A Simple Thought
Stephen D. Williams
sdw at lig.net
Fri Mar 26 13:43:04 GMT 1999
This is in fact exactly the kind of thing that I am thinking, with at least a
couple other optimizations thrown in to make processing in-place in Java fast.
"Samuel R. Blackburn" wrote:
> You know, if you parse the XML into a carefully designed data structure,
> you could write that structure to a file. To re-read the data, you would
> simply memory map the file (or put the structure into a shared memory
> segment). If the structure is designed so offsets are used instead of
> pointers, you could navigate is quickly and not have to worry about
> memory addresses involved. The OS will only page in those portions
> of the file that are really used.
> Just a thought,
> -----Original Message-----
> From: Stephen D. Williams <sdw at lig.net>
> To: xml-dev at ic.ac.uk <xml-dev at ic.ac.uk>
> Date: Thursday, March 25, 1999 10:08 PM
> Subject: Re: Is there anyone working on a binary version of XML?
> >"Simon St.Laurent" wrote:
> >> At 03:36 PM 3/25/99 -0500, DuCharme, Robert wrote:
> >> >>I know, I know, this is anathema to what many of you feel is the
> >> >>essence of XML, and I agree to a point.
> >> >
> >> >It's not so much about feelings, as about contradicting the XML spec.
> >> >
> >> >[...]
> >> >
> >> >Applying XML concepts to a binary data format sounds interesting and
> >> >potentially useful, but it wouldn't be XML.
> >> One of these days I'd really love to stop talking about what is and isn't
> >> XML, though I know it's fun, and start talking about what we can do with
> >> XML and XML-like structures, whether they are SAX event flows, DOM trees,
> >> or binary formats that build on an XML foundation.
> >> We might even get some real work done - and it might even be fun.
> >I agree with the sentiment Simon.
> >I'm required (or am requiring myself) to get a lot of real work done very
> >quickly in the next
> >6 months hence my focus...
> >Semantically, I am talking about using XML. After parsing and creating a
> >DOM tree or SAX
> >events, you no longer have XML but a data structure semantically equivalent
> >to an XML
> >document. Another way to think about what I'm proposing is that it is a
> >cache of the data
> >structures produced from processing an XML document, cast in a openly
> >documented data
> >structure that is already flattened and ready for IO.
> >In fact, this is how I arrived at this design after following a few other
> >design constraints
> >and observations. Of course from there it is a short stop to say that you
> >can throw away the
> >'external' XML representation if you can recreate it from XMLb.
> >My scheme makes parsing of XML a non-issue. If I only have that advantage
> >within my closed
> >system, so be it, converting to and from XML for external purposes is in
> >fact what I intend to
> >In my case, I'm architecting a high speed clustering system, primarily
> >targeted at Linux/Unix
> >and Java. In this kind of system of course you are splitting applications
> >into many servers.
> >Of course the communication between those nodes is really internal
> >application communication,
> >the equivalent of that DOM tree, so it makes sense to optimize it. Think
> >it this way,
> >you'd seldom design a large app where every method needs to parse the XML
> >text block passed to
> >it to get a DOM tree (or SAX events) if the calling method has a DOM tree
> >that it could just
> >> Simon St.Laurent
> >> XML: A Primer
> >> Sharing Bandwidth / Cookies
> >> http://www.simonstl.com
> >OptimaLogic - Finding Optimal Solutions
> >sdw at lig.net Stephen D. Williams Senior Consultant/Architect
> >43392 Wayside Cir,Ashburn,VA 20147-4622 703-724-0118W 703-995-0407Fax
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