My arrival in Montreal was somewhat marred by the fact that British Airways managed to lose my luggage. Which on a direct flight from Heathrow takes some doing

Fulminating at the BA desk ellicited a £35 ex-gratia payment, but with no fresh clothes, or sponge bag content, the beginning of this trip is somewhat grungy.

Despite this, excellent progress was made at today's WG1 meeting, where Jeni Tennison was able to attend to go through the latest draft of DTLL. With all substantive points now settled, all that remains is for me to prepare a revised document and we are on track for a final candidate draft (FCD) text.

There are two significant changes to DTLL as compared to the last draft.

The first is that the 1:1 relationship between a DTLL documents and a Namespace (for its declared datatypes) has been relaxed and brought into line with RELAX NG's more liberal approach. DTLL instances will now be able to declare a bunch of datatypes from different Namespaces.

The second is that when parsing values using regular expressions, DTLL processors no longer build a mini XML document behind the scenes, but instead merely a set of bound variables. This should make implementation somewhat simpler (though, having already done the work on this I felt - perhaps rather unreasonably - that this was a feature worth preserving).

During the lunch break I made a quick visit to a department store for fresh sets of clothes and toiletries, since the online baggage tracker revealed that my suitcase was still 'being traced'.

After lunch we discussed DSDL Parts 8, 7 and 9 — and our view is that now all of these texts will be nearing their final form in or before September 2006. So it looks likely a January WG1 meeting will be necessary to resolve ballot comments received and move them towards the the final stages of their standards status.

The Propaganda Tiles are a number of exotic abstract graphics that can be seamlessly tiled to form backgrounds. I am particularly keen on using them for desktop backgrounds to avoid plain solid desktops (too boring) and photos of one's children (a but naff). Mind you, some of the Propaganda Tiles are somewhat psychedelic, so careful choice is required.

The tiles were originally created by Bowie J Poag and released under the GNU GPL. But finding them on the Web has been difficult of late.

But to my joy, I have discovered a mirror of the complete set here.

One off the odder things about them are the peculiarly evocative names of the tiles, such as plastic-dinner-plate-1.jpg and lowdown-popcorn-1.jpg.

Me? I've just chosen the-alias-line-1.jpg. Smart.

While browsing my favourite newsgroup, rec.music.classical.recordings, this morning I came across a link to a YouTube video of Arturo Benedetti Michelangeli playing Chopin's 1st Ballade.

The combination of my favourite Chopin composition and a pianist whose performances are always interesting proved irresistible, especially since the recording through which I've got to know the piece, Artur Rubinstein's on RCA, has – though fabulous – made me think that this is music that is, as Artur Schnabel put it, ‘better than it could be performed’.


Rubinstein's late 1950s Chopin studio recordings
of the Scherzos and Ballades


And the video was tantalising, with Michelangeli showing all the executive perfection, good taste and narrative sense that is expected of him. The one disappointment was the sound quality (obviously one doesn't expect high fidelity through YouTube) and so I was prompted to look to see if I could buy a CD with his performance in decent sound.

Some googling revealed that there was a modern recording in print from DGG, but on looking at the CD cover I was surprised to see this was a recording I already owned. Somehow I had overlooked the existence of the Ballade recording on this disc! (maybe because I bought it principally to hear Michelangeli's Mazurka performances).


Michelangeli's 1972 studio Chopin recital disc


The CD recording is of very high fidelity (though a little dry) and presents a similarly conceived – though a little less austere – performance in fuller tonal splendour. This is a first Ballade to rank in my affections alongside that of my Rubinstein disc.

Somehow though, I feel the perfect 1st Ballade recording is out there somewhere; though equally part of me knows searching for it is fruitless.

Hmmm, I wonder what Sviatoslav Richter's recordings of it are like …

On Tuesday I attended (and spoke at) an XML UK member presentation day in Reading.

Unfortunately things got off to a bad start when I was caught in the transport chaos caused by the closure of King's Cross station, meaning I arrived late and would have to leave early.

Nevertheless I did arrive in time to catch most of Antony Scott and Bilal Baig talking about their "Information Modelling Toolkit". The heart of this was software that allowed round tripping between XML and a form-based UI that would allow it to be edited (rendered via Microsoft Excel). This is an interesting area and one of the questions afterward pinpointed what I think is still the biggest question here: can good looking (i.e. more usable) forms be produced automatically for editing XML? Often there is a heavy design component on good forms, just as there is for any user interface onto data.

Next up was Stephen Green, representing a new Bristol-based company SystML. It is always good to see new ventures coming into the XML UK scene! Stephen has been working closely with the development of UBL (Universal Business Language) and his talk focused mainly on the formal definition of UBL using W3C XML Schema. Whether intentional or not, Stephen's talk turned into a damning indictment of XML Schema, as he chronically how ambition after ambition were thwarted by problems with the language, its implementations or both.

This talk reinforced my conviction that W3C XML Schema is best avoided (Since my first thoughts on this topic I have, in my commercial life, been recommending against the use of W3C Schemas in most circumstances). In many cases, good old DTDs + Schematron give an excellent modelling solution. But sometimes the will-o-the-wisp lure of W3C Schema's supposed advanced features (polymorphism, etc.) just proves irresitible to customers -- especially when developers who are new to XML (but used to OO programming) have a strong say.

During the coffee break it was great to catch up with old friends and customers and swap notes on projects and technologies. Among the publishers there seemed to be little stomach for schema-based solutions to projects; yet there is noticeably now more talk about using XML for semantic modelling of information using triples, RDF, OWL, Topic Maps, or the like. Maybe these technologies' time is finally coming ...

After the coffee break Francis Cave spoke about DSDL in general and in particular about Part 9 of the standard, of which he is editor. This introduces XML Namespaces and proper data typing into DTDs by extending the DTD syntax (though in a backwards-compatible way). Having observed the gestation of this standard I can vouch for the fact that it's been surprising hard to get right. However, in its current form I feel the big technical problems have been overcome and this is ready to roll.

The biggest issue is perhaps implementation. There really needs to be some implementation of these "enhanced DTDs" before they'll enjoy any take-up, and the necessary validating parser surgery will be non-trivial. If done though, datatype- and Namespace- aware DTDs would be a useful means of extending the life of all those 'legacy' DTDs out there.

I was up next to speak about DSDL Part 5 (blogged elsewhere). My talk went OK, I think, but some comments afterwards made me think I needed to be more ambitious in showing what DTLL can do. If I gave this presentation again I might be tempted to have less technical detail and talk more about how it addresses data validation problems that currently can't be solved (checksum testing during validation would make a good example).


Eamonn Neylon holding forth

After lunch, my colleague Eamonn Neylon spoke about "Creating an XML Data Firewall". This talk was based on our commercial experience putting validation technologies into customer workflows, but in order to comply with XML UK's ethic it had been abstracted so as to avoid becoming a product pitch.

Eamonn focused on how validation was not just a one-off process, but something that must be continually applied throughout a workflow. Validation (he said) was not just a technical issue, but something that actually helps to specify and document an organisation's business processes.

Judging by the number of questions this provoked, it seems these themes resonated with the audience.

Following this, I had to be rude and slip away for a tortuous return journey through London's broken transport system.

Slides from the event will be made available at XML UK's web site in due course.

At Deoksugung Palace


I am back in the UK (though my body clock isn't) after the SC34 meetings in Seoul.

Overall, and not withstanding the Office politics, the trip was very worthwhile, though the packed meetings schedule and jet lag combination led one UK colleague to describe the week as 'brutal'.

Technically, I felt very good progress was made on the evolving DSDL multi-part standard. The part which I am editing (DTLL) has been well received and I have been instructed to prepare a FCD (Final Committee Draft) before the next SC34 meetings in Montréal in August, just before the Extreme Markup 2006 Conference.

The iconoclastic DSRL (Document Schema Renaming Language) also took some bigs steps forward. Rick Jelliffe has blogged this if you want to know more.

Seoul itself proved to be an excellent backdrop to the meetings, and the admirable Hotel Lotte ran very smoothly, though with some eye-watering prices: a portion fish and chips in the lobby restaurant was 40,000 Korean Won – equivalent to US $40!

Our Korean hosts took excellent care of us, with lunch (and sometimes supper) provided. The high point was a Korean banquet of many courses, many of which centred around vegetables completely unlike anything I've eaten before, and all of which were delicious.

Much in Seoul was novel, nothing more than the streetside hotel bar's way of serving pitchers of beer. These transparent vessels featured both electric lighting and an internal compartment into which cubes of dry ice and water had been placed. The result was a glowing vessel, bubbling violently and pumping out vapour. In my opinion the exciting visual effect more than made up for the slightly bland nature of the beer, something Lars Marius Garshol – something of a beer connoisseur – would beg to differ from me on.


Graham Moore pouring bubbly beer


It was following an encounter with one of these that Lars Marius, myself, Graham Moore and Martin Bryan headed out into town in search of some authentic Korean cuisine (this was before our Korean hosts had spared us this effort, by providing it for us!) We wandered along and came to a place I had noted earlier because of the delicious smells drifting from it. A quick inspection revealed a sign saying "good restaurant" and so we decided that was recommendation enough, and went in.

Char-grilling. In the middle of each table was a hole, and above each table a lowerable metal pipe fitted with an extractor fan. We chose some beef (or 'tasty pieces of cow abdomen' as the menu had it) and watched as an urn of glowing coals was fitted into the table and a waitress proceeded to cook pieces of beef for us. The other (Korean) diners were cooking their own pieces, but we had obviously been singled-out for special assistance after I had committed a series of dining faux-pas, such as pouring my sake into my rice bowl, and dropping my chopsticks, a few times.

Nevertheless, the food was excellent with the char-grilled beef nicely complemented by a range of piquant pickled vegetables and unusual pastes and relishes. Our knees did get rather hot from the radiant heat of the coals, though ...


Plaza at dusk