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> -----Original Message-----
> From: Alessandro Triglia [mailto:firstname.lastname@example.org]
> Sent: Monday, April 12, 2004 22:17
> To: 'Dennis Sosnoski'; 'email@example.com'
> Cc: 'Bullard, Claude L (Len)'; 'Elliotte Rusty Harold'; 'Eric
> van der Vlist'; 'firstname.lastname@example.org'
> Subject: RE: [xml-dev] XML Binary Characterization WG public
> list available
> > -----Original Message-----
> > From: Dennis Sosnoski [mailto:email@example.com]
> > Sent: Sunday, April 11, 2004 17:50
> > To: firstname.lastname@example.org
> > Cc: 'Bullard, Claude L (Len)'; 'Elliotte Rusty Harold'; 'Eric
> > van der Vlist'; email@example.com
> > Subject: Re: [xml-dev] XML Binary Characterization WG public
> > list available
> > Bob Wyman wrote:
> > > Just as XML works well in both "schema-based" and "schema-free"
> > >environments, it is critical that any alternative binary
> encoding do
> > >the same. But, it is also useful to recognize that when
> > you're working
> > >with XML, you are never really in a "schema-free"
> > environment... Even
> > >if you don't have an application-specific schema, you've
> > still got the
> > >schema for XML itself -- the InfoSet .
> > > If you have an application-specific schema, you can do
> > all sorts of
> > >optimizations in the binary encodings and get really great
> > compression
> > >as well as parsing efficiencies based on your knowledge of
> > the schema.
> > >When working with the Infoset alone, you can't get quite as much
> > >benefit from a binary encoding, but for many (not all)
> > applications the
> > >benefit will still be great enough to justify the effort.
> > For instance,
> > >you won't get as much compression with an Infoset based
> > encoding, but
> > >you'll still usually benefit from having counted length strings and
> > >other benefits that make parsing more efficient. (We exploit these
> > >efficiencies at PubSub.com, for more info see  below.)
> > >
> > >
> > I'm well aware of Infoset-based encodings, since my own XBIS project
> > (http://www.xbis.org) is one of them. I was curious how ASN.1
> > deals with
> > data at the Infoset level, rather than schema-specific versions.
> > I didn't see anything about this in a quick look through the
> > references.
> The "fast infoset" standard is still under development in
> ISO/ITU-T, along with the "fast web services" standard.
> Originally, they were two parts of the same document, named
> "X.695". This number is no longer valid, so it is better to
> call them just "fast infoset" and "fast web services". They
> will be two separate standards, but will hopefully be
> available at the same time.
> Fast web services rely on both X.694 and the fast infoset.
> - X.694 is used for translating XML Schema definitions
> (present in a WSDL) to ASN.1, so that instances of "content"
> (body, header blocks) can be encoded very efficiently in PER.
> (The envelope itself is also encoded in PER.)
> - The fast infoset is used whenever an XML Schema is not available.
... or when people believe that using the schema will not help much (for
example, when the particular schema has a wildcard that is typically filled
with a big element).
> We believe, anyway, that the fast infoset has a wider
> applicability than its use in fast web services.
> Alessandro Triglia
> OSS Nokalva
> > Sun claims both schema and Infoset support for "Fast Web
> Services" in
> > the "Binary Interchange of XML Infosets" report
> > (http://www.idealliance.org/papers/dx_xml03/papers/05-01-02/05
> > but doesn't mention the Infoset at all in the paper describing this
> find their specific results of dubious use, but don't doubt that when a
> specific schema is known it's possible to get better results (in terms
> of both data size and processing speed) for an encoding that matches the
> schema rather than a general Infoset encoding.
> - Dennis
> Dennis M. Sosnoski
> Enterprise Java, XML, and Web Services
> Training and Consulting
> Redmond, WA 425.885.7197
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