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Re: Request for Comment

At 11:39 AM 10/31/96 PST, Daniel W. Connolly wrote:

>
>Could you give an example of "the location parameter of a node" that's
>not expressible as a URL.
>
>Keep in mind that if you have any string S representation of "the
>location parameter of a node", we can encode that string using %xx
>syntax into S', make up a new URL scheme sch (if necessary), and write
>the URL:
>
>	sch:S'
>
>If using URLs is (1) sufficient to express location parameters and (2)
>necessary to exploit the infrastructure that understands them, then
>I suggest that allowing anything besides URLs unnecessarily complicates
>the design.
>
>Dan
>
>
>
Sorry, I've gotten WAY behind on processing my mail.

I don't want to say that the location parameter for something in a
repository can't be expressed as a URL, only that a DMS might prefer to have
it expressed in some way it natively understands.  

Just to give a sense of what it's like to reference an object in a DMS,
here's what DMA has proposed as a URL syntax for identifying objects in
DMA-compliant repositories:

dma://[<dma pop>]/<system id>/<docspace id>/<object id>[;guid=<object guid>]

The <dma pop> (read DMA Point of Presence) is a host name (e.g.
library.xyz.com) that can be optionally present in the DMA OIID.  Its
purpose is to provide a DMA client with a name of an Internet host that most
likely can connect to an OIID's DMA System and DMA DocSpace.

The <system id> is the DMA GUID used to register the DMA System that
generated the OIID.  It is considered a hint in that a DMA DocSpace may be
accessible from multiple DMA Systems.  Any DMA System that supports the DMA
DocSpace <docspace id> may suffice for accessing the persistent object
referenced by the OIID, however the <system id> is considered the best
choice since it was known to work at some time in the past.

The <object id> is any sequence of data encoded into a subset of ASCII
according to the rules governing Internet URLs.  Beyond the encoding rules,
the structure of the <object id> is determined entirely by the underlying
Document Space implementation.

If a Document Space maintains a DMA GUID for a particular object, it is
encouraged to expose that object GUID in its DMA URL using the optional
";guid=<object guid>" syntax.

--Judy
Name:		Judith A. Slein
E-Mail:		slein@wrc.xerox.com
Phone:  	8*222-5169
Fax:		(716) 265-7133
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