Subject: IPP> PRO - Thoughts around use of XML

From: Carl-Uno Manros <[email-masked]>
Date: Tue, 13 Jan 1998 09:11:37 PST

We already have an intensive internal discussion on the use of XML
inside Xerox. I have copied out a few comments from one of our
researchers at PARC, Dennis Hamilton. 

These might be food for thought for MS and others, who want to discuss
the subject of using XML in IPP.

Regards,

Carl-Uno

---

I would be surprised to see XML used to describe interfaces, though I 
suppose it could be.  Basically, what I have seen of it in my limited 
encounters is that it is more like job or document metadata and references 
to things assume availability of distribution mechanisms that are not 
themselves described.  (URL's and URI's are very popular in this context.) 

I agree that it doesn't appear to be efficient at communicating data 
structures among applications that can rely on a stronger agreement that 
has less redundancy in the transmitted data encodings because there is 
strong application agreement.

In a way, that is exactly the sense in which XML is lighter-weight, plus it 
needs to be used at a not-too-fine-grained level.  So delivering job 
parameters and providing descriptive status responses is perfect.  It also 
fits into the idea of having a small delta between that and HTML or 
something a script could handle.

One thing I am not sure about is what happens when scripts start being 
included as the values of XML attributes.  That and the ability to refer to 
applets and components at the scripting / automation level may be something 
that is perhaps considered easier to migrate to.  I don't have a thought 
about that, I just wonder if it is something that Microsoft is noticing as 
a possibility.  Also, I wouldn't be surprised if script engines start 
supporting access to these babies.

Your characterization of the difference between XML and a data stream 
designed for marshalling and efficient transmission fits my impression 
also.

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Carl-Uno Manros
Principal Engineer - Advanced Printing Standards - Xerox Corporation
701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231
Phone +1-310-333 8273, Fax +1-310-333 5514
Email: [email-masked]