I recently started writing for O’Reilly Media. I posted an article on XRX.
Here is the link:
http://www.oreillynet.com/xml/blog/2008/05/xrx_a_simple_elegant_disruptiv_1.html
We are just getting started moving to a new MoveableType (MT) system so not all of the features (like keywords and feedback) are working.
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Here is a comment from Arun Batchu:
An elegant introduction to an elegant architecture, Dan. Thank you. The essential takeaway from what you describe is the exploitation of XML from one end to the other end - especially from the Developer's perspective, for, how XRX actually manifests in runtime could be left to implementation technologies. Thus the logical architecture of XRX could be realized by a few variations of concrete technology - which is great. The XForms could be realized by XForms server technology (such as the excellent Orbeon stack), the ReST could be realized by any middle tier and the XQuery could be realized by an XQuery engine (such as Data Direct) that may actually be driving any one or a combination of datastores (XML, SQL, file system or ...) . The symmetrical and consistent leverage of XML as a data model from creation to transport to rest and back eliminates a whole lot of wasteful work. Like you point out, XPath is one of the most powerful query systems I have encountered; you can pack so much in so little and reuse it across the board with little if any change from the drawing board to production. In such a system as you describe, a business rule expressed once can be reused anywhere - from one end-to-end , however long the travel, as long as the architecture is XRX, like you have described. Thanks for expressing it so well. A few of your readers will not get it - it is one of those things that once you experience it, you are left wondering why this did not happen before. Oh, well!
You are welcome! Thank for your feedback Arun!