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Re: Meta Data Redux

From: Jim Whitehead <ejw@ics.uci.edu>
Date: Wed, 19 Mar 1997 12:04:02 -0800
Message-Id: <af55eed10202100413d2@[]>
To: w3c-dist-auth@w3.org

Ron Daniel, Jr. wrote:
>At some point this group is going to have to decide on
>a minimal set of headers.

This issue has been previously discussed on this list.  Back in late
October, early November, Yaron Goland posted that this group needed to
develop a "fairly robust set of attributes," [1] to which Larry Masinter
wisely replied, "Danger! Here Be Dragons!" before explaining his assessment
of the issue as a rathole based on his experience with the Dublin Core [2].
I followed up [3] with a post where I gave two criteria an attribute must
meet to be included in the WEBDAV specification:

>An attribute may be included in the distributed authoring and versioning
>specification if it meets one of the following two conditions:
>1) The attribute must be integral to the technical approach described in
>the specification OR must be required to directly satisfy a distributed
>authoring and versioning requirement.
>2) The data format of the attribute must be specified to ensure
>interoperability of distributed authoring tools AND the data format for the
>attribute must not have been previously defined in an open specification
>AND the attribute must be in use in an existing Configuration Management or
>Document Management system.

Of these two criteria, the only one I still think we should still adhere to
is criteria #1.  The second criteria is too tightly limited to just DMS and
CM systems, and I don't think we should define any attribute semantics
beyond those we absolutely need to implement the WEBDAV requirements, which
is criteria #1.  However, criteria #1 has been very effective to date in
providing reasonable bounds to the scope of WEBDAV definition of attribute
semantics, and I am very much in favor of its continuation.

For example, by this criteria, defining the semantics of an "Author
attribute in the WEBDAV spec. is out of bounds, because it is not directly
needed to implement any of the WEBDAV requirements.  Its consideration by
other groups, such as Dublin Core, also clearly delimits it as out of scope
for WEBDAV, since we have a policy, stated in our Charter, of leveraging
off of related work, where it is applicable.  Finally, our Charter clearly
states that the definition of core attribute sets (beyond those necessary
to implement the WEBDAV requirements) is out of scope.

Ron Daniel, Jr also wrote:
>Second, I think the attribute/value approach is going to lead you directly
>into one of the IETF's most infamous ratholes - metadata hell. Here is
>a rather detailed explanation of how.

So, as a group we have recognized the difficulty inherent in the core
metadata definition issue space, and have chosen ways to limit our exposure
to it.  To date we have been successful at limiting the scope of metadata
definition arguments.

What we are focusing on in WEBDAV are mechanisms for creating, modifying,
deleting, and searching metadata, emphasizing the mechanics of how the
metadata is manipulated without considering the semantics of that metadata
once it exists.  As a soundbite, WEBDAV is about "How" not "What".  How:
how is the metadata created, modified, deleted, searched.  What: what does
it mean to have a particular piece or collection of metadata.

[1] http://lists.w3.org/Archives/Public/w3c-dist-auth/msg00339.html
[2] http://lists.w3.org/Archives/Public/w3c-dist-auth/msg00341.html
[3] http://lists.w3.org/Archives/Public/w3c-dist-auth/msg00350.html

- Jim
Received on Wednesday, 19 March 1997 15:08:31 UTC

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