Re: Version identifier in URL

Robert C. Pettengill (
Wed, 29 May 1996 02:08:38 -0500

It isn't clear to me that it is necessary to standardize the syntax of
version identifiers across all servers.  As long as the version appears as
some kind of path extention, URLs can point to a unique version object
without need for agreement on how the path is exteneded.

The proposal in
seems to be pretty heavy weight.  I can't simply have a URL to a specific
document in the "version space", I need to define a resource and then
provide a URL to that resource which seems more than a little awkward.
Why not allow link attributes to be specified in the anchor, e.g.
<A HREF="mumble/foo" VERSION="x">?

It might be worthwhile discussing the requirements for versioned links
before discussing the syntax.  Some questions that occur to me are:

Is the versioning model constrained to be single threaded?  (i.e. unique
answers to the queries below)

Fetch the version previous to URL(x).
Fetch the version subsequent to URL(x).
Fetch the version of URL(x) current at time t.
Fetch the version of URL(x) current as of the creation time of URL(y)
Fetch the most recent version of URL(y)


  Robert C. Pettengill
  Schlumberger Austin Research, P. O. Box 200015, Austin, Texas  78720 Internet, +1 512-331-3728 Voice, +1 512-331-3760 Fax
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