Date:         Thu, 1 Nov 2001 12:14:56 -0500
Reply-To:     [log in to unmask]
Sender:       "Z39.50 Next-Generation Initiative" <[log in to unmask]>
From:         Ray Denenberg <[log in to unmask]>
Organization: Library of Congress
Subject:      Re: SOAP packet content questions
Comments: To: "Z39.50 Next-Generation Initiative" <[log in to unmask]>
Content-Type: text/plain; charset=us-ascii

Matthew Dovey wrote:

> > Question 1: What is SRW? Should I be saying that instead of ZNG?
>
> Search/Retrieve for the Web. Ray wants ZNG or rather ZiNG to refer to
> the umbrella of project looking at new ways of doing Z39.50 like things
> (so SOAP, ZOOM etc.)

Right.  We agreed at the Boston Spa meeting to change the name ZNG to ZING
-- z39.50-International: Next Generation" (I wasn't contemplating using
lower case i though, as I think it just complicates things; like OAI used to
be OAi and changed it, because they got tired of explaining why the i was
lower case, which they could never explain anyway).   And we also agreed
that ZING would refer to a broader effort; thus the specification and
implementation of what had been ZNG/ZING would be renamed SRW (Search and
Retrieval for the Web) which would be a component of ZING, one of several
eventually; the only other component currently is ZOOM.


> > Question 4: Is record schema the same as record syntax? Or different?
>
> Not quite. In traditional Z39.50 we appear to have mixed up record
> syntax and record schema. I would argue that ISO 2709 (Binary Marc) and
> XML are record syntaxes, whilst MARC21, UKMARC are schemas/flavours of
> ISO2709, and METS, ONIX etc. are schema/flavours of XML. In SRW, we only
> use one record syntax namely XML, but need to support different XML
> schemas.
>
> However, in practice this does the same thing as the record syntax
> specification in Z39.50.

I see it differently. SRW reduces the concept of record syntax to a single
one, XML, thus effectively eliminating the concept of record syntax
altogether (if it's always XML then it doesn't need to be specificed).  All
the other things are schemas: METS, ONIX, SOX, etc.  These are acutally all
XML schemas, analogous to Z39.50 schemas (that is, Z39.50 schemas are used
with GRS, as XML schemas are used with XML; and in the new version of
Z39.50 you'll be able to use a string identifier for a schema, not just an
OID, so that XML schemas can be specified, via url).

> > Question 5: In order to simplify things, is it worth dropping all
> > diagnostics codes, additional information, etc and using SOAP
> > fault codes instead (ie standard SOAP mechanism). You only get one
> > error per packet, but is this a problem in practice?
>
> Possibly. This does raise the question on how surrogate diagnostics are
> handled. In the current form I used the same structure for both
> non-surrogate and surrogate diagnostics (again KISS principle).

I think it is a bad idea to use SOAP fault codes to represent application
level diagnostics. And the W3C folks developing the new SOAP version think
so too.


-Ray


--
Ray Denenberg
Library of Congress
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202-707-5795