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   Re: [xml-dev] XML Pipeline vs an XML Grid

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Hi Ron,

Normally a pipe wouldn't modify the contents of what it
is transporting. As you say, Unix pipes transport the contents
to the destination where one assumes they arrive unchanged.

On these XML pipelines, when data or a document comes
out of a pipe, it is then modified by a process or
program. That's where I got confused. I thought the
modifications were being done in the pipe. It seems
that they are actually being done once the data
comes out, and that seems logical to me.

And this pretty much sums up the paradigm that most
people are using to build xml applications. A set of
custom pipes, put together, with custom processes do
stuff with whatever comes out of the pipe. Validation,
transformation etc.

It's a conventional paradigm where the programmer handcrafts
a process and a set of messages into a tightly coupled
set to do some job of work.

Pipe sizes vary, and all have a multitude of different

There is little or no conformity.

Every pipe that appears in a business (customer request?)
must be custom crafted by a programmer so that the data that
pops out is useful.

So we have lots of custom tools and thousands of
combinations of everything so that there is never a
shortage of programming work when trying to do something
with xml. This is supposed to be good I guess.

But I would suggest the ability to build every different
size of pipe with "any connector you could possibly want"
is an impediment to interoperability.

XML Grids on the other hand are very different. Instead
of a custom made connector at the end of each pipe to
process each type of message, the approach is to use a
mass-produced connector and make hundreds or thousands of
copies of it, and make an array of those. With the
array online, you have an automatic grid.

The key concept of the Grid approach is to use a simpler
type of message server but make it in such a way that it can be
duplicated many times over.

So this is just a slightly different paradigm I guess
and possibly something for the future.

Best Regards


Quoting Ronald Bourret <rpbourret@rpbourret.com>:

> I'm not sure why a pipeline wouldn't modify the contents. Isn't that the
> point of pipes? For example, UNIX pipes are used to pass a character
> stream from program A to program B, which modifies that stream and
> passes it to program C, and so on. An XML pipeline, it seems, would do
> the same thing, with the data stored in a document and the programs
> being XML aware.
> -- Ron
> david.lyon@computergrid.net wrote:
> > ok, I know nothing...
> >
> > but it doesn't sound like an xml pipeline to me..
> >
> > one would normally think that the pipes wouldn't
> > be modifying the contents. You wouldn't normally
> > want that in a pipeline.
> >
> > It might be a relay, or a daisy-chain, but it
> > doesn't really sound like what you need is
> > a pipeline...
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