow'
+and described as an `International State of the Art
+Seminar'.
+
+The first talk was from Angela Scheller on `Graphics in
+Document Standards', a popular topic these days, perhaps
+as a reaction to the apparent ease with which graphics
+are pasted into your average dtp package. Why should they
+have all the fun? Here the accent was on `standards'
+(real, {\sc iso} standards, not the {\it de facto} ones).
+The two document standards which were examined here were
+\sgml\ and {\sc oda} (Office Document Architecture). Of
+course, there are other `standards' or quasi-`standards'
+like telex, telefax\slash facsimile, teletext, {\sc
+ccitt} and {\sc ecma}. There is a bit of politicking
+going on at the moment between \sgml\ and {\sc oda}, due
+partly to their origins (\sgml\ has its origins in
+publishing, and {\sc oda} in computer vendors). {\sc oda}
+is claimed to be an `open system'. I'm still waiting for
+a clear and concise description of {\sc oda}, but the
+points I gathered here were that it involved a
+hierarchical structure, with defined inter-relationships;
+it supported the notion of logical views and layout views
+(conceptually orthogonal); and that it allowed
+interchange between different systems. When {\sc oda}
+handles graphics, it does so with respect to other
+standards, in one of three modes: character based,
+raster based, and geometric. Obviously~(?) the most
+powerful mode is geometric, where {\sc cgm} is considered
+the standard. Clearly there are limitations, but most are
+due to the degree to which the standards themselves have
+evolved: areas like colour\slash grey scale, moving
+images, business graphics, 3D, {\sc cadcam} and maps
+still need to be incorporated, beside image overlay,
+handling of non-rectangular areas, and also `external
+references' (e.g.~images from a picture database).
+
+\sgml\ offers a different approach. While graphics in
+{\sc oda} have limited functionality, but are (or should
+be) usable in open systems, graphics in \sgml\ have
+unlimited functionality, but only within special
+applications environments. In \TeX\ we could contrast
+this with the \LaTeX\ picture environment (which offers
+limited functionality) over all systems (`open'), and the
+use of |\special|s, which have unlimited functionality,
+but are system specific. One of \sgml's interesting
+features is its `let-out' clause, where it can allow part
+of a document to be coded in a non-`standard' ({\it sensu
+ISO\/}) way. The usual example is maths, where \sgml\
+usually hands over to \TeX, but here the appropriate
+example is some alternative graphics language or system.
+
+John Harris made some interesting observations on `Demand
+Printing': his main objective was to give some
+explanation of why demand publishing had not mushroomed.
+He presented a vision of bookshops which stocked
+hundreds\slash thousands of titles which would then be run
+off on the local laser printer, stitched, bound,
+dust-jacketed, and placed in the customer's hands, all
+within a few minutes. At last, \PS\ reared its head. Harris
+concentrated on the fact that \PS\ is a common {\it de
+facto} standard, pointing out that it was just what the
+record industry had been waiting for (alluding
+to one of the examples in the {\sl Cookbook\/}). But he
+felt that \PS\ offered us too much: text is essentially
+orthogonal, and therefore \PS's capability to skew and
+rotate text was usually redundant. He argued that \PS\
+solved many problems we didn't know we had. The key
+difficulty for demand publishing was speed and cost.
+Taking a minimum desirable throughput at 200\,ppm, at
+300\,dpi resolution this comes out at about 3\,Mbytes/sec
+transmission speed. For bulk printing a 10-fold
+improvement was needed. The rip (raster image processor)
+could be speeded up, for example by using Transputers
+(there is already a \PS\ clone typesetter which uses
+Transputers, and is substantially faster than your average
+Linotron rip). But technological changes are also needed,
+like continuous paper rolls.
+
+Although I enjoyed the knockabout with \PS, I was left
+doubting whether demand publishing was ever
+likely to come about, and that even if it did, it
+wouldn't make books any cheaper.
+
+Crispin Goswell of {\sc ral}, gave the paper I had been
+waiting for, `\PS\ in the real world'. I'm not convinced
+that {\sc ral} is quite my notion of the real world,
+but they have done a great deal with \PS. I recall
+a BCS-EP meeting some years ago where someone from
+{\sc ral} described early encounters with the
+language. Goswell has written a public domain display
+\PS\ for the Sun workstation which was shown at the
+meeting. This facility goes a long way to resolving one of
+the persistent problems with \PS\ --- the lack of
+screen preview. I find development work with \PS\ a
+nightmare. An aside: how is it that \PS\ is wonderful, and
+has been embraced by all my user-%
+ friendly {\it wysiwyg\/}
+chums, despite its obvious unfriendliness, while \TeX\
+remains an anathema to them: could it be something to do
+with marketing?
+
+Goswell's talk was extremely competent, and neutral.
+Fortunately here was someone who knew enough about \PS\
+to know its strong and weak points. One of the items he
+covered was the problem of device independence. In
+theory, sending your \PS\ file to a laser printer, then to
+a typesetter should only change the resolution --- the
+document should look the same, only better.
+Unfortunately, as we all (?) know, this is not always the
+case. Rules in particular can change their appearance;
+memory usage is different in different rips (i.e.~your
+pages may not print at all), and of course the fonts you
+think you have used may not be available. Most \PS\ users
+will also have encountered the `preamble' problem --- and
+will know that there are lots of different releases of
+the \PS\ software for printers, all with different bugs
+(Let's ignore the clone problem for now.)
+
+Looking at \PS\ as a programming language, he pointed out
+that it is a plain text language -- you can read it ---
+it is complete, and it really is a language, not data. As
+a programming language it offers extensibility: Goswell
+saw no reason why \PS\ could not offer non-linear font
+scaling (a charge often levied against it). But he also
+noted that the language did encourage hacking, that it
+could be hard to read, and was difficult to debug ---
+consequences of the dynamic binding of the language and
+the ability to redefine anything whenever you pleased.
+Portability was generally good, although there were
+problems with manufacturer-specific extensions (as
+usual), and with fonts.
+
+This was very useful, evenly balanced and informative
+talk which may have swept away some of the
+misunderstandings and misconceptions which surround \PS.
+
+There were three other talks, from Heather Brown, Wendy
+Hall, and J\"urgen Sch\"onhut, but none were \TeX-relevant.
+\smallskip
+\rightline{\sl Malcolm Clark}
+