Re: Binary XML

[Alaric Snell <alaric@alaric-snell.com>]

Quoting PavitraA@riskinc.com:

Heheh, here goes :-)

> Dear All,
> 
> I am new to xml so keeping that in mind can you please put osome light
> on
> 
> I) What Binary XML really mean??
>          1)Is it compiled form of XML into Byte code OR
>          2)Is it compressing XML using some algorithms OR
>          3)Is it something else??

Binary XML does not refer to any fixed, defined, standard right now, no more
than "christianity" or "good food" does. It's a concept, that the XML Infoset or
a simple DOM model (thus not requiring schema type information) can be stored in
a format designed with differing constraints to "normal" textual XML - generally
one or more from the feature set "Small file size", "Fast to parse and
generate", or "Possible to run XPath expressions across and even update without
needing to slurp the whole thing into memory".

Why is this being discussed? Well, some people want a way of using the XML data
model without incurring the costs of textual XML encoding, since being able to
read the data with a text editor instead of a special editor is necessary.

Why is this sometimes violently opposed? Because many people feel that human
readability without a special editor is crucial to data communications in the
modern heterogenous Internet, and that the costs in size and parser complexity
are negligble compared to the benefits of programmers being able to mock up test
data in Notepad. And because at least one proponent of a binary XML format (me!)
is incapable of objecting to an argument without seeming like he's deliberately
trying to be obnoxious :-)

> II)What is the difference between Binary XML and XML Serialization??

I'm not sure. XML serialisation may refer to binary XML as I have defined it
above - serialising a DOM tree in a binary format - or it may refer to a
programming language interface like Java serialisation that uses XML as the
actual underlying format.

> I am quite confused on this topic why at all it is required ?

I suspect that the many answers to this could cause a flame war :-)

............................................................................

If the idea interests you, I have created a low-volume mailing lists where the
various binary XML efforts post occasional status reports and discuss issues:

http://lists.warhead.org.uk/mailman/listinfo/xml-bin

There are efforts to define a simple binary representation of a series of SAX
events, efforts to encode DOM trees for read and in-place update with indexing
to support fast XPath (basically a portable XML database format), and efforts to
take an XML schema and use it to generate a compact, fast, encoding format that
requires the same schema at the other end to decode, the advantage being that
you don't need to transport weighty element and attribute names over the wire,
and it can encode a number as a native number rather than as a series of decimal
digits.

The latter approach is being taken by the ISO, defining a means for XML Schemas
to be automatically translated into ASN.1 abstract types, and an XML encoding
for ASN.1 information. ASN.1 is a type notation like XML Schema, but not tied to
any particular encoding; various encodings for it are available, and XML is
being added to this list.

ABS

-- 
                               Alaric B. Snell
 http://www.alaric-snell.com/  http://RFC.net/  http://www.warhead.org.uk/
   Any sufficiently advanced technology can be emulated in software